[Longterm results of mitral valve replacement (author's transl)].

PubMed

Erhard, W; Reichmann, M; Delius, W; Sebening, H; Herrmann, G

1977-04-22

210 patients were followed up by the actuary method for over 5 years after isolated mitral valve replacement or a double valve replacement. After isolated valve replacement the one month survival including the operative mortality was 92+/-2%. The survival after one year was 83+/-3% and after 5 years 66+/-7%. The five year survival of patients in preoperative class III (according to the NYHA) was 73+/-8% and of class IV 57+/-8% (P less than or equal to 0.1). A comparison of valve replacements for pure mitral stenosis or mitral insufficiency showed no statistically significant differences. In the 37 patients who had a double valve replacement the survival risk was not increased in comparison with those patients who had had a single valve replacement. Age above 45 years and a preoperative markedly raised pulmonary arteriolar resistance reduced the chances of survival.

Aortic valve replacement for papillary fibroelastoma.

PubMed

Arikan, Ali Ahmet; Omay, Oğuz; Aydın, Fatih; Kanko, Muhip; Gür, Sibel; Derviş, Emir; Yılmaz, Cansu Eda; Müezzinoğlu, Bahar

2017-06-01

Surgery is indicated for symptomatic patients with papillary fibroelastomas (PFE) on the aortic valve. The valve is commonly spared during tumor excision. Rarely, aortic valve replacement (AVR) is needed. We present a case requiring AVR for an aortic valve PFE and review the literature to determine the risk factors for failure of aortic valve-sparing techniques in patients with PFE. © 2017 Wiley Periodicals, Inc.

MANAGEMENT OF FAILED MITRAL VALVE REPLACEMENT. THE DURBAN EXPERIENCE.

PubMed

Kistan, D; Booysen, M; Alexander, G; Madiba, T E

2017-06-01

Mitral valve replacement is the procedure of choice in patients with severe mitral valve disease. However, these patients are surviving longer and are thus at an increased risk of prosthesis failure or valve-related complications. Study setting: Inkosi Albert Luthuli Central Hospital, a tertiary referral Hospital in Durban. Study population: All patients undergoing redo mechanical mitral valve replacement surgery between January 2005 and December 2014. Study design: Retrospective analysis of patients undergoing redo mitral valve replacement. Patients were identified from theatre record books, their files were electronically accessed and pertinent information extracted onto a data capture sheet. Information documented included demographics, duration to failure, INR, Albumin, HIV status, clinical findings and outcome. The data was stored on an Excel datasheet. Fifty-eight patients were documented (mean age 32 ± 15.81 years; M:F 1:3). Ten patients (17%) were HIV positive (median CD4 count 478). Mean duration between first surgery and redo was 8.8 years. Thirty-five patients (60%) had no co-morbidities. Presenting features at redo surgery were congestive cardiac failure (27), chest pain (11) and palpitations (17). Mean preoperative Ejection Fraction was 51.65 %. Twenty-nine patients (55%) had emergency redo surgery. Twenty-two patients (75%) had acute prosthetic valve thrombosis. Thirty-two patients had tricuspid regurgitation. Original pathology was documented in 23 patients (40%) as Rheumatic valve disease. Prosthetic valve thrombosis was documented in 31 patients (54%). The most commonly used valve was the On-X. Mean presenting INR was 1.96 + 1.2 and mean presenting serum albumin was 36.7 + 7.8 g/l. Forty-one patients (71%) were found to be compliant to Warfarin therapy prior to redo surgery. Mean ICU stay was 6 +9 days. Two patients died postoperatively. Mean followup was 32 + 26.6 months. Twelve patients (20.7%) developed postoperative complications. Patients

Mitral valve replacement with the Hancock stabilized glutaraldehyde valve. Clinical and laboratory evaluation.

PubMed

Buch, W S; Pipkin, R D; Hancock, W D; Fogarty, T J

1975-11-01

From March 1971 through April 1975, one hundred twenty patients underwent mitral valve replacement with a Hancock "stabilized glutaraldehyde process" porcine aortic xenograft. A simultaneous canine experimental series was also carried out. In the clinical series, the early mortality was 8.3%. Actuarial analyses of all patients predicts survival at two years of 81.0% and at four years of 70.0%. The predicted survival for patients without coronary disease or prior prosthetic valve replacement is 87.5% at two years and 77.5% at four years. There were four thromboembolic episodes, a rate of 2.4% per patient-year. None were fatal. No valve failure were noted. Histologic examination and shrink temperature analysis of recovered valves show excellent tissue preservation at 40 months. The data indicate that the Hancock valve is durable, enjoys a low incidence of thromboembolism, and may be the valve of choice for mitral valve replacement.

Heart valve replacement with the Sorin tilting-disc prosthesis. A 10-year experience.

PubMed

Milano, A; Bortolotti, U; Mazzucco, A; Mossuto, E; Testolin, L; Thiene, G; Gallucci, V

1992-02-01

From 1978 to 1988, 697 patients with a mean age of 48 +/- 11 years (range 5 to 75 years) received a Sorin tilting-disc prosthesis; 358 had had aortic valve replacement, 247 mitral valve replacement, and 92 mitral and aortic valve replacement. Operative mortality rates were 7.8%, 11.3%, and 10.8%, respectively, in the three groups. Cumulative duration of follow-up is 1650 patient-years for aortic valve replacement (maximum follow-up 11.4 years), 963 patient-years for mitral valve replacement (maximum follow-up 9.9 years) and 328 patient-years for mitral and aortic valve replacement (maximum follow-up 9.4 years). Actuarial survival at 9 years is 72% +/- 4% after mitral valve replacement, 70% +/- 3% after aortic valve replacement, and 50% +/- 12% after mitral and aortic valve replacement, and actuarial freedom from valve-related deaths is 97% +/- 2% after mitral valve replacement, 92% +/- 2% after aortic valve replacement, and 62% +/- 15% after mitral and aortic valve replacement. Thromboembolic events occurred in 21 patients with aortic valve replacement (1.3% +/- 0.2%/pt-yr), in 12 with mitral valve replacement (1.2% +/- 0.3% pt-yr), and in seven with mitral and aortic valve replacement (2.1% +/- 0.8%), with one case of prosthetic thrombosis in each group; actuarial freedom from thromboembolism at 9 years is 92% +/- 3% after mitral valve replacement, 91% +/- 3% after aortic valve replacement, and 74% +/- 16% after mitral and aortic valve replacement. Anticoagulant-related hemorrhage was observed in 15 patients after aortic valve replacement (0.9% +/- 0.2%/pt-yr), in 9 after mitral valve replacement (0.9% +/- 0.3%/pt-yr), and in 6 with mitral and aortic valve replacement (0.9% +/- 0.5%/pt-yr); actuarial freedom from this complication at 9 years is 94% +/- 2% after aortic valve replacement, 91% +/- 4% after mitral valve replacement, and 68% +/- 16% after mitral and aortic valve replacement. Actuarial freedom from reoperation at 9 years is 97% +/- 2% after mitral and

Leaving Moderate Tricuspid Valve Regurgitation Alone at the Time of Pulmonary Valve Replacement: A Worthwhile Approach.

PubMed

Kogon, Brian; Mori, Makoto; Alsoufi, Bahaaldin; Kanter, Kirk; Oster, Matt

2015-06-01

Pulmonary valve disruption in patients with tetralogy of Fallot and congenital pulmonary stenosis often results in pulmonary insufficiency, right ventricular dilation, and tricuspid valve regurgitation. Management of functional tricuspid regurgitation at the time of subsequent pulmonary valve replacement remains controversial. Our aims were to (1) analyze tricuspid valve function after pulmonary valve replacement through midterm follow-up and (2) determine the benefits, if any, of concomitant tricuspid annuloplasty. Thirty-five patients with tetralogy of Fallot or congenital pulmonary stenosis were analyzed. All patients had been palliated in childhood by disrupting the pulmonary valve, and all patients had at least moderate tricuspid valve regurgitation at the time of subsequent pulmonary valve replacement. Preoperative and serial postoperative echocardiograms were analyzed. Pulmonary and tricuspid regurgitation, along with right ventricular dilation and dysfunction were scored as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Right ventricular volume and area were also calculated. Comparisons were made between patients who underwent pulmonary valve replacement alone and those who underwent concomitant tricuspid valve annuloplasty. At 1 month after pulmonary valve replacement, there were significant reductions in pulmonary valve regurgitation (mean 3 vs 0.39, p < 0.0001), tricuspid valve regurgitation (mean 2.33 vs 1.3, p < 0.0001), and in right ventricular dilation, volume, and area. There was no difference in the degree of tricuspid regurgitation 1 month postoperatively between patients who underwent concomitant tricuspid annuloplasty and those who underwent pulmonary valve replacement alone (mean 1.31 vs 1.29, p = 0.81). However, at latest follow-up (mean 7.0 ± 2.8 years), the degree of tricuspid regurgitation was significantly higher in the concomitant annuloplasty group (mean 1.87 vs 1.12, p = 0.005). In patients with at least moderate tricuspid valve

Transcatheter Mitral Valve Replacement for Native and Failed Bioprosthetic Mitral Valves

PubMed Central

Sarkar, Kunal; Reardon, Michael J.; Little, Stephen H.; Barker, Colin M.; Kleiman, Neal S.

2017-01-01

Transcatheter mitral valve replacement (TMVR) is a novel approach for treatment of severe mitral regurgitation. A number of TMVR devices are currently undergoing feasibility trials using both transseptal and transapical routes for device delivery. Overall experience worldwide is limited to fewer than 200 cases. At present, the 30-day mortality exceeds 30% and is attributable to both patient- and device-related factors. TMVR has been successfully used to treat patients with degenerative mitral stenosis (DMS) as well as failed mitral bioprosthesis and mitral repair using transcatheter mitral valve-in-valve (TMViV)/valve-in-ring (ViR) repair. These patients are currently treated with devices designed for transcatheter aortic valve replacement. Multicenter registries have been initiated to collect outcomes data on patients currently undergoing TMViV/ViR and TMVR for DMS and have confirmed the feasibility of TMVR in these patients. However, the high periprocedural and 30-day event rates underscore the need for further improvements in device design and multicenter randomized studies to delineate the role of these technologies in patients with mitral valve disease. PMID:29743999

Valve replacement in children: a challenge for a whole life.

PubMed

Henaine, Roland; Roubertie, François; Vergnat, Mathieu; Ninet, Jean

2012-10-01

Valvular pathology in infants and children poses numerous challenges to the paediatric cardiac surgeon. Without question, valvular repair is the goal of intervention because restoration of valvular anatomy and physiology using native tissue allows for growth and a potentially better long-term outcome. When reconstruction fails or is not feasible, valve replacement becomes inevitable. Which valve for which position is controversial. Homograft and bioprosthetic valves achieve superior haemodynamic results initially but at the cost of accelerated degeneration. Small patient size and the risk of thromboembolism limit the usefulness of mechanical valves, and somatic outgrowth is an universal problem with all available prostheses. The goal of this article is to address valve replacement options for all four valve positions within the paediatric population. We review current literature and our practice to support our preferences. To summarize, a multitude of opinions and surgical experiences exist. Today, the valve choices that seem without controversy are bioprosthetic replacement of the tricuspid valve and Ross or Ross-Konno procedures when necessary for the aortic valve. On the other hand, bioprostheses may be implanted when annular pulmonary diameter is adequate; if not or in case of right ventricular outflow tract discontinuity, it is better to use a pulmonary homograft with the Ross procedure. Otherwise, a valved conduit. Mitral valve replacement remains the most problematic; the mechanical prosthesis must be placed in the annular position, avoiding oversizing. Future advances with tissue-engineered heart valves for all positions and new anticoagulants may change the landscape for valve replacement in the paediatric population. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Anesthetic Considerations for Transcatheter Pulmonary Valve Replacement.

PubMed

Gregory, Stephen H; Zoller, Jonathan K; Shahanavaz, Shabana; Chilson, Kelly L; Ridley, Clare H

2018-02-01

The introduction of transcatheter therapy for valvular heart disease has revolutionized the care of patients with valvular disorders. Pathologic regurgitation or stenosis of the pulmonary valve, right ventricular outflow tract, or a right ventricle-to-pulmonary artery conduit represent emerging indications for transcatheter therapy. To date, minimal literature exists detailing the anesthetic management of patients undergoing transcatheter pulmonary valve replacement. In this review, the pathophysiology and indications for transcatheter pulmonary valve replacement and possible complications unique to this procedure are reviewed. Anesthetic management, including preoperative assessment, intraoperative considerations, and early postoperative monitoring, are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Recurrent pannus formation causing prosthetic aortic valve dysfunction: is excision without valve re-replacement applicable?

PubMed

Darwazah, Ahmad K

2012-06-29

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function.The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement.A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve.Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function.

Will Catheter Interventions Replace Surgery for Valve Abnormalities?

PubMed Central

O’Byrne, Michael L; Gillespie, Matthew J

2015-01-01

Purpose of Review Catheter-based valve technologies have evolved rapidly over the last decade. Transcatheter aortic valve replacement (TAVR) has become a routine procedure in high-risk adult patients with calcific aortic stenosis. In patients with congenital heart disease (CHD), transcatheter pulmonary valve replacement represents a transformative technology for right ventricular outflow tract dysfunction with the potential to expand to other indications. This review aims to summarize 1) the current state of the art for transcatheter valve replacement (TVR) in CHD, 2) the expanding indications for TVR, and 3) the technological obstacles to optimizing TVR. Recent findings Multiple case series have demonstrated that TVR with the Melody transcatheter pulmonary valve in properly selected patients is safe, effective, and durable in short-term follow-up. The Sapien transcatheter heart valve represents an alternative device with similar safety and efficacy in limited studies. Innovative use of current valves has demonstrated the flexibility of TVR, while highlighting the need for devices to address the broad range of post-operative anatomies either with a single device or strategies to prepare the outflow tract for subsequent device deployment. Summary The potential of TVR has not been fully realized, but holds promise in treatment of CHD. PMID:24281347

Recurrent pannus formation causing prosthetic aortic valve dysfunction: Is excision without valve re-replacement applicable?

PubMed Central

2012-01-01

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function. The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement. A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve. Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function. PMID:22747790

Should patients with Björk-Shiley valves undergo prophylactic replacement?

PubMed

Birkmeyer, J D; Marrin, C A; O'Connor, G T

1992-08-29

About 85,000 patients have undergone replacement of diseased heart valves with prosthetic Björk-Shiley convexo-concave (CC) valves. These valves are prone to fracture of the outlet strut, which leads to acute valve failure that is usually fatal. Should patients with these valves undergo prophylactic replacement to avoid fracture? The incidence of strut fracture varies between 0% and 1.5% per year, depending on valve opening angle (60 degrees or 70 degrees), diameter (less than 29 mm or greater than or equal to 29 mm), and location (aortic or mitral). Other factors include the patient's life expectancy and the expected morbidity and mortality associated with reoperation. We have used decision analysis to identify the patients most likely to benefit from prophylactic reoperation. The incidence of outlet strut fracture was estimated from the data of three large studies on CC valves, and stratified by opening angle, diameter, and location. A Markov decision analysis model was used to estimate life expectancy for patients undergoing prophylactic valve replacement and for those not undergoing reoperation. Prophylactic valve replacement does not benefit patients with CC valves that have low strut fracture risks (60 degrees aortic valves and less than 29 mm, 60 degrees mitral valves). For most patients with CC valves that have high strut fracture risks (greater than or equal to 29 mm, 70 degrees CC), prophylactic valve replacement increases life expectancy. However, elderly patients with such valves benefit from prophylactic reoperation only if the risk of operative mortality is low. Patient age and operative risk are most important in recommendations for patients with CC valves that have intermediate strut fracture risks (less than 29 mm, 70 degrees valves and greater than or equal to 29 mm, 60 degrees mitral valves). For all patients and their doctors facing the difficult decision on whether to replace CC valves, individual estimates of operative mortality risk that

Mitral valve replacement with preservation of the subvalvular apparatus.

PubMed

Reardon, M J; David, T E

1999-03-01

The introduction of the Starr-Edwards valve allowed complete replacement of diseased left-sided heart valves. With improved cardiopulmonary bypass, myocardial protection, and surgical techniques the mortality rate from aortic valve replacement decreased substantially, whereas the mortality rate from mitral valve replacement remained high, largely because of low cardiac output syndrome. Increasing use of mitral valve repair techniques resulted in a marked decrease in short-term and long-term morbidity and mortality when treating patients with mitral regurgitation. Some believed that this resulted from maintenance of the mitral annular papillary muscle continuity during mitral valve repair. Subsequent experimental and clinical studies have validated the positive short-term and long-term effects of maintaining the integrity of the mitral valve subvalvular apparatus. This article considers the history of the clinical use of preservation of the subvalvular apparatus, the physiologic studies examining this concept, and the clinical data available on its use. It also examines the following: 1) mitral stenosis versus mitral regurgitation and the preservation of the subvalvular apparatus; 2) whether the anterior, posterior, or both areas of the subvalvular apparatus should be preserved; and 3) the surgical techniques for the preservation of the subvalvular apparatus and valve implantation.

Cost-effectiveness of homograft heart valve replacement surgery: an introductory study.

PubMed

Yaghoubi, Mohsen; Aghayan, Hamid Reza; Arjmand, Babak; Emami-Razavi, Seyed Hassan

2011-05-01

The clinical effectiveness of heart valve replacement surgery has been well documented. Mechanical and homograft valves are used routinely for replacement of damaged heart valves. Homograft valves are produced in our country but we import the mechanical valves. To our knowledge the cost-effectiveness of homograft valve has not been assessed. The objective of the present study was to compare the cost-effectiveness of homograft valve replacement with mechanical valve replacement surgery. Our samples were selected from 200 patients that underwent homograft and mechanical heart valve replacement surgery in Imam-Khomeini hospital (2000-2005). In each group we enrolled 30 patients. Quality of life was measured using the SF-36 questionnaire and utility was measured in quality-adjusted life years (QALYs). For each group we calculated the price of heart valve and hospitalization charges. Finally the cost-effectiveness of each treatment modalities were summarized as costs per QALYs gained. Forty male and twenty female participated in the study. The mean score of quality of life was 66.06 (SD = 9.22) in homograft group and 57.85 (SD = 11.30) in mechanical group (P < 0.05). The mean QALYs gained in homograft group was 0.67 more than mechanical group. The incremental cost-effectiveness ratio (ICER) revealed a cost savings of 1,067 US$ for each QALY gained in homograft group. Despite limitation of this introductory study, we concluded that homograft valve replacement was more effective and less expensive than mechanical valve. These findings can encourage healthcare managers and policy makers to support the production of homograft valves and allocate more recourse for developing such activities.

Evaluation of mitral valve replacement anchoring in a phantom

NASA Astrophysics Data System (ADS)

McLeod, A. Jonathan; Moore, John; Lang, Pencilla; Bainbridge, Dan; Campbell, Gordon; Jones, Doug L.; Guiraudon, Gerard M.; Peters, Terry M.

2012-02-01

Conventional mitral valve replacement requires a median sternotomy and cardio-pulmonary bypass with aortic crossclamping and is associated with significant mortality and morbidity which could be reduced by performing the procedure off-pump. Replacing the mitral valve in the closed, off-pump, beating heart requires extensive development and validation of surgical and imaging techniques. Image guidance systems and surgical access for off-pump mitral valve replacement have been previously developed, allowing the prosthetic valve to be safely introduced into the left atrium and inserted into the mitral annulus. The major remaining challenge is to design a method of securely anchoring the prosthetic valve inside the beating heart. The development of anchoring techniques has been hampered by the expense and difficulty in conducting large animal studies. In this paper, we demonstrate how prosthetic valve anchoring may be evaluated in a dynamic phantom. The phantom provides a consistent testing environment where pressure measurements and Doppler ultrasound can be used to monitor and assess the valve anchoring procedures, detecting pararvalvular leak when valve anchoring is inadequate. Minimally invasive anchoring techniques may be directly compared to the current gold standard of valves sutured under direct vision, providing a useful tool for the validation of new surgical instruments.

Collagen organization in canine myxomatous mitral valve disease: an x-ray diffraction study.

PubMed

Hadian, Mojtaba; Corcoran, Brendan M; Han, Richard I; Grossmann, J Günter; Bradshaw, Jeremy P

2007-10-01

Collagen fibrils, a major component of mitral valve leaflets, play an important role in defining shape and providing mechanical strength and flexibility. Histopathological studies show that collagen fibrils undergo dramatic changes in the course of myxomatous mitral valve disease in both dogs and humans. However, little is known about the detailed organization of collagen in this disease. This study was designed to analyze and compare collagen fibril organization in healthy and lesional areas of myxomatous mitral valves of dogs, using synchrotron small-angle x-ray diffraction. The orientation, density, and alignment of collagen fibrils were mapped across six different valves. The findings reveal a preferred collagen alignment in the main body of the leaflets between two commissures. Qualitative and quantitative analysis of the data showed significant differences between affected and lesion-free areas in terms of collagen content, fibril alignment, and total tissue volume. Regression analysis of the amount of collagen compared to the total tissue content at each point revealed a significant relationship between these two parameters in lesion-free but not in affected areas. This is the first time this technique has been used to map collagen fibrils in cardiac tissue; the findings have important applications to human cardiology.

[Transcatheter aortic valve replacement].

PubMed

Sawa, Yoshiki

2014-07-01

While transcatheter aortic valve replacement( TAVR) has spread rapidly all over the world for highrisk patients with severe aortic stenosis (AS), SAPIEN XT was approved in Japan in October 2013. Since that, approximately 400 TAVR cases were performed in Japan. In our institute, we have performed 164 cases since first case in Japan in 2009 and have achieved satisfactory early results(30-day mortality:1.2%). At the same time, however, simultaneously various TAVR-related complications including a paravalvular leak, stroke, vascular complications, and coronary obstruction were observed. A reduction in the incidence and severity of these complications had led technical improvements in various new devices(2nd generation TAVR device such as the SAPIEN 3, ACURATE, and JenaValve) and in implantation techniques including repositioning/recapturing features, paravalvular sealing technologies, and prevention of coronary obstruction. Furthermore, there is also increasing experience with special indications for TAVR such as pure aortic valve insufficiency or valve-in-valve techniques. Currently, an increasing number of publications of midterm results demonstrate good prosthetic valve function and durability, with good quality of life and low morbidity after TAVR. There are also some randomized trials such as PARTNER 2 or SURTAVI to investigate potential benefits of TAVR for intermediate-risk patients. These improvements in the TAVR devices promises the expansion of TAVR towards the treatment of lower-risk patients in the near future.

X-ray light valve (XLV): a novel detectors' technology for digital mammography

NASA Astrophysics Data System (ADS)

Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

2014-03-01

A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

Early Outcomes for Valve-in-valve Transcatheter Aortic Valve Replacement in Degenerative Freestyle Bioprostheses.

PubMed

Sang, Stephane Leung Wai; Beute, Tyler; Heiser, John; Berkompas, Duane; Fanning, Justin; Merhi, William

2017-11-20

Transcatheter aortic valve replacement (TAVR) is used increasingly to treat bioprosthetic valve failure. A paucity of data exists regarding valve-in-valve (ViV) TAVR in degenerated Freestyle stentless bioprostheses (FSBs). This study sought to evaluate the feasibility and short-term outcomes of ViV TAVR in previously placed FSB. From October 2014 to September 2016, 22 patients at a single institution underwent ViV TAVR with a self-expanding transcatheter valve for a failing FSB. Patient baseline characteristics and clinical outcomes data were collected retrospectively and entered into a dedicated database. The mean patient age was 74 ± 9years, and the mean Society of Thoracic Surgeons' Risk score was 9.0 ± 7.4%. Ten patients presented with acute heart failure requiring urgent intervention. The most common mode of failure of the FSB was regurgitation caused by a flail or malcoapting leaflet. Seventeen (77%) patients had a modified subcoronary implantation, 3 (14%) had a full root replacement, and 2 (9%) had a root inclusion. Device success using a self-expanding transcatheter valve was 95%, all via transfemoral approach. The mean implant depth was 7 ± 3 mm. Thirty-day survival was 100%. No patient had more than mild paravalvular regurgitation at 30days, and the permanent pacemaker rate was 9%. The mean hospital stay after intervention was 5 ± 2days. ViV TAVR using a self-expanding transcatheter valve is safe, feasible, and can be used successfully to treat a failed FSB. Procedural challenges suggest referral to valve centers of excellence. Copyright © 2017 Elsevier Inc. All rights reserved.

Aortic valve replacement with the Biocor PSB stentless xenograft.

PubMed

Bertolini, P; Luciani, G B; Vecchi, B; Pugliese, P; Mazzucco, A

1998-08-01

The midterm clinical results after aortic valve replacement with the Biocor PSB stentless xenograft on all patients operated between October 1992 and October 1996 were reviewed. One hundred six patients, aged 70+/-6 years, had aortic valve replacement for aortic stenosis (67%), regurgitation (11%), or both (22%). Associated procedures were done in 49 patients (46%), including coronary artery bypass in 30 patients, mitral valve repair/replacement in 16, and ascending aorta replacement in 5 patients. Aortic cross-clamp and cardiopulmonary bypass times were 96+/-24 and 129+/-31 minutes, respectively. There were 3 (3%) early deaths due to low output (2 patients) and cerebrovascular accident (1 patient). Follow-up of survivors ranged from 6 to 66 months (mean, 39+/-14 months). Survival was 94%+/-2% and 90%+/-3% at 1 and 5 years. There were 5 late deaths due to cardiac cause (2), cancer (2), and pulmonary embolism (1 patient). No patient had structural valve deterioration, whereas 100% and 95%+/-3% were free from valve-related events at 1 and 5 years. There were two reoperations due to narrowing of the left coronary ostium and endocarditis, with an actuarial freedom from reoperation of 99%+/-1% and 98+/-1% at 1 and 5 years, respectively. Functional results demonstrated a mean peak transprosthetic gradient of 16+/-12 mm Hg, with only 1 patient (1%) with a 55 mm Hg gradient. No cases of valve regurgitation greater than mild were recorded at follow-up. Assessment of New York Heart Association functional class demonstrated a significant improvement (2.9+/-0.6 versus 1.4+/-0.7; p=0.01). All patients were free from anticoagulation. Aortic valve replacement using the Biocor PSB stentless xenograft offers excellent midterm survival, negligible valve deterioration, and a very low rate of valve-related events, which are comparable to estimates reported with other models of stentless xenografts and currently available stented xenografts. Hemodynamic performance is favorable and

X-ray structure determination using low-resolution electron microscopy maps for molecular replacement

DOE PAGES

Jackson, Ryan N.; McCoy, Airlie J.; Terwilliger, Thomas C.; ...

2015-07-30

Structures of multi-subunit macromolecular machines are primarily determined by either electron microscopy (EM) or X-ray crystallography. In many cases, a structure for a complex can be obtained at low resolution (at a coarse level of detail) with EM and at higher resolution (with finer detail) by X-ray crystallography. The integration of these two structural techniques is becoming increasingly important for generating atomic models of macromolecular complexes. A low-resolution EM image can be a powerful tool for obtaining the "phase" information that is missing from an X-ray crystallography experiment, however integration of EM and X-ray diffraction data has been technically challenging.more » Here we show a step-by-step protocol that explains how low-resolution EM maps can be placed in the crystallographic unit cell by molecular replacement, and how initial phases computed from the placed EM density are extended to high resolution by averaging maps over non-crystallographic symmetry. As the resolution gap between EM and Xray crystallography continues to narrow, the use of EM maps to help with X-ray crystal structure determination, as described in this protocol, will become increasingly effective.« less

Bioprosthetic Valve Fracture Improves the Hemodynamic Results of Valve-in-Valve Transcatheter Aortic Valve Replacement.

PubMed

Chhatriwalla, Adnan K; Allen, Keith B; Saxon, John T; Cohen, David J; Aggarwal, Sanjeev; Hart, Anthony J; Baron, Suzanne J; Dvir, Danny; Borkon, A Michael

2017-07-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P <0.001) and an increase in valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P <0.001). No procedural complications were reported. BVF can be performed safely in small surgical valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

Valve-sparing aortic root replacement in bicuspid aortic valves: a reasonable option?

PubMed

Aicher, Diana; Langer, Frank; Kissinger, Anke; Lausberg, Henning; Fries, Roland; Schäfers, Hans-Joachim

2004-11-01

Aortic dilatation occurs in many patients with bicuspid aortic valves. We have added root replacement using the remodeling technique originally designed for tricuspid aortic valves to bicuspid aortic valve repair for treatment of the dilated root. We compared the results of remodeling in bicuspid aortic valves with those in tricuspid aortic valves. From October 1995 through January 2004, 60 patients underwent root remodeling for bicuspid aortic valves (group A), and 130 patients underwent root remodeling for tricuspid aortic valves (group B). Correction of cusp prolapse was more often performed in group A (group A, 50/60; group B, 47/130; P < .0001). Transthoracic echocardiography was performed at 1 week, 6 and 12 months, and every year thereafter. Cumulative follow-up was 527 patient-years (mean, 2.9 +/- 2 years). No patient died in group A. Hospital mortality in group B was 5% (5/100; 95% confidence interval,1.6%-11.3%) after elective operations and 10% (3/30; 95% confidence interval, 2.1%-26.5%) after emergency operations. Mean systolic gradients were identical at 1 year (group A, 4.8 +/- 2.1 mm Hg; group B, 4.0 +/- 2 mm Hg) and 5 years (group A, 4.5 +/- 2.3 mm Hg; group B, 3.9 +/- 2.2 mm Hg). Freedom from aortic regurgitation of grade 2 or higher at 5 years was 96% in group A and 83% in group B ( P = .07), and freedom from reoperation at 5 years was 98% in group A and 98% in group B ( P = .73). Valve-sparing aortic replacement with root remodeling can be applied to aortic dilatation and a regurgitant bicuspid aortic valve. Hemodynamic function and valve stability of a repaired bicuspid aortic valve are comparable with those seen in cases of tricuspid anatomy.

Aorta-atria-septum combined incision for aortic valve re-replacement

PubMed Central

Xu, Yiwei; Ye, Xiaofeng; Li, Zhaolong

2018-01-01

This case report illustrates a patient who underwent supra-annular mechanical aortic valve replacement then suffered from prosthesis dysfunction, increasing pressure gradient with aortic valve. She was successfully underwent aortic valve re-replacement, sub-annular pannus removing and aortic annulus enlargement procedures through combined cardiac incision passing through aortic root, right atrium (RA), and upper atrial septum. This incision provides optimal visual operative field and simplifies dissection. PMID:29850170

Aortic valve insufficiency in the teenager and young adult: the role of prosthetic valve replacement.

PubMed

Bradley, Scott M

2013-10-01

The contents of this article were presented in the session "Aortic insufficiency in the teenager" at the congenital parallel symposium of the 2013 Society of Thoracic Surgeons (STS) annual meeting. The accompanying articles detail the approaches of aortic valve repair and the Ross procedure.(1,2) The current article focuses on prosthetic valve replacement. For many young patients requiring aortic valve surgery, either aortic valve repair or a Ross procedure provides a good option. The advantages include avoidance of anticoagulation and potential for growth. In other patients, a prosthetic valve is an appropriate alternative. This article discusses the current state of knowledge regarding mechanical and bioprosthetic valve prostheses and their specific advantages relative to valve repair or a Ross procedure. In current practice, young patients requiring aortic valve surgery frequently undergo valve replacement with a prosthetic valve. In STS adult cardiac database, among patients ≤30 years of age undergoing aortic valve surgery, 34% had placement of a mechanical valve, 51% had placement of a bioprosthetic valve, 9% had aortic valve repair, and 2% had a Ross procedure. In the STS congenital database, among patients 12 to 30 years of age undergoing aortic valve surgery, 21% had placement of a mechanical valve, 18% had placement of a bioprosthetic valve, 30% had aortic valve repair, and 24% had a Ross procedure. In the future, the balance among these options may be altered by design improvements in prosthetic valves, alternatives to warfarin, the development of new patch materials for valve repair, and techniques to avoid Ross autograft failure.

Factors influencing mortality after bioprosthetic valve replacement; a midterm outcome.

PubMed

Javadzadegan, Hassan; Javadzadegan, Amir; Mehdizadeh Baghbani, Jafar

2013-01-01

Although valve repair is applied routinely nowadays, particularly for mitral regurgitation (MR) or tricuspid regurgitation (TR), valve replacement using prosthetic valves is also common especially in adults. Unfortunately the valve with ideal hemodynamic performance and long-term durability without increasing the risk of bleeding due to long-term anticoagulant therapy has not been introduced. Therefore, patients and physicians must choose either bioprosthetic or mechanical valves. Currently, there is an increasing clinical trend of using bioprosthetic valves instead of mechanical valves even in young patients apparently because of their advantages. Seventy patients undergone valvular replacement using bioprosthetic valves were evaluated by ECG and Echocardiography to assess the rhythm and ejection fracture. Mean follow-up time was 33 months (min 9, max 92). Mortality rate was 25.9% (n=18) within 8 years of follow-up. Statistical analysis showed a significant relation between atrial fibrillation rhythm and mortality (P=0.02). Morbidities occurred in 30 patients (42.8%). Significant statistical relation was found between the morbidities and age over 65 years old (P=0.005). In follow-up period, 4 cases (5.7%) underwent re-operation due to global valve dysfunction. Our study shows that using biprosthetic valve could reduce the risk of morbidity occurrence in patient who needs valve replacement. However, if medical treatments fail, patients should be referred for surgery. This would reduce the risk of mortality because of lower incident of complications such as atrial fibrillation and morbidities due to younger patients' population.

Transcatheter aortic-valve replacement with a self-expanding prosthesis.

PubMed

Adams, David H; Popma, Jeffrey J; Reardon, Michael J; Yakubov, Steven J; Coselli, Joseph S; Deeb, G Michael; Gleason, Thomas G; Buchbinder, Maurice; Hermiller, James; Kleiman, Neal S; Chetcuti, Stan; Heiser, John; Merhi, William; Zorn, George; Tadros, Peter; Robinson, Newell; Petrossian, George; Hughes, G Chad; Harrison, J Kevin; Conte, John; Maini, Brijeshwar; Mumtaz, Mubashir; Chenoweth, Sharla; Oh, Jae K

2014-05-08

We compared transcatheter aortic-valve replacement (TAVR), using a self-expanding transcatheter aortic-valve bioprosthesis, with surgical aortic-valve replacement in patients with severe aortic stenosis and an increased risk of death during surgery. We recruited patients with severe aortic stenosis who were at increased surgical risk as determined by the heart team at each study center. Risk assessment included the Society of Thoracic Surgeons Predictor Risk of Mortality estimate and consideration of other key risk factors. Eligible patients were randomly assigned in a 1:1 ratio to TAVR with the self-expanding transcatheter valve (TAVR group) or to surgical aortic-valve replacement (surgical group). The primary end point was the rate of death from any cause at 1 year, evaluated with the use of both noninferiority and superiority testing. A total of 795 patients underwent randomization at 45 centers in the United States. In the as-treated analysis, the rate of death from any cause at 1 year was significantly lower in the TAVR group than in the surgical group (14.2% vs. 19.1%), with an absolute reduction in risk of 4.9 percentage points (upper boundary of the 95% confidence interval, -0.4; P<0.001 for noninferiority; P = 0.04 for superiority). The results were similar in the intention-to-treat analysis. In a hierarchical testing procedure, TAVR was noninferior with respect to echocardiographic indexes of valve stenosis, functional status, and quality of life. Exploratory analyses suggested a reduction in the rate of major adverse cardiovascular and cerebrovascular events and no increase in the risk of stroke. In patients with severe aortic stenosis who are at increased surgical risk, TAVR with a self-expanding transcatheter aortic-valve bioprosthesis was associated with a significantly higher rate of survival at 1 year than surgical aortic-valve replacement. (Funded by Medtronic; U.S. CoreValve High Risk Study ClinicalTrials.gov number, NCT01240902.).

Missed aortic valve endocarditis resulting in complete atrioventricular block and redo mechanical valve replacement.

PubMed

Harky, Amer; Garner, Megan; Popa, Miruna; Shipolini, Alex

2017-08-03

Infective endocarditis is a rare disease associated with high morbidity and mortality. As a result, early diagnosis and prompt antibiotic treatment with or without surgical intervention is crucial in the management of such condition.We report a case of missed infective endocarditis of the aortic valve. The patient underwent mechanical aortic valve replacement, with the native valve being sent for histopathological examination. On re-admission 16 months later, he presented with syncope, shortness of breathing and complete heart block. On review of the histopathology of native aortic valve, endocarditis was identified which had not been acted on. The patient underwent redo aortic valve replacement for severe aortic regurgitation.We highlight the importance of following up histopathological results as well as the need for multidisciplinary treatment of endocarditis with a combination of surgical and antibiotic therapy. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements.

PubMed

Vig, Asger Laurberg; Haldrup, Kristoffer; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh; Eriksen, Johan; Kristensen, Anders; Feidenhans'l, Robert; Nielsen, Martin Meedom

2009-11-01

We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 microm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 degrees can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vig, Asger Laurberg; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh

2009-11-15

We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 {mu}m. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown tomore » be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 deg. can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.« less

Complementary role of cardiac CT in the assessment of aortic valve replacement dysfunction

PubMed Central

Moss, Alastair J; Dweck, Marc R; Dreisbach, John G; Williams, Michelle C; Mak, Sze Mun; Cartlidge, Timothy; Nicol, Edward D; Morgan-Hughes, Gareth J

2016-01-01

Aortic valve replacement is the second most common cardiothoracic procedure in the UK. With an ageing population, there are an increasing number of patients with prosthetic valves that require follow-up. Imaging of prosthetic valves is challenging with conventional echocardiographic techniques making early detection of valve dysfunction or complications difficult. CT has recently emerged as a complementary approach offering excellent spatial resolution and the ability to identify a range of aortic valve replacement complications including structural valve dysfunction, thrombus development, pannus formation and prosthetic valve infective endocarditis. This review discusses each and how CT might be incorporated into a multimodal cardiovascular imaging pathway for the assessment of aortic valve replacements and in guiding clinical management. PMID:27843568

Aortic valve replacement for Libman-Sacks endocarditis

PubMed Central

Keenan, Jack B; Janardhanan, Rajesh; Larsen, Brandon T; Khalpey, Zain

2016-01-01

A 24-year-old man with systemic lupus erythematosus and antiphospholipid syndrome complicated by lupus nephritis presented with acute limb ischaemia secondary to an embolus. Following embolectomy, the patient underwent a transthoracic echocardiogram which revealed a large vegetation on all three cusps of the aortic valve. The patient was taken for an urgent aortic valve replacement with a mechanical valve. Cultures of one cusp remained sterile. Histopathological examination of the remaining two cusps revealed sterile fibrin-rich thrombotic vegetations characteristic of non-bacterial thrombotic endocarditis. PMID:27702929

A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

PubMed

Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

2015-12-01

We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (P< .001) and peripheral vascular complications occurred in 0% of surgicalaortic valve replacement vs 0% of sutureless vs 9.8% transcatheter aortic valve replacement (P< .001). At 24-month follow-up, overall survival (surgical aortic valve replacement = 91.3% ± 2.4% vs sutureless = 94.9% ± 2.1% vs transcatheter aortic valve replacement = 79.5% ± 4.3%; P < .001) and survival free from the composite end point of major adverse cardiovascular events and periprosthetic regurgitation were significantly

Factors Influencing Mortality after Bioprosthetic Valve Replacement; A Midterm Outcome

PubMed Central

Javadzadegan, Hassan; Javadzadegan, Amir; Mehdizadeh Baghbani, Jafar

2013-01-01

Introduction: Although valve repair is applied routinely nowadays, particularly for mitral regurgitation (MR) or tricuspid regurgitation (TR), valve replacement using prosthetic valves is also common especially in adults. Unfortunately the valve with ideal hemodynamic performance and long-term durability without increasing the risk of bleeding due to long-term anticoagulant therapy has not been introduced. Therefore, patients and physicians must choose either bioprosthetic or mechanical valves. Currently, there is an increasing clinical trend of using bioprosthetic valves instead of mechanical valves even in young patients apparently because of their advantages. Methods: Seventy patients undergone valvular replacement using bioprosthetic valves were evaluated by ECG and Echocardiography to assess the rhythm and ejection fracture. Mean follow-up time was 33 months (min 9, max 92). Results: Mortality rate was 25.9% (n=18) within 8 years of follow-up. Statistical analysis showed a significant relation between atrial fibrillation rhythm and mortality (P=0.02). Morbidities occurred in 30 patients (42.8%). Significant statistical relation was found between the morbidities and age over 65 years old (P=0.005). In follow-up period, 4 cases (5.7%) underwent re-operation due to global valve dysfunction. Conclusion: Our study shows that using biprosthetic valve could reduce the risk of morbidity occurrence in patient who needs valve replacement. However, if medical treatments fail, patients should be referred for surgery. This would reduce the risk of mortality because of lower incident of complications such as atrial fibrillation and morbidities due to younger patients' population. PMID:24404348

Cost-Effectiveness of Transcatheter Aortic Valve Replacement With a Self-Expanding Prosthesis Versus Surgical Aortic Valve Replacement.

PubMed

Reynolds, Matthew R; Lei, Yang; Wang, Kaijun; Chinnakondepalli, Khaja; Vilain, Katherine A; Magnuson, Elizabeth A; Galper, Benjamin Z; Meduri, Christopher U; Arnold, Suzanne V; Baron, Suzanne J; Reardon, Michael J; Adams, David H; Popma, Jeffrey J; Cohen, David J

2016-01-05

Previous studies of the cost-effectiveness of transcatheter aortic valve replacement (TAVR) have been based primarily on a single balloon-expandable system. The goal of this study was to evaluate the cost-effectiveness of TAVR with a self-expanding prosthesis compared with surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis and high surgical risk. We performed a formal economic analysis on the basis of individual, patient-level data from the CoreValve U.S. High Risk Pivotal Trial. Empirical data regarding survival and quality of life over 2 years, and medical resource use and hospital costs through 12 months were used to project life expectancy, quality-adjusted life expectancy, and lifetime medical costs in order to estimate the incremental cost-effectiveness of TAVR versus SAVR from a U.S. Relative to SAVR, TAVR reduced initial length of stay an average of 4.4 days, decreased the need for rehabilitation services at discharge, and resulted in superior 1-month quality of life. Index admission and projected lifetime costs were higher with TAVR than with SAVR (differences $11,260 and $17,849 per patient, respectively), whereas TAVR was projected to provide a lifetime gain of 0.32 quality-adjusted life-years ([QALY]; 0.41 LY) with 3% discounting. Lifetime incremental cost-effectiveness ratios were $55,090 per QALY gained and $43,114 per LY gained. Sensitivity analyses indicated that a reduction in the initial cost of TAVR by ∼$1,650 would lead to an incremental cost-effectiveness ratio <$50,000/QALY gained. In a high-risk clinical trial population, TAVR with a self-expanding prosthesis provided meaningful clinical benefits compared with SAVR, with incremental costs considered acceptable by current U.S. With expected modest reductions in the cost of index TAVR admissions, the value of TAVR compared with SAVR in this patient population would become high. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of

Aortic valve replacement for Libman-Sacks endocarditis.

PubMed

Keenan, Jack B; Janardhanan, Rajesh; Larsen, Brandon T; Khalpey, Zain

2016-10-04

A 24-year-old man with systemic lupus erythematosus and antiphospholipid syndrome complicated by lupus nephritis presented with acute limb ischaemia secondary to an embolus. Following embolectomy, the patient underwent a transthoracic echocardiogram which revealed a large vegetation on all three cusps of the aortic valve. The patient was taken for an urgent aortic valve replacement with a mechanical valve. Cultures of one cusp remained sterile. Histopathological examination of the remaining two cusps revealed sterile fibrin-rich thrombotic vegetations characteristic of non-bacterial thrombotic endocarditis. 2016 BMJ Publishing Group Ltd.

Valve Repair Is Superior to Replacement in Most Patients With Coexisting Degenerative Mitral Valve and Coronary Artery Diseases.

PubMed

Javadikasgari, Hoda; Gillinov, A Marc; Idrees, Jay J; Mihaljevic, Tomislav; Suri, Rakesh M; Raza, Sajjad; Houghtaling, Penny L; Svensson, Lars G; Navia, José L; Mick, Stephanie L; Desai, Milind Y; Sabik, Joseph F; Blackstone, Eugene H

2017-06-01

For mitral regurgitation (MR) from degenerative mitral disease in patients with coexisting coronary artery disease, the appropriate surgical strategy remains controversial. From 1985 to 2011, 1,071 adults (age 70 ± 9.3 years, 77% men) underwent combined coronary artery bypass grafting and either mitral valve repair (n = 872, 81%) or replacement (n=199, 19%) for degenerative MR. Propensity matching (177 patient pairs, 89% of possible matches) was used to compare early outcomes and time-related recurrence of MR after mitral valve repair, mitral valve reoperation, and mortality. Risk factors for death were identified with multivariable, multiphase hazard-function analysis. Patients undergoing valve replacement were older, with more valve calcification and a higher prevalence of preoperative atrial fibrillation and heart failure (all p < .0001). Among matched pairs, mitral replacement versus repair was associated with higher hospital mortality (5.0% vs 1.0%, p = .0001) and more postoperative renal failure (7.0% vs 3.2%, p = .01), reexplorations for bleeding (6.0% vs 3.1%, p = .05), and respiratory failure (14% vs 4.7%, p < .0001). Of matched patients undergoing repair, 18% had MR above 3+ by 5 years. Mitral valve durability was similar between matched groups, but survival at 15 years was 18% after replacement versus 52% after repair. Nomograms from the multivariable equation revealed that in 94% of cases, 10-year survival was calculated to be higher after repair than after replacement. In patients with coexisting degenerative mitral valve and coronary artery diseases, mitral valve repair is expected to confer a long-term survival advantage over replacement despite some recurrence of MR. When feasible, it is the procedure of choice for these patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Intraoperative echocardiographic detection of regurgitant jets after valve replacement

NASA Technical Reports Server (NTRS)

Morehead, A. J.; Firstenberg, M. S.; Shiota, T.; Qin, J.; Armstrong, G.; Cosgrove, D. M. 3rd; Thomas, J. D.

2000-01-01

BACKGROUND: Paravalvular jets, documented by intraoperative transesophageal echocardiography, have prompted immediate valve explantation by others, yet the significance of these jets is unknown. METHODS: Twenty-seven patients had intraoperative transesophageal two-dimensional color Doppler echocardiography, performed to assess the number and area of regurgitant jets after valve replacement, before and after protamine. Patients were grouped by first time versus redo operation, valve position and type. RESULTS: Before protamine, 55 jets were identified (2.04+/-1.4 per patient) versus 29 jets after (1.07+/-1.2 per patient, p = 0.0002). Total jet area improved from 2.0+/-2.2 cm2 to 0.86+/-1.7 cm2 with protamine (p<0.0001). In all patients jet area decreased (average decrease, 70.7%+/-27.0%). First time and redo operations had similar improvements in jet number and area (both p>0.6). Furthermore, mitral and mechanical valves each had more jets and overall greater jet area when compared to aortic and tissue valves, respectively. CONCLUSIONS: Following valve replacement, multiple jets are detected by intraoperative transesophageal echocardiography. They are more common and larger in the mitral position and with mechanical valves. Improvement occurs with reversal of anticoagulation.

Acquired discrete subaortic stenosis late after mitral valve replacement.

PubMed

Mohan, Jagdish C; Shukla, Madhu; Mohan, Vishwas; Sethi, Arvind

2016-09-01

Although acquired left ventricular outflow obstruction has been reported in a variety of conditions, there are scant reports of its occurrence following mitral valve replacement (MVR). This study describes two female patients, who developed severe discrete subaortic stenosis, five years following MVR. In both cases, the mitral valve was replaced by a porcine Carpentier-Edwards 27-mm bioprosthesis with preservation of mitral valve leaflets. The risk of very late left ventricular outflow tract obstruction after bio-prosthetic MVR with preservation of subvalvular apparatus needs to be kept in mind in symptomatic patients. Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Pannus Formation Leads to Valve Malfunction in the Tricuspid Position 19 Years after Triple Valve Replacement.

PubMed

Alskaf, Ebraham; McConkey, Hannah; Laskar, Nabila; Kardos, Attila

2016-06-20

The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation.

One-year outcomes after rapid-deployment aortic valve replacement.

PubMed

Young, Christopher; Laufer, Günther; Kocher, Alfred; Solinas, Marco; Alamanni, Francesco; Polvani, Gianluca; Podesser, Bruno K; Aramendi, Jose Ignacio; Arribas, Jose; Bouchot, Olivier; Livi, Ugolino; Massetti, Massimo; Terp, Kim; Giot, Christophe; Glauber, Mattia

2018-02-01

The goals of rapid-deployment aortic valve replacement include facilitation of minimally invasive surgery and reduced aortic crossclamp time. We report the short-term outcomes of a series of 493 patients undergoing rapid-deployment aortic valve replacement with the EDWARDS INTUITY valve system (Edwards Lifesciences, LLC, Irvine, Calif). Assessing Standard oF Care and Clinical Outcomes UsiNg the EDWARDS INTUITY VAlve SysTem in a European multI-center, Active, pOst-market surveillaNce Study was a prospective, multicenter (n = 26) European registry designed to evaluate the safety and performance of the valve system. During rapid-deployment aortic valve replacement, device technical success and crossclamp time were assessed. Procedural outcomes, hemodynamic performance, and various adverse events and clinical outcomes were evaluated up to 2 years. Between 2012 and 2014, 493 of 517 enrolled patients successfully received implants with the study valve (95.4% technical success). Mean crossclamp times for 163 full sternotomies, 128 mini-upper sternotomies, and 36 right anterior thoracotomies isolated aortic valve replacements were 47.3, 52.0, and 73.3 minutes, respectively. Mean follow-up was 1.8 years, with 870 total patient-years of follow-up. Mean effective orifice area increased from 0.72 (baseline) to 1.88 cm 2 , and mean pressure gradient decreased from 47.6 to 9.6 mm Hg (1 year). Mean effective orifice area index increased (0.39-1.01 cm 2 /m 2 ), and 28 of 287 patients (9.8%) exhibited severe prosthesis-patient mismatch at 1 year. After 1 year, 68.1% and 21.7% of patients were in New York Heart Association class I and II, respectively. Freedom from death, major bleeding, major perivalvular leak, reoperation, and device explant at 1 year were 0.935, 0.939, 0.976, 0.975, and 0.983, respectively. These results demonstrate commendable safety and performance of the test valve system over the short term in a broad European setting. Copyright © 2017 The

Trends in Aortic Valve Replacement Procedures Between 2009 and 2015: Has Transcatheter Aortic Valve Replacement Made a Difference?

PubMed

Culler, Steven D; Cohen, David J; Brown, Phillip P; Kugelmass, Aaron D; Reynolds, Matthew R; Ambrose, Karen; Schlosser, Michael L; Simon, April W; Katz, Marc R

2018-04-01

This study reports trends in volume and adverse events associated with isolated aortic valve procedures performed in Medicare beneficiaries between 2009 and 2015. This retrospective study used the annual fiscal year Medicare Provider Analysis and Review file to identify all Medicare beneficiaries undergoing an isolated aortic valve procedure. Outcome measures included three mortality rates and nine in-hospital adverse events. The final study population consisted of 233,660 hospitalizations. During the study period, Medicare beneficiaries undergoing an aortic valve procedure increased from 22,076 to 49,362, for an average annual growth rate of 14.45%. Transcatheter aortic valve replacement (TAVR) procedures per 100,000 Medicare beneficiaries grew from 10.7 in 2012 to 41.1 in 2015. Overall, in-hospital mortality rates, cumulative 30-day mortality rates, and 90-day postdischarge mortality rates declined annually during the study period. However, the 90-day mortality rate for TAVR was nearly double the rate for the tissue surgical aortic valve replacement group. Nearly 68% of Medicare beneficiaries experienced at least one in-hospital adverse event during their index hospitalization. Medicare beneficiaries undergoing TAVR had the lowest observed adverse events rates among the aortic valve procedures in 2015. The total number of Medicare beneficiaries undergoing isolated aortic valve procedures increased from 47.5 to 88.9 per 100,000 Medicare beneficiaries during the study period. Aortic valve procedures increased significantly during this study period primarily due to the increase in TAVR, with clinical outcomes improving as well. Although long-term outcomes of TAVR are still under investigation, these results are promising. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Optimal Elastomeric Scaffold Leaflet Shape for Pulmonary Heart Valve Leaflet Replacement

PubMed Central

Fan, Rong; Bayoumi, Ahmed S.; Chen, Peter; Hobson, Christopher M.; Wagner, William R.; Mayer, John E.; Sacks, Michael S.

2012-01-01

Surgical replacement of the pulmonary valve (PV) is a common treatment option for congenital pulmonary valve defects. Engineered tissue approaches to develop novel PV replacements are intrinsically complex, and will require methodical approaches for their development. Single leaflet replacement utilizing an ovine model is an attractive approach in that candidate materials can be evaluated under valve level stresses in blood contact without the confounding effects of a particular valve design. In the present study an approach for optimal leaflet shape design based on finite element (FE) simulation of a mechanically anisotropic, elastomeric scaffold for PV replacement is presented. The scaffold was modeled as an orthotropic hyperelastic material using a generalized Fung-type constitutive model. The optimal shape of the fully loaded PV replacement leaflet was systematically determined by minimizing the difference between the deformed shape obtained from FE simulation and an ex-vivo microCT scan of a native ovine PV leaflet. Effects of material anisotropy, dimensional changes of PV root, and fiber orientation on the resulting leaflet deformation were investigated. In-situ validation demonstrated that the approach could guide the design of the leaflet shape for PV replacement surgery. PMID:23294966

Latest-Generation Transcatheter Aortic Valve Replacement Devices and Procedures.

PubMed

Chamandi, Chekrallah; Puri, Rishi; Rodriguez-Gabella, Tania; Rodés-Cabau, Josep

2017-09-01

Transcatheter aortic valve replacement (TAVR) is a well-established treatment for patients with severe symptomatic aortic stenosis who are at high or prohibitive surgical risk. More recently, TAVR has emerged as a valid alternative to surgical aortic valve replacement for treating intermediate-risk patients, and several studies are currently evaluating the role of TAVR in low-risk patients. Transcatheter heart valve (THV) technologies have evolved considerably over time, and important iterations have been implemented in many of the latest-generation devices to (1) reduce the size and improve delivery system properties; (2) improve valve deployment, repositioning, and retrievability; and (3) reduce paravalvular leaks. This article reviews the main characteristics of, and clinical results associated with, the newer-generation THVs while providing an overview of novel TAVR indications. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

[Pannus Formation Six-years after Aortic and Mitral Valve Replacement with Tissue Valves;Report of a Case].

PubMed

Nakamura, Makoto; Muraoka, Arata; Aizawa, Kei; Akutsu, Hirohiko; Kurumisawa, Soki; Misawa, Yoshio

2015-07-01

A 77-year-old man presented with exertional dyspnea. He had undergone aortic and mitral valve replacement with tissue valves 6-years earlier. The patient's hemoglobin level was 9.8 g/dl and serum aspartate aminotransferase (70 mU/ml) and lactate dehydrogenase (1,112 mU/ml) were elevated. Echocardiography revealed stenosis of the prosthetic valve in the aortic position with peak flow velocity of 3.8 m/second and massive mitral regurgitation. The patient underwent repeat valve replacement. Pannus formation around both implanted valves was observed. The aortic valve orifice was narrowed by the pannus, and one cusp of the prosthesis in the mitral position was fixed and caused the regurgitation, but they were free from cusp laceration or calcification. The patient's postoperative course was uneventful, and he continues to do well 14 months after surgery.

Survival after Aortic Valve Replacement with Bovine or Porcine Valve Prostheses: A Systematic Review and Meta-Analysis.

PubMed

Glaser, Natalie; Jackson, Veronica; Franco-Cereceda, Anders; Sartipy, Ulrik

2018-05-17

 Bovine and porcine bioprostheses are commonly used for surgical aortic valve replacement. It is unknown if the long-term survival differs between the two valve types.We performed a systematic review and meta-analysis to compare survival in patients who underwent aortic valve replacement and received a bovine or a porcine prosthesis.  We performed a systematic search of Medline, Embase, Web of Science, and the Cochrane Library. Cohort studies that compared survival between patients who underwent aortic valve replacement and received either a bovine or a porcine bioprosthesis and that reported overall long-term survival with hazard ratio (HR) and 95% confidence interval (CI) were included. Two authors independently reviewed articles considered for inclusion, extracted the information from each study, and performed the quality assessment. We performed a meta-analysis using a random effects model to calculate the pooled HR (95% CI) for all-cause mortality. We did sensitivity analyses to assess the robustness of our findings.  Seven studies published between 2010 and 2015 were included, and the combined study population was 49,190 patients. Of these, 32,235 (66%) received a bovine, and 16,955 (34%) received a porcine bioprosthesis. There was no significant difference in all-cause mortality between patients who received a bovine compared with a porcine bioprosthesis (pooled HR 1.00, 95% CI: 0.92-1.09). Heterogeneity between studies was moderate (55.8%, p  = 0.04).  This systematic review and meta-analysis suggest no difference in survival between patients who received a bovine versus a porcine bioprosthesis after aortic valve replacement. Our study provides valuable evidence for the continuing use of both bovine and porcine bioprosthetic valves for surgical aortic valve replacement. Georg Thieme Verlag KG Stuttgart · New York.

Late complications in patients with Björk-Shiley and St. Jude Medical heart valve replacement.

PubMed

Horstkotte, D; Körfer, R; Seipel, L; Bircks, W; Loogen, F

1983-09-01

Valve-related complications after Björk-Shiley mitral valve implantation (n = 475), aortic valve implantation (n = 424), or mitral-aortic valve implantation (n = 119) were compared with those after St. Jude Medical mitral valve replacement (n = 173), aortic valve replacement (n = 152), or mitral-aortic valve replacement (n = 69). All patients were placed on anticoagulant therapy with phenprocoumon early after operation. All patients had a comparable follow-up time of approximately 23 months, which showed that cumulative thromboembolic rates were significantly higher after St. Jude valve implantation than after Björk-Shiley valve implantation. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2.2%), or prosthetic valve endocarditis with perivalvular regurgitation (0.46%). One Björk-Shiley mitral valve prosthesis had to be replaced because of fracture of the outlet strut. Without significant intergroup differences, hemorrhage due to anticoagulant treatment was the most frequent complication. Thromboembolic complications were significantly more frequent after Björk-Shiley mitral, aortic, and double valve replacements than after St. Jude valve implantation. This may lead to consideration of changes in the prophylaxis of thrombus formations in the St. Jude valve, especially in aortic valve replacements, in patients with sinus rhythm.

Tricuspid valve replacement with mechanical prostheses: Short and long-term outcomes.

PubMed

Rossello, Xavier; Muñoz-Guijosa, Christian; Mena, Elisabet; Camprecios, Marta; Mendez, Ana B; Borras, Xavier; Padro, Josep M

2017-09-01

Tricuspid valve replacement has been associated with high mortality and poor long-term outcomes. We report the preoperative risk factors associated with short and long-term outcomes following tricuspid valve replacement with mechanical prostheses. In 62 patients who underwent mechanical tricuspid valve replacement, clinical, laboratory, and echocardiographic findings were analyzed using both univariate and multivariate analyses to describe operative and long-term mortality. In our population (mean age 59 ± 9.7 years, 82.3% female), most common causes of tricuspid valve disease were rheumatic fever (69.4%) and functional regurgitation (19.4%). Operative and long-term mortality were 17.7 and 33.9%, respectively. Age, diabetes mellitus, and coronary artery disease were independently associated with increased long-term mortality. New York Heart Association (NYHA) class and right heart failure symptoms significantly improved during follow-up. In this series of mechanical tricuspid valve replacements in patients with predominately rheumatic heart disease, operative and long-term mortality were increased; however, survivors had significant improvement in their NYHA class and freedom from right heart failure symptoms. Three preoperative factors (age, diabetes mellitus, and coronary artery disease) were independently associated with long-term mortality. © 2017 Wiley Periodicals, Inc.

Left main coronary artery obstruction by dislodged native-valve calculus after transcatheter aortic valve replacement.

PubMed

Durmaz, Tahir; Ayhan, Huseyin; Keles, Telat; Aslan, Abdullah Nabi; Erdogan, Kemal Esref; Sari, Cenk; Bilen, Emine; Akcay, Murat; Bozkurt, Engin

2014-08-01

Transcatheter aortic valve replacement can be an effective, reliable treatment for severe aortic stenosis in surgically high-risk or ineligible patients. However, various sequelae like coronary artery obstruction can occur, not only in the long term, but also immediately after the procedure. We present the case of a 78-year-old woman whose left main coronary artery became obstructed with calculus 2 hours after the transfemoral implantation of an Edwards Sapien XT aortic valve. Despite percutaneous coronary intervention in that artery, the patient died. This case reminds us that early recognition of acute coronary obstruction and prompt intervention are crucial in patients with aortic stenosis who have undergone transcatheter aortic valve replacement.

Left Main Coronary Artery Obstruction by Dislodged Native-Valve Calculus after Transcatheter Aortic Valve Replacement

PubMed Central

Durmaz, Tahir; Keles, Telat; Aslan, Abdullah Nabi; Erdogan, Kemal Esref; Sari, Cenk; Bilen, Emine; Akcay, Murat; Bozkurt, Engin

2014-01-01

Transcatheter aortic valve replacement can be an effective, reliable treatment for severe aortic stenosis in surgically high-risk or ineligible patients. However, various sequelae like coronary artery obstruction can occur, not only in the long term, but also immediately after the procedure. We present the case of a 78-year-old woman whose left main coronary artery became obstructed with calculus 2 hours after the transfemoral implantation of an Edwards Sapien XT aortic valve. Despite percutaneous coronary intervention in that artery, the patient died. This case reminds us that early recognition of acute coronary obstruction and prompt intervention are crucial in patients with aortic stenosis who have undergone transcatheter aortic valve replacement. PMID:25120396

High-risk Trans-Catheter Aortic Valve Replacement in a Failed Freestyle Valve with Low Coronary Height: A Case Report.

PubMed

Karimi, Ashkan; Pourafshar, Negiin; Dibu, George; Beaver, Thomas M; Bavry, Anthony A

2017-06-01

A 55-year-old male with a history of two prior cardiac surgeries presented with decompensated heart failure due to severe bioprosthetic aortic valve insufficiency. A third operation was viewed prohibitively high risk and valve-in-valve trans-catheter aortic valve replacement was considered. There were however several high-risk features and technically challenging aspects including low coronary ostia height, poor visualization of the aortic sinuses, and difficulty in identification of the coplanar view due to severe aortic insufficiency, and a highly mobile aortic valve mass. After meticulous peri-procedural planning, trans-catheter aortic valve replacement was carried out with a SAPIEN 3 balloon-expandable valve without any complication. Strategies undertaken to navigate the technically challenging aspects of the case are discussed.

Dissection of the atrial wall after mitral valve replacement.

PubMed Central

Lukács, L; Kassai, I; Lengyel, M

1996-01-01

We describe an unusual sequela of mitral valve replacement in a 50-year-old woman who had undergone a closed mitral commissurotomy in 1975. She was admitted to our hospital because of mitral restenosis in November 1993, at which time her mitral valve was replaced with a mechanical prosthesis. On the 8th postoperative day, the patient developed symptoms of heart failure; transesophageal echocardiography revealed dissection and rupture of the left atrial wall. At prompt reoperation, we found an interlayer dissection and rupture of the atrial wall into the left atrium. We repaired the ruptured atrial wall with a prosthetic patch. The postoperative course was uneventful, and postoperative transesophageal echocardiography showed normal prosthetic valve function and no dissection. Images PMID:8680278

[Late complications following Björk-Shiley and St. Jude Medical heart valve replacement].

PubMed

Horstkotte, D; Körfer, R; Budde, T; Haerten, K; Schulte, H D; Bircks, W; Loogen, F

1983-05-01

Valve-related complications after Björk-Shiley mitral (n = 475), aortic (n = 424), or mitral-aortic implantation (n = 119) were compared to complications after St. Jude mitral (n = 173), aortic (n = 152), and St. Jude mitral and aortic (n = 63) replacements. The 1,018 consecutive patients with Björk-Shiley valves had been operated upon between 1974 and 1982, those with St. Jude valves between 1978 and 1982. All patients were placed on anticoagulant therapy with phenprocoumon early after operation and no significant intergroup differences in the effectiveness of the anticoagulant therapy were found. At a comparable follow-up time of approximately 23 months, 24 major thromboembolic episodes were observed after Björk-Shiley mitral (BSM) and 3 after St. Jude mitral valve implantation (SJM), corresponding to a thromboembolic rate of 2.82/100 patient years with BSM and 0.93/100 patient years with SJM. After aortic valve replacements, 1.93 events in 100 patient years occurred after Björk-Shiley aortic (BSA) and 0.73 after St. Jude aortic implantation (SJA). In patients with double valve replacements, these rates were 3.2 (BSM + BSA) and 0.88 (SJM + SJA), respectively. The cerebral vessels were involved in 52% and the arteries of the extremities in 22% of these major events. Six Björk-Shiley prostheses had to be replaced because of valve thrombosis. The overall incidence of severe hemorrhagic complications was 2.94/100 patient years in BSM and 1.79 in SJM. After aortic valve replacement, we found rates of 1.80/100 patient years (BSA) and 2.57/100 patient years (SJA), respectively. Intravascular hemolysis no longer seems to be a significant clinical problem. However, indications of red cell damage after heart valve replacement were significantly greater in patients with perivalvular leakage, valve thrombosis, or dysfunction than in those with normally functioning prostheses. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2

Pledget Induced Cardiogenic Shock Following a Minimally Invasive Aortic Valve Replacement.

PubMed

Tedesco, Alexandra E; Tedesco, Victor E

2017-01-01

Within the last decade, minimally invasive valve replacements have become exceedingly popular, and as a result, so has the rise of technology aimed at refining and simplifying these techniques. With new technology, new complications are inevitable. We present a routine Minimally invasive aortic valve replacement through a right anterior minithoracotomy complicated by pledget impaction in a coronary artery.

Haemodynamic results of replacement of mitral and aortic valves with autologous fascia lata prostheses

PubMed Central

Talavlikar, P. H.; Walbaum, P. R.; Kitchin, A. H.

1973-01-01

Twelve patients undergoing aortic and 28 undergoing mitral valve replacement with autologous fascia lata valves were studied before and six months after surgery. One aortic and 10 mitral valves were found to be significantly incompetent. Of the incompetent mitral valves, two appeared to have perivalvular leaks. Six of the remainder were associated with abnormal ventricular filling patterns. Valve failure was much less common when the design was modified to provide a loose cusp structure; out of 12 such valves none was incompetent. Transvalvular gradients persist with fascial valves though they are lower than with most mechanical prostheses. Ventricular function was greatly improved in successful aortic replacement but remained impaired in the case of mitral replacement. Valve failure appeared to be associated with, or accelerated by, haemodynamic stress rather than due to inevitable degenerative pathological processes. PMID:4731108

Percutaneous transluminal alcohol septal myocardial ablation after aortic valve replacement

NASA Technical Reports Server (NTRS)

Sitges, M.; Kapadia, S.; Rubin, D. N.; Thomas, J. D.; Tuzcu, M. E.; Lever, H. M.

2001-01-01

When left ventricular outflow tract obstruction develops after aortic valve replacement, few treatment choices have been available until now. We present a patient with prior aortic valve replacement who developed left ventricle outflow tract obstruction that was successfully treated with a percutaneous transcoronary myocardial septal alcohol ablation. This technique is a useful tool for the treatment of obstructive hypertrophic cardiomyopathy, especially in those patients with prior heart surgery. Copyright 2001 Wiley-Liss, Inc.

Aortic valve replacement in a patient with severe nickel allergy.

PubMed

Lusini, Mario; Barbato, Raffaele; Spadaccio, Cristiano; Chello, Massimo

2011-11-01

Nickel allergy can raise clinical problems in patients undergoing cardiac surgery who require sternal closure with stainless steel wire. We describe the case of a 51-year-old woman with severe nickel allergy who underwent aortic valve replacement with a nickel-free ON-X prosthesis and sternal closure by Fiberwire # 2 suture without complications. Considering its biocompatibility and its mechanical characteristics including optimal strength and knot resistance, this suture might be a viable alternative in patients in which the use of stainless steel wire is contraindicated. © 2011 Wiley Periodicals, Inc.

Prosthetic Aortic Valve Fixation Study: 48 Replacement Valves Analyzed Using Digital Pressure Mapping.

PubMed

Lee, Candice Y; Wong, Joshua K; Ross, Ronald E; Liu, David C; Khabbaz, Kamal R; Martellaro, Angelo J; Gorea, Heather R; Sauer, Jude S; Knight, Peter A

Prostheses attachment is critical in aortic valve replacement surgery, yet reliable prosthetic security remains a challenge. Accurate techniques to analyze prosthetic fixation pressures may enable the use of fewer sutures while reducing the risk of paravalvular leaks (PVL). Customized digital thin film pressure transducers were sutured between aortic annulus models and 21-mm bioprosthetic valves with 15 × 4-mm, 12 × 4-mm, or 9 × 6-mm-wide pledgeted mattress sutures. Simulating open and minimally invasive access, 4 surgeons, blinded to data acquisition, each secured 12 valves using manual knot-tying (hand-tied [HT] or knot-pusher [KP]) or automated titanium fasteners (TFs). Real-time pressure measurements and times were recorded. Two-dimensional (2D) and 3D pressure maps were generated for all valves. Pressures less than 80 mm Hg were considered at risk for PVL. Pressures under each knot (intrasuture) fell less than 80 mm Hg for 12 of 144 manual knots (5/144 HT, 7/144 KP) versus 0 of 288 TF (P < 0.001). Pressures outside adjacent sutures (extrasuture) were less than 80 mm Hg in 10 of 60 HT, zero of 60 KP, and zero of 120 TF sites for 15 × 4-mm valves; 17 of 48 HT, 25 of 48 KP, and 12 of 96 TF for 12 × 4-mm valves; and 15 of 36 HT, 17 of 36 KP, and 9 and 72 TF for 9 × 6-mm valves; P < 0.001 all manual versus TF. Annular areas with pressures less than 80 mm Hg ranged from 0% of the sewing-ring area (all open TF) to 31% (12 × 4 mm, KP). The average time per manual knot, 46 seconds (HT, 31 seconds; KP, 61 seconds), was greater than TF, 14 seconds (P < 0.005). Reduced operative times and PVL risk would fortify the advantages of surgical aortic valve replacement. This research encourages continued exploration of technical factors in optimizing prosthetic valve security.

Valve-sparing aortic root replacement in Loeys-Dietz syndrome.

PubMed

Patel, Nishant D; Arnaoutakis, George J; George, Timothy J; Allen, Jeremiah G; Alejo, Diane E; Dietz, Harry C; Cameron, Duke E; Vricella, Luca A

2011-08-01

Loeys-Dietz syndrome (LDS) is a recently recognized aggressive aortic disorder characterized by root aneurysm, arterial tortuosity, hypertelorism, and bifid uvula or cleft palate. The results of prophylactic root replacement using valve-sparing procedures (valve-sparing root replacement [VSRR]) in patients with LDS is not known. We reviewed all patients with clinical and genetic (transforming growth factor-β receptor mutations) evidence of LDS who underwent VSRR at our institution. Echocardiographic and clinical data were obtained from hospital and follow-up clinic records. From 2002 to 2009, 31 patients with a firm diagnosis of LDS underwent VSRR for aortic root aneurysm. Mean age was 15 years, and 24 (77%) were children. One (3%) patient had a bicuspid aortic valve. Preoperative sinus diameter was 3.9±0.8 cm (z score 7.0±2.9) and 2 (6%) had greater than 2+ aortic insufficiency. Thirty patients (97%) underwent reimplantation procedures using a Valsalva graft. There were no operative deaths. Mean follow-up was 3.6 years (range, 0 to 7 years). One patient required late repair of a pseudoaneurysm at the distal aortic anastomosis, and 1 had a conversion to a David reimplantation procedure after a Florida sleeve operation. No patient suffered thromboembolism or endocarditis, and 1 (3%) patient experienced greater than 2+ late aortic insufficiency. No patient required late aortic valve repair or replacement. Loeys-Dietz syndrome is an aggressive aortic aneurysm syndrome that can be addressed by prophylactic aortic root replacement with low operative risk. Valve-sparing procedures have encouraging early and midterm results, similar to those in Marfan syndrome, and are an attractive option for young patients. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Surgical Approaches to Aortic Valve Replacement and Repair—Insights and Challenges

PubMed Central

Ramchandani, Mahesh; Reardon, Michael J

2014-01-01

Since 1960, surgical aortic valve replacement (sAVR) had been the only effective treatment for symptomatic severe aortic stenosis until the recent development of transcatheter aortic valve replacement (TAVR). TAVR has offered an alternative, minimally invasive treatment approach particularly for patients whose age or co-morbidities make them unsuitable for sAVR. The rapid and enthusiastic utilization of this new technique has triggered some speculation about the imminent demise of sAVR. We believe that despite the recent advances in TAVR, surgical approach to aortic valve replacement has continued to develop and will continue to be highly relevant in the future. This article will discuss the recent developments and current approaches for sAVR, and how these approaches will keep pace with catheter-based technologies. PMID:29588775

The value of aortic valve replacement in elderly patients: an economic analysis.

PubMed

Wu, YingXing; Grunkemeier, Gary L; Starr, Albert

2007-03-01

Economists have designed frameworks to measure the economic value of improvements in health and longevity. Heart valve replacement surgery has significantly prolonged life expectancy and quality of life. For the example of aortic valve replacement, what is its economic value according to this framework? From 1961 through 2003, a total of 4617 adult patients underwent aortic valve replacement by one team of cardiac surgeons. These patients were provided with a prospective lifetime follow-up service. As of 2005, observed follow-up was 31,671 patient-years, with a maximum of 41 years. A statistical model was used to generate the future life-years of patients currently alive. The value of life-years proposed by economists was applied to determine the economic value of the additional life given to these patients by aortic valve replacement. The total life-years after aortic valve replacement were 53,323, with a gross value of 14.6 billion dollars. The total expected life-years without surgery were 10,157, with an estimated value of 3.0 billion dollars. Thus the net life-years gained by AVR were 43,166, worth 11.6 billion dollars. Subtracting the 451 million dollars total lifetime cost of surgery, the net value of the life-years gained by AVR was 11.2 billion dollars. The mean net value decreases according to age at surgery but is still worth 600,000 dollars for octogenarians and 200,000 dollars for nonagenarians. According to the economic concept of the value of a statistical life, the return on the investment for aortic valve replacement is enormous for patients of all ages, even very elderly patients.

Earlier Pulmonary Valve Replacement in Down Syndrome Patients Following Tetralogy of Fallot Repair.

PubMed

Sullivan, Rachel T; Frommelt, Peter C; Hill, Garick D

2017-08-01

The association between Down syndrome and pulmonary hypertension could contribute to more severe pulmonary regurgitation after tetralogy of Fallot repair and possibly earlier pulmonary valve replacement. We compared cardiac magnetic resonance measures of pulmonary regurgitation and right ventricular dilation as well as timing of pulmonary valve replacement between those with and without Down syndrome after tetralogy of Fallot repair. Review of our surgical database from 2000 to 2015 identified patients with tetralogy of Fallot with pulmonary stenosis. Those with Down syndrome were compared to those without. The primary outcome of interest was time from repair to pulmonary valve replacement. Secondary outcomes included pulmonary regurgitation and indexed right ventricular volume on cardiac magnetic resonance imaging. The cohort of 284 patients included 35 (12%) with Down syndrome. Transannular patch repair was performed in 210 (74%). Down syndrome showed greater degree of pulmonary regurgitation (55 ± 14 vs. 37 ± 16%, p = 0.01) without a significantly greater rate of right ventricular dilation (p = 0.09). In multivariable analysis, Down syndrome (HR 2.3, 95% CI 1.2-4.5, p = 0.02) and transannular patch repair (HR 5.5, 95% CI 1.7-17.6, p = 0.004) were significant risk factors for valve replacement. Those with Down syndrome had significantly lower freedom from valve replacement (p = 0.03). Down syndrome is associated with an increased degree of pulmonary regurgitation and earlier pulmonary valve replacement after tetralogy of Fallot repair. These patients require earlier assessment by cardiac magnetic resonance imaging to determine timing of pulmonary valve replacement and evaluation for and treatment of preventable causes of pulmonary hypertension.

Long-Term Mortality Effect of Early Pacemaker Implantation After Surgical Aortic Valve Replacement.

PubMed

Greason, Kevin L; Lahr, Brian D; Stulak, John M; Cha, Yong-Mei; Rea, Robert F; Schaff, Hartzell V; Dearani, Joseph A

2017-10-01

The need for pacemaker implantation is a well-described complication of aortic valve replacement. Not so well described is the effect such an event has on long-term outcome. This study reviewed a 21-year experience at the Mayo Clinic (Rochester, Minnesota) with aortic valve replacement to understand the influence of early postoperative pacemaker implantation on long-term mortality rates more clearly. This study retrospectively reviewed the records of 5,842 patients without previous pacemaker implantation who underwent surgical aortic valve replacement from January 1993 through June 2014. The median age of these patients was 73 years (range, 65 to 79 years), the median ejection fraction was 62% (range, 53% to 68%), 3,853 patients were male (66%), and coronary artery bypass graft operation was performed in 2,553 (44%) of the patients studied. Early pacemaker implantation occurred in 146 patients (2.5%) within 30 days of surgical aortic valve replacement. The median follow-up of patients was 11.1 years (range, 5.8 to 16.5 years), and all-cause mortality rates were 2.4% at 30 days, 6.4% at 1 year, 23.1% at 5 years, 48.3% at 10 years, and 67.9% at 15 years postoperatively. Early pacemaker implantation was associated with an increased risk of death after multivariable adjustment for baseline patients' characteristics (hazard ratio, 1.49; 95% confidence interval, 1.20, 1.84; p < 0.001). Early pacemaker implantation as a complication of surgical aortic valve replacement is associated with an increased risk of long-term death. Valve replacement-related pacemaker implantation rates should be important considerations with respect to new valve replacement paradigms, especially in younger and lower-risk patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Aortic valve replacement for aortic stenosis caused by alkaptonuria.

PubMed

Hiroyoshi, Junko; Saito, Aya; Panthee, Nirmal; Imai, Yasushi; Kawashima, Dai; Motomura, Noboru; Ono, Minoru

2013-03-01

We report a case of aortic stenosis associated with ochronosis in a 70-year-old man who underwent biologic aortic valve replacement. Intraoperative findings included ochronosis of a severely calcified pigmented aortic valve along with pigmentation of the intima of the aorta. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Valve in valve transcatheter aortic valve implantation (ViV-TAVI) versus redo-Surgical aortic valve replacement (redo-SAVR): A systematic review and meta-analysis.

PubMed

Nalluri, Nikhil; Atti, Varunsiri; Munir, Abdullah B; Karam, Boutros; Patel, Nileshkumar J; Kumar, Varun; Vemula, Praveen; Edla, Sushruth; Asti, Deepak; Paturu, Amrutha; Gayam, Sriramya; Spagnola, Jonathan; Barsoum, Emad; Maniatis, Gregory A; Tamburrino, Frank; Kandov, Ruben; Lafferty, James; Kliger, Chad

2018-05-20

Bioprosthetic (BP) valves have been increasingly used for aortic valve replacement over the last decade. Due to their limited durability, patients presenting with failed BP valves are rising. Valve in Valve - Transcatheter Aortic Valve Implantation (ViV-TAVI) emerged as an alternative to the gold standard redo-Surgical Aortic Valve Replacement (redo-SAVR). However, the utility of ViV-TAVI is poorly understood. A systematic electronic search of the scientific literature was done in PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov. Only studies which compared the safety and efficacy of ViV-TAVI and redo-SAVR head to head in failed BP valves were included. Six observational studies were eligible and included 594 patients, of whom 255 underwent ViV- TAVI and 339 underwent redo-SAVR. There was no significant difference between ViV-TAVI and redo- SAVR for procedural, 30 day and 1 year mortality rates. ViV-TAVI was associated with lower risk of permanent pacemaker implantation (PPI) (OR: 0.43, CI: 0.21-0.89; P = 0.02) and a trend toward increased risk of paravalvular leak (PVL) (OR: 5.45, CI: 0.94-31.58; P = 0.06). There was no significant difference for stroke, major bleeding, vascular complications and postprocedural aortic valvular gradients more than 20 mm-hg. Our results reiterate the safety and feasibility of ViV-TAVI for failed aortic BP valves in patients deemed to be at high risk for surgery. VIV-TAVI was associated with lower risk of permanent pacemaker implantation with a trend toward increased risk of paravalvular leak. © 2018, Wiley Periodicals, Inc.

Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients.

PubMed

Reardon, Michael J; Van Mieghem, Nicolas M; Popma, Jeffrey J; Kleiman, Neal S; Søndergaard, Lars; Mumtaz, Mubashir; Adams, David H; Deeb, G Michael; Maini, Brijeshwar; Gada, Hemal; Chetcuti, Stanley; Gleason, Thomas; Heiser, John; Lange, Rüdiger; Merhi, William; Oh, Jae K; Olsen, Peter S; Piazza, Nicolo; Williams, Mathew; Windecker, Stephan; Yakubov, Steven J; Grube, Eberhard; Makkar, Raj; Lee, Joon S; Conte, John; Vang, Eric; Nguyen, Hang; Chang, Yanping; Mugglin, Andrew S; Serruys, Patrick W J C; Kappetein, Arie P

2017-04-06

Although transcatheter aortic-valve replacement (TAVR) is an accepted alternative to surgery in patients with severe aortic stenosis who are at high surgical risk, less is known about comparative outcomes among patients with aortic stenosis who are at intermediate surgical risk. We evaluated the clinical outcomes in intermediate-risk patients with severe, symptomatic aortic stenosis in a randomized trial comparing TAVR (performed with the use of a self-expanding prosthesis) with surgical aortic-valve replacement. The primary end point was a composite of death from any cause or disabling stroke at 24 months in patients undergoing attempted aortic-valve replacement. We used Bayesian analytical methods (with a margin of 0.07) to evaluate the noninferiority of TAVR as compared with surgical valve replacement. A total of 1746 patients underwent randomization at 87 centers. Of these patients, 1660 underwent an attempted TAVR or surgical procedure. The mean (±SD) age of the patients was 79.8±6.2 years, and all were at intermediate risk for surgery (Society of Thoracic Surgeons Predicted Risk of Mortality, 4.5±1.6%). At 24 months, the estimated incidence of the primary end point was 12.6% in the TAVR group and 14.0% in the surgery group (95% credible interval [Bayesian analysis] for difference, -5.2 to 2.3%; posterior probability of noninferiority, >0.999). Surgery was associated with higher rates of acute kidney injury, atrial fibrillation, and transfusion requirements, whereas TAVR had higher rates of residual aortic regurgitation and need for pacemaker implantation. TAVR resulted in lower mean gradients and larger aortic-valve areas than surgery. Structural valve deterioration at 24 months did not occur in either group. TAVR was a noninferior alternative to surgery in patients with severe aortic stenosis at intermediate surgical risk, with a different pattern of adverse events associated with each procedure. (Funded by Medtronic; SURTAVI ClinicalTrials.gov number

[Minor strut fracture of the Björk-Shiley mitral valve].

PubMed

Sugita, T; Yasuda, R; Watarida, S; Onoe, M; Tabata, R; Mori, A

1990-06-01

In May, 1982, a 49-year-old man underwent mitral valve replacement (MVR) in our hospital with a 31 mm Björk-Shiley prosthesis for mitral regurgitation. He had been doing well until his episode of palpitation and dyspnea of sudden onset, and was transferred to our ICU with severe cardiogenic shock in Aug, 1986. Chest X-ray film revealed pulmonary edema and breakage of the valve with migration of the disc and the minor strut of the prosthesis. He was operated upon 5 hours after the onset of his complaints. The minor strut was removed from the left upper pulmonary vein and mitral valve re-replacement was done with a 29 mm Björk-Shiley Monostrut valve. The disc which had dislocated into the abdominal aorta was also recovered on the twenty-third post operative day. His postoperative course was uneventful. Immediate diagnosis and subsequent re-operation is absolute indication for rescue from acute cardiac failure due to mechanical failure of any prosthetic valve.

Patch enlargement of the aortic and mitral valve rings with aortic and mitral double valve replacement. Experimental study.

PubMed

Manouguian, S; Abu-Aishah, N; Neitzel, J

1979-09-01

The experimental results of patch enlargement of the aortic and mitral valve rings with aortic and mitral double valve replacement are reported. The operative technique of this new surgical method is described and the indications are discussed.

Real-time magnetic resonance imaging-guided transcatheter aortic valve replacement.

PubMed

Miller, Justin G; Li, Ming; Mazilu, Dumitru; Hunt, Tim; Horvath, Keith A

2016-05-01

To demonstrate the feasibility of Real-time magnetic resonance imaging (rtMRI) guided transcatheter aortic valve replacement (TAVR) with an active guidewire and an MRI compatible valve delivery catheter system in a swine model. The CoreValve system was minimally modified to be MRI-compatible by replacing the stainless steel components with fluoroplastic resin and high-density polyethylene components. Eight swine weighing 60-90 kg underwent rtMRI-guided TAVR with an active guidewire through a left subclavian approach. Two imaging planes (long-axis view and short-axis view) were used simultaneously for real-time imaging during implantation. Successful deployment was performed without rapid ventricular pacing or cardiopulmonary bypass. Postdeployment images were acquired to evaluate the final valve position in addition to valvular and cardiac function. Our results show that the CoreValve can be easily and effectively deployed through a left subclavian approach using rtMRI guidance, a minimally modified valve delivery catheter system, and an active guidewire. This method allows superior visualization before deployment, thereby allowing placement of the valve with pinpoint accuracy. rtMRI has the added benefit of the ability to perform immediate postprocedural functional assessment, while eliminating the morbidity associated with radiation exposure, rapid ventricular pacing, contrast media renal toxicity, and a more invasive procedure. Use of a commercially available device brings this rtMRI-guided approach closer to clinical reality. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Cost-effectiveness of aortic valve replacement in the elderly: an introductory study.

PubMed

Wu, YingXing; Jin, Ruyun; Gao, Guangqiang; Grunkemeier, Gary L; Starr, Albert

2007-03-01

With increased life expectancy and improved technology, valve replacement is being offered to increasing numbers of elderly patients with satisfactory clinical results. By using standard econometric techniques, we estimated the relative cost-effectiveness of aortic valve replacement by drawing on a large prospective database at our institution. By using aortic valve replacement as an example, this introductory report paves the way to more definitive studies of these issues in the future. From 1961 to 2003, 4617 adult patients underwent aortic valve replacement at our service. These patients were provided with a prospective lifetime follow-up. As of 2005, these patients had accumulated 31,671 patient-years of follow-up (maximum 41 years) and had returned 22,396 yearly questionnaires. A statistical model was used to estimate the future life years of patients who are currently alive. In the absence of direct estimates of utility, quality-adjusted life years were estimated from New York Heart Association class. The cost-effectiveness ratio was calculated by the patient's age at surgery. The overall cost-effectiveness ratio was approximately 13,528 dollars per quality-adjusted life year gained. The cost-effectiveness ratio increased according to age at surgery, up to 19,826 dollars per quality-adjusted life year for octogenarians and 27,182 dollars per quality-adjusted life year for nonagenarians. Given the limited scope of this introductory study, aortic valve replacement is cost-effective for all age groups and is very cost-effective for all but the most elderly according to standard econometric rules of thumb.

Evolving trends in aortic valve replacement: A statewide experience.

PubMed

Kim, Karen M; Shannon, Francis; Paone, Gaetano; Lall, Shelly; Batra, Sanjay; Boeve, Theodore; DeLucia, Alphonse; Patel, Himanshu J; Theurer, Patricia F; He, Chang; Clark, Melissa J; Sultan, Ibrahim; Deeb, George Michael; Prager, Richard L

2018-06-17

Transcatheter aortic valve replacement (TAVR) is an alternative to surgical aortic valve replacement (SAVR) for the treatment of aortic stenosis in patients at intermediate, high, and extreme risk for mortality from SAVR. We examined recent trends in aortic valve replacement (AVR) in Michigan. The Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative (MSTCVS-QC) database was used to determine the number of SAVR and TAVR cases performed from January 2012 through June 2017. Patients were divided into low, intermediate, high, and extreme risk groups based on STS predicted risk of mortality (PROM). TAVR patients in the MSTCVS-QC database were also matched with those in the Transcatheter Valve Therapy Registry to determine their Heart Team-designated risk category. During the study period 9517 SAVR and 4470 TAVR cases were performed. Total annual AVR volume increased by 40.0% (from 2086 to 2920), with a 13.3% decrease in number of SAVR cases (from 1892 to 1640) and a 560% increase in number of TAVR cases (from 194 to 1280). Greater than 90% of SAVR patients had PROM ≤8%. While >70% of TAVR patients had PROM ≤ 8%, they were mostly designated as high or extreme risk by a Heart Team. During the study period, SAVR volume gradually declined and TAVR volume dramatically increased. This was mostly due to a new group of patients with lower STS PROM who were designated as higher risk by a Heart Team due to characteristics not completely captured by the STS PROM score. © 2018 Wiley Periodicals, Inc.

Prevalence of pannus formation after aortic valve replacement: clinical aspects and surgical management.

PubMed

Sakamoto, Yoshimasa; Hashimoto, Kazuhiro; Okuyama, Hiroshi; Ishii, Shinichi; Shingo, Taguchi; Kagawa, Hiroshi

2006-01-01

Pannus formation after aortic valve replacement is not common, but obstruction due to chronic pannus is one of the most serious complications of valve replacement. The causes of pannus formation are still unknown and effective preventive methods have not been fully elucidated. We reviewed our clinical experience of all patients who underwent reoperation for prosthetic aortic valve obstruction due to pannus formation between 1973 and 2004. We compared the initial 18-year period of surgery, when the Björk-Shiley tilting-disk valve was used, and the subsequent 13-year period of surgery, when the St. Jude Medical valve was used. Seven of a total of 390 patients (1.8%) required reoperation for prosthetic aortic valve obstruction due to pannus formation. All seven patients were women; four patients underwent resection of the pannus and three patients needed replacement of the valve. The frequency of pannus formation in the early group was 2.4% (6/253), whereas it was 0.73% (1/137) in the late group (P < 0.05). Pannus was localized at the minor orifice of the Björk-Shiley valve in the early group and turbulent transvalvular blood flow was considered to be one of the important factors triggering its growth. We also consider that small bileaflet valves have the possibility of promoting pannus formation and that the implantation of a larger prosthesis can contribute to reducing the occurrence of pannus.

Management of mitral regurgitation in Marfan syndrome: Outcomes of valve repair versus replacement and comparison with myxomatous mitral valve disease.

PubMed

Helder, Meghana R K; Schaff, Hartzell V; Dearani, Joseph A; Li, Zhuo; Stulak, John M; Suri, Rakesh M; Connolly, Heidi M

2014-09-01

The study objective was to evaluate patients with Marfan syndrome and mitral valve regurgitation undergoing valve repair or replacement and to compare them with patients undergoing repair for myxomatous mitral valve disease. We reviewed the medical records of consecutive patients with Marfan syndrome treated surgically between March 17, 1960, and September 12, 2011, for mitral regurgitation and performed a subanalysis of those with repairs compared with case-matched patients with myxomatous mitral valve disease who had repairs (March 14, 1995, to July 5, 2013). Of 61 consecutive patients, 40 underwent mitral repair and 21 underwent mitral replacement (mean [standard deviation] age, 40 [18] vs 31 [19] years; P = .09). Concomitant aortic surgery was performed to a similar extent (repair, 45% [18/40] vs replacement, 43% [9/21]; P = .87). Ten-year survival was significantly better in patients with Marfan syndrome with mitral repair than in those with replacement (80% vs 41%; P = .01). Mitral reintervention did not differ between mitral repair and replacement (cumulative risk of reoperation, 27% vs 15%; P = .64). In the matched cohort, 10-year survival after repair was similar for patients with Marfan syndrome and myxomatous mitral disease (84% vs 78%; P = .63), as was cumulative risk of reoperation (17% vs 12%; P = .61). Patients with Marfan syndrome and mitral regurgitation have better survival with repair than with replacement. Survival and risk of reoperation for patients with Marfan syndrome were similar to those for patients with myxomatous mitral disease. These results support the use of mitral valve repair in patients with Marfan syndrome and moderate or more mitral regurgitation, including those having composite replacement of the aortic root. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Medium-term outcome of Toronto aortic valve replacement: single center experience.

PubMed

Li, Wei; Price, Susanna; O'Sullivan, Christine A; Kumar, Pankaj; Jin, Xu Y; Henein, Michael Y; Pepper, John R

2008-09-26

Long-term competence of any aortic prosthesis is critical to its clinical durability. Bioprosthetic valves, and in particular the stentless type have been proposed to offer superior haemodynamic profiles with consequent potential for superior left-ventricular mass regression. These benefits however are balanced by the potential longevity of the implanted valve. The aims of this study were to assess medium-term Toronto aortic valve function and its effect on left-ventricular function. Between 1992 and 1996 86 patients underwent Toronto aortic valve replacement for aortic valve disease and were followed up annually. Prospectively collected data was analyzed for all patients where detailed echocardiographic follow-up was available. Echocardiographic studies were analyzed at 2+/-0.6 and 6+/-1.4 years after valve replacement. Data collected included left-ventricular systolic and diastolic dimensions, fractional shortening and left-ventricular mass. In addition, data on aortic valve and root morphology, peak aortic velocities, time velocity integral, stroke volume and the mechanism of valve failure where relevant, were also collected. Complete echocardiographic data were available for eighty-four patients, age 69+/-9 years, 62 male. Additional coronary artery bypass grafting was performed in 38% of patients. Twelve (14%) valves had failed during follow-up, 7 (8%) requiring re-operation. Valve failure was associated with morphologically bicuspid native aortic valve (9/12), and progressive dilatation of the aortic sinuses, sino-tubular junction and ascending aorta (11/12). Left-ventricular mass index remained high (184+/-75 g/m(2)) and did not continue to regress between early and medium-term follow-up (175.8+/-77 g/m(2)). Although more than 90% of implanted Toronto aortic valves remained haemodynamically stable with low gradient at medium-term follow-up, young age and larger aortic dimensions in patients with valve failure suggest better outcome if used in the elderly

The impact of mitral stenosis on outcomes of aortic valve stenosis patient undergoing surgical aortic valve replacement or transcatheter aortic valve replacement.

PubMed

Al-Khadra, Yasser; Darmoch, Fahed; Baibars, Motaz; Kaki, Amir; Fanari, Zaher; Alraies, M Chadi

2018-05-17

The concomitant presence of mitral stenosis (MS) in the setting of symptomatic aortic stenosis represent a clinical challenge. Little is known regarding the outcome of mitral stenosis (MS) patients undergoing transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). Therefore, we sought to study the outcome of MS patients undergoing aortic valve replacement (AVR). Using weighted data from the National Inpatient Sample (NIS) database between 2011 and 2014, we identified patients who were diagnosed with MS. Patients who had undergone TAVR as a primary procedure were identified and compared to patients who had SAVR. Univariate and multivariate logistic regression analysis were performed for the outcomes of in-hospital mortality, length of stay (LOS), blood transfusion, postprocedural hemorrhage, vascular, cardiac and respiratory complications, permanent pacemaker placement (PPM), postprocedural stroke, acute kidney injury (AKI), and discharge to an outside facility. A total of 4524 patients were diagnosed with MS, of which 552 (12.2%) had TAVR and 3972 (87.8%) had SAVR. TAVR patients were older (79.9 vs 70.0) with more females (67.4% vs 60.0%) and African American patients (7.7% vs 7.1%) (P < 0.001). In addition, the TAVR group had more comorbidities compared to SAVR in term of coronary artery disease (CAD), congestive heart failure (CHF), chronic lung disease, hypertension (HTN), chronic kidney disease (CKD), and peripheral vascular disease (PVD) (P < 0.001 for all). Using Multivariate logistic regression, and after adjusting for potential risk factors, TAVR patients had lower in-hospital mortality (7.9% vs 8.1% adjusted Odds Ratio [aOR], 0.615; 95% confidence interval [CI], 0.392-0.964, P = 0.034), shorter LOS. Also, TAVR patients had lower rates of cardiac and respiratory complications, PPM, AKI, and discharge to an outside facility compared with the SAVR group. In patients with severe aortic stenosis and concomitant

Neurocognitive functions after beating heart mitral valve replacement without cross-clamping the aorta.

PubMed

Cicekcioglu, Ferit; Ozen, Anil; Tuluce, Hicran; Tutun, Ufuk; Parlar, Ali Ihsan; Kervan, Umit; Karakas, Sirel; Katircioglu, Salih Fehmi

2008-01-01

Although neurologic outcome after cardiac surgery is well-established, neurocognitive functions after beating heart mitral valve replacement still needs to be elucidated. The aim of this study was to compare preoperative and postoperative neurocognitive functions in patients who underwent beating heart mitral valve replacement on cardiopulmonary bypass without cross-clamping the aorta. The prospective study included 25 consecutive patients who underwent mitral valve replacement. The operations were carried out on a beating heart method using normothermic cardiopulmonary bypass without cross-clamping the aorta. All patients were evaluated preoperatively (E1) and postoperatively (at sixth day [E2] and second month [E3]) for neurocognitive functions. Neurologic deficit was not observed in the postoperative period. Comparison of the neurocognitive test results, between the preoperative and postoperative assessment for both hemispheric cognitive functions, demonstrated that no deterioration occurred. In the three subsets of left hemispheric cognitive function test evaluation, total verbal learning, delayed recall, and recognition, significant improvements were detected at the postoperative second month (E3) compared to the preoperative results (p = 0.005, 0.01, and 0.047, respectively). Immediate recall and retention were significantly improved within the first postoperative week (E2) when compared to the preoperative results (p = 0.05 and 0.05, respectively). The technique of mitral valve replacement with normothermic cardiopulmonary bypass without cross-clamping of the aorta may be safely used for majority of patients requiring mitral valve replacement without causing deterioration in neurocognitive functions.

Thrombocytopenia after aortic valve replacement with freedom solo bioprosthesis: a propensity study.

PubMed

Piccardo, Alessandro; Rusinaru, Dan; Petitprez, Benoit; Marticho, Paul; Vaida, Ioana; Tribouilloy, Christophe; Caus, Thierry

2010-05-01

The incidence of postoperative thrombocytopenia after aortic valve replacement with the Freedom Solo bioprosthesis remains unclear. This propensity-matched study was carried out to evaluate the incidence and clinical impact of thrombocytopenia in patients receiving the Freedom Solo bioprosthesis. Patients who underwent aortic valve replacement with a Freedom Solo or Carpentier-Edwards Perimount pericardial prosthesis at our institution between 2006 and 2008 were screened retrospectively. Exclusion criteria included double valve replacement, redo surgery, and active endocarditis. Two hundred six patients were considered eligible for this analysis. Using propensity scores 36 matched pairs of patients with a Freedom Solo or Perimount bioprosthesis were obtained. The primary end point was the occurrence of postoperative thrombocytopenia. Secondary end points were postoperative thromboembolic or hemorrhagic events and 30-day mortality. Before matching, severe thrombocytopenia (<30 x 10(9) platelets/L) occurred in 22% of patients with a Freedom Solo bioprosthesis and 1% with a Perimount bioprosthesis (p < 0.0001), thromboembolic or hemorrhagic events occurred in 3% and 2%, respectively (p = 0.37), and 30-day mortality was 4% and 6%, respectively (p = 0.48). Multivariate analysis identified preoperative platelet count (p = 0.01) and Freedom Solo (p < 0.0001) as independent risk factors for severe postoperative thrombocytopenia. After matching, severe thrombocytopenia occurred in 25% and 3% of patients with Freedom Solo and Perimount bioprostheses, respectively (p < 0.0001), thromboembolic or hemorrhagic events occurred in 0%, and 30-day mortality was 3% and 6%, respectively (p = 0.99). The risk of thrombocytopenia was high after Freedom Solo implantation. However, this complication was not related to any deleterious events in our study population. Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Successful replacement of the systemic tricuspid valve with a mechanical valve in a 3-month-old boy with congenitally corrected transposition of the great arteries having a dysplastic tricuspid valve.

PubMed

Asada, Dai; Ikeda, Kazuyuki; Yamagishi, Masaaki

2017-04-01

There are a few reports of successful replacement of the left-sided systemic tricuspid valve with a mechanical valve in small infants with congenitally corrected transposition of the great arteries having Ebstein's anomaly. Tricuspid valve replacement is the preferred option when pulmonary artery banding, performed as a prelude to performing the double-switch operation, is not feasible because of severe heart failure caused by tricuspid regurgitation.

Mitral valve replacement for mitral stenosis: A 15-year single center experience.

PubMed

Al Mosa, Alqasem F; Omair, Aamir; Arifi, Ahmed A; Najm, Hani K

2016-10-01

Mitral valve replacement with either a bioprosthetic or a mechanical valve is the treatment of choice for severe mitral stenosis. However, choosing a valve implant type is still a subject of debate. This study aimed to evaluate and compare the early and late outcomes of mitral valve replacement [mechanical (MMV) vs. bioprosthetic (BMV)] for severe mitral stenosis. A retrospective cohort study was performed on data involving mitral stenosis patients who have undergone mitral valve replacement with either BMV (n = 50) or MMV (n = 145) valves from 1999 to 2012. Data were collected from the patients' records and follow-up through telephone calls. Data were analyzed for early and late mortality, New York Heart Association (NYHA) functional classes, stroke, pre- and postoperative echocardiographic findings, early and late valve-related complications, and survival. Chi-square test, logistic regression, Kaplan-Meier curve, and dependent proportions tests were some of the tests employed in the analysis. A total of 195 patients were included in the study with a 30-day follow-up echocardiogram available for 190 patients (97.5%), while 103 (53%) were available for follow-up over the telephone. One patient died early postoperatively; twelve patients died late in the postoperative period, six in the bioprosthesis group and six in the mechanical group. The late mortality had a significant association with postoperative stroke (p < 0.001) and postoperative NYHA Classes III and IV (p = 0.002). Postoperative NYHA class was significantly associated with age (p = 0.003), pulmonary disease (p = 0.02), mitral valve implant type (p = 0.01), and postoperative stroke (p = 0.02); 14 patients had strokes in the mechanical (9) and in the bioprosthetic (5) groups. NYHA classes were significantly better after the replacement surgeries (p < 0.001). BMV were significantly associated with worse survival (p = 0.03), worse NYHA postoperatively (p = 0.01), and more reoperations

Long-term Outcomes of Mitral Valve Repair Versus Replacement for Degenerative Disease: A Systematic Review

PubMed Central

McNeely, Christian A; Vassileva, Christina M

2015-01-01

The short-term advantage of mitral valve repair versus replacement for degenerative disease has been extensively documented. These advantages include lower operative mortality, improved survival, better preservation of left-ventricular function, shorter post-operative hospital stay, lower total costs, and fewer valve-related complications, including thromboembolism, anticoagulation-related bleeding events and late prosthetic dysfunction. More recent written data are available indicating the long-term advantage of repair versus replacement. While at some institutions, the repair rate for degenerative disease may exceed 90%, the national average in 2007 was only 69%. Making direct comparisons between mitral valve repair and replacement using the available studies does present some challenges however, as there are often differences in baseline characteristics between patient groups as well as other dissimilarities between studies. The purpose of this review is to systematically summarize the long-term survival and reoperation data of mitral valve repair versus replacement for degenerative disease. A PubMed search was done and resulted in 12 studies that met our study criteria for comparing mitral valve repair versus replacement for degenerative disease. A systematic review was then conducted abstracting survival and reoperation data. PMID:25158683

Aortic valve replacement in elderly patients.

PubMed

Glock, Y; Pecoul, R; Cerene, A; Laguerre, J; Puel, P

1984-01-01

The results for 62 consecutive patients aged 70 or more given aortic valve replacement (A.V.R.) between 1970 and 1982 are reported. All the patients were in the New York Heart Association (N.Y.H.A.) functional class III (29%) or IV (71%); 54.8% had angina and 30.6% had experienced syncope. Forty patients had aortic stenosis (A.S.), 10 had aortic regurgitation and 12 had mixed aortic valve disease. The operative myocardial infarction rate was 6.4%. Tilting disk valves were used. Eighty percent of the patients were anticoagulated with Warfarin whilst twenty percent received only antiplatelet drugs. All the patients were followed up for a mean period of 26 months; late mortality was 22.6% with 4.8% cardiac deaths. The thromboembolic rate was 1.6% and the disinsertion rate was 3.2%. Cerebral stroke was fatal in 3 cases in anticoagulated patients but the mechanism of the accident was not known. At the termination of the study 93% of surviving patients were in N.Y.H.A. class I or II. No patient was in class IV. The probability of five year survival is 71% for the entire group.

High Risk Aortic Valve Replacement - The Challenges of Multiple Treatment Strategies with an Evolving Technology.

PubMed

Booth, K; Beattie, R; McBride, M; Manoharan, G; Spence, M; Jones, J M

2016-01-01

Deciding on the optimal treatment strategy for high risk aortic valve replacement is challenging. Transcatheter Aortic Valve implantation (TAVI) has been available in our centre as an alternative treatment modality for patients since 2008. We present our early experience of TAVI and SAVR (surgical Aortic Valve Replacement) in high risk patients who required SAVR because TAVI could not be performed. The database for Surgical aortic valve and Transcatheter aortic valve replacement referrals was interrogated to identify relevant patients. Survival to hospital discharge was 95.5% in the forty five patients who had SAVR when TAVI was deemed technically unsuitable. One year survival was 86%. Defining who is appropriate for TAVI or high risk SAVR is challenging and multidisciplinary team discussion has never been more prudent in this field of evolving technology with ever decreasing risks of surgery. The introduction of TAVI at our institution has seen a rise in our surgical caseload by approximately by 25%. Overall, the option of aortic valve intervention is being offered to more patients in general which is a substantial benefit in the treatment of aortic valve disease.

Transcatheter Aortic Valve Replacement: a Kidney’s Perspective

PubMed Central

Cheungpasitporn, Wisit; Thongprayoon, Charat; Kashani, Kianoush

2016-01-01

Transcatheter aortic valve replacement (TAVR) has now emerged as a viable treatment option for high-risk patients with severe aortic stenosis (AS) who are not suitable candidates for surgical aortic valve replacement (SAVR). Despite encouraging published outcomes, acute kidney injury (AKI) is common and lowers the survival of patients after TAVR. The pathogenesis of AKI after TAVR is multifactorial including TAVR specific factors such as the use of contrast agents, hypotension during rapid pacing, and embolization; preventive measures may include pre-procedural hydration, limitation of contrast dye exposure, and avoidance of intraprocedural hypotension. In recent years, the number of TAVR performed worldwide has been increasing, as well as published data on renal perspectives of TAVR including AKI, chronic kidney disease, end-stage kidney disease, and kidney transplantation. This review aims to present the current literature on the nephrology aspects of TAVR, ultimately to improve the patients’ quality of care and outcomes. PMID:27069960

Transcatheter or Surgical Aortic-Valve Replacement in Intermediate-Risk Patients.

PubMed

Leon, Martin B; Smith, Craig R; Mack, Michael J; Makkar, Raj R; Svensson, Lars G; Kodali, Susheel K; Thourani, Vinod H; Tuzcu, E Murat; Miller, D Craig; Herrmann, Howard C; Doshi, Darshan; Cohen, David J; Pichard, Augusto D; Kapadia, Samir; Dewey, Todd; Babaliaros, Vasilis; Szeto, Wilson Y; Williams, Mathew R; Kereiakes, Dean; Zajarias, Alan; Greason, Kevin L; Whisenant, Brian K; Hodson, Robert W; Moses, Jeffrey W; Trento, Alfredo; Brown, David L; Fearon, William F; Pibarot, Philippe; Hahn, Rebecca T; Jaber, Wael A; Anderson, William N; Alu, Maria C; Webb, John G

2016-04-28

Previous trials have shown that among high-risk patients with aortic stenosis, survival rates are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. We evaluated the two procedures in a randomized trial involving intermediate-risk patients. We randomly assigned 2032 intermediate-risk patients with severe aortic stenosis, at 57 centers, to undergo either TAVR or surgical replacement. The primary end point was death from any cause or disabling stroke at 2 years. The primary hypothesis was that TAVR would not be inferior to surgical replacement. Before randomization, patients were entered into one of two cohorts on the basis of clinical and imaging findings; 76.3% of the patients were included in the transfemoral-access cohort and 23.7% in the transthoracic-access cohort. The rate of death from any cause or disabling stroke was similar in the TAVR group and the surgery group (P=0.001 for noninferiority). At 2 years, the Kaplan-Meier event rates were 19.3% in the TAVR group and 21.1% in the surgery group (hazard ratio in the TAVR group, 0.89; 95% confidence interval [CI], 0.73 to 1.09; P=0.25). In the transfemoral-access cohort, TAVR resulted in a lower rate of death or disabling stroke than surgery (hazard ratio, 0.79; 95% CI, 0.62 to 1.00; P=0.05), whereas in the transthoracic-access cohort, outcomes were similar in the two groups. TAVR resulted in larger aortic-valve areas than did surgery and also resulted in lower rates of acute kidney injury, severe bleeding, and new-onset atrial fibrillation; surgery resulted in fewer major vascular complications and less paravalvular aortic regurgitation. In intermediate-risk patients, TAVR was similar to surgical aortic-valve replacement with respect to the primary end point of death or disabling stroke. (Funded by Edwards Lifesciences; PARTNER 2 ClinicalTrials.gov number, NCT01314313.).

Beating heart mitral valve replacement with a bovine pericardial bioprosthesis for treatment of mitral valve dysplasia in a Bull Terrier.

PubMed

Behr, Luc; Chetboul, Valérie; Sampedrano, Carolina Carlos; Vassiliki, Gouni; Pouchelon, Jean-Louis; Laborde, François; Borenstein, Nicolas

2007-04-01

To describe an open, beating heart surgical technique and use of a bovine pericardial prosthetic valve for mitral valve replacement (MVR) in the dog. Clinical case report. Male Bull Terrier (17-month-old, 26 kg) with mitral valve dysplasia and severe regurgitation. A bovine pericardial bioprosthesis was used to replace the mitral valve using an open beating heart surgical technique and cardiopulmonary bypass. Successful MVR was achieved using a beating heart technique. Mitral regurgitation resolved and cardiac performances improved (left ventricular end-diastolic diameter decreased from 57.6 to 48.7 mm, and left atrium/aorta ratio returned to almost normal, from 1.62 to 1.19). Cardiopulmonary by-pass time and total surgical duration were decreased compared with standard cardioplegic techniques. Surgical recovery was uneventful and on echocardiography 6 months later valve function was excellent. Considering the technique advantages (no cardiac arrest, ischemic reperfusion injury, and hypothermia, or the need for aortic dissection and cannulation for administration of cardioplegic solution), short-term mortality and morbidity may be reduced compared with standard cardioplegic techniques. Based on experience in this dog, beating heart mitral valvular replacement is a seemingly safe and viable option for the dog and bovine pericardial prosthesis may provide better long-term survival than mechanical prostheses.

Vascular complications of transcatheter aortic valve replacement: A concise literature review

PubMed Central

Chaudhry, Muhammad Ali; Sardar, Muhammad Rizwan

2017-01-01

Transcatheter aortic valve replacement (TAVR) is a relatively newer therapeutic modality which offers a promising alternative to surgical aortic valve replacement for patients with prohibitive, high and intermediate surgical risk. The increasing trend to pursue TAVR in these patients has also led to growing awareness of the associated potential vascular complications. The significant impact of these complications on eventual clinical outcome and mortality makes prompt recognition and timely management a critical factor in TAVR patients. We hereby present a concise review with emphasis on diverse vascular complications associated with TAVR and their effective management to improve overall clinical outcomes. PMID:28824787

COMBINED REPLACEMENT OF THE AORTIC VALVE AND ASCENDING AORTA IN JEHOVAH'S WITNESSES: REPORT OF TWO CASES

PubMed Central

Beddermann, Christoph; Norman, John C.; Cooley, Denton A.

1979-01-01

Two Jehovah's Witnesses with large ascending thoracic aortic aneurysms and aortic insufficiency secondary to annuloaortic ectasia underwent successful combined replacement of the aortic valve and the ascending aorta. One patient received a composite graft containing an aortic valve prosthesis, which necessitated supravalvular coronary ostia reimplantation; the other patient underwent separate aortic valve and left supracoronary ascending aneurysm replacement, with reimplantation of the right coronary ostium into the graft. No blood or blood derivatives were administered. Both patients had uneventful recoveries and continue to do well. To our knowledge, they represent the first reported cases of successful combined replacement of the aortic valve and ascending aorta in Jehovah's Witnesses. Images PMID:15216324

Coronary ostia obstruction after replacement of aortic valve prostesis

PubMed Central

2011-01-01

Aortic valve replacement (AVR) is the gold standard for the treatment of severe symptomatic aortic stenosis. Complications directly related to surgical procedure are relatively infrequent. Coronary ostial stenosis is, generally, referred as late complication. Anecdotal reports concern coronary ostial stenosis as acute complication. A unique fatal case of intraoperative, bilateral coronary ostial obstruction by prosthetic valve leading to an extensive myocardial infarction is reported. Surgeons must have a high level of vigilance regarding the occurrence of acute myocardial ischemia and sudden death soon after AVR. PMID:21810231

One-year outcome following biological or mechanical valve replacement for infective endocarditis.

PubMed

Delahaye, F; Chu, V H; Altclas, J; Barsic, B; Delahaye, A; Freiberger, T; Gordon, D L; Hannan, M M; Hoen, B; Kanj, S S; Lejko-Zupanc, T; Mestres, C A; Pachirat, O; Pappas, P; Lamas, C; Selton-Suty, C; Tan, R; Tattevin, P; Wang, A

2015-01-15

Nearly half of patients require cardiac surgery during the acute phase of infective endocarditis (IE). We describe the characteristics of patients according to the type of valve replacement (mechanical or biological), and examine whether the type of prosthesis was associated with in-hospital and 1-year mortality. Among 5591 patients included in the International Collaboration on Endocarditis Prospective Cohort Study, 1467 patients with definite IE were operated on during the active phase and had a biological (37%) or mechanical (63%) valve replacement. Patients who received bioprostheses were older (62 vs 54years), more often had a history of cancer (9% vs 6%), and had moderate or severe renal disease (9% vs 4%); proportion of health care-associated IE was higher (26% vs 17%); intracardiac abscesses were more frequent (30% vs 23%). In-hospital and 1-year death rates were higher in the bioprosthesis group, 20.5% vs 14.0% (p=0.0009) and 25.3% vs 16.6% (p<.0001), respectively. In multivariable analysis, mechanical prostheses were less commonly implanted in older patients (odds ratio: 0.64 for every 10years), and in patients with a history of cancer (0.72), but were more commonly implanted in mitral position (1.60). Bioprosthesis was independently associated with 1-year mortality (hazard ratio: 1.298). Patients with IE who receive a biological valve replacement have significant differences in clinical characteristics compared to patients who receive a mechanical prosthesis. Biological valve replacement is independently associated with a higher in-hospital and 1-year mortality, a result which is possibly related to patient characteristics rather than valve dysfunction. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Consequence of patient substitution of nattokinase for warfarin after aortic valve replacement with a mechanical prosthesis.

PubMed

Elahi, Maqsood M; Choi, Charles H; Konda, Subbareddy; Shake, Jay G

2015-01-01

This report describes a patient's self-substitution of nattokinase for the vitamin K antagonist warfarin after aortic valve replacement with a mechanical prosthesis. Nattokinase is an enzyme derived from a popular fermented soybean preparation in Japan (natto), which has fibrinolytic properties and is gaining popularity in nontraditional health journals and nonmedical health websites as an over-the-counter thrombolytic. After nearly a year of use of nattokinase without warfarin, the patient developed thrombus on the mechanical valve and underwent successful repeat valve replacement. We believe this is the first documented case of nattokinase being used as a substitute for warfarin after valve replacement, and we strongly discourage its use for this purpose.

Consequence of patient substitution of nattokinase for warfarin after aortic valve replacement with a mechanical prosthesis

PubMed Central

Elahi, Maqsood M.; Choi, Charles H.; Konda, Subbareddy

2015-01-01

This report describes a patient's self-substitution of nattokinase for the vitamin K antagonist warfarin after aortic valve replacement with a mechanical prosthesis. Nattokinase is an enzyme derived from a popular fermented soybean preparation in Japan (natto), which has fibrinolytic properties and is gaining popularity in nontraditional health journals and nonmedical health websites as an over-the-counter thrombolytic. After nearly a year of use of nattokinase without warfarin, the patient developed thrombus on the mechanical valve and underwent successful repeat valve replacement. We believe this is the first documented case of nattokinase being used as a substitute for warfarin after valve replacement, and we strongly discourage its use for this purpose. PMID:25552810

Aortic valve replacement and tricuspid valve annuloplasty via a left thoracotomy in an adult with left pulmonary agenesis.

PubMed

Furutachi, Akira; Furukawa, Kojiro; Shimauchi, Kouta; Yunoki, Junji; Itoh, Manabu; Takamatsu, Masanori; Nogami, Eijiro; Mukae, Yosuke; Nishida, Takahiro

2018-06-06

We report a case of a 66-year-old man who was diagnosed with severe aortic regurgitation, moderate tricuspid regurgitation and chronic atrial fibrillation. Preoperative computed tomography showed left lung agenesis. We performed aortic valve replacement, tricuspid valve annuloplasty and right pulmonary vein isolation via a left thoracotomy. This approach provided an adequate field of view.

Root replacement using stentless valves in the small aortic root: a propensity score analysis.

PubMed

Kunihara, Takashi; Schmidt, Kathrin; Glombitza, Petra; Dzindzibadze, Vachtang; Lausberg, Henning; Schäfers, Hans-Joachim

2006-10-01

Root replacement using a stentless bioprosthesis may be the optimal approach to avoid patient-prosthesis mismatch in patients with a small aortic root. Primary root replacement, however, is considered to be associated with increased surgical risk. We compared early outcome of full root replacement with a stentless bioprosthesis with that of aortic valve replacement with a stented bioprosthesis using propensity score-matching analysis. Of 231 patients undergoing elective, first-time aortic valve replacement with a small root (< or = 22 mm), 120 patients were selected using propensity score-matching analysis. They underwent either root replacement using a 23-mm stentless bioprosthesis (stentless group, n = 60) or supra-annular aortic valve replacement using a 21-mm stented bioprosthesis (stented group, n = 60). Preoperative characteristics and frequency of concomitant operations were identical. Duration of operation (196 +/- 54 versus 174 +/- 49 minutes), cardiopulmonary bypass (112 +/- 36 versus 91 +/- 33 minutes), and aortic cross-clamping (76 +/- 21 versus 61 +/- 21 minutes) were significantly longer in the stentless group. However, the need for perioperative transfusion and the incidence of postoperative reexploration for bleeding (3% versus 8%) was lower, and ventilation time was shorter. Mean duration of intensive care and hospital stay were also significantly shorter (2.3 +/- 1.7 versus 4.0 +/- 3.9 days, 8.9 +/- 3.1 versus 12.4 +/- 5.7 days). In-hospital mortality was identical (5% each). No independent predictor for in-hospital mortality was identified. Full root replacement using a stentless bioprosthesis does not increase postoperative morbidity or mortality of aortic valve replacement and may be advantageous in patients with a small aortic root.

Intracardiac echocardiography to diagnose pannus formation after aortic valve replacement.

PubMed

Yamamoto, Yoshiya; Ohara, Takahiro; Funada, Akira; Takahama, Hiroyuki; Amaki, Makoto; Hasegawa, Takuya; Sugano, Yasuo; Kanzaki, Hideaki; Anzai, Toshihisa

2016-03-01

A 66-year-old female, under regular follow-up for 20 years after aortic valve replacement (19-mm Carbomedics), presented dyspnea on effort and hypotension during hemodialysis. A transthoracic echocardiogram showed elevation of transvalvular velocity up to 4 m/s, but the structure around the aortic prosthesis was difficult to observe due to artifacts. Fluoroscopy revealed normal motion of the leaflets of the mechanical valve. Intracardiac echocardiography (ICE) revealed a pannus-like structure in the left ventricular outflow tract. Transesophageal echocardiogram also revealed this structure. ICE can visualize structural abnormalities around a prosthetic valve after cardiac surgery even in patients in whom conventional imaging modalities failed.

Minimally Invasive Aortic Valve Replacement Following Root Enlargement on too Narrow Annulus to Perform Transcatheter Aortic Valve Implantation.

PubMed

Sakamoto, Kosuke; Totsugawa, Toshinori; Hiraoka, Arudo; Tamura, Kentaro; Yoshitaka, Hidenori; Sakaguchi, Taichi

2018-05-30

An 88-year-old woman was diagnosed with aortic stenosis and an aortic annulus that was too narrow to perform transcatheter aortic valve implantation. Surgery was performed through a 7-cm right mini-thoracotomy at the fourth intercostal space. A 19-mm aortic valve bioprosthesis was implanted after root enlargement. The fourth intercostal space was a suitable site for aortic root enlargement because of the shorter skin-to-root distance and the detailed exposure of the aortic valve after cutting the aortic wall. This study concluded that minimally-invasive aortic valve replacement following root enlargement can be an option for the treatment of elderly patients with aortic stenosis accompanied by an annulus that is too small to perform transcatheter aortic valve implantation.

Transcatheter Aortic Valve-in-Valve Procedure in Patients with Bioprosthetic Structural Valve Deterioration

PubMed Central

Reul, Ross M.; Ramchandani, Mahesh K.; Reardon, Michael J.

2017-01-01

Surgical aortic valve replacement is the gold standard procedure to treat patients with severe, symptomatic aortic valve stenosis or insufficiency. Bioprosthetic valves are used for surgical aortic valve replacement with a much greater prevalence than mechanical valves. However, bioprosthetic valves may fail over time because of structural valve deterioration; this often requires intervention due to severe bioprosthetic valve stenosis or regurgitation or a combination of both. In select patients, transcatheter aortic valve replacement is an alternative to surgical aortic valve replacement. Transcatheter valve-in-valve (ViV) replacement is performed by implanting a transcatheter heart valve within a failing bioprosthetic valve. The transcatheter ViV operation is a less invasive procedure compared with reoperative surgical aortic valve replacement, but it has been associated with specific complications and requires extensive preoperative work-up and planning by the heart team. Data from experimental studies and analyses of results from clinical procedures have led to strategies to improve outcomes of these procedures. The type, size, and implant position of the transcatheter valve can be optimized for individual patients with knowledge of detailed dimensions of the surgical valve and radiographic and echocardiographic measurements of the patient's anatomy. Understanding the complexities of the ViV procedure can lead surgeons to make choices during the original surgical valve implantation that can make a future ViV operation more technically feasible years before it is required. PMID:29743998

Rheumatic mitral valve stenosis mimicking advanced lung cancer.

PubMed

von Lueder, Thomas; Steine, Kjetil; Nerdrum, Tone; Steen, Torkel; Bay, Dag; Humerfelt, Sjur; Atar, Dan

2007-09-01

This report describes a patient with a perihilar mass and mediastinal lymphadenopathy mimicking advanced lung cancer. The patient, a 45-year old regular smoker, was admitted to hospital for dyspnea and tachyarrhythmia, and during hospitalization he was diagnosed with severe rheumatic mitral valve stenosis (MVS) and aortic regurgitation as well as pulmonary venous hypertension. Surgical valve replacement and removal of an atrial thrombus was delayed considerably by diagnostic work-up for suspected malignancy. After cardiac surgery had been performed, recovery was uneventful. On follow-up 1 year later, echocardiography showed well-functioning prosthetic mitral and aortic valves, and normal findings on chest X-ray. Perihilar masses and mediastinal lymphadenopathy presented in this case constitute infrequent yet established findings in MVS, resulting from pulmonary venous congestion and hypertension, and focal lymphedema.

Transcatheter aortic valve replacement: historical perspectives, current evidence, and future directions.

PubMed

Horne, Aaron; Reineck, Elizabeth A; Hasan, Rani K; Resar, Jon R; Chacko, Matthews

2014-10-01

Severe aortic stenosis (AS) results in considerable morbidity and mortality without aortic valve replacement and is expected to increase in prevalence with the aging population. Because AS primarily affects the elderly, many patients with comorbidities are poor candidates for surgical aortic valve replacement (SAVR) and may not be referred. Transcatheter aortic valve replacement (TAVR) has emerged as transformative technology for the management of AS over the past decade. Randomized trials have established the safety and efficacy of TAVR with improved mortality and quality of life compared with medical therapy in inoperable patients, while demonstrating noninferiority and even superiority to SAVR among high-risk operative candidates. However, early studies demonstrated an early penalty of stroke and vascular complications with TAVR as well as increased paravalvular leak as compared with SAVR. Two device platforms have been evaluated and approved for use in the United States: the Edwards SAPIEN and the Medtronic CoreValve. Early studies also suggest cost-effectiveness for TAVR. Ongoing studies are evaluating new iterations of the aforementioned TAVR devices, novel device designs, and applications of TAVR in expanded populations of patients including those with lower risk profiles as well as those with comorbidities that were excluded from early clinical trials. Future improvements in TAVR technology will likely reduce periprocedural and long-term complications. Further studies are needed to confirm device durability over long-term follow-up and explore the applicability of TAVR to broader AS patient populations. Copyright © 2014 Mosby, Inc. All rights reserved.

Criteria for determining the need for surgical treatment of tricuspid regurgitation during mitral valve replacement

PubMed Central

2012-01-01

Background Tricuspid regurgitation (TR) is common in patients with mitral valve disease; however, there are no straightforward, rapidly determinably criteria available for deciding whether TR repair should be performed during mitral valve replacement. The aim of our retrospective study was to identify a simple and fast criterion for determining whether TR repair should be performed in patients undergoing mitral valve replacement. Methods We reviewed the records of patients who underwent mitral valve replacement with or without (control) TR repair (DeVega or Kay procedure) from January 2005 to December 2008. Preoperative and 2-year postoperative echocardiographic measurements included right ventricular and atrial diameter, interventricular septum size, TR severity, ejection fraction, and pulmonary artery pressure. Results A total of 89 patients were included (control, n = 50; DeVega, n = 27; Kay, n = 12). Demographic and clinical characteristics were similar between groups. Cardiac variables were similar between the DeVega and Kay groups. Right atrium and ventricular diameter and ejection fraction were significantly decreased postoperatively both in the control and operation (DeVega + Kay) group (P < 0.05). Pulmonary artery pressure was significantly decreased postoperatively in-operation groups (P < 0.05). Our findings indicate that surgical intervention for TR should be considered during mitral valve replacement if any of the following preoperative criteria are met: right atrial transverse diameter > 57 mm; right ventricular end-diastolic diameter > 55 mm; pulmonary artery pressure > 58 mmHg. Conclusions Our findings suggest echocardiography may be used as a rapid and simple means of determining which patients require TR repair during mitral valve replacement. PMID:22443513

Long-term outcome in dogs undergoing mitral valve repair with suture annuloplasty and chordae tendinae replacement.

PubMed

Mizuno, T; Mizukoshi, T; Uechi, M

2013-02-01

Mitral valve repair under cardiopulmonary bypass was performed in three dogs with clinical signs associated with mitral regurgitation that were not controlled by medication. Mitral valve repair comprised circumferential annuloplasty and chordal replacement with expanded polytetrafluoroethylene. One dog died 2 years after surgery because of severe mitral regurgitation resulting from partial circumferential suture detachment. The others survived for over 5 years, but mild mitral valve stenosis persisted in one. The replaced chordae did not rupture in any dog. Mitral valve repair appears to be an effective treatment for mitral regurgitation in dogs. Chordal replacement with expanded polytetrafluoroethylene is a feasible technique, demonstrating long-term durability in dogs. However, mitral annuloplasty techniques need improvement. © 2012 British Small Animal Veterinary Association.

Aortic valve replacement for stenosis with or without coronary artery bypass grafting after 2 previous isolated coronary artery bypass grafting operations

PubMed Central

Lee Henry, Christopher; Ko, Jong Mi; Henry, Albert Carl; Matter, Gregory John

2011-01-01

Aortic valve replacement following an earlier coronary artery bypass grafting (CABG) procedure is fairly common. When this situation occurs, the type of valve dysfunction is usually stenosis (with or without regurgitation), and whether it was missed at the time of the earlier CABG or developed subsequently is usually unclear. We attempted to determine the survival in patients who had had aortic valve replacement after 2 previous CABG procedures. We describe 12 patients who had aortic valve replacement for aortic stenosis; rather than one previous CABG operation, all had had 2 previous CABG procedures. Only one patient died in the early postoperative period after aortic valve replacement, and the remaining 11 were improved substantially: all have lived at least 11 months, and one is still alive at over 101 months after aortic valve replacement. Aortic valve replacement remains beneficial for most patients even after 2 previous CABG procedures. PMID:21307968

Mitral valve disease in patients with Marfan syndrome undergoing aortic root replacement.

PubMed

Kunkala, Meghana R; Schaff, Hartzell V; Li, Zhuo; Volguina, Irina; Dietz, Harry C; LeMaire, Scott A; Coselli, Joseph S; Connolly, Heidi

2013-09-10

Cardiac manifestations of Marfan syndrome include aortic root dilation and mitral valve prolapse (MVP). Only scant data exist describing MVP in patients with Marfan syndrome undergoing aortic root replacement. We retrospectively analyzed data from 166 MFS patients with MVP who were enrolled in a prospective multicenter registry of patients who underwent aortic root aneurysm repair. Of these 166 patients, 9% had mitral regurgitation (MR) grade >2, and 10% had MR grade 2. The severity of MVP and MR was evaluated by echocardiography preoperatively and ≤ 3 years postoperatively. Forty-one patients (25%) underwent composite graft aortic valve replacement, and 125 patients (75%) underwent aortic valve-sparing procedures; both groups had similar prevalences of MR grade >2 (P=0.7). Thirty-three patients (20%) underwent concomitant mitral valve (MV) intervention (repair, n=29; replacement, n=4), including all 15 patients with MR grade >2. Only 1 patient required MV reintervention during follow-up (mean clinical follow-up, 31 ± 10 months). Echocardiography performed 21 ± 13 months postoperatively revealed MR >2 in only 3 patients (2%). One early death and 2 late deaths occurred. Although the majority of patients with Marfan syndrome who undergo elective aortic root replacement have MVP, only 20% have concomitant MV procedures. These concomitant procedures do not seem to increase operative risk. In patients with MR grade ≤ 2 who do not undergo a concomitant MV procedure, the short-term incidence of progressive MR is low; however, more follow-up is needed to determine whether patients with MVP and MR grade ≤ 2 would benefit from prophylactic MV intervention.

Aortic valve replacement during acute rheumatic fever.

PubMed

Khan, A; Chi, S; Gonzalez-Lavin, L

1978-07-01

Emergency aortic valve replacement was performed during an attack of acute rheumatic fever in a 12-year-old black boy. He had an uneventful recovery and has remained asymptomatic 27 months after operation. In the light of this experience and that of others, one might conclude that the decision to operate on these patients should be based on the severity of the haemodynamic derangement rather than on the state of activity in the rheumatic process.

Aortic valve replacement in octogenarians.

PubMed

Bose, Amal K; Aitchison, James D; Dark, John H

2007-07-13

As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR) in octogenarians. 68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37) underwent isolated AVR whilst 46% (31) underwent combined AVR and CABG. Follow up was 100% complete. The mean age was 83.1 +/- s.d. 2.9 years, a mean gradient of 83 +/- s.d. 31 mmHg and mean AVA of 0.56 cm2. The mean additive EuroSCORE was 8.6 +/- s.d. 1.2, the logistic EuroSCORE mean 12.0 +/- s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p < 0.05). Survival was not adversely affected by the addition of coronary artery bypass grafts to aortic valve replacement, the presence of peripheral vascular disease, hypertension or diabetes. In this study duration of cross clamp or bypass time were not found to reach significance as independent predictors of mortality. Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

Cost-Effectiveness of Transcatheter Aortic Valve Replacement With a Self-Expanding Prosthesis Versus Surgical Aortic Valve Replacement

PubMed Central

Reynolds, Matthew R.; Lei, Yang; Wang, Kaijun; Chinnakondepalli, Khaja; Vilain, Katherine A.; Magnuson, Elizabeth A.; Galper, Benjamin Z.; Meduri, Christopher U.; Arnold, Suzanne V.; Baron, Suzanne J.; Reardon, Michael J.; Adams, David H.; Popma, Jeffrey J.; Cohen, David J.

2016-01-01

Background Prior studies of the cost-effectiveness of transcatheter aortic valve replacement (TAVR) have been based primarily on a single balloon-expandable system. Objectives The goal of this study was to evaluate the cost-effectiveness of TAVR with a self-expanding prosthesis compared with surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis and high surgical risk. Methods We performed a formal economic analysis on the basis of individual, patient-level data from the CoreValve U.S. High Risk pivotal trial. Empirical data regarding survival and quality of life (QOL) over 2 years, and medical resource use and hospital costs through 12 months were used to project life expectancy, quality-adjusted life expectancy, and lifetime medical costs in order to estimate the incremental cost-effectiveness of TAVR versus SAVR from a U.S. perspective. Results Relative to SAVR, TAVR reduced initial length of stay an average of 4.4 days, decreased the need for rehabilitation services at discharge, and resulted in superior 1-month QOL. Index admission and projected lifetime costs were higher with TAVR than with SAVR (differences $11,260 and $17,849 per patient, respectively), whereas TAVR was projected to provide a lifetime gain of 0.32 quality-adjusted life-years (QALYs; 0.41 life-years [LYs]) with 3% discounting. Lifetime incremental cost-effectiveness ratios (ICERs) were $55,090 per QALY gained and $43,114 per LY gained. Sensitivity analyses indicated that a reduction in the initial cost of TAVR by ~$1,650 would lead to an ICER <$50,000/QALY gained. Conclusions In a high-risk clinical trial population, TAVR with a self-expanding prosthesis provided meaningful clinical benefits compared with SAVR, with incremental costs considered acceptable by current U.S. standards. With expected modest reductions in the cost of index TAVR admissions, the value of TAVR compared with SAVR in this patient population would become high. PMID:26764063

Society of Thoracic Surgeons Risk Score predicts hospital charges and resource use after aortic valve replacement.

PubMed

Arnaoutakis, George J; George, Timothy J; Alejo, Diane E; Merlo, Christian A; Baumgartner, William A; Cameron, Duke E; Shah, Ashish S

2011-09-01

The impact of Society of Thoracic Surgeons predicted mortality risk score on resource use has not been previously studied. We hypothesize that increasing Society of Thoracic Surgeons risk scores in patients undergoing aortic valve replacement are associated with greater hospital charges. Clinical and financial data for patients undergoing aortic valve replacement at The Johns Hopkins Hospital over a 10-year period (January 2000 to December 2009) were reviewed. The current Society of Thoracic Surgeons formula (v2.61) for in-hospital mortality was used for all patients. After stratification into risk quartiles, index admission hospital charges were compared across risk strata with rank-sum and Kruskal-Wallis tests. Linear regression and Spearman's coefficient assessed correlation and goodness of fit. Multivariable analysis assessed relative contributions of individual variables on overall charges. A total of 553 patients underwent aortic valve replacement during the study period. Average predicted mortality was 2.9% (±3.4) and actual mortality was 3.4% for aortic valve replacement. Median charges were greater in the upper quartile of patients undergoing aortic valve replacement (quartiles 1-3, $39,949 [interquartile range, 32,708-51,323] vs quartile 4, $62,301 [interquartile range, 45,952-97,103], P < .01]. On univariate linear regression, there was a positive correlation between Society of Thoracic Surgeons risk score and log-transformed charges (coefficient, 0.06; 95% confidence interval, 0.05-0.07; P < .01). Spearman's correlation R-value was 0.51. This positive correlation persisted in risk-adjusted multivariable linear regression. Each 1% increase in Society of Thoracic Surgeons risk score was associated with an added $3000 in hospital charges. This is the first study to show that increasing Society of Thoracic Surgeons risk score predicts greater charges after aortic valve replacement. As competing therapies, such as percutaneous valve replacement, emerge to

Outcome of aortic valve replacement for active infective endocarditis in patients on chronic hemodialysis.

PubMed

Dohmen, Pascal M; Binner, Christian; Mende, Meinhart; Bakhtiary, Farhad; Etz, Christian; Pfannmüller, Bettina; Davierwala, Piroze; Borger, Michael A; Misfeld, Martin; Mohr, Friedrich W

2015-02-01

The high risk of morbidity and mortality for patients on hemodialysis who are undergoing cardiac surgery is increased for those with active infective endocarditis (AIE). This retrospective observational single-center study evaluated the impact of chronic hemodialysis on the outcome of aortic valve replacement in patients with aortic AIE. Data were retrospectively collected for consecutive patients undergoing aortic valve surgery for AIE diagnosed according to modified Duke criteria between October 1994 and January 2011. Characteristics and outcomes of patients receiving preoperative chronic hemodialysis were analyzed. Aortic valve AIE was present in 992 patients. Forty-five (4.5%) of the aortic valve AIE patients were receiving long-term hemodialysis preoperatively, 19 of whom (42.2%) had diabetes mellitus. Mean logistic EuroSCORE was 64.2% ± 32.2%. Twenty-four preoperative septic emboli were found in 15 patients. Results of microbiologic cultures were positive in 36 patients, with the major causative organisms identified as Staphylococcus aureus (n = 17) and Enterococcus faecalis (n = 10). Isolated aortic valve replacement was performed in 19 patients (42.2%), and 26 patients (57.8%) underwent concomitant procedures. The mean follow-up was 5.3 ± 5.2 years (range, 0.1 to 17.1 years). Postoperative complications occurred in 30 patients (66.7%). Nineteen patients (42.2%) died within 30 days of surgery, which in 8 patients was attributable to a cardiac cause. In patients receiving chronic hemodialysis who undergo aortic valve replacement for acute AIE, postoperative mortality is high, especially in patients undergoing aortic root replacement or culture-negative AIE. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The impact of the metabolic syndrome on the outcome after aortic valve replacement.

PubMed

Tadic, Marijana; Vukadinovic, Davor; Cvijanovic, Dane; Celic, Vera; Kocica, Mladen; Putnik, Svetozar; Ivanovic, Branislava

2014-10-01

The aim of this study was to examine the influence of the metabolic syndrome on the left ventricular geometry as well as on the early and mid-time outcome in patients with aortic stenosis who underwent aortic valve replacement. The study included 182 patients who underwent aortic valve replacement due to aortic stenosis. The metabolic syndrome was defined by the presence of at least three AHA-NHLB (American Heart Association/National Heart, Lung and Blood Institute) criteria. All the patients were followed for at least 2 years after the surgery. The metabolic syndrome did not influence the severity of aortic stenosis (mean gradient and aortic valve area). However, the metabolic syndrome was associated with the reduced prevalence of the normal left ventricular geometry and the increased risk of concentric left ventricular hypertrophy in patients with aortic stenosis. Among the metabolic syndrome criteria, only increased blood pressure was simultaneously associated with the short-term and mid-term outcome, independently of other risk factors. Increased fasting glucose level was an independent predictor of the only 30-day outcome after the valve replacement. The metabolic syndrome and left ventricular hypertrophy were, independently of hypertension and diabetes, associated with the 30-day outcome, as well as incidence of major cerebrovascular and cardiovascular events in the 2-year postoperative period. The metabolic syndrome does not change severity of the aortic stenosis, but significantly impacts the left ventricular remodeling in these patients. The metabolic syndrome and left ventricular hypertrophy, irrespective of hypertension and diabetes, are predictors of the short-term and mid-term outcome of patients with aortic stenosis who underwent aortic valve replacement.

Mitral-valve repair versus replacement for severe ischemic mitral regurgitation.

PubMed

Acker, Michael A; Parides, Michael K; Perrault, Louis P; Moskowitz, Alan J; Gelijns, Annetine C; Voisine, Pierre; Smith, Peter K; Hung, Judy W; Blackstone, Eugene H; Puskas, John D; Argenziano, Michael; Gammie, James S; Mack, Michael; Ascheim, Deborah D; Bagiella, Emilia; Moquete, Ellen G; Ferguson, T Bruce; Horvath, Keith A; Geller, Nancy L; Miller, Marissa A; Woo, Y Joseph; D'Alessandro, David A; Ailawadi, Gorav; Dagenais, Francois; Gardner, Timothy J; O'Gara, Patrick T; Michler, Robert E; Kron, Irving L

2014-01-02

Ischemic mitral regurgitation is associated with a substantial risk of death. Practice guidelines recommend surgery for patients with a severe form of this condition but acknowledge that the supporting evidence for repair or replacement is limited. We randomly assigned 251 patients with severe ischemic mitral regurgitation to undergo either mitral-valve repair or chordal-sparing replacement in order to evaluate efficacy and safety. The primary end point was the left ventricular end-systolic volume index (LVESVI) at 12 months, as assessed with the use of a Wilcoxon rank-sum test in which deaths were categorized below the lowest LVESVI rank. At 12 months, the mean LVESVI among surviving patients was 54.6±25.0 ml per square meter of body-surface area in the repair group and 60.7±31.5 ml per square meter in the replacement group (mean change from baseline, -6.6 and -6.8 ml per square meter, respectively). The rate of death was 14.3% in the repair group and 17.6% in the replacement group (hazard ratio with repair, 0.79; 95% confidence interval, 0.42 to 1.47; P=0.45 by the log-rank test). There was no significant between-group difference in LVESVI after adjustment for death (z score, 1.33; P=0.18). The rate of moderate or severe recurrence of mitral regurgitation at 12 months was higher in the repair group than in the replacement group (32.6% vs. 2.3%, P<0.001). There were no significant between-group differences in the rate of a composite of major adverse cardiac or cerebrovascular events, in functional status, or in quality of life at 12 months. We observed no significant difference in left ventricular reverse remodeling or survival at 12 months between patients who underwent mitral-valve repair and those who underwent mitral-valve replacement. Replacement provided a more durable correction of mitral regurgitation, but there was no significant between-group difference in clinical outcomes. (Funded by the National Institutes of Health and the Canadian Institutes of

Aortic valve replacement during acute rheumatic fever.

PubMed Central

Khan, A; Chi, S; Gonzalez-Lavin, L

1978-01-01

Emergency aortic valve replacement was performed during an attack of acute rheumatic fever in a 12-year-old black boy. He had an uneventful recovery and has remained asymptomatic 27 months after operation. In the light of this experience and that of others, one might conclude that the decision to operate on these patients should be based on the severity of the haemodynamic derangement rather than on the state of activity in the rheumatic process. Images PMID:687481

[Periodontal microbiota and microorganisms isolated from heart valves in patients undergoing valve replacement surgery in a clinic in Cali, Colombia].

PubMed

Moreno, Sandra; Parra, Beatriz; Botero, Javier E; Moreno, Freddy; Vásquez, Daniel; Fernández, Hugo; Alba, Sandra; Gallego, Sara; Castillo, Gilberto; Contreras, Adolfo

2017-12-01

Periodontitis is an infectious disease that affects the support tissue of the teeth and it is associated with different systemic diseases, including cardiovascular disease. Microbiological studies facilitate the detection of microorganisms from subgingival and cardiovascular samples. To describe the cultivable periodontal microbiota and the presence of microorganisms in heart valves from patients undergoing valve replacement surgery in a clinic in Cali. We analyzed 30 subgingival and valvular tissue samples by means of two-phase culture medium, supplemented blood agar and trypticase soy agar with antibiotics. Conventional PCR was performed on samples of valve tissue. The periodontal pathogens isolated from periodontal pockets were: Fusobacterium nucleatum (50%), Prevotella intermedia/ nigrescens (40%), Campylobacter rectus (40%), Eikenella corrodens (36.7%), Gram negative enteric bacilli (36.7%), Porphyromonas gingivalis (33.3%), and Eubacterium spp. (33.3%). The pathogens isolated from the aortic valve were Propionibacterium acnes (12%), Gram negative enteric bacilli (8%), Bacteroides merdae (4%), and Clostridium bifermentans (4%), and from the mitral valve we isolated P. acnes and Clostridium beijerinckii. Conventional PCR did not return positive results for oral pathogens and bacterial DNA was detected only in two samples. Periodontal microbiota of patients undergoing surgery for heart valve replacement consisted of species of Gram-negative bacteria that have been associated with infections in extraoral tissues. However, there is no evidence of the presence of periodontal pathogens in valve tissue, because even though there were valve and subgingival samples positive for Gram-negative enteric bacilli, it is not possible to maintain they corresponded to the same phylogenetic origin.

Comparison of acute elastic recoil between the SAPIEN-XT and SAPIEN valves in transfemoral-transcatheter aortic valve replacement.

PubMed

Garg, Aatish; Parashar, Akhil; Agarwal, Shikhar; Aksoy, Olcay; Hammadah, Muhammad; Poddar, Kanhaiya Lal; Puri, Rishi; Svensson, Lars G; Krishnaswamy, Amar; Tuzcu, E Murat; Kapadia, Samir R

2015-02-15

The SAPIEN-XT is a newer generation balloon-expandable valve created of cobalt chromium frame, as opposed to the stainless steel frame used in the older generation SAPIEN valve. We sought to determine if there was difference in acute recoil between the two valves. All patients who underwent transfemoral-transcatheter aortic valve replacement using the SAPIEN-XT valve at the Cleveland Clinic were included. Recoil was measured using biplane cine-angiographic image analysis of valve deployment. Acute recoil was defined as [(valve diameter at maximal balloon inflation) - (valve diameter after deflation)]/valve diameter at maximal balloon inflation (reported as percentage). Patients undergoing SAPIEN valve implantation were used as the comparison group. Among the 23 mm valves, the mean (standard deviation-SD) acute recoil was 2.77% (1.14) for the SAPIEN valve as compared to 3.75% (1.52) for the SAPIEN XT valve (P = 0.04). Among the 26 mm valves, the mean (SD) acute recoil was 2.85% (1.4) for the SAPIEN valve as compared to 4.32% (1.63) for the SAPIEN XT valve (P = 0.01). Multivariable linear regression analysis demonstrated significantly greater adjusted recoil in the SAPIEN XT valves as compared to the SAPIEN valves by 1.43% [(95% CI: 0.69-2.17), P < 0.001]. However, the residual peak gradient was less for SAPIEN XT compared to SAPIEN valves [18.86 mm Hg versus 23.53 mm Hg (P = 0.01)]. Additionally, no difference in paravalvular leak was noted between the two valve types (P = 0.78). The SAPIEN XT valves had significantly greater acute recoil after deployment compared to the SAPIEN valves. Implications of this difference in acute recoil on valve performance need to be investigated in future studies. © 2014 Wiley Periodicals, Inc.

The x-ray light valve: a potentially low-cost, digital radiographic imaging system--a liquid crystal cell design for chest radiography.

PubMed

Szeto, Timothy C; Webster, Christie Ann; Koprinarov, Ivaylo; Rowlands, J A

2008-03-01

Digital x-ray radiographic systems are desirable as they offer high quality images which can be processed, transferred, and stored without secondary steps. However, current clinical systems are extraordinarily expensive in comparison to film-based systems. Thus, there is a need for an economical digital imaging system for general radiology. The x-ray light valve (XLV) is a novel digital x-ray detector concept with the potential for high image quality and low cost. The XLV is comprised of a photoconductive detector layer and liquid crystal (LC) cell physically coupled in a sandwich structure. Upon exposure to x rays, charge is collected at the surface of the photoconductor, causing a change in the reflective properties of the LC cell. The visible image so formed can subsequently be digitized with an optical scanner. By choosing the properties of the LC cell in combination with the appropriate photoconductor thickness and bias potentials, the XLV can be optimized for various diagnostic imaging tasks. Specifically for chest radiography, we identified three potentially practical reflective cell designs by selecting from those commonly used in LC display technology. The relationship between reflectance and x-ray exposure (i.e., the characteristic curve) was determined for all three cells using a theoretical model. The results indicate that the reflective electrically controlled birefringence (r-ECB) cell is the preferred choice for chest radiography, provided that the characteristic curve can be shifted towards lower exposures. The feasibility of the shift of the characteristic curve is shown experimentally. The experimental results thus demonstrate that an XLV based on the r-ECB cell design exhibits a characteristic curve suitable for chest radiography.

Repair or Replacement for Isolated Tricuspid Valve Pathology? Insights from a Surgical Analysis on Long-Term Survival

PubMed Central

Farag, Mina; Arif, Rawa; Sabashnikov, Anton; Zeriouh, Mohamed; Popov, Aron-Frederik; Ruhparwar, Arjang; Schmack, Bastian; Dohmen, Pascal M.; Szabó, Gábor; Karck, Matthias; Weymann, Alexander

2017-01-01

Background Long-term follow-up data concerning isolated tricuspid valve pathology after replacement or reconstruction is limited. Current American Heart Association guidelines equally recommend repair and replacement when surgical intervention is indicated. Our aim was to investigate and compare operative mortality and long-term survival in patients undergoing isolated tricuspid valve repair surgery versus replacement. Material/Methods Between 1995 and 2011, 109 consecutive patients underwent surgical correction of tricuspid valve pathology at our institution for varying structural pathologies. A total of 41 (37.6%) patients underwent tricuspid annuloplasty/repair (TAP) with or without ring implantation, while 68 (62.3%) patients received tricuspid valve replacement (TVR) of whom 36 (53%) were mechanical and 32 (47%) were biological prostheses. Results Early survival at 30 days after surgery was 97.6% in the TAP group and 91.1% in the TVR group. After 6 months, 89.1% in the TAP group and 87.8% in the TVR group were alive. In terms of long-term survival, there was no further mortality observed after one year post surgery in both groups (Log Rank p=0.919, Breslow p=0.834, Tarone-Ware p=0.880) in the Kaplan-Meier Survival analysis. The 1-, 5-, and 8-year survival rates were 85.8% for TAP and 87.8% for TVR group. Conclusions Surgical repair of the tricuspid valve does not show survival benefit when compared to replacement. Hence valve replacement should be considered generously in patients with reasonable suspicion that regurgitation after repair will reoccur. PMID:28236633

Reoperations after tricuspid valve repair: re-repair versus replacement

PubMed Central

Hwang, Ho Young; Kim, Kyung-Hwan; Kim, Ki-Bong

2016-01-01

Background Data demonstrating results of reoperation after initial tricuspid valve repair are scarce. We evaluated outcomes of tricuspid reoperations after tricuspid valve repair and compared the results of tricuspid re-repair with those of tricuspid valve replacement (TVR). Methods From 1994 to 2012, 53 patients (56±15 years, male:female =14:39) underwent tricuspid reoperations due to recurrent tricuspid regurgitation (TR) after initial repair. Twenty-two patients underwent tricuspid re-repair (TAP group) and 31 patients underwent TVR (TVR group). Results Early mortality occurred in 6 patients (11%). Early mortality and incidence of postoperative complications were similar between the 2 groups. There were 14 cases of late mortality including 9 cardiac deaths. Five- and 10-year free from cardiac death rates were 82% and 67%, respectively, without any intergroup difference. Recurrent TR (> moderate) developed in 6 TAP group patients and structural valve deterioration occurred in 1 TVR group patient (P=0.002). Isolated tricuspid valve surgery (P=0.044) and presence of atrial fibrillation during the follow-up (P=0.051) were associated with recurrent TR after re-repair. However, the overall tricuspid valve-related event rates were similar between the 2 groups with 5- and 10-year rates of 61% and 41%, respectively. Conclusions Tricuspid valve reoperation after initial repair resulted in high rates of operative mortality and complications. Long-term event-free rate was similar regardless of the type of surgery. However, great care might be needed when performing re-repair in patients with atrial fibrillation and those who had isolated tricuspid valve disease due to high recurrence of TR after re-repair. PMID:26904221

Prosthetic valve sparing aortic root replacement: an improved technique.

PubMed

Leacche, Marzia; Balaguer, Jorge M; Umakanthan, Ramanan; Byrne, John G

2008-10-01

We describe a modified surgical technique to treat patients with a previous history of isolated aortic valve replacement who now require aortic root replacement for an aneurysmal or dissected aorta. This technique consists of replacing the aortic root with a Dacron conduit, leaving intact the previously implanted prosthesis, and re-implanting the coronary arteries in the Dacron graft. Our technique differs from other techniques in that we do not leave behind any aortic tissue remnant and also in that we use a felt strip to obliterate any gap between the old sewing ring and the newly implanted graft. In our opinion, this promotes better hemostasis. We demonstrate that this technique is safe, feasible, and results in acceptable outcomes.

Longevity after aortic root replacement: is the mechanically valved conduit really the gold standard for quinquagenarians?

PubMed

Etz, Christian D; Girrbach, Felix F; von Aspern, Konstantin; Battellini, Roberto; Dohmen, Pascal; Hoyer, Alexandro; Luehr, Maximilian; Misfeld, Martin; Borger, Michael A; Mohr, Friedrich W

2013-09-10

The choice of the best conduit for root/ascending disease and its impact on longevity remain controversial in quinquagenarians. A total of 205 patients (men=155) between 50 and 60 years (mean, 55.7 ± 2.9 years) received either a stentless porcine xenoroot (n=78) or a mechanically valved composite prosthesis (n=127) between February 1998 and July 2011. Of these, 166 patients underwent root replacement for aneurysmal disease (porcine: 39% [n=65]; mechanical: 61% [n=101]; P=0.5), 25 for acute type A aortic dissection (porcine: 32% [n=8]; mechanical: 68% [n=17]; P=0.51), and 14 for endocarditis/iatrogenic injury involving the aortic root (6.4% [n=5] versus 7.1% [n=9]; P=1.0). The predominant aortic valve pathology was stenosis in 19% (n=38), regurgitation in 50% (n=102), combined valvular dysfunction in 26% (n=54), and normal aortic valve function in 5% (n=11). Concomitant procedures included coronary artery bypass grafting (13%), mitral valve repair (7%), and partial/complete arch replacement (12%/4%), with no significant differences between porcine and mechanical root replacement. Overall hospital mortality was 7.3%, with no difference between the 2 types of valve prostheses (7.7% for porcine and 7.1% for mechanical root replacement; P=1.0). Follow-up averaged 5.4 ± 3.7 years (1096 patient-years) and was 100% complete. Freedom from aorta-related reoperation at 12 years was not statistically different between the groups (porcine: 94.9% versus mechanical: 96.1%; P=0.73). Survival was equivalent between both groups, with a 5-year survival of 86 ± 3% (porcine: 88 ± 4%; mechanical: 85 ± 3%; P=0.96) and a 10-year survival of 76% (porcine: 80 ± 7%; mechanical: 75 ± 5%; P=0.84). The linearized mortality rate was 3.1%/patient-year (porcine: 2.9%/patient-year; mechanical: 3.2%/patient-year). In quinquagenerians, long-term survival after stentless porcine xenograft aortic root replacement is equivalent to that after a mechanical Bentall procedure. These results bring

Incidence, Timing, and Predictors of Valve Hemodynamic Deterioration After Transcatheter Aortic Valve Replacement: Multicenter Registry.

PubMed

Del Trigo, Maria; Muñoz-Garcia, Antonio J; Wijeysundera, Harindra C; Nombela-Franco, Luis; Cheema, Asim N; Gutierrez, Enrique; Serra, Vicenç; Kefer, Joelle; Amat-Santos, Ignacio J; Benitez, Luis M; Mewa, Jumana; Jiménez-Quevedo, Pilar; Alnasser, Sami; Garcia Del Blanco, Bruno; Dager, Antonio; Abdul-Jawad Altisent, Omar; Puri, Rishi; Campelo-Parada, Francisco; Dahou, Abdellaziz; Paradis, Jean-Michel; Dumont, Eric; Pibarot, Philippe; Rodés-Cabau, Josep

2016-02-16

Scarce data exist on the incidence of and factors associated with valve hemodynamic deterioration (VHD) after transcatheter aortic valve replacement (TAVR). This study sought to determine the incidence, timing, and predictors of VHD in a large cohort of patients undergoing TAVR. This multicenter registry included 1,521 patients (48% male; 80 ± 7 years of age) who underwent TAVR. Mean echocardiographic follow-up was 20 ± 13 months (minimum: 6 months). Echocardiographic examinations were performed at discharge, at 6 to 12 months, and yearly thereafter. Annualized changes in mean gradient (mm Hg/year) were calculated by dividing the difference between the mean gradient at last follow-up and the gradient at discharge by the time between examinations. VHD was defined as a ≥10 mm Hg increase in transprosthetic mean gradient during follow-up compared with discharge assessment. The overall mean annualized rate of transprosthetic gradient progression during follow-up was 0.30 ± 4.99 mm Hg/year. A total of 68 patients met criteria of VHD (incidence: 4.5% during follow-up). The absence of anticoagulation therapy at hospital discharge (p = 0.002), a valve-in-valve (TAVR in a surgical valve) procedure (p = 0.032), the use of a 23-mm valve (p = 0.016), and a greater body mass index (p = 0.001) were independent predictors of VHD. There was a mild but significant increase in transvalvular gradients over time after TAVR. The lack of anticoagulation therapy, a valve-in-valve procedure, a greater body mass index, and the use of a 23-mm transcatheter valve were associated with higher rates of VHD post-TAVR. Further prospective studies are required to determine whether a specific antithrombotic therapy post-TAVR may reduce the risk of VHD. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Dynamic Course of Serratia marcescens Pulmonic Valve Endocarditis Resulting in Submassive PE and Valve Replacement.

PubMed

Meyer, Chloe Grace; Vacek, Thomas Paul; Bansal, Amit; Gurujal, Ravi; Parikh, Analkumar

2018-01-01

This report illustrates a case of a 42-year-old male with a history of intravenous drug abuse who presented with septic shock. Diagnostic studies, including a transthoracic echocardiogram, chest computed tomography angiography, transesophageal echocardiogram, and blood cultures ultimately revealed Serratia marcescens pulmonic valve infective endocarditis that was treated with intravenous antibiotics. In addition to the rare form of endocarditis and bacterium involved, this case brings into awareness the dynamic nature of the hospital course that requires vigilance in responding to hypotensive episodes for consideration of pulmonary embolism. Surgical valve replacement was opted for due to such a complication in addition to the large size of the vegetation, 2.5 cm.

Aortic valve replacement using continuous suture technique in patients with aortic valve disease.

PubMed

Choi, Jong Bum; Kim, Jong Hun; Park, Hyun Kyu; Kim, Kyung Hwa; Kim, Min Ho; Kuh, Ja Hong; Jo, Jung Ku

2013-08-01

The continuous suture (CS) technique has several advantages as a method for simple, fast, and secure aortic valve replacement (AVR). We used a simple CS technique without the use of a pledget for AVR and evaluated the surgical outcomes. Between October 2007 and 2012, 123 patients with aortic valve disease underwent AVR alone (n=28) or with other concomitant cardiac procedures (n=95), such as mitral, tricuspid, or aortic surgery. The patients were divided into two groups: the interrupted suture (IS) group (n=47), in which the conventional IS technique was used, and the CS group (n=76), in which the simple CS technique was used. There were two hospital deaths (1.6%), which were not related to the suture technique. There were no significant differences in cardiopulmonary bypass time or aortic cross-clamp time between the two groups for AVR alone or AVR with concomitant cardiac procedures. In the IS group, two patients had prosthetic endocarditis and one patient experienced significant perivalvular leak. These patients underwent reoperations. In the CS group, there were no complications related to the surgery. Postoperatively, the two groups had similar aortic valve gradients. The simple CS method is useful and secure for AVR in patients with aortic valve disease, and it may minimize surgical complications, as neither pledgets nor braided sutures are used.

Long-term survival, valve durability, and reoperation for 4 aortic root procedures combined with ascending aorta replacement.

PubMed

Svensson, Lars G; Pillai, Saila T; Rajeswaran, Jeevanantham; Desai, Milind Y; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Thamilarasan, Maran; Roselli, Eric E; Pettersson, Gösta B; Gillinov, A Marc; Navia, Jose L; Smedira, Nicholas G; Sabik, Joseph F; Lytle, Bruce W; Blackstone, Eugene H

2016-03-01

To evaluate long-term results of aortic root procedures combined with ascending aorta replacement for aneurysms, using 4 surgical strategies. From January 1995 to January 2011, 957 patients underwent 1 of 4 aortic root procedures: valve preservation (remodeling or modified reimplantation, n = 261); composite biologic graft (n = 297); composite mechanical graft (n = 156); or allograft root (n = 243). Seven deaths occurred (0.73%), none after valve-preserving procedures, and 13 strokes (1.4%). Composite grafts exhibited higher gradients than allografts or valve preservation, but the latter 2 exhibited more aortic regurgitation (2.7% biologic and 0% mechanical composite grafts vs 24% valve-preserving and 19% allografts at 10 years). Within 2 to 5 years, valve preservation exhibited the least left ventricular hypertrophy, allograft replacement the greatest; however, valve preservation had the highest early risk of reoperation, allograft replacement the lowest. Patients receiving allografts had the highest risk of late reoperation (P < .05), and those receiving composite mechanical grafts and valve preservation had the lowest. Composite bioprosthesis patients had the highest risk of late death (57% at 15 years vs 14%-26% for the remaining procedures, P < .0001), because they were substantially older and had more comorbidities (P < .0001). These 4 aortic root procedures, combined with ascending aorta replacement, provide excellent survival and good durability. Valve-preserving and allograft procedures have the lowest gradients and best ventricular remodeling, but they have more late regurgitation, and likely, less risk of valve-related complications, such as bleeding, hemorrhage, and endocarditis. Despite the early risk of reoperation, we recommend valve-preserving procedures for young patients when possible. Composite bioprostheses are preferable for the elderly. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights

Is mitral valve repair superior to replacement for chronic ischemic mitral regurgitation with left ventricular dysfunction?

PubMed Central

2010-01-01

Background This study was undertaken to compare mitral valve repair and replacement as treatments for ischemic mitral regurgitation (IMR) with left ventricular dysfunction (LVD). Specifically, we sought to determine whether the choice of mitral valve procedure affected survival, and discover which patients were predicted to benefit from mitral valve repair and which from replacement. Methods A total of 218 consecutive patients underwent either mitral valve repair (MVP, n = 112) or mitral valve replacement (MVR, n = 106). We retrospectively reviewed the clinical material, operation methods, echocardiography check during operation and follow-up. Patients details and follow-up outcomes were compared using multivariate and Kaplan-Meier analyses. Results No statistical difference was found between the two groups in term of intraoperative data. Early mortality was 3.2% (MVP 2.7% and MVR 3.8%). At discharge, Left ventricular end-systolic and end-diastolic diameter and left ventricular ejection fraction (LVEF) were improved more in the MVP group than MVR group (P < 0.05), however, in follow-up no statistically significant difference was observed between the MVR and MVP group (P > 0.05). Follow-up mitral regurgitation grade was significantly improved in the MVR group compared with the MVP group (P < 0.05). The Kaplan-Meier survival estimates at 1, 3, and 5 years were simlar between MVP and MVR group. Logistic regression revealed poor survival was associated with old age(#75), preoperative renal insufficiency and low left ventricular ejection fraction (< 30%). Conclusion Mitral valve repair is the procedure of choice in the majority of patients having surgery for severe ischemic mitral regurgitation with left ventricular dysfunction. Early results of MVP treatment seem to be satisfactory, but several lines of data indicate that mitral valve repair provided less long-term benefit than mitral valve replacement in the LVD patients. PMID:21059216

Long-Term Risk for Aortic Complications After Aortic Valve Replacement in Patients With Bicuspid Aortic Valve Versus Marfan Syndrome.

PubMed

Itagaki, Shinobu; Chikwe, Joanna P; Chiang, Yuting P; Egorova, Natalia N; Adams, David H

2015-06-09

Bicuspid aortic valves are associated with valve dysfunction, ascending aortic aneurysm and dissection. Management of the ascending aorta at the time of aortic valve replacement (AVR) in these patients is controversial and has been extrapolated from experience with Marfan syndrome, despite the absence of comparative long-term outcome data. This study sought to assess whether the natural history of thoracic aortopathy after AVR in patients with bicuspid aortic valve disease is substantially different from that seen in patients with Marfan syndrome. In this retrospective comparison, outcomes of 13,205 adults (2,079 with bicuspid aortic valves, 73 with Marfan syndrome, and 11,053 control patients with acquired aortic valve disease) who underwent primary AVR without replacement of the ascending aorta in New York State between 1995 and 2010 were compared. The median follow-up time was 6.6 years. The long-term incidence of thoracic aortic dissection was significantly higher in patients with Marfan syndrome (5.5 ± 2.7%) compared with those with bicuspid valves (0.55 ± 0.21%) and control group patients (0.41 ± 0.08%, p < 0.001). Thoracic aortic aneurysms were significantly more likely to be diagnosed in late follow-up in patients with Marfan syndrome (10.8 ± 4.4%) compared with those with bicuspid valves (4.8 ± 0.8%) and control group patients (1.4 ± 0.2%) (p < 0.001). Patients with Marfan syndrome were significantly more likely to undergo thoracic aortic surgery in late follow-up (10.4 ± 4.3%) compared with those with bicuspid valves (2.5 ± 0.6%) and control group patients (0.50 ± 0.09%) (p < 0.001). The much higher long-term rates of aortic complications after AVR observed in patients with Marfan syndrome compared with those with bicuspid aortic valves confirm that operative management of patients with bicuspid aortic valves should not be extrapolated from Marfan syndrome and support discrete treatment algorithms for these different clinical entities

Posterior leaflet preservation during mitral valve replacement for rheumatic mitral stenosis.

PubMed

Djukić, P L; Obrenović-Kirćanski, B B; Vranes, M R; Kocica, M J; Mikić, A Dj; Velinović, M M; Kacar, S M; Kovacević, N S; Parapid, B J

2006-01-01

Mitral valve replacement with posterior leaflet preservation was shown beneficial for postoperative left vetricular (LV) performance in patients with mitral regurgitation. Some authors find it beneficial even for the long term LV function. We investigated a long term effect of this technique in patients with rheumatic mitral stenosis. We studied 20 patents with mitral valve replacement due to rheumatic mitral stenosis, in the period from January 1988 to December 1989. In group A (10 patients) both leaflets and coresponding chordal excision was performed, while in group B (10 patients) the posterior leaflet was preserved. In all patients a Carbomedics valve was inserted. We compared clinical pre and postoperative status, as well as hemodynamic characteristics of the valve and left ventricle in both groups. Control echocardiographyc analysis included: maximal (PG) and mean (MG) gradients; effective valve area (AREA); telediastolic (TDV) and telesystolic (TSV) LV volume; stroke volume (SV); ejection fraction (EF); fractional shortening (FS) and segmental LV motion. The mean size of inserted valve was 26.6 in group A and 27.2 in group B. Hemodynamic data: PG (10.12 vs 11.1); MG (3.57 vs 3.87); AREA (2.35 vs 2.30); TDV 126.0 vs 114.5); TSV (42.2 vs 36.62); SV (83.7 vs 77.75); EF (63.66 vs 67.12); FS (32.66 vs 38.25). Diaphragmal segmental hypokinesis was evident in one patient from group A and in two patients from group B. In patients with rheumatic stenosis, posterior leaflet preservation did not have increased beneficial effect on left ventricular performance during long-term follow-up. An adequate posterior leaflet preservation does not change hemodynamic valvular characteristics even after long-term follow-up.

[Experimental investigation of laser plasma soft X-ray source with gas target].

PubMed

Ni, Qi-liang; Gong, Yan; Lin, Jing-quan; Chen, Bo; Cao, Jian-lin

2003-02-01

This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

Aortic valve replacement and concomitant right coronary artery bypass grafting performed via a right minithoracotomy approach.

PubMed

Mihos, Christos G; Santana, Orlando; Pineda, Andres M; La Pietra, Angelo; Lamelas, Joseph

2014-01-01

We present our experience of concomitant right coronary artery bypass grafting (CABG) and aortic valve replacement performed via a right minithoracotomy in patients with coronary lesions not amenable to percutaneous intervention. A total of 17 patients underwent concomitant aortic valve replacement and right CABG between April 2008 and July 2013. A 5- to 6-cm minithoracotomy incision was made over the right second or third intercostal space, and the costochondral cartilage was transected. A saphenous vein bypass to the right coronary artery was then performed, initiating the anastomosis from the toe of the graft. Subsequently, the aortic valve was replaced using standard techniques. There were 6 men and 11 women. The median European System for Cardiac Operative Risk Evaluation II score mortality risk was 5% [interquartile range (IQR), 2%-8%]. The mean (SD) age was 77 (10) years, the left ventricular ejection fraction was 59% (8%), and the New York Heart Association functional class was 2.4 (0.8). One patient had a history of CABG. The mean (SD) cardiopulmonary bypass time was 168 (57) minutes, and the aortic cross-clamp time was 133 (36) minutes. Three patients underwent concomitant mitral valve surgery (replacement, 2; repair, 1). The median intensive care unit and hospital lengths of stay were 47 hours (IQR, 24-90) and 9 days (IQR, 5-13), respectively. There was one reoperation for bleeding, and there was one postoperative stroke. All patients were alive at a mean (SD) follow-up of 2 (1.1) years. Aortic valve replacement with concomitant CABG performed via a right minithoracotomy approach is feasible.

Hemodynamic deterioration after aortic valve replacement in a patient with mixed systemic amyloidosis.

PubMed

Seki, Tatsuya; Hattori, Atsuo; Yoshida, Toshihito

2017-08-01

We report a case of hemodynamic deterioration after aortic valve replacement in a patient with mixed systemic amyloidosis. A 77-year-old male with severe aortic valve stenosis and 19 years hemodialysis underwent aortic valve replacement. Postoperatively, the patient died of hemodynamic deterioration. Autopsy findings showed massive, whole-body edema and mixed systemic amyloidosis (dialysis-related and AA amyloidosis). Clinical and autopsy findings implied that hemodynamic deterioration was caused by increased vascular permeability. The amyloid deposit to the vessel causes inflammatory changes and increases vascular permeability. Mixed systemic amyloidosis occurs very rarely and could increases vascular permeability even more than each single type of amyloidosis. Systemic amyloidosis may be a risk factor for hemodynamic deterioration after cardiac surgery. Patients with longtime hemodialysis and a history associated with dialysis-related amyloidosis would have at least single systemic amyloidosis, which should be considered a contraindication to cardiac surgery with cardiopulmonary bypass.

Percutaneous closure of acute aorto-right ventricular fistula following transcatheter bicuspid aortic valve replacement.

PubMed

Nakamura, Kenta; Passeri, Jonathan J; Inglessis-Azuaje, Ignacio

2017-07-01

We report a case of acute aorto-right ventricular fistula following transcatheter bicuspid aortic valve replacement and subsequent percutaneous closure. The diagnosis and treatment of this rare complication is illustrated through multi-modality imaging. We hypothesize that the patient's heavily calcified bicuspid aortic valve anatomy led to asymmetric deployment of the transcatheter aortic valve replacement (TAVR) prosthesis, traumatizing the right sinus of Valsalva at the distal edge of the TAVR stent and ultimately fistulized to the right ventricle. The patient acutely decompensated with heart failure five days after TAVR and underwent emergent intervention. The aorto-right ventricular fistula was closed using an 18-mm septal occluder device with marked clinical recovery. Transcatheter closure is a viable treatment option for acute aorto-right ventricular fistula. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement.

PubMed

Huenges, Katharina; Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed.

Aortic cusp extension valvuloplasty with or without tricuspidization in children and adolescents: long-term results and freedom from aortic valve replacement.

PubMed

Polimenakos, Anastasios C; Sathanandam, Shyam; Elzein, Chawki; Barth, Mary J; Higgins, Robert S D; Ilbawi, Michel N

2010-04-01

Aortic cusp extension valvuloplasty is increasingly used in the management of children and adolescents with aortic stenosis or regurgitation. The durability of this approach and the freedom from valve replacement are not well defined. A study was undertaken to investigate outcomes. From July 1987 to November 2008, 142 patients aged less than 19 years underwent aortic cusp extension valvuloplasty in the form of pericardial cusp extension and tricuspidization (when needed). Three patients with truncus arteriosus and severe truncal valve insufficiency were excluded. From the available follow-up data of 139 patients, 50 had bicuspid aortic valves, 40 had congenital aortic valve stenosis, 41 had combined congenital aortic valve stenosis/insufficiency, and 8 had other diagnoses. Median follow-up was 14.4 years (0.1-21.4). Long-term mortality and freedom from aortic valve replacement were studied. There were no early, intermediate, or late deaths. Z-values of left ventricular end-diastolic dimension, aortic annulus, aortic sinus diameter, and sinotubular junction diameter before aortic valve replacement were 4.2 +/- 3.11, 2.3 +/- 1.25, 4.4 +/- 1.23, and 1.84 +/- 1.28, respectively. During the follow-up period, 64 patients underwent aortic valve reinterventions. The Ross procedure was performed in 32 of 139 patients (23%) undergoing aortic cusp extension valvuloplasty. Other aortic valve replacements were undertaken after 16 aortic cusp extension valvuloplasties (11.5%). Freedom from a second aortic cusp extension valvuloplasty or aortic valve replacement at 18 years was 82.1% +/- 4.2% and 60.0% +/- 7.2%, respectively. Aortic cusp extension valvuloplasty is a safe and effective surgical option with excellent survival and good long-term outcomes in children and adolescents. The procedure provides acceptable durability and satisfactory freedom from aortic valve replacement. Copyright 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights

Illness Perception Profiles and Their Association with 10-Year Survival Following Cardiac Valve Replacement.

PubMed

Crawshaw, Jacob; Rimington, Helen; Weinman, John; Chilcot, Joseph

2015-10-01

The aim of the present study was to examine whether profiles of illness perceptions are associated with 10-year survival following cardiac valve replacement surgery. Illness perceptions were evaluated in 204 cardiac patients awaiting first-time valve replacement and again 1 year post-operatively using cluster analysis. All-cause mortality was recorded over a 10-year period. At 1 year, 136 patients were grouped into one of four profiles (stable positive, stable negative, changed from positive to negative, changed from negative to positive). The median follow-up was 3063 days (78 deaths). After controlling for clinical covariates, including markers of function, patients who changed illness perceptions from positive to negative beliefs 1 year post-surgery had an increased mortality risk (hazard ratio (HR) = 3.2, 95% confidence interval (CI) 1.2-8.3, p = .02) compared to patients who held positive stable perceptions. Following cardiac valve replacement, developing negative illness perceptions over the first post-operative year predicts long-term mortality. Early screening and intervention to alter this pattern of beliefs may be beneficial.

Handbook of X-Ray Astronomy

NASA Technical Reports Server (NTRS)

Arnaud, Keith A. (Editor); Smith, Randall K.; Siemiginowska, Aneta

2011-01-01

X-ray astronomy was born in the aftermath of World War II as military rockets were repurposed to lift radiation detectors above the atmosphere for a few minutes at a time. These early flights detected and studied X-ray emission from the Solar corona. The first sources beyond the Solar System were detected during a rocket flight in 1962 by a team headed by Riccardo Giaccom at American Science and Engineering, a company founded by physicists from MIT. The rocket used Geiger counters with a system designed to reduce non-X-ray backgrounds and collimators limiting the region of sky seen by the counters. As the rocket spun, the field of view (FOV) happened to pass over what was later found to be the brightest non-Solar X-ray source; later designated See X-1. It also detected a uniform background glow which could not be resolved into individual sources. A follow-up campaign using X-ray detectors with better spatial resolution and optical telescopes identified See X-1 as an interacting binary with a compact (neutron star) primary. This success led to further suborbital rocket flights by a number of groups. More X-ray binaries were discovered, as well as X-ray emission from supernova remnants, the radio galaxies M87 and Cygnus-A, and the Coma cluster. Detectors were improved and Geiger counters were replaced by proportional counters, which provided information about energy spectra of the sources. A constant challenge was determining precise positions of sources as only collimators were available.

Twin Valve Caval Stent for Functional Replacement of Incompetent Tricuspid Valve: A Feasibility Animal Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sochman, Jan, E-mail: jan.sochman@medicon.cz; Peregrin, Jan H., E-mail: jape@medicon.cz; Pavcnik, Dusan, E-mail: pavcnikd@ohsu.edu

Objective: To evaluate feasibility of a twin valve caval stent (TVCS) for functional replacement of an incompetent tricuspid valve (TV) in an acute animal study. Methods: One swine and three sheep were used in the study. TVCS placement was tested in a swine with a normal TV. TVCS function was tested in three sheep with TV regurgitation created by papillary muscle avulsion. Cardiac angiograms and pressure measurements were used to evaluate TVCS function. Two sheep were studied after fluid overload. Results: TVCS was percutaneously placed properly at the central portions of the superior vena cava (SVC) and inferior vena cavamore » (IVC) in the swine. Papillary muscle avulsion in three sheep caused significant tricuspid regurgitation with massive reflux into the right atrium (RA) and partial reflux into the SVC and IVC. TVCS placement eliminated reflux into the SVC and IVC. After fluid overload, there was enlargement of the right ventricle and RA and significant increase in right ventricle, RA, SVC, and IVC pressures, but no reflux into the IVC and SVC. Conclusion: The results of this feasibility study justify detailed evaluation of TVCS insertion for functional chronic replacement of incompetent TV.« less

The valve choice in tricuspid valve replacement: 25 years of experience.

PubMed

Van Nooten, G J; Caes, F L; François, K J; Taeymans, Y; Primo, G; Wellens, F; Leclerq, J L; Deuvaert, F E

1995-01-01

This study reviews 146 consecutive patients who underwent tricuspid valve replacement (TVR) with 69 bioprostheses (porcine and bovine pericardial) and 77 mechanical ball, disc or bileaflet valves between 1967 and 1987. The mean age was 51.4 +/- 12.1 years. Preoperatively, 97% were in New York Heart Association (NYHA) functional class III or more and over 40% had undergone previous cardiac surgery. Hospital mortality was high (16.1%). Incremental risk factors for hospital death were preoperative icterus (P < 0.01), hepatomegaly (P = 0.02), NYHA functional class IV (P = 0.02) and male sex (P = 0.04) (univariate analysis). Ninety-eight percent of the hospital survivors were followed up for a mean of 92 months. Cumulative follow-up added up to 955 patient-years. There were 70 late deaths. The actuarial survival rate was 74% at 60 months and less than 25% at 14 years. Incremental risk factors for late death indicated by univariate analysis were the type of tricuspid prosthesis (Smel-off-Cutter and Kay-Shiley prostheses) (P = 0.04), the type of operative myocardial protection (normothermia and coronary perfusion) (P = 0.05) and preoperative NYHA functional class IV (P = 0.05). We conclude that TVR carries a high operative risk and poor long-term survival, both influenced by preoperative and perioperative variables. Bearing in mind the poor prognosis for TVR, we prefer a large-sized bioprosthesis, in view of its initial good durability and low risk of valve-related events. However, in patients with good life expectancy, a bileaflet mechanical prosthesis may be an acceptable alternative.

Bioprosthetic Valve Fracture to Facilitate Transcatheter Valve-in-Valve Implantation.

PubMed

Allen, Keith B; Chhatriwalla, Adnan K; Cohen, David J; Saxon, John T; Aggarwal, Sanjeev; Hart, Anthony; Baron, Suzanne; Davis, J Russell; Pak, Alex F; Dvir, Danny; Borkon, A Michael

2017-11-01

Valve-in-valve transcatheter aortic valve replacement is less effective in small surgical bioprostheses. We evaluated the feasibility of bioprosthetic valve fracture with a high-pressure balloon to facilitate valve-in-valve transcatheter aortic valve replacement. In vitro bench testing on aortic tissue valves was performed on 19-mm and 21-mm Mitroflow (Sorin, Milan, Italy), Magna and Magna Ease (Edwards Lifesciences, Irvine, CA), Trifecta and Biocor Epic (St. Jude Medical, Minneapolis, MN), and Hancock II and Mosaic (Medtronic, Minneapolis, MN). High-pressure balloons Tru Dilation, Atlas Gold, and Dorado (C.R. Bard, Murray Hill, NJ) were used to determine which valves could be fractured and at what pressure fracture occurred. Mitroflow, Magna, Magna Ease, Mosaic, and Biocor Epic surgical valves were successfully fractured using high-pressures balloon 1 mm larger than the labeled valve size whereas Trifecta and Hancock II surgical valves could not be fractured. Only the internal valve frame was fractured, and the sewing cuff was never disrupted. Manufacturer's rated burst pressures for balloons were exceeded, with fracture pressures ranging from 8 to 24 atmospheres depending on the surgical valve. Testing further demonstrated that fracture facilitated the expansion of previously constrained, underexpanded transcatheter valves (both balloon and self-expanding) to the manufacturer's recommended size. Bench testing demonstrates that the frame of most, but not all, bioprosthetic surgical aortic valves can be fractured using high-pressure balloons. The safety of bioprosthetic valve fracture to optimize valve-in-valve transcatheter aortic valve replacement in small surgical valves requires further clinical investigation. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement

PubMed Central

Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed. PMID:29552039

Cold crystalloid versus warm blood cardioplegia in patients undergoing aortic valve replacement.

PubMed

Nardi, Paolo; Vacirca, Sara R; Russo, Marco; Colella, Dionisio F; Bassano, Carlo; Scafuri, Antonio; Pellegrino, Antonio; Melino, Gerry; Ruvolo, Giovanni

2018-03-01

Myocardial protection techniques during cardiac arrest have been extensively investigated in the clinical setting of coronary revascularization. Fewer studies have been carried out of patients affected by left ventricular hypertrophy, where the choice of type and temperature of cardioplegia remain controversial. We have retrospectively investigated myocardial injury and short-term outcome in patients undergoing aortic valve replacement plus or minus coronary artery bypass grafting with using cold crystalloid cardioplegia (CCC) or warm blood cardioplegia (WBC). From January 2015 to October 2016, 191 consecutive patients underwent aortic valve replacement plus or minus coronary artery bypass grafting in normothermic cardiopulmonary bypass. Cardiac arrest was obtained with use of intermittent antegrade CCC group (n=32) or WBC group (n=159), according with the choice of the surgeon. As compared with WBC group, in CCC group creatine-kinase-MB (CK-MB), cardiac troponin I (cTnI), aspartate aminotransferase (AST) release, and their peak levels, were lower during each time points of evaluation, with the greater statistically significant difference at time 0 (P<0.05, for all comparisons). A time 0, CK-MB/CK ratio >10% was 5.9% in CCC group versus 7.8% in WBC group (P<0.0001). At time 0 CK-MB/CK ratio >10% in patients undergoing isolated aortic valve replacement was 6.0% in CCC group versus 8.0% in WBC group (P<0.01). No any difference was found in perioperative myocardial infarction (0% versus 3.8%), postoperative (PO) major complications (15.6% versus 16.4%), in-hospital mortality (3.1% versus 1.3%). In aortic valve surgery a significant decrease of myocardial enzymes release is observed in favor of CCC, but this difference does not translate into different clinical outcome. However, this study suggests that in presence of cardiac surgical conditions associated with significant left ventricular hypertrophy, i.e., the aortic valve disease, a better myocardial protection can

Mitral annular calcification in patients undergoing aortic valve replacement for aortic valve stenosis.

PubMed

Takami, Yoshiyuki; Tajima, Kazuyoshi

2016-02-01

Limited data exis t on clinical relevance of aortic valve stenosis (AVS) and mitral annular calcification (MAC), although with similar pathophysiologic basis. We sought to reveal the prevalence of MAC and its clinical features in the patients undergoing aortic valve replacement (AVR) for AVS. We reviewed 106 consecutive patients who underwent isolated AVR from 2004 to 2010. Before AVR, CT scans were performed to identify MAC, whose severity was graded on a scale of 0-4, with grade 0 denoting no MAC and grade 4 indicating severe MAC. Echocardiography was performed before AVR and at follow-up over 2 years after AVR. MAC was identified in 56 patients with grade 1 (30 %), 2 (39 %), 3 (18 %), and 4 (13 %), respectively. Patients with MAC presented older age (72 ± 8 versus 66 ± 11 years), higher rate of dialysis-dependent renal failure (43 versus 4 %), and less frequency of bicuspid aortic valve (9 versus 36 %), when compared to those without MAC. No significant differences were seen in short- and mid-term mortality after AVR between the groups. In patients with MAC, progression of neither mitral regurgitation nor stenosis was observed at follow-up of 53 ± 23 months for 102 survivors, although the transmitral flow velocities were higher than in those without MAC. In conclusion, MAC represented 53 % of the patients undergoing isolated AVR for AVS, usually appeared in dialysis-dependent elder patients with tricuspid AVS. MAC does not affect adversely upon the survival, without progression of mitral valve disease, at least within 2 years after AVR.

Percutaneous Transcatheter Mitral Valve Replacement: Patient-specific Three-dimensional Computer-based Heart Model and Prototyping.

PubMed

Vaquerizo, Beatriz; Theriault-Lauzier, Pascal; Piazza, Nicolo

2015-12-01

Mitral regurgitation is the most prevalent valvular heart disease worldwide. Despite the widespread availability of curative surgical intervention, a considerable proportion of patients with severe mitral regurgitation are not referred for treatment, largely due to the presence of left ventricular dysfunction, advanced age, and comorbid illnesses. Transcatheter mitral valve replacement is a promising therapeutic alternative to traditional surgical valve replacement. The complex anatomical and pathophysiological nature of the mitral valvular complex, however, presents significant challenges to the successful design and implementation of novel transcatheter mitral replacement devices. Patient-specific 3-dimensional computer-based models enable accurate assessment of the mitral valve anatomy and preprocedural simulations for transcatheter therapies. Such information may help refine the design features of novel transcatheter mitral devices and enhance procedural planning. Herein, we describe a novel medical image-based processing tool that facilitates accurate, noninvasive assessment of the mitral valvular complex, by creating precise three-dimensional heart models. The 3-dimensional computer reconstructions are then converted to a physical model using 3-dimensional printing technology, thereby enabling patient-specific assessment of the interaction between device and patient. It may provide new opportunities for a better understanding of the mitral anatomy-pathophysiology-device interaction, which is of critical importance for the advancement of transcatheter mitral valve replacement. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

[Short and long term results of aortic valve replacement in patients 80 years of age and older].

PubMed

Mortasawi, A; Gehle, S; Yaghmaie, M; Schröder, T; Ennker, I C; Rosendahl, U; Albert, A; Ennker, J

2001-03-01

Due to demographic changes in average life expectancy the age of patients undergoing cardiac surgery is increasing as well. We have reviewed the short- and long-term outcome in patients over 80 years of age after aortic valve replacement with or without concomitant coronary grafting. From 1.1.1995 until 31.12.1999, 126 patients (93 women, 33 men between 80 and 89 years, 82.8 +/- 2.4) underwent aortic valve replacement. 64 patients (group A) received isolated valve replacement, 62 (group B) underwent myocardial revascularization as well. The 30-day hospital mortality rate was 6.3% for group A and 14.5% for group B. The follow-up time ranged between 3 and 63 months (32 +/- 16). None of the patients had to be reoperated for prosthetic valve dysfunction or endocarditis. Bleeding complications due to anticoagulation therapy were observed by one patient from group A 3 years after the operation. Of the 15 deaths during the follow-up period seven (47%) were cardiac in nature and two (13%) related to stroke. Acturial survival rates for group A were 89%, 85% and 77% at 1, 2 and 3 years, and for group B 76%, 72% and 70%. Permanent nursing care was not required 1 year after the operation by 100% of patients in group A (2 years: 98%, 3 years 95%) and by 100% of patients in group B (2 years: 93%, 3 years: 90%). At an interval of 1 year after the operation 96% of patients in group A had not been hospitalized as a result of cardiac disorders (2 years: 96%, 3 years: 94%). The rates for group B were 88%, 81% and 75%. Compared with younger age groups, aortic valve replacement in patients 80 years of age and older is associated with a distinctly increased mortality and morbidity. However, our data suggest that considering the poor prognosis of conservative therapy of symptomatic aortic valve disease, functional status as well as life expectancy in this age group seem to be positively influenced by aortic valve replacement.

Midterm results after aortic valve replacement with freehand stentless xenografts: a comparison of three prostheses.

PubMed

Luciani, G B; Bertolini, P; Vecchi, B; Mazzucco, A

1998-06-01

The ideal substitute for the diseased aortic valve is yet to be found. For the assessment and comparison of the midterm results after aortic valve replacement with three different types of freehand stentless xenografts, all patients who underwent the operation between October 1992 and April 1997 were reviewed. Of 231 patients undergoing aortic valve replacement, 106 patients (group 1) were given the Biocor PSB (Biocor Industria e Pesquisa Ltda, Belo Horizonte, MG, Brazil); 76 patients (group 2) were given the Toronto SPV (St. Jude Medical, Inc., St. Paul, Minn.), and 49 patients (group 3) were given the O'Brien-Angell valve (Bravo Cardiovascular model 300, Cryolife, Inc., Marietta, Ga.). The first two xenografts require inflow and outflow suturelines; the third xenograft needs a single-sutureline implantation. Mean age (70 +/- 6 years; 70 +/- 7 years; 72 +/- 9 years; p = 0.6), prevalence of male sex (56 patients, 53%; 37 patients, 49%; 22 patients, 45%; p = 0.7), of aortic stenosis (72 patients, 68%; 54 patients, 71%; 37 patients, 73%; p = 0.6), and need for associated procedures (51 patients, 48%; 30 patients, 40%; 21 patients, 43%; p = 0.1) were comparable among groups. Mean aortic crossclamp time was shorter in group 3 (96 +/- 24 minutes; 100 +/- 23 minutes; 88 +/- 25 minutes;p = 0.01). Early deaths were 3 of 106 (3%) in group 1, 2 of 76 (3%) in group 2, and 2 of 49 (4%) in group 3. Follow-up of survivors ranged from 1 to 54 months (mean 32 +/- 13 months). Survival at 4 years was 90% +/- 3% in group 1, 95% +/- 3% in group 2, 85% +/- 8% in group 3 (p = 0.3). At 4 years, freedom from valve-related events was 95% +/- 6%, 100%, 70% +/- 8% (p = 0.004), while freedom from valve deterioration was 99% +/- 1%, 100%, 73% +/- 8% (p = 0.001), in group 1, 2, and 3, respectively (p = 0.001). At follow-up, reintervention on the xenograft was necessary in one patient (endocarditis) in group 1, none in group 2, and six in group 3 (technical cause, group 3; valve tear, group 2

Computerized system for the follow-up of patients with heart valve replacements.

PubMed

Bain, W H; Fyfe, I C; Rodger, R A

1985-04-01

A system is described which will accept, store, retrieve and analyze information on large numbers of patients who undergo valve replacement surgery. The purpose of the database is to yield readily available facts concerning the patient's clinical course, prosthetic valve function, length of survival, and incidence of complications. The system uses the Apple Macintosh computer, which is one of the current examples of small, desk-top microprocessors. The software for the input, editing and analysis programs has been written by a professional software writer in close collaboration with a cardiac surgeon. Its content is based on 8 years' experience of computer-based valve follow-up. The system is inexpensive and has proved easy to use in practice.

Late-term results of mitral valve replacement with St. Jude Medical mechanical valve prosthesis: Samsun experience.

PubMed

Demirag, Mustafa Kemal; Keceligil, Hasan Tahsin; Kolbakir, Fersat

2006-10-01

We have reported the short- and long-term results of mitral valve replacement in this article. Mitral valve replacement was conducted in 276 patients in our clinic between January 1989 and March 2005. The youngest patient was 4 years old and the oldest patient was 74 years old. Mean age was 40.08 +/- 1.06 y. Of these patients, 41.3% were men and 58.7% were women. The reason for operation was mitral stenosis in 96 patients (34.78%), mitral insufficiency in 78 patients (29.26%) and mitral stenosis plus mitral insufficiency in 102 patients (36.96%). The aetiology of mitral valve lesions was acute rheumatic fever in 208 patients (75.36%). The aetiology of mitral valve lesions was degenerative in 37 patients (13.41%), ischaemic in 23 patients (8.33%) and congenital in 8 patients (2.9%). In the 5, 10 and 15-year periods, the actual survival rates were 87.64% +/- 2.02%, 83.35% +/- 2.38% and 68.19% +/- 5.63%, respectively. Thromboembolism was observed in 38 patients (13.77%). The rates of actual freedom from thromboembolism in the 5, 10 and 15-year periods were 93.08% +/- 1.53%, 88.48% +/- 1.99% and 81.06% +/- 3.43%, respectively. Of the 276 patients who had been observed for 15 years, 5 had (1.81%) valvular thrombosis. The rates of actual freedom from valvular thrombosis in the 5, 10 and 15-year periods were 98.89% +/- 0.64%, 98.04% +/- 0.87% and 98.04% +/- 0.87%, respectively. In the 15-year period, 23 patients (8.33%) had haemorrhage due to anti-coagulation. The rates of actual freedom from haemorrhage due to anti-coagulation in the 5, 10 and 15-year periods were 95.64% +/- 1.23%, 93.40% +/- 1.56% and 87.73% +/- 2.96%, respectively. Seven patients (2.54%) had prosthetic valvular endocarditis. The rates of actual freedom from endocarditis in the 5, 10 and 15-year periods were 98.51% +/- 0.74%, 97.60% +/- 0.97% and 97.01% +/- 1.13%, respectively. Nine patients (3.27%) were re-operated. The rates of actual freedom from re-operation in the 5, 10 and 15-year periods were 97

Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

PubMed Central

Xu, Tong-yi; Zhang, Zhi-gang; Li, Xin; Han, Lin; Xu, Zhi-yun

2014-01-01

Background Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. Methods We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically. Findings Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen

78 FR 20103 - Radiation Protection Guidance for Diagnostic and Interventional X-Ray Procedures

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-03

... for Diagnostic and Interventional X-Ray Procedures AGENCY: Environmental Protection Agency (EPA... for Diagnostic and Interventional X-Ray Procedures. This document is Federal Guidance Report No. 14. It replaces Federal Guidance Report No. 9, ``Radiation Protection Guidance for Diagnostic X-rays...

Comparison between transcatheter and surgical aortic valve replacement: a single-center experience.

PubMed

Silberman, Shuli; Abu Akr, Firas; Bitran, Daniel; Almagor, Yaron; Balkin, Jonathan; Tauber, Rachel; Merin, Ofer

2013-07-01

A comparison was made of the outcomes after transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (AVR) in high-risk patients. All patients aged > 75 years that underwent a procedure for severe aortic stenosis with or without coronary revascularization at the authors' institution were included in the study; thus, 64 patients underwent TAVI and 188 underwent AVR. Patients in the TAVI group were older (mean age 84 +/- 5 versus 80 +/- 4 years; p < 0.0001) and had a higher logistic EuroSCORE (p = 0.004). Six patients (9%) died during the procedure in the TAVI group, and 23 (12%) died in the AVR group (p = 0.5). Predictors for mortality were: age (p < 0.0001), female gender (p = 0.02), and surgical valve replacement (p = 0.01). Gradients across the implanted valves at one to three months postoperatively were lower in the TAVI group (p < 0.0001). Actuarial survival at one, two and three years was 78%, 64% and 64%, respectively, for TAVI, and 83%, 78% and 75%, respectively, for AVR (p = 0.4). Age was the only predictor for late mortality (p < 0.0001). TAVI patients were older and posed a higher predicted surgical risk. Procedural mortality was lower in the TAVI group, but mid-term survival was similar to that in patients undergoing surgical AVR. Age was the only predictor for late survival. These data support the referral of high-risk patients for TAVI.

Emergency aortic valve replacement and Caesarian section in a primigravida with severe aortic stenosis: a case report.

PubMed

Kochhar, Puneet K; Zutshi, V; Shamsunder, S; Batra, S; Ghosh, P

2011-01-01

Congenital bicuspid aortic valve with severe aortic stenosis (AS) is a rare condition (3-6% of patients with congenital heart disease). Pregnancy in these patients carries a high risk of maternal and fetal mortality. With advancing gestational age, these women may develop cardiac failure due to increased cardiorespiratory requirements. When medical therapy proves insufficient, cardiac surgery becomes mandatory to save the patient's life. Balloon valvuloplasty is only palliative treatment, the duration of benefit being only 6 months. Valve replacement is thus recommended. Cardiopulmonary bypass (CPB) surgery with valve replacement has been reported to carry a lower risk of maternal mortality (1.5-13%) but a very high fetal risk (16-40%). This paper reports the case of a 30-year-old primigravida with severe AS with bicuspid aortic valve and pulmonary congestion clinically uncontrolled, in whom CPB surgery and aortic valve replacement was performed as an emergency procedure, along with a lower segment Caesarian section. The outcome of unrelieved severe symptomatic AS in pregnancy is poor. Multidisciplinary management is important to avoid deterioration in cardiac performance in parturients with severe AS. CPB during pregnancy carries a high risk to the fetus. Therefore, open heart surgery during pregnancy should be advised only in extreme emergencies (ie, heart failure refractory to conventional therapy).

A dynamic model-based approach to motion and deformation tracking of prosthetic valves from biplane x-ray images.

PubMed

Wagner, Martin G; Hatt, Charles R; Dunkerley, David A P; Bodart, Lindsay E; Raval, Amish N; Speidel, Michael A

2018-04-16

Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure in which a prosthetic heart valve is placed and expanded within a defective aortic valve. The device placement is commonly performed using two-dimensional (2D) fluoroscopic imaging. Within this work, we propose a novel technique to track the motion and deformation of the prosthetic valve in three dimensions based on biplane fluoroscopic image sequences. The tracking approach uses a parameterized point cloud model of the valve stent which can undergo rigid three-dimensional (3D) transformation and different modes of expansion. Rigid elements of the model are individually rotated and translated in three dimensions to approximate the motions of the stent. Tracking is performed using an iterative 2D-3D registration procedure which estimates the model parameters by minimizing the mean-squared image values at the positions of the forward-projected model points. Additionally, an initialization technique is proposed, which locates clusters of salient features to determine the initial position and orientation of the model. The proposed algorithms were evaluated based on simulations using a digital 4D CT phantom as well as experimentally acquired images of a prosthetic valve inside a chest phantom with anatomical background features. The target registration error was 0.12 ± 0.04 mm in the simulations and 0.64 ± 0.09 mm in the experimental data. The proposed algorithm could be used to generate 3D visualization of the prosthetic valve from two projections. In combination with soft-tissue sensitive-imaging techniques like transesophageal echocardiography, this technique could enable 3D image guidance during TAVR procedures. © 2018 American Association of Physicists in Medicine.

A 20-year study on treating childhood infective endocarditis with valve replacement in a single cardiac center in China.

PubMed

Xiao, Jian; Yin, Liang; Lin, Yiyun; Zhang, Yufeng; Wu, Lihui; Wang, Zhinong

2016-07-01

Children with infective endocarditis (IE) have to undergo valve replacement instead of valve repair in China due to severe valve damage. The present study is to review our experience on surgical treatment of children with IE in reference to the incidence, pathologic status, diagnosis, surgical strategies and outcomes. We reviewed 35 patients with a mean age of 13.7±2.2 years who were underwent valve replacement surgery for IE during the period from January 1993 to December 2013. Preoperative transthoracic echocardiographic (TTE) evaluation and transesophageal echocardiography during operation were performed in all patients. All the children underwent chart review and retrospective risk-hazard analysis. Among the patients surveyed congenital cardiac lesions were present in 15 (42.8%), rheumatic heart valve disease in 2 (5.7%) and previous heart surgery in 2 (5.7%). The median stay of intensive care unit was 6 days. Intraoperative findings showed that the endocarditis involved mostly the mitral and aortic valves (88.5%). Triple or quadruple valve involvement was found in one patient each. Ten-year freedom from IE-related death and re-intervention was 94.2% and 91.6%, respectively. Children undergoing surgery for IE frequently have advanced disease with embolic complications. Although valve replacement is not the primary option for pediatric IE, the rate of 5-year survival and freedom from re-operation was optimal prognostically. Pediatric physicians should pay attention to the common clinical features of IE so that the native valve is preserved well.

Acute gastrointestinal bleeding following aortic valve replacement in a patient with Heyde's sindrome. Case report.

PubMed

De Palma, G D; Salvatori, F; Masone, S; Simeoli, I; Rega, M; Celiento, M; Persico, G

2007-09-01

A 58-year old man was admitted to the hospital because of melena. He had a 1-year history of mechanical aortic valve replacement and coronary stent placement because of myocardial infarction and he was taking warfarin and clopidogrel. Esophagogastroduodenoscopy and colonoscopy were negative for bleeding. Capsule endoscopy showed bleeding diffuse angiodysplasia of the small bowel. The patient was treated with octreotide 20 mg, at monthly interval. After 25 months there had been no recurrence of gastrointestinal bleeding. The case suggests that mechanical valve replacement may not prevent gastrointestinal bleeding in Heyde syndrome and that octreotide treatment should be considered in these cases.

Double-arterial cannulation for aortic valve replacement with porcelain aorta.

PubMed

De Paulis, Ruggero; Maselli, Daniele; Scaffa, Raffaele; Nardella, Saverio

2009-10-01

We describe a new technique of aortic valve replacement (AVR) in patients with porcelain aorta. Three patients (mean age 75 years) were treated. The cardiopulmonary bypass (CPB) was established after side-graft right axillary artery and direct femoral artery cannulation. Venous drainage was obtained by atrio-caval cannulation. The procedures were performed in mild hypothermia (30 degrees C). Cerebral perfusion was carried out by clamping the innominate artery and all epiaortic vessels. The aorta was endoclamped by a Foley balloon inserted into the isthmus. The aorta was then opened longitudinally for 10 cm to expose and replace the aortic valve. Near-infra-red spectroscopy (NIRS) and bilateral radial artery pressure were used to monitor effective cerebral perfusion. Operative mortality was absent. The mean time of CPB was 73 min. NIRS-derived tissue oxygenation was maintained above 55%. Postoperative course was uneventful. This technique has several advantages: first, the cannulation of right axillary and the common femoral artery allows simultaneous cerebral and systemic perfusion. Second, any form of cross-clamp is avoided and the aorta is occluded away from the epiaortic vessels. Third, there is an increased freedom to choose the best place for aortotomy.

Novel valve replacement with an extracellular matrix scaffold in an infant with single ventricle physiology.

PubMed

Guariento, Alvise; Burke, Redmond; Fedrigo, Marny; Angelini, Annalisa; Maschietto, Nicola; Vida, Vladimiro; Thiene, Gaetano; Stellin, Giovanni; Padalino, Massimo

2016-01-01

Valve replacement in children with functionally univentricular hearts remains challenging. The absence of small prostheses, the lack of growth, and the need for anticoagulation limit these procedures. We describe a 1-year follow-up of an extracellular matrix scaffold tube used as systemic atrio-ventricular valve in an infant. Copyright © 2015 Elsevier Inc. All rights reserved.

Injuries to the Aorta, Aortic Annulus, and Left Ventricle During Transcatheter Aortic Valve Replacement: Management and Outcomes.

PubMed

Langer, Nathaniel B; Hamid, Nadira B; Nazif, Tamim M; Khalique, Omar K; Vahl, Torsten P; White, Jonathon; Terre, Juan; Hastings, Ramin; Leung, Diana; Hahn, Rebecca T; Leon, Martin; Kodali, Susheel; George, Isaac

2017-01-01

The experience with transcatheter aortic valve replacement is increasing worldwide; however, the incidence of potentially catastrophic cardiac or aortic complications has not decreased. In most cases, significant injuries to the aorta, aortic valve annulus, and left ventricle require open surgical repair. However, the transcatheter aortic valve replacement patient presents a unique challenge as many patients are at high or prohibitive surgical risk and, therefore, an open surgical procedure may not be feasible or appropriate. Consequently, prevention of these potentially catastrophic injuries is vital, and practitioners need to understand when open surgical repair is required and when alternative management strategies can be used. The goal of this article is to provide an overview of current management and prevention strategies for major complications involving the aorta, aortic valve annulus, and left ventricle. © 2016 American Heart Association, Inc.

Purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies of great cormorant (Phalacrocorax carbo) haemoglobin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jagadeesan, G.; Malathy, P.; Gunasekaran, K.

2014-10-25

The great cormorant hemoglobin has been isolated, purified and crystallized and the three dimensional structure is solved using molecular replacement technique. Haemoglobin is the iron-containing oxygen-transport metalloprotein that is present in the red blood cells of all vertebrates. In recent decades, there has been substantial interest in attempting to understand the structural basis and functional diversity of avian haemoglobins. Towards this end, purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies have been carried out on cormorant (Phalacrocorax carbo) haemoglobin. Crystals were grown by the hanging-drop vapour-diffusion method using PEG 3350, NaCl and glycerol as precipitants. The crystals belonged to themore » trigonal system P3{sub 1}21, with unit-cell parameters a = b = 55.64, c = 153.38 Å, β = 120.00°; a complete data set was collected to a resolution of 3.5 Å. Matthews coefficient analysis indicated that the crystals contained a half-tetramer in the asymmetric unit.« less

Multicenter Analysis of Clinical Follow-Ups in Patients with a Star GK Cardiac Valve Replacement for More than One Year.

PubMed

Li, Mingwen; Xiao, Yingbin; Chen, Daozhong; Liu, Liming; Ma, Liming; Wang, Pingfan; Jia, Kui; Yang, Kai; Chen, Lin

2016-05-18

Star GK valves were widely used in China, and we studied the clinical follow-up results of patients with Star GK valve implants for more than one year.  Clinical data were collected from those patients who had Star GK valve implants for over one year. Patients were divided into three groups: (1) AVR group: received aortic valve replacement surgery. Based on the valve model this group was further sub-divided into two groups: 21A group, and 23A group; (2) MVR group: received mitral valve replacement surgery. Based on the valve model this group was further sub-divided into three groups: 25M group, 27M group, and 29M group; (3) DVR group: received combined replacement surgeries including AVR + MVR. According to postoperative follow-up time these patients were divided into two groups: 1-year group and 3-year group. Follow-up data were collected by telephone, outpatient visits, or correspondence. Clinical data were aggregated by professional data scientists to conduct independent analyses.  959 patients were included in the study following Star GK valve implant. Follow-up after 1 year found that thrombosis occurred in 4 cases, hemorrhage in 15 cases, left heart failure in 13 cases, paravalvular leakage in 5 cases, and death due to cardiac causes in 2 cases.  The long-term efficacy of Star GK valve implants was satisfactory with low incidence of valve-related complications, and following Star GK valve implant, valve and blood were highly compatible and blood component damage was minor. Very low incidence rate of thrombosis was observed following Star GK valve implant, however, attention should be paid to adjust the anticoagulation intensity.

Monitoring X-Ray Emission from X-Ray Bursters

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Kaaret, Philip

1999-01-01

The scientific goal of this project was to monitor a selected sample of x-ray bursters using data from the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer together with data from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory to study the long-term temporal evolution of these sources in the x-ray and hard x-ray bands. The project was closely related to "Long-Term Hard X-Ray Monitoring of X-Ray Bursters", NASA project NAG5-3891, and and "Hard x-ray emission of x-ray bursters", NASA project NAG5-4633, and shares publications in common with both of these. The project involved preparation of software for use in monitoring and then the actual monitoring itself. These efforts have lead to results directly from the ASM data and also from Target of Opportunity Observations (TOO) made with the Rossi X-Ray Timing Explorer based on detection of transient hard x-ray outbursts with the ASM and BATSE.

Special functions of valve organs of blood-sucking female mosquitoes

NASA Astrophysics Data System (ADS)

Kim, Boheum; Lee, Sangjoon

2010-11-01

Food-feeding insects usually have valve organs to regulate the sucking flow effectively. Female mosquitoes sucking lots of blood instantaneously have a unique valve system between two pumping organs located in their head. The valve system seems to prevent reverse flow and to grind granule particles such as red blood cells. To understand the functional characteristics of this valve organ in detail, the volumetric flow rate passing through the valves and their interaction with the two-pumps need to be investigated. However, it is very difficult to observe the dynamic behaviors of pumping organs and valve system. In this study, the dynamic motions of valve organs of blood-sucking female mosquitoes were observed under in vivo condition using synchrotron X-ray micro imaging technique. X-ray micro computed tomography was also employed to examine the three-dimensional internal structure of the blood pumping system including valve organs.

[Experience of Mitral Valve Replacement Using a Pulmonary Autograft (Ross II Operation) in an Infant;Report of a Case].

PubMed

Kawahito, Tomohisa; Egawa, Yoshiyasu; Yoshida, Homare; Shimoe, Yasushi; Onishi, Tatsuya; Miyagi, Yuhichi; Terada, Kazuya; Ohta, Akira

2015-07-01

A 24-day-old boy suddenly developed progressive heart failure and was transported to our hospital. Echocardiography showed massive mitral regurgitation due to chordal rupture. Mitral valve repair was performed at 28 days of life, but postoperative valvular function was not satisfactory. A mechanical valve was implanted in the supra-annular position at 37 days of life. Two months after valve replacement, the mechanical valve was suddenly stuck. Emergent redo valve replacement was performed, but the prosthetic valve became stuck again 2 months after the 3rd operation, despite sufficient anti-coagulation therapy. At the 4th operation (6 months after birth), we implanted a pulmonary autograft in the mitral position instead of another mechanical valve in an emergent operation. The right ventricular outflow tract was reconstructed with a valved conduit. A postoperative catheter examination, which was performed 1 year after the Ross II operation, showed mild mitral stenosis with no regurgitation. Previous reports of Ross II operations in infants are rare and long-term results are unknown. However, we advocate that this procedure should be a rescue operation for mitral valve dysfunction in the early period of infants.

Multi-physics 3D computational study of leaflet thrombus formation following surgical and transcatheter aortic valve replacement

NASA Astrophysics Data System (ADS)

Vahidkhah, Koohyar; Abbasi, Mostafa; Barakat, Mohammed; Dvir, Danny; Azadani, Ali

2017-11-01

An increasingly recognized complication following surgical/transcatheter aortic valve replacement is thrombosis or blood clot formation on replacement valve leaflets. A predisposing factor in thrombus formation on biomaterial surfaces of a bioprosthetic heart valve is blood stasis. Longer residence time of blood provides an opportunity for platelets and agonists to accumulate to critical concentrations that leads to platelet activation and then thrombosis. In this study, we have developed a fluid-solid interaction (FSI) modeling approach, to quantify blood stasis on the leaflets of bioprosthetic aortic valves with different design operating in a patient-specific geometry. We have validated our FSI model against experimental measurements of valve opening/closing as well as in-vitro particle image velocimetry. We have also embedded in our method a model for transport of platelets and agonists (ADP, TxA2, and thrombin) and their interactions that result in platelets activation and adhesion to biomaterial bioprosthetic surfaces. We have provided quantitative evidence for the correlation between long residence of blood on bioprosthetic aortic valve leaflets and formation of high thrombogenicity risk regions on the leaflets that are characterized by accumulation of activated platelet.

Two-photon x-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stohr, J.

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Two-photon x-ray diffraction

DOE PAGES

Stohr, J.

2017-01-11

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Impact of preoperative atrial fibrillation on mortality and cardiovascular outcomes of mechanical mitral valve replacement for rheumatic mitral valve disease.

PubMed

Wang, Bin; Xu, Zhi-yun; Han, Lin; Zhang, Guan-xin; Lu, Fang-lin; Song, Zhi-gang

2013-03-01

The prognostic significance of preoperative atrial fibrillation on mitral valve replacement remains unclear. The aim of this study was to explore the effects of the presence of preoperative atrial fibrillation on mortality and cardiovascular outcomes of mitral valve replacement for rheumatic valve disease. A retrospective analysis was performed on a total of 793 patients who underwent mitral valve replacement with or without tricuspid valve repair in our hospital. The patients selected were divided into two groups according to preoperative rhythm status. Patients with preoperative atrial fibrillation were assigned to the AF group, while patients in preoperative sinus rhythm were assigned to the SR group. Postoperative follow-up was performed by outpatient visits, as well as by telephone and written correspondence. Data gathered included survivorship, postoperative complications, left ventricular function and tricuspid regurgitation. For patients with atrial fibrillation vs those in sinus rhythm, there was no difference in postoperative mortality and morbidity. Follow-up was a mean of 8.6 ± 2.4 years. For patients with preoperative atrial fibrillation, 10-year survival from a Kaplan-Meier curve was 88.7%, compared with 96.6% in patients with preoperative sinus rhythm (P = 0.002). Multivariate analysis identified low left ventricular ejection fraction, older age, large left atrium and preoperative atrial fibrillation as significant adverse predictors for overall survival. Freedom from thromboembolism complications at 13 years was lower for patients with preoperative atrial fibrillation without maze procedure and left atrial appendage ligation, compared with that for patients with preoperative sinus rhythm without maze procedure and left atrial appendage ligation, and patients with concomitant maze procedure and left atrial appendage ligation (76.3 vs 94.8 vs 94.0%, respectively; P = 0.001). On echocardiography, the proportion of patients with significant tricuspid

Conscious Sedation Versus General Anesthesia in Transcatheter Aortic Valve Replacement: The German Aortic Valve Registry.

PubMed

Husser, Oliver; Fujita, Buntaro; Hengstenberg, Christian; Frerker, Christian; Beckmann, Andreas; Möllmann, Helge; Walther, Thomas; Bekeredjian, Raffi; Böhm, Michael; Pellegrini, Costanza; Bleiziffer, Sabine; Lange, Rüdiger; Mohr, Friedrich; Hamm, Christian W; Bauer, Timm; Ensminger, Stephan

2018-03-26

The aims of this study were to report on the use of local anesthesia or conscious sedation (LACS) and general anesthesia in transcatheter aortic valve replacement and to analyze the impact on outcome. Transcatheter aortic valve replacement can be performed in LACS or general anesthesia. Potential benefits of LACS, such as faster procedures and shorter hospital stays, need to be balanced with safety. A total of 16,543 patients from the German Aortic Valve Registry from 2011 to 2014 were analyzed, and propensity-matched analyses were performed to correct for potential selection bias. LACS was used in 49% of patients (8,121 of 16,543). In hospital, LACS was associated with lower rates of low-output syndrome, respiratory failure, delirium, cardiopulmonary resuscitation, and death. There was no difference in paravalvular leakage (II+) between LACS and general anesthesia in the entire population (5% vs. 4.8%; p = 0.76) or in the matched population (3.9% vs. 4.9%, p = 0.13). The risk for prolonged intensive care unit stay (≥3 days) was significantly reduced with LACS (odds ratio: 0.82; 95% confidence interval [CI]: 0.73 to 0.92; p = 0.001). Thirty-day mortality was lower with LACS in the entire population (3.5% vs. 4.9%; hazard ratio [HR]: 0.72; 95% CI: 0.60 to 0.86; p < 0.001) and in the matched population (2.8% vs. 4.6%; HR: 0.6; 95% CI: 0.45 to 0.8; p < 0.001). However, no differences in 1-year mortality between both groups in the entire population (16.5% vs. 16.9%; HR: 0.93; 95% CI: 0.85 to 1.02; p = 0.140) and in the propensity-matched population (14.1% vs. 15.5%; HR: 0.90; 95% CI: 0.78 to 1.03; p = 0.130) were observed. Use of LACS in transcatheter aortic valve replacement is safe, with fewer post-procedural complications and lower early mortality, suggesting its broad application. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Long-term results of aortic valve replacement with Edwards Prima Plus stentless bioprosthesis: eleven years' follow up.

PubMed

Auriemma, Stefano; D'Onofrio, Augusto; Brunelli, Massimo; Magagna, Paolo; Paccanaro, Mariemma; Rulfo, Fanny; Fabbri, Alessandro

2006-09-01

The Edwards Lifesciences Prima Plus stentless valve (ELSV) is a bioprosthesis manufactured from a porcine aortic root. The study aim was to evaluate late clinical outcomes after aortic valve replacement (AVR) with ELSV implanted as a miniroot in patients with aortic valve disease. Between 1993 and 2004, 318 patients (232 males, 86 females; mean age 69 +/- 9 years; range: 37-83 years) underwent AVR with the ELSV. Preoperatively, 102 patients (32%), 162 (51%) and 54 (17%) were in NYHA classes I/II, III and IV, respectively. Aortic stenosis, aortic regurgitation and combined lesions were present in 124 patients (39%), 114 (36%) and 41 (13%), respectively. Twenty patients (6%) were referred for an acute aortic dissection, 20 (6%) for an aortic root aneurysm, and 139 (44%) had an associated aneurysmal dilatation of the ascending aorta. The ascending aorta was replaced in 159 patients (50%); aortic arch replacement was required in 10 (3%). Coronary artery bypass graft was performed in 86 patients (27%). The follow up was based on clinical data. Operative mortality was 5% (n = 17). There were 49 late deaths (5.2%/pt-yr). Valve-related mortality occurred in 10 patients (1%/pt-yr). Actuarial survival at five and 10 years was 78% and 33%, respectively. Actuarial freedom from valve reoperation and structural valve deterioration at 10 years were 100% and 64%. Actuarial freedom from embolic events and endocarditis at 10 years were 84% and 81%, respectively. The ELSV, when implanted as a miniroot, provided good early and long-term results in terms of survival and freedom from major complications.

Percutaneous Closure of 2 Paravalvular Leaks and a Gerbode Defect after Mitral Valve Replacement for Infective Endocarditis.

PubMed

Peñalver, Jorge; Shatila, Wassim; Silva, Guilherme V

2017-04-01

Surgical valve replacement after infective endocarditis can result in local destructive paravalvular lesions. A 30-year-old woman with infective endocarditis underwent mitral valve replacement that was complicated postoperatively by 2 paravalvular leaks. During percutaneous closure of the leaks, a Gerbode defect was also found and closed. We discuss our patient's case and its relation to others in the relevant medical literature. To our knowledge, we are the first to describe the use of a percutaneous approach to close concomitant paravalvular leaks and a Gerbode defect.

Implementation of transcatheter aortic valve replacement in California: Influence on aortic valve surgery.

PubMed

Maximus, Steven; Milliken, Jeffrey C; Danielsen, Beate; Shemin, Richard; Khan, Junaid; Carey, Joseph S

2018-04-01

Transcatheter aortic valve replacement (TAVR) procedures were introduced in 2011. Initially, procedures were limited to patients who were not surgical candidates, but subsequently high-risk surgical candidates were considered for TAVR. The influence on aortic valve surgery in California is unknown. The California Office of Statewide Health Planning and Development hospitalized patient discharge database was queried for the years 2009 through 2014. isolated surgical aortic valve and aortic valve/coronary artery bypass graft (SAVR) and TAVR procedures were identified by International Classification of Diseases-9th revision clinical modification procedure codes. Seven TAVR programs were introduced in 2011, 12 in 2012, 3 in 2013, and 6 in 2014. SAVR procedure volumes were compared from the 2 years before institution with SAVR volumes during the year(s) after institution of the TAVR program in these 28 hospitals. Overall, surgical volumes increased during the first, second, and third years after implementation of TAVR procedures. Among 7 hospitals with 4-year programs, surgical volumes increased to a maximum of 15.5% during the third year, then began to decrease. The hospital performing the largest number of TAVR procedures showed a marked decrease in SAVR volume by the fourth year, suggesting a shift of SAVR candidates to TAVR. Among all hospitals with 4-year programs, TAVR exceeded SAVR procedures by the fourth year. In California overall, SAVR increased during 2011 through 2013, due primarily to increasing volume of isolated SAVR procedures. Statewide, isolated SAVR increased from a yearly average of 3111 procedures during 2009-2010 to 3592 (+15.5%) in 2013, then decreased slightly in 2014. SAVR plus coronary artery bypass graft procedures decreased during the same time period. After implementation of TAVR, hospital SAVR volumes increased moderately, then began to decrease by the fourth year, when TAVR volume exceeded SAVR. Surgical candidates may be identified

X-ray filter for x-ray powder diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.

Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and wallsmore » defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.« less

Coronary artery compression by teflon pledget granuloma following aortic valve replacement.

PubMed

Cohle, S D; Delavan, J W

1997-09-01

We describe a massive fatal posterior myocardial infarct resulting from compression of the right coronary artery by a Teflon pledget granuloma in a patient who had undergone aortic valve replacement six months before death. Other iatrogenic causes of coronary artery occlusion or compression are discussed in this paper. To our knowledge this is the first report of this surgical complication.

Minimally invasive aortic valve replacement – pros and cons of keyhole aortic surgery

PubMed Central

Szałański, Przemysław; Zembala, Michał; Filipiak, Krzysztof; Karolak, Wojciech; Wojarski, Jacek; Garbacz, Marcin; Kaczmarczyk, Aleksandra; Kwiecień, Anna; Zembala, Marian

2015-01-01

Over the last twenty years, minimally invasive aortic valve replacement (MIAVR) has evolved into a safe, well-tolerated and efficient surgical treatment option for aortic valve disease. It has been shown to reduce postoperative morbidity, providing faster recovery and rehabilitation, shorter hospital stay and better cosmetic results compared with conventional surgery. A variety of minimally invasive accesses have been developed and utilized to date. This concise review demonstrates and discusses surgical techniques used in contemporary approaches to MIAVR and presents the most important results of MIAVR procedures. PMID:26336491

X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yennawar, Hemant; Møller, Magda; University of Copenhagen, DK-2100 Copenhagen

The X-ray crystal structure and a small-angle X-ray scattering solution structure of sheep liver sorbitol dehydrogenase have been determined. The details of the interactions that enable the tetramer scaffold to be the functional biological unit have been analyzed. The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer that superposes well with that seen in hSDH (despite belonging to a different space group) and obeying the 222 crystalmore » symmetry is seen in slSDH. An acetate molecule is bound in the active site, coordinating to the active-site zinc through a water molecule. Glycerol, a substrate of slSDH, also occupies the substrate-binding pocket together with the acetate designed by nature to fit large polyol substrates. The substrate-binding pocket is seen to be in close proximity to the tetramer interface, which explains the need for the structural integrity of the tetramer for enzyme activity. Small-angle X-ray scattering was also used to identify the quaternary structure of the tetramer of slSDH in solution.« less

Regional Systems of Care to Optimize Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

PubMed

Stub, Dion; Lauck, Sandra; Lee, May; Gao, Min; Humphries, Karin; Chan, Albert; Cheung, Anson; Cook, Richard; Della Siega, Anthony; Leipsic, Jonathon; Charania, Jay; Dvir, Danny; Latham, Tim; Polderman, Jopie; Robinson, Simon; Wong, Daniel; Thompson, Christopher R; Wood, David; Ye, Jian; Webb, John

2015-12-28

This study sought to describe the development of a multicenter, transcatheter aortic valve replacement program and regional systems of care intended to optimize coordinated, efficient, and appropriate delivery of this new therapy. Transcatheter aortic valve replacement (TAVR) has become an accepted treatment option for patients with severe aortic stenosis who are at high surgical risk. Regional systems of care have led to improvements in outcomes for patients undergoing intervention for myocardial infarction, cardiac arrest, and stroke. We implemented a regional system of care for patients undergoing TAVR in British Columbia, Canada. We describe a prospective observational cohort of 583 patients who underwent TAVR in British Columbia between 2012 and 2014. Regionalization of TAVR care in British Columbia refers to a centrally coordinated, funded, and evaluated program led by a medical director and a multidisciplinary advisory group that oversees planning, access to care, and quality of outcomes at the 4 provincial sites. Risk-stratified case selection for transfemoral TAVR is performed by heart teams at each site on the basis of consensus provincial indications. Referrals for lower volume and more complicated TAVR, including nontransfemoral access and valve-in-valve procedures, are concentrated at a single site. In-hospital and 30-day outcomes are reported. The median age was 83 years (interquartile range [IQR]: 78 to 87 years) and median STS score was 6% (IQR: 4% to 8%). Transfemoral access was performed in 499 (85.6%) cases and nontransfemoral in 84 (14.4%). Transcatheter valve-in-valve procedures in for failed bioprosthetic valves were performed in 43 patients (7.4%). A balloon-expandable valve was inserted in 386 (66.2%) and a self-expanding valve in 189 (32.4%). All-cause 30-day mortality was 3.5%. All-cause in-hospital mortality and disabling stroke occurred in 3.1% and 1.9%, respectively. Median length of stay was 3 days (IQR: 3 to 6 days), with 92.8% of

Ground Calibration of the Astro-H (Hitomi) Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Eckart, M. E.; Adams, J. S.; Boyce, K. R.; Brown, G. V.; Chiao, Meng P.; Fujimoto, R. J.; Haas, D.; Den Herder, J. W.; Ishisaki, Y.; Kelley, R. L.;

[Electroacupuncture intervention combined with general anesthesia for 80 cases of heart valve replacement surgery under cardiopulmonary bypass].

PubMed

Chi, Hao; Zhou, Wen-Xiong; Wu, Yao-Yao; Chen, Tong-Yu; Ge, Wen; Yuan, Lan; Shen, Wei-Dong; Zhou, Jia

2014-02-01

To determine whether electroacupuncture (EA) intervention combined with general anesthesia (GA) strategy can reduce early post-operative morbidity and medical costs in patients undergoing heart valve replacement operation under cardiopulmonary bypass. A total of 160 heart valve replacement surgery patients undergoing cardiopulmonary bypass were randomly divided into GA and EA + GA groups (n = 80 in each group). Patients of the GA group were given with intravenous injection of Fentanyl, Midazolam, Vecuronium Bromide, etc. and routine tracheal intubation. EA (3-4 Hz, 2.0-2.2 mA) was applied to bilateral Zhongfu (LU 1), Chize (LU 5) and Ximen (PC 4) beginning about 20 mm before the surgery in the EA + GA group. Endotracheal intubation was not employed but only prepared as a standby for patients of the EA + GA group. The dosage of narcotic drugs, duration of surgery, duration of aertic blockage, rate of cardiac re-beating, volumes of post-operative blood transfusion, discharge volume, cases of post-operative pulmonary infection, vocal cord injury, and the time of first bed-off, first eating and duration in intensive care unit (IOU) residence. etc. were recorded. The successful rates of heart valve replacement surgery were similar in both GA and EA + GA groups. Compared with the GA group, the dosages of Fentanyl, Midazolam and Vecuronium of the EA + GA group were significantly lower (P < 0.05, P < 0.01), the numbers of patients needing blood-transfusion, antibiotics treatment, and suffering from pulmonary infection were fewer, the time of first bed-off and duration of hospitalizetion and IOU residence were considerably shorter (P < 0.05, P < 0.01) and the total medical cost was obviously lower (P < 0.05) in the EA + GA group. EA combined with general anesthesia strategy for heart valve replacement surgery without endotracheal intubation is safe and can reduce post-operative morbidity and medical costs in patients undergoing heart valve replacement surgery under

Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience

PubMed Central

2011-01-01

Objectives To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React® BioConduit) implanted using the Bentall procedure over ten years in a single centre. Methods Between 27/10/99 and 19/01/08, the No-React® BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from questionnaires. A cohort of patients had 2D-echocardiogram with an average of 4.3 ± 0.45 years post-operatively to evaluate valve function, calcification, and the diameter of the conduit. Results Implantation in 67 patients represented a follow-up of 371.3 patient-year. Males were 60% of the operated population, with a mean age of 67.9 ± 1.3 years (range 34.1-83.8 years), 21 of them below the age of 65. After a mean follow-up of 7.1 ± 0.3 years (range of 2.2-10.5 years), more than 50% of the survivors were in NYHA I/II and more than 60% of the survivors were angina-free (CCS 0). The overall 10-year survival following replacement of the aortic valve and root was 51%. During this period, 88% of patients were free from valved-conduit related complications leading to mortality. Post-operative echocardiography studies showed no evidence of stenosis, dilatation, calcification or thrombosis. Importantly, during the 10-year follow-up period no failures of the valved conduit were reported, suggesting that the tissue of the conduit does not structurally change (histology of one explant showed normal cusp and conduit). Conclusions The No-React® BioConduit composite stentless aortic valved conduit provides excellent long-term clinical results for aortic root replacement with few prosthesis-related complications in the first post-operative decade. PMID:21699696

Contemporary Costs Associated With Transcatheter Aortic Valve Replacement: A Propensity-Matched Cost Analysis.

PubMed

Ailawadi, Gorav; LaPar, Damien J; Speir, Alan M; Ghanta, Ravi K; Yarboro, Leora T; Crosby, Ivan K; Lim, D Scott; Quader, Mohammed A; Rich, Jeffrey B

2016-01-01

The Placement of Aortic Transcatheter Valve (PARTNER) trial suggested an economic advantage for transcatheter aortic valve replacement (TAVR) for high-risk patients. The purpose of this study was to evaluate the cost effectiveness of TAVR in the "real world" by comparing TAVR with surgical aortic valve replacement (SAVR) in intermediate-risk and high-risk patients. A multiinstitutional database of The Society of Thoracic Surgeons (STS) (2011 to 2013) linked with estimated cost data was evaluated for isolated TAVR and SAVR operations (n = 5,578). TAVR-treated patients (n = 340) were 1:1 propensity matched with SAVR-treated patients (n = 340). Patients undergoing SAVR were further stratified into intermediate-risk (SAVR-IR: predicted risk of mortality [PROM] 4% to 8%) and high-risk (SAVR-HR: PROM >8%) cohorts. Median STS PROM for TAVR was 6.32% compared with 6.30% for SAVR (SAVR-IR 4.6% and SAVR-HR 12.4%). A transfemoral TAVR approach was most common (61%). Mortality was higher for TAVR (10%) compared with SAVR (6%, p < 0.047), whereas the SAVR group accrued higher major morbidity (27% vs 14%, p < 0.001) and longer postoperative hospital duration (7 days vs 6 days, p < 0.001). Importantly, TAVR incurred twice the median total costs compared with SAVR ($69,921 vs $33,598, p < 0.001). The increased cost of TAVR was largely driven by the cost of the valve (all p < 0.001). Intermediate-risk patients undergoing SAVR demonstrated the most exaggerated cost savings versus TAVR. TAVR was associated with greater total costs and mortality compared with SAVR in intermediate-risk and high-risk patients while conferring lower major morbidity and improved resource use. Increased cost of TAVR appears largely related to the cost of the valve. Until the price of TAVR valves decreases, these data suggest that TAVR may not provide the most cost-effective strategy, particularly for intermediate-risk patients. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc

X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy

NASA Technical Reports Server (NTRS)

Park, Yoonjoon; Choi, Sang Hyouk; King, Glen C.; Elliott, James R.; Dimarcantonio, Albert L.

2010-01-01

A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization.

Blood Pressure and Arterial Load After Transcatheter Aortic Valve Replacement for Aortic Stenosis.

PubMed

Lindman, Brian R; Otto, Catherine M; Douglas, Pamela S; Hahn, Rebecca T; Elmariah, Sammy; Weissman, Neil J; Stewart, William J; Ayele, Girma M; Zhang, Feifan; Zajarias, Alan; Maniar, Hersh S; Jilaihawi, Hasan; Blackstone, Eugene; Chinnakondepalli, Khaja M; Tuzcu, E Murat; Leon, Martin B; Pibarot, Philippe

2017-07-01

After aortic valve replacement, left ventricular afterload is often characterized by the residual valve obstruction. Our objective was to determine whether higher systemic arterial afterload-as reflected in blood pressure, pulsatile and resistive load-is associated with adverse clinical outcomes after transcatheter aortic valve replacement (TAVR). Total, pulsatile, and resistive arterial load were measured in 2141 patients with severe aortic stenosis treated with TAVR in the PARTNER I trial (Placement of Aortic Transcatheter Valve) who had systolic blood pressure (SBP) and an echocardiogram obtained 30 days after TAVR. The primary end point was 30-day to 1-year all-cause mortality. Lower SBP at 30 days after TAVR was associated with higher mortality (20.0% for SBP 100-129 mm Hg versus 12.0% for SBP 130-170 mm Hg; P <0.001). This association remained significant after adjustment, was consistent across subgroups, and confirmed in sensitivity analyses. In adjusted models that included SBP, higher total and pulsatile arterial load were associated with increased mortality ( P <0.001 for all), but resistive load was not. Patients with low 30-day SBP and high pulsatile load had a 3-fold higher mortality than those with high 30-day SBP and low pulsatile load (26.1% versus 8.1%; hazard ratio, 3.62; 95% confidence interval, 2.36-5.55). Even after relief of valve obstruction in patients with aortic stenosis, there is an independent association between post-TAVR blood pressure, systemic arterial load, and mortality. Blood pressure goals in patients with a history of aortic stenosis may need to be redefined. Increased pulsatile arterial load, rather than blood pressure, may be a target for adjunctive medical therapy to improve outcomes after TAVR. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894. © 2017 American Heart Association, Inc.

Impact of Annular Size on Outcomes After Surgical or Transcatheter Aortic Valve Replacement.

PubMed

Deeb, G Michael; Chetcuti, Stanley J; Yakubov, Steven J; Patel, Himanshu J; Grossman, P Michael; Kleiman, Neal S; Heiser, John; Merhi, William; Zorn, George L; Tadros, Peter N; Petrossian, George; Robinson, Newell; Mumtaz, Mubashir; Gleason, Thomas G; Huang, Jian; Conte, John V; Popma, Jeffrey J; Reardon, Michael J

2018-04-01

This analysis evaluates the relationship of annular size to hemodynamics and the incidence of prosthesis-patient mismatch (PPM) in surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) patients. The CoreValve US Pivotal High Risk Trial, described previously, compared TAVR using a self-expanding valve with SAVR. Multislice computed tomography was used to categorize TAVR and SAVR subjects according to annular perimeter-derived diameter: large (≥26 mm), medium (23 to <26 mm), and small (<23 mm). Hemodynamics, PPM, and clinical outcomes were assessed. At all postprocedure visits, mean gradients were significantly lower for TAVR compared with SAVR in small and medium size annuli (p < 0.001). Annular size was significantly associated with mean gradient after SAVR, with small annuli having the highest gradients (p < 0.05 at all timepoints); gradients were similar across all annular sizes after TAVR. In subjects receiving SAVR, the frequency of PPM was significantly associated with annular size, with small annuli having the greatest incidence. No difference in PPM incidence by annular sizing was observed with TAVR. In addition, TAVR subjects had significantly less PPM than SAVR subjects in small and medium annuli (p < 0.001), with no difference in the incidence of PPM between TAVR and SAVR in large annuli (p = 0.10). Annular size has a significant effect on hemodynamics and the incidence of PPM in SAVR subjects, not observed in TAVR subjects. With respect to annular size, TAVR results in better hemodynamics and less PPM for annuli less than 26 mm and should be strongly considered when choosing a tissue valve for small and medium size annuli. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Clinical Outcomes Following Transcatheter Aortic Valve Replacement in Asian Population.

PubMed

Yoon, Sung-Han; Ahn, Jung-Min; Hayashida, Kentaro; Watanabe, Yusuke; Shirai, Shinichi; Kao, Hsien-Li; Yin, Wei-Hsian; Lee, Michael Kang-Yin; Tay, Edgar; Araki, Motoharu; Yamanaka, Futoshi; Arai, Takahide; Lin, Mao-Shin; Park, Jun-Bean; Park, Duk-Woo; Kang, Soo-Jin; Lee, Seung-Whan; Kim, Young-Hak; Lee, Cheol Whan; Park, Seong-Wook; Muramatsu, Toshiya; Hanyu, Michiya; Kozuma, Ken; Kim, Hyo-Soo; Saito, Shigeru; Park, Seung-Jung

2016-05-09

This study describes the characteristics of a real-world Asian patient population treated with transcatheter aortic valve replacement (TAVR) and evaluates their clinical outcomes. No previously reported randomized or observational studies adequately assess the safety and efficacy of TAVR in an Asian population. The Asian TAVR registry is an international multicenter study that enrolled patients with aortic stenosis who underwent TAVR in Asian countries. In total, 848 patients with mean STS score of 5.2 ± 3.8% were enrolled between March 2010 and September 2014 at 11 centers in 5 countries. The Edwards Sapien or Medtronic CoreValve was implanted in 64.7% and 35.3% of patients, respectively. The procedural success rate was 97.5%. The 30-day and 1-year mortality rates were 2.5% and 10.8%, respectively. There was no difference in 1-year mortality between devices (Sapien: 9.4%; CoreValve: 12.2%; log-rank p = 0.40). The rates of stroke, life-threatening bleeding, major vascular complications and acute kidney injury (stage 2 to 3) were 3.8%, 6.4%, 5.0% and 3.3%, respectively. Moderate or severe paravalvular leakage was significantly more common with the CoreValve than Sapien (14.4% vs. 7.3%; p = 0.001). According to the multivariate model, a higher STS score, lower body mass index, New York Heart Association functional class III-IV symptoms, diabetes mellitus, prior cerebrovascular accident, low mean gradient at baseline, and moderate or severe paravalvular leakage were significantly associated with reduced survival. Despite anatomical features of concern, the clinical outcomes of TAVR in our Asian population were favorable in comparison with those of previously published trials and observational studies. (The Asian Transcatheter Aortic Valve Replacement Registry [Asian TAVR]; NCT02308150). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Advanced refractory-metal and process technology for the fabrication of x-ray masks

NASA Astrophysics Data System (ADS)

Brooks, Cameron J.; Racette, Kenneth C.; Lercel, Michael J.; Powers, Lynn A.; Benoit, Douglas E.

1999-06-01

This paper provides an in-depth report of the advanced materials and process technology being developed for x-ray mask manufacturing at IBM. Masks using diamond membranes as replacement for silicon carbide are currently being fabricated. Alternate tantalum-based absorbers, such as tantalum boron, which offer improved etch resolution and critical dimension control, as well as higher x-ray absorption, are also being investigated. In addition to the absorber studies, the development of conductive chromium- based hard-mask films to replace the current silicon oxynitride layer is being explored. The progress of this advanced-materials work, which includes significant enhancements to x-ray mask image-placement performance, will be outlined.

Bioprosthetic mitral valve replacement in patients aged 65 years or younger: long-term outcomes with the Carpentier-Edwards PERIMOUNT pericardial valve.

PubMed

Bourguignon, Thierry; Espitalier, Fabien; Pantaleon, Clémence; Vermes, Emmanuelle; El-Arid, Jean Marc; Loardi, Claudia; Karam, Elias; Candolfi, Pascal; Ivanes, Fabrice; Aupart, Michel

2018-02-12

Mitral valve replacement using a bioprosthesis remains controversial in young patients because data on long-term outcomes are missing. This study evaluated the long-term results of the PERIMOUNT pericardial mitral bioprosthesis in patients aged 65 years or younger. From 1984 to 2010, 148 Carpentier-Edwards PERIMOUNT mitral bioprostheses were implanted in 148 patients aged 65 years or younger. Baseline clinical, perioperative and follow-up data were recorded prospectively. Structural valve deterioration (SVD) was defined by strict echocardiographic assessment. The mean follow-up period was 8.6 ± 5.5 years, for a total of 1269 valve-years. Operative mortality rate was 2.0%. Fifty-one late deaths occurred (linearized rate 4.0% per valve-year). Actuarial survival rates averaged 70 ± 4%, 53 ± 6% and 31 ± 7% after 10, 15 and 20 years of follow-up, respectively. Actuarial freedom from SVD at 10, 15 and 20 years was 78 ± 5%, 47 ± 7% and 19 ± 7%, respectively. Reoperation was associated with no operative mortality. Actuarial freedom from reoperation due to SVD at 10, 15 and 20 years was 82 ± 4%, 50 ± 6% and 25 ± 8%, respectively. Competing risk analysis demonstrated an actual risk of explantation secondary to SVD at 20 years of 44 ± 5%. Expected valve durability was 14.2 years for this age group. In the selected patients aged 65 years or younger undergoing mitral valve replacement with a pericardial bioprosthesis, the expected valve durability was 14.2 years. Reoperation for SVD was associated with a low risk of mortality. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Immediate Outcomes of Aortic Valve Replacement with Sutureless versus Stentless Bioprosthesis.

PubMed

Ihsan Parlar, Ali; Onur Hanedan, Muhammet; Mataraci, Ilker; Ali Yuruk, Mehmet; Sayar, Ufuk; Kemal Arslan, Ali; Ozer, Tanil

2016-01-01

Aortic valve replacement (AVR) with a sutureless valve is an innovative therapy in high-risk elderly patients. The study aim was to compare the early results of AVR using sutureless aortic valves or stentless aortic bioprostheses. A retrospective analysis was conducted of 55 patients who underwent AVR with either a sutureless valve (Perceval S; n = 24 or Edwards Intuity; n = 9) or a stentless valve (Sorin Freedom SOLO™; n = 22). Baseline patient characteristics were similar in both groups, except for NYHA class. Concomitant procedures were performed in 17 patients (51.5%) of the sutureless group and in nine patients (40.9%) of the stentless group (p = 0.44). The aortic cross-clamp time was 55 ± 23 min in the sutureless group and 102 ± 36 min in the stentless group (p <0.0001), while the postoperative peak aortic gradient was 19.5 ± 5.0 mmHg and 29.3 ± 15.4 mmHg for the sutureless group and stentless group, respectively (p = 0.037). The postoperative mean gradient was 9.3 ± 3.4 mmHg for the sutureless group and 15.1 ± 10.5 mmHg for the stentless group (p = 0.06). Blood product transfusion was required less frequently by the sutureless group, but drainage and bleeding was similar in both groups. The intensive care unit and hospital stays were significantly shorter in favor of the sutureless group. One sutureless patient (3.0%) and two stentless patients (9.1%) died in hospital (p = 0.557). Early results of the present study suggested that surgical AVR with a sutureless valve is associated with a good hemodynamic performance and an improved early outcome.

Quality of life following heart valve replacement in the elderly.

PubMed

Spaziano, Marco; Carrier, Michel; Pellerin, Michel; Choinière, Manon

2010-07-01

The purpose of this investigation was to evaluate both long-term functional status and quality of life (QoL) following valvular replacement surgery in octogenarians. The influence of gender and discharge location was also examined. A total of 133 patients (age range: 80-89 years) who underwent surgical valve replacement between January 2003 and December 2006 was identified. Two questionnaires evaluating QoL (SF-12v2 and MLHFQ), as well as a demographic questionnaire, were sent to these patients. The response rate was 64.4%. Among the participants, the mean NYHA functional class improved from 2.7 to 1.4 after surgery. Men showed results similar to those of the age-matched general Canadian population on the mental and physical component scales of the SF-12v2. The data on women were similar to those of the general population on the physical component scale, but their scores were significantly lower on the mental component scale of the SF-12v2. Further analysis of the results comparing discharge location for each gender revealed that women discharged to a convalescence resource had significantly better QoL scores than those discharged to home with regards to the physical component scale of the SF-12v2, the total score of the MLHFQ, and the physical dimension score of the MLHFQ. Patients aged > or = 80 years benefit from heart valve replacement surgery in terms of both QoL and functional status. Women may be at increased risk of a decline in their emotional well-being and, postoperatively, may benefit more from convalescence than from discharge to home.

Use of bovine pericardial tissue for aortic valve and aortic root replacement: long-term results.

PubMed

Vrandecic, M; Gontijo Filho, B; Fantini, F; Barbosa, J; Martins, I; de Oliveira, O C; Martins, C; Max, R; Drumond, L; Oliveira, C; Ferrufino, A; Alcocer, E; Silva, J A; Vrandecic, E

1998-03-01

The study aimed to determine the clinical performance of bovine pericardial aldehyde-treated products alone or in combination with aortic leaflets of porcine origin. These included a composite porcine stentless aortic valve attached to a scalloped pericardial tube (BSAV), and valved and non-valved bovine pericardial conduits for use in left-sided heart lesions (BPG). For BSAV grafts, between January 1990 and August 1996, 163 patients (119 males) had their aortic valves replaced by SJM Biocor BASV. Mean age was 37.9 +/- 17.6 years (range: 1 to 76 years). Rheumatic heart disease sequelae (n = 72) and replacement of a prosthetic heart valve (n = 46) were predominant. Preoperative NYHA functional class showed 90 patients (55.2%) in class III and 50 (30.7%) in class IV. BPVC and NVPC grafts were used in 166 patients: acute aortic dissection was the main indication in 52 (31.3%) and chronic in 36 (21/7%). The ascending aorta was involved in 141 patients (84.9%); grafts were seldom used at other sites. In most patients the graft implanted was either a non-valved (n = 79) or a valved (n = 75) pericardial conduit. Twelve patients had a localized lesion and required a patch repair. For BASV grafts, the non-valve-related hospital mortality rate was 4.9%. There were 14.7% non-fatal complications with full recovery of all patients. Mean follow up in 141 patients was 3.0 +/- 1.4 years (range: 1 month to 7.2 years); 14 patients were lost to follow up. Late, non-conduit-related, mortality occurred in seven patients (4.9%). Eight patients underwent reoperation. The current clinical follow up of 127 patients has shown 118 (92.9%) with competent valves and nine (7.0%) with mild stable aortic insufficiency. For BPVC and NVPC grafts, hospital mortality rate was 16.9%, death being related to poor preoperative clinical condition. Postoperative follow up was accomplished in 125 patients; reoperation was necessary in seven patients. Histology showed good tissue preservation up to five

Mycobacterium chimaera Infection After Aortic Valve Replacement Presenting With Aortic Dissection and Pseudoaneurysm.

PubMed

O'Neil, C R; Taylor, G; Smith, S; Joffe, A M; Antonation, K; Shafran, S; Kunimoto, D

2018-02-01

We present a case of Mycobacterium chimaera infection presenting with aortic dissection and pseudoaneuysm in a 22-year-old man with a past history of aortic valve replacement. Clinicians should consider M. chimaera infection in those presenting with aortic dissection as a late complication of cardiovascular surgery.

Costs of transcatheter versus surgical aortic valve replacement in intermediate-risk patients.

PubMed

Osnabrugge, Ruben L J; Head, Stuart J; Genders, Tessa S S; Van Mieghem, Nicolas M; De Jaegere, Peter P T; van der Boon, Robert M A; Kerkvliet, J Marco; Kalesan, Bindu; Bogers, Ad J J C; Kappetein, A Pieter; Hunink, M G Myriam

2012-12-01

Transcatheter aortic valve replacement (TAVR) offers a new treatment option for patients with aortic stenosis, but costs may play a decisive role in decision making. Current studies are evaluating TAVR in an intermediate-risk population. We assessed the in-hospital and 1-year follow-up costs of patients undergoing TAVR and surgical aortic valve replacement (SAVR) at intermediate operative risk and identified important cost components. We prospectively collected clinical data on 141 patients undergoing TAVR and 405 undergoing SAVR. Propensity score matching yielded 42 matched pairs at intermediate risk. Costs were assessed using a detailed resource-use approach and compared using bootstrap methods. In-hospital costs were higher in TAVR patients than in SAVR patients (€40802 vs €33354, respectively; p=0.010). The total costs at 1 year were €46217 vs €35511, respectively (p=0.009). The TAVR was less costly with regard to blood products, operating room use, and length-of-stay. For intermediate-risk patients with severe aortic stenosis the costs at 1 year are higher for TAVR than for SAVR. The difference was mainly caused by the higher costs of the transcatheter valve and was not compensated by the lower costs for blood products and hospital stay in TAVR patients. Therefore, SAVR remains a clinically and economically attractive treatment option. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The economic value of rapid deployment aortic valve replacement via full sternotomy.

PubMed

Moore, Matt; Barnhart, Glenn R; Chitwood, W Randolph; Rizzo, John A; Gunnarsson, Candace; Palli, Swetha R; Grossi, Eugene A

2017-06-01

To compare the economic value of EDWARDS INTUITY Elite™ (EIE) valve system for rapid-deployment aortic valve replacement (RDAVR) in a full sternotomy (FS) approach (EIE-FS-RDAVR) versus FS-AVR using conventional stented bioprosthesis. A simulation model to compare each treatment's 30-day inpatient utilization and complication rates utilized: clinical end points obtained from the TRANSFORM trial patient subset (EIE-FS-RDAVR) and a best evidence review of the published literature (FS-AVR); and costs from the Premier database and published literature. EIE-FS-RDAVR costs $800 less than FS-AVR per surgery episode attributable to lowered complication rates and utilization. Combined with the lower mortality, EIE-FS-RDAVR was a superior (dominant) technology versus FS-AVR. This preliminary investigation of EIE-FS-RDAVR versus conventional FS-AVR found the EIE valve offered superior economic value over a 30-day period. Real-world analyses with additional long-term follow-up are needed to evaluate if this result can be replicated over a longer timeframe.

Total ellipse of the heart valve: the impact of eccentric stent distortion on the regional dynamic deformation of pericardial tissue leaflets of a transcatheter aortic valve replacement

PubMed Central

Gunning, Paul S.; Saikrishnan, Neelakantan; Yoganathan, Ajit P.; McNamara, Laoise M.

2015-01-01

Transcatheter aortic valve replacements (TAVRs) are a percutaneous alternative to surgical aortic valve replacements and are used to treat patients with aortic valve stenosis. This minimally invasive procedure relies on expansion of the TAVR stent to radially displace calcified aortic valve leaflets against the aortic root wall. However, these calcium deposits can impede the expansion of the device causing distortion of the valve stent and pericardial tissue leaflets. The objective of this study was to elucidate the impact of eccentric TAVR stent distortion on the dynamic deformation of the tissue leaflets of the prosthesis in vitro. Dual-camera stereophotogrammetry was used to measure the regional variation in strain in a leaflet of a TAVR deployed in nominal circular and eccentric (eccentricity index = 28%) orifices, representative of deployed TAVRs in vivo. It was observed that (i) eccentric stent distortion caused incorrect coaptation of the leaflets at peak diastole resulting in a ‘peel-back’ leaflet geometry that was not present in the circular valve and (ii) adverse bending of the leaflet, arising in the eccentric valve at peak diastole, caused significantly higher commissure strains compared with the circular valve in both normotensive and hypertensive pressure conditions (normotension: eccentric = 13.76 ± 2.04% versus circular = 11.77 ± 1.61%, p = 0.0014, hypertension: eccentric = 15.07 ± 1.13% versus circular = 13.56 ± 0.87%, p = 0.0042). This study reveals that eccentric distortion of a TAVR stent can have a considerable impact on dynamic leaflet deformation, inducing deleterious bending of the leaflet and increasing commissures strains, which might expedite leaflet structural failure compared to leaflets in a circular deployed valve. PMID:26674192

In vitro investigation of a novel elastic vascular prosthesis for valve-sparing aortic root and ascending aorta replacement.

PubMed

Scharfschwerdt, Michael; Leonhard, Moritz; Lehmann, Judith; Richardt, Doreen; Goldmann, Helmut; Sievers, Hans-Hinrich

2016-05-01

Prosthetic replacement of the thoracic aorta with common Dacron prostheses impairs the aortic 'windkessel' and, in valve-sparing procedures, also aortic valve function. Elastic graft material may overcome these deficiencies. Fresh porcine aortas including the root were set up in a mock circulation before and after replacement of the ascending part with a novel vascular prosthesis providing elastic behaviours. In a first series (n = 14), haemodynamics and leaflet motions of the aortic valve were investigated and also cyclic changes of aortic dimensions at different levels of the root. In a second series (n = 7), intravascular pressure and dimensions of the proximal descending aorta were measured and the corresponding wall tension was calculated. Haemodynamics of the aortic valve remain comparable after replacement. Though the novel prosthesis does not feature such high distensibility as the native aorta, the dynamic of the root was significantly increased compared with common Dacron prostheses at the commissural level, preserving 'windkessel' function. Thus, wall tension of the residual aorta remained unchanged; nevertheless, maximum pressure-time differential dp/dt increased by 13%. The use of the novel elastic prosthesis for replacement of the ascending aorta seems to be beneficial, especially with regard to the preservation of the aortic windkessel. Further studies will be needed to clarify long-term utilization of the material in vivo. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Successful simultaneous ipsilateral stenting of common iliac artery stenosis and transfemoral aortic valve replacement.

PubMed

Aslan, Abdullah Nabi; Kasapkara, Hacı Ahmet; Sivri, Serkan; Güney, Murat Can; Bozkurt, Engin

2017-01-01

Transcatheter aortic valve replacement (TAVR) was designed to treat elderly patients with severe aortic stenosis at high risk for surgery, and is most commonly performed with retrograde approach through femoral arteries. However, in up to 30% of cases, it is either not possible to use this access route or it is considered to have high risk of vascular injury. Alternative approaches have been described for patients with no suitable femoral access: trans-subclavian, transaortic, or direct aortic access; however, since the introduction of new valves deployed with low-profile delivery systems, another alternative transcatheter approach has been discovered. Presently described is experience in 2 cases in which patients were treated with transfemoral TAVR using Edwards SAPIEN 3 transcatheter heart valves immediately following ipsilateral common iliac artery stenting.

An unusual cause of hemolysis in a patient with an aortic valved conduit replacement.

PubMed

Allman, Christine; Rajaratnam, Rohan; Kachwalla, Hashim; Hughes, Clifford F; Bannon, Paul; Leung, Dominic Y

2003-02-01

Hemolytic anemia is a well-known but uncommon complication in patients with prosthetic heart valves. It is most commonly a result of prosthetic valve dysfunction, periprosthetic valvular regurgitation, or both. We report a case of a 41-year-old man who had a previous aortic valve and root replacement for acute proximal aortic dissection, now presenting with hemolytic anemia. This was a result of flow obstruction at the distal anastomosis of the aortic conduit by the presence of multiple dissection flaps resulting in severe flow turbulence. Although the pathology was at the blind spot for transesophageal echocardiography, the dissection flaps, the flow turbulence, and the degree of obstruction were well-demonstrated by this technique after careful manipulation of the probe and a high index of suspicion.

Tidal tearing of circumstellar disks in Be/X-ray and gamma-ray binaries

NASA Astrophysics Data System (ADS)

Okazaki, Atsuo T.

2017-11-01

About one half of high-mass X-ray binaries host a Be star [an OB star with a viscous decretion (slowly outflowing) disk]. These Be/X-ray binaries exhibit two types of X-ray outbursts (Stella et al. 1986), normal X-ray outbursts (L X~1036-37 erg s-1) and occasional giant X-ray outbursts (L X > 1037 erg s-1). The origin of giant X-ray outbursts is unknown. On the other hand, a half of gamma-ray binaries have a Be star as the optical counterpart. One of these systems [LS I +61 303 (P orb = 26.5 d)] shows the superorbital (1,667 d) modulation in radio through X-ray bands. No consensus has been obtained for its origin. In this paper, we study a possibility that both phenomena are caused by a long-term, cyclic evolution of a highly misaligned Be disk under the influence of a compact object, by performing 3D hydrodynamic simulations. We find that the Be disk cyclically evolves in mildly eccentric, short-period systems. Each cycle consists of the following stages: 1) As the Be disk grows with time, the initially circular disk becomes eccentric by the Kozai-Lidov mechanism. 2) At some point, the disk is tidally torn off near the base and starts precession. 3) Due to precession, a gap opens between the disk base and mass ejection region, which allows the formation of a new disk in the stellar equatorial plane (see Figure 1). 4) The newly formed disk finally replaces the precessing old disk. Such a cyclic disk evolution has interesting implications for the long-term behavior of high energy emission in Be/X-ray and gamma-ray binaries.

1-Year Outcomes After Transcatheter Aortic Valve Replacement With Balloon-Expandable Versus Self-Expandable Valves: Results From the CHOICE Randomized Clinical Trial.

PubMed

Abdel-Wahab, Mohamed; Neumann, Franz-Josef; Mehilli, Julinda; Frerker, Christian; Richardt, Doreen; Landt, Martin; Jose, John; Toelg, Ralph; Kuck, Karl-Heinz; Massberg, Steffen; Robinson, Derek R; El-Mawardy, Mohamed; Richardt, Gert

2015-08-18

The use of a balloon-expandable transcatheter heart valve previously resulted in a greater rate of device success compared with a self-expandable transcatheter heart valve. The aim of this study was to evaluate clinical and echocardiographic outcome data at longer term follow-up. The investigator-initiated trial randomized 241 high-risk patients with symptomatic severe aortic stenosis and anatomy suitable for treatment with both balloon- and self-expandable transcatheter heart valves to transfemoral transcatheter aortic valve replacement with either device. Patients were followed-up for 1 year, with assessment of clinical outcomes and echocardiographic evaluation of valve function. At 1 year, the rates of death of any cause (17.4% vs. 12.8%; relative risk [RR]: 1.35; 95% confidence interval [CI]: 0.73 to 2.50; p = 0.37) and of cardiovascular causes (12.4% vs. 9.4%; RR: 1.32; 95% CI: 0.63 to 2.75; p = 0.54) were not statistically significantly different in the balloon- and self-expandable groups, respectively. The frequencies of all strokes (9.1% vs. 3.4%; RR: 2.66; 95% CI: 0.87 to 8.12; p = 0.11) and repeat hospitalization for heart failure (7.4% vs. 12.8%; RR: 0.58; 95% CI: 0.26 to 1.27; p = 0.19) did not statistically significantly differ between the 2 groups. Elevated transvalvular gradients during follow-up were observed in 4 patients in the balloon-expandable group (3.4% vs. 0%; p = 0.12); all were resolved with anticoagulant therapy, suggesting a thrombotic etiology. More than mild paravalvular regurgitation was more frequent in the self-expandable group (1.1% vs. 12.1%; p = 0.005). Despite the higher device success rate with the balloon-expandable valve, 1-year follow-up of patients in CHOICE (Randomized Comparison of Transcatheter Heart Valves in High Risk Patients With Severe Aortic Stenosis: Medtronic CoreValve Versus Edwards SAPIEN XT Trial), with limited statistical power, revealed clinical outcomes after transfemoral transcatheter aortic valve

Intra-Operative Vector Flow Imaging Using Ultrasound of the Ascending Aorta among 40 Patients with Normal, Stenotic and Replaced Aortic Valves.

PubMed

Hansen, Kristoffer Lindskov; Møller-Sørensen, Hasse; Kjaergaard, Jesper; Jensen, Maiken Brit; Lund, Jens Teglgaard; Pedersen, Mads Møller; Lange, Theis; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

2016-10-01

Stenosis of the aortic valve gives rise to more complex blood flows with increased velocities. The angle-independent vector flow ultrasound technique transverse oscillation was employed intra-operatively on the ascending aorta of (I) 20 patients with a healthy aortic valve and 20 patients with aortic stenosis before (IIa) and after (IIb) valve replacement. The results indicate that aortic stenosis increased flow complexity (p < 0.0001), induced systolic backflow (p < 0.003) and reduced systolic jet width (p < 0.0001). After valve replacement, the systolic backflow and jet width were normalized (p < 0.52 and p < 0.22), but flow complexity was not (p < 0.0001). Flow complexity (p < 0.0001), systolic jet width (p < 0.0001) and systolic backflow (p < 0.001) were associated with peak systolic velocity. The study found that aortic stenosis changes blood flow in the ascending aorta and valve replacement corrects some of these changes. Transverse oscillation may be useful for assessment of aortic stenosis and optimization of valve surgery. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Preoperative Aspirin Use and Lung Injury After Aortic Valve Replacement Surgery: A Retrospective Cohort Study.

PubMed

Mazzeffi, Michael; Kassa, Woderyelesh; Gammie, James; Tanaka, Kenichi; Roman, Philip; Zhan, Min; Griffith, Bartley; Rock, Peter

2015-08-01

Acute respiratory distress syndrome (ARDS) occurs uncommonly after cardiac surgery but has a mortality rate as high as 80%. Aspirin may prevent lung injury in at-risk patients by reducing platelet-neutrophil aggregates in the lung. We hypothesized that preoperative aspirin use would be associated with a decreased risk of ARDS after aortic valve replacement surgery. We performed a retrospective single-center cohort study that included all adult patients who had aortic valve replacement surgery during a 5-year period. The primary outcome variable was postoperative ARDS. The secondary outcome variable was nadir PaO2/FIO2 ratio during the first 72 hours after surgery. Both crude and propensity score-adjusted logistic regression analyses were performed to estimate the odds ratio for developing ARDS in aspirin users. Subgroups were analyzed to determine whether preoperative aspirin use might be associated with improved oxygenation in patients with specific risk factors for lung injury. Of the 375 patients who had aortic valve replacement surgery during the study period, 181 patients took aspirin preoperatively (48.3%) with most taking a dose of 81 mg (72.0%). There were 22 cases of ARDS in the cohort (5.5%). There was no significant difference in the rate of ARDS between aspirin users and nonusers (5.0% vs 6.7%, P = 0.52). There was also no significant difference in the nadir PaO2/FIO2 ratio between aspirin users and nonusers (P = 0.12). The crude odds ratio for ARDS in aspirin users was 0.725 (99% confidence interval, 0.229-2.289; P = 0.47), and the propensity score-adjusted odds ratio was 0.457 (99% confidence interval, 0.120-1.730; P = 0.13). Within the constraints of this analysis that included only 22 affected patients, preoperative aspirin use was not associated with a decreased incidence of ARDS after aortic valve replacement surgery or improved oxygenation.

Robotic artificial chordal replacement for repair of mitral valve prolapse.

PubMed

Brunsting, Louis A; Rankin, J Scott; Braly, Kimberly C; Binford, Robert S

2009-07-01

Artificial chordal replacement (ACR) has emerged as a superior method of mitral valve repair with excellent early and late efficacy. It is also ideal to combine with robotic techniques for correction of mitral prolapse, and this article presents a current method of robotic Gore-Tex ACR. Patients with isolated posterior leaflet prolapse are approached with the fourth-generation DaVinci robotic system and endoaortic balloon occlusion. A pledgetted anchor stitch is placed in a papillary muscle, and a 2-o Gore-Tex suture is passed through the anchor pledget. After full annuloplasty ring placement, the Gore-Tex suture is woven into the prolapsing segment and positioned temporarily with robotic forceps. Chordal length is then "adjusted" by lengthening or shortening the temporary knot over 1-cm increments as the valve is tested by injection of cold saline into the ventricle. After achieving good leaflet position and valve competence, the chord is tied permanently. The "adjustable" ACR procedure preserves leaflet surface area and produces a competent valve in the majority of patients. Postoperative transesophageal echo shows a large surface area of coaptation. Patient recovery is facilitated by the minimally invasive approach, while long-term stability of similar open ACR techniques have been excellent with a 2% to 3% failure rate over 10 years of follow-up. Robotic Gore-Tex ACR without leaflet resection is a reproducible procedure that simplifies mitral repair for prolapse. The outcomes observed in early robotic applications have been excellent. It is suggested that most patients with simple prolapse might validly be approached in this manner.

The effect of postoperative medical treatment on left ventricular mass regression after aortic valve replacement.

PubMed

Helder, Meghana R K; Ugur, Murat; Bavaria, Joseph E; Kshettry, Vibhu R; Groh, Mark A; Petracek, Michael R; Jones, Kent W; Suri, Rakesh M; Schaff, Hartzell V

2015-03-01

The study objective was to analyze factors associated with left ventricular mass regression in patients undergoing aortic valve replacement with a newer bioprosthesis, the Trifecta valve pericardial bioprosthesis (St Jude Medical Inc, St Paul, Minn). A total of 444 patients underwent aortic valve replacement with the Trifecta bioprosthesis from 2007 to 2009 at 6 US institutions. The clinical and echocardiographic data of 200 of these patients who had left ventricular hypertrophy and follow-up studies 1 year postoperatively were reviewed and compared to analyze factors affecting left ventricular mass regression. Mean (standard deviation) age of the 200 study patients was 73 (9) years, 66% were men, and 92% had pure or predominant aortic valve stenosis. Complete left ventricular mass regression was observed in 102 patients (51%) by 1 year postoperatively. In univariate analysis, male sex, implantation of larger valves, larger left ventricular end-diastolic volume, and beta-blocker or calcium-channel blocker treatment at dismissal were significantly associated with complete mass regression. In the multivariate model, odds ratios (95% confidence intervals) indicated that male sex (3.38 [1.39-8.26]) and beta-blocker or calcium-channel blocker treatment at dismissal (3.41 [1.40-8.34]) were associated with increased probability of complete left ventricular mass regression. Patients with higher preoperative systolic blood pressure were less likely to have complete left ventricular mass regression (0.98 [0.97-0.99]). Among patients with left ventricular hypertrophy, postoperative treatment with beta-blockers or calcium-channel blockers may enhance mass regression. This highlights the need for close medical follow-up after operation. Labeled valve size was not predictive of left ventricular mass regression. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

The effects of contrast media volume on acute kidney injury after transcatheter aortic valve replacement: a systematic review and meta-analysis.

PubMed

Thongprayoon, Charat; Cheungpasitporn, Wisit; Podboy, Alexander J; Gillaspie, Erin A; Greason, Kevin L; Kashani, Kianoush B

2016-11-01

The goal of this systematic review was to assess the effects of contrast media volume on transcatheter aortic valve replacement-related acute kidney injury. A literature search was performed using Medline, EMbase, the Cochrane Database of Systematic Reviews, and clinicaltrials.gov from the inception of these databases through December 2015. Studies that reported relative risk, odds ratio, or hazard ratio comparing the risks of acute kidney injury following transcatheter aortic valve replacement in patients who received high contrast media volume were included. Pooled risk ratio (RR) and 95% confidence intervals (95% CI) were calculated using a random-effect, generic inverse variance method. Four cohort studies composed of 891 patients were included in the analyses to assess the risk of acute kidney injury after transcatheter aortic valve replacement in patients who received high contrast media volume. The pooled RR of acute kidney injury after transcatheter aortic valve replacement in patients who received a large volume of contrast media was 1.41 (95% CI, 0.87 to 2.28) compared with low contrast media volume. The meta-analysis was limited to studies using standard acute kidney injury definitions, and the pooled RR of acute kidney injury in patients who received high contrast media volume is 1.12 (95% CI, 0.78 to 1.62). Our meta-analysis shows no significant association between contrast media volume and risk of acute kidney injury after transcatheter aortic valve replacement. © 2016 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

Outcomes following transcatheter aortic valve replacement in patients with native aortic valve regurgitation

PubMed Central

Bob-Manuel, Tamunoinemi; Kadire, Siri; Heckle, Mark R.; Wang, Jiajing

2018-01-01

Due to the absence of annular calcification for device anchoring, it is presumed that transcatheter aortic valve replacement (TAVR) is not suitable for the treatment of native aortic valve regurgitation (NAVR) resulting in very limited data and experience concerning its safety and efficacy. We sought to review published data on the safety and efficacy of TAVR in high-risk patients with NAVR. Studies including case reports, case series and original articles published between 2002 and 2016 on TAVR in patients with NAVR were identified with a systematic electronic search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Only studies reporting data on demographic and procedural characteristics, management and follow up outcomes were analyzed. A total of 30 publications describing 182 patients were identified. Most patients (54%) were men, with a mean age of 70.1±2.6 years, mean logistic European System for Cardiac Operative Risk Evaluation score (EuroSCORE) of 21.8%±4.5% and mean Society of Thoracic Surgeons (STS) score of 8%±1.8% for mortality. The majority (87%) of patients had severe NAVR with no valvular calcification. TAVR was mostly performed through the femoral (58.8%) and apical (33.1%) approach. Device success, defined by VARC-2, was achieved in 86.3% of our study population. A second valve was required in 17 patients (9.3%) during the index procedure for residual aortic regurgitation or malposition. Post-procedure aortic regurgitation of grade 1 or less was present in 80 patients (81%). Pacemaker implantation was required post procedure in 17 patients (9.3%). The 30-day and 1-year mortality was 11.9% and 16.2%, respectively. TAVR is associated with favorable pacemaker implantation and 1-year mortality rates with a high 30-day mortality among selected patients with NAVR. PMID:29404354

Radiobiological studies using gamma and x rays.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R.

2013-02-01

There are approximately 500 self-shielded research irradiators used in various facilities throughout the U.S. These facilities use radioactive sources containing either 137Cs or 60Co for a variety of biological investigations. A report from the National Academy of Sciences[1] described the issues with security of particular radiation sources and the desire for their replacement. The participants in this effort prepared two peer-reviewed publications to document the results of radiobiological studies performed using photons from 320-kV x rays and 137Cs on cell cultures and mice. The effectiveness of X rays was shown to vary with cell type.

Concomitant replacement of the dilated ascending aorta during aortic valve replacement; does it increase the perioperative morbidity and mortality risks?

PubMed

Lim, Ju Y; Jung, Sung H; Kim, Joon B; Kim, Dong K; Chung, Cheol H; Song, Hyun; Lee, Jae W; Choo, Suk J

2013-05-01

Concerns of increased surgical risks with ascending aortic replacement have led surgeons to manage post-stenotic aortic dilatation more conservatively during aortic valve replacement (AVR). The present study aimed to assess the prognostic implications and surgical risks of replacing the dilated aorta during AVR. Between January 1999 and March 2010, 134 patients who received surgery for aortic stenosis and post-stenotic dilatation (aorta size ≥40 mm) were included in the present study. AVR was performed in 92 patients (AVR group) while aortic valve and ascending aorta replacement (AVR + aorta group) were performed in 42 patients. Overall survival was compared between the two groups using Cox proportional hazard model after adjustment with inverse-probability-of-treatment weighting. The mean follow-up duration was 3.5 ± 3 years. There were no significant differences in the operative mortality and morbidity between the two groups. The late cardiac deaths were also not significantly different between the two groups (p = 1.00). In the AVR group, the ascending aortic expansion rate which was 0.18 mm/year over a mean follow-up duration of 2.3 ± 2.2 years by echocardiography showed a positive correlation with time (r = 0.3, p = 0.08). A relatively greater aortic expansion rate was identified as a risk factor for late mortality (p = 0.015, HR 1.08 (CI: 1.02 to 1.15). Concomitant replacement of the dilated ascending aorta during AVR did not increase the immediate postoperative morbidity or mortality risks and tended to exert a long-term beneficial effect on the risk of late mortality. © 2013 Wiley Periodicals, Inc.

Effect of tricuspid regurgitation and the right heart on survival after transcatheter aortic valve replacement: insights from the Placement of Aortic Transcatheter Valves II inoperable cohort.

PubMed

Lindman, Brian R; Maniar, Hersh S; Jaber, Wael A; Lerakis, Stamatios; Mack, Michael J; Suri, Rakesh M; Thourani, Vinod H; Babaliaros, Vasilis; Kereiakes, Dean J; Whisenant, Brian; Miller, D Craig; Tuzcu, E Murat; Svensson, Lars G; Xu, Ke; Doshi, Darshan; Leon, Martin B; Zajarias, Alan

2015-04-01

Tricuspid regurgitation (TR) and right ventricular (RV) dysfunction adversely affect outcomes in patients with heart failure or mitral valve disease, but their impact on outcomes in patients with aortic stenosis treated with transcatheter aortic valve replacement has not been well characterized. Among 542 patients with symptomatic aortic stenosis treated in the Placement of Aortic Transcatheter Valves (PARTNER) II trial (inoperable cohort) with a Sapien or Sapien XT valve via a transfemoral approach, baseline TR severity, right atrial and RV size and RV function were evaluated by echocardiography according to established guidelines. One-year mortality was 16.9%, 17.2%, 32.6%, and 61.1% for patients with no/trace (n=167), mild (n=205), moderate (n=117), and severe (n=18) TR, respectively (P<0.001). Increasing severity of RV dysfunction as well as right atrial and RV enlargement were also associated with increased mortality (P<0.001). After multivariable adjustment, severe TR (hazard ratio, 3.20; 95% confidence interval, 1.50-6.82; P=0.003) and moderate TR (hazard ratio, 1.60; 95% confidence interval, 1.02-2.52; P=0.042) remained associated with increased mortality as did right atrial and RV enlargement, but not RV dysfunction. There was an interaction between TR and mitral regurgitation severity (P=0.04); the increased hazard of death associated with moderate/severe TR only occurred in those with no/trace/mild mitral regurgitation. In inoperable patients treated with transcatheter aortic valve replacement, moderate or severe TR and right heart enlargement are independently associated with increased 1-year mortality; however, the association between moderate or severe TR and an increased hazard of death was only found in those with minimal mitral regurgitation at baseline. These findings may improve our assessment of anticipated benefit from transcatheter aortic valve replacement and support the need for future studies on TR and the right heart, including whether

X-Rays

MedlinePlus

X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat ...

Outcomes of Transcatheter and Surgical Aortic Valve Replacement in Patients on Maintenance Dialysis.

PubMed

Alqahtani, Fahad; Aljohani, Sami; Boobes, Khaled; Maor, Elad; Sherieh, Assem; Rihal, Charanjit S; Holmes, David R; Alkhouli, Mohamad

2017-12-01

The introduction of transcatheter aortic valve replacement (TAVR) expanded definitive therapy of aortic stenosis to many high-risk patients, but it has not been fully evaluated in the dialysis population. We aimed to evaluate the current trend and in-hospital outcome of surgical aortic valve replacement (SAVR) and TAVR in the dialysis population. Severe aortic stenosis patients on maintenance dialysis who underwent SAVR or TAVR in the Nationwide Inpatient Sample database from January 1, 2005, through December 31, 2014, were included in our comparative analysis. The trends of SAVR and TAVR were assessed. In-hospital mortality, rates of major adverse events, hospital length of stay, cost of care, and intermediate care facility utilization were compared between the 2 groups using both unadjusted and propensity-matched data. Utilization of aortic valve replacement in dialysis patients increased 3-fold; a total of 2531 dialysis patients who underwent either SAVR (n = 2264) or TAVR (n = 267) between 2005 and 2014 were identified. Propensity score matching yielded 197 matched pairs. After matching, a 2-fold increase in in-hospital mortality was found with SAVR compared with TAVR (13.7% vs 6.1%, P = .021). Patients who underwent TAVR had more permanent pacemaker implantation (13.2% vs 5.6%, P = .012) but less blood transfusion (43.7% vs 56.8%, P = .02). Rates of other key morbidities were similar. Hospital length of stay (19 ± 16 vs 11 ± 11 days, P <.001) and non-home discharges (44.7% vs 31.5%, P = .002) were significantly higher with SAVR. Cost of hospitalization was 25% less with TAVR. In patients on maintenance dialysis, TAVR is associated with lower hospital mortality, resource utilization, and cost in comparison with SAVR. Copyright © 2017 Elsevier Inc. All rights reserved.

Recent Development in Pulmonary Valve Replacement after Tetralogy of Fallot Repair: The Emergence of Hybrid Approaches

PubMed Central

Suleiman, Tariq; Kavinsky, Clifford J.; Skerritt, Clare; Kenny, Damien; Ilbawi, Michael N.; Caputo, Massimo

2015-01-01

An increasing number of patients with tetralogy of Fallot require repeat surgical intervention for pulmonary valve replacement secondary to pulmonary regurgitation. Catheter-based interventions have emerged as an attractive alternative to surgery in this patient population but it is limited by patient size or the anatomy of the right ventricular outflow tract. Hybrid approaches involving both cardiac interventionists and surgeons are being developed to overcome these limitations. The purpose of this review is to highlight the recent advances in the hybrid field of pulmonary valve replacement, summarizing the advantages and disadvantages of the “traditional” surgical and the new catheter-based techniques and discuss the direction future research should take to determine the optimal management for individual patients. PMID:26082929

Element Specific Imaging Using Muonic X-rays

NASA Astrophysics Data System (ADS)

Hillier, Adrian; Ishida, Katsu; Seller, Paul; Veale, Matthew C.; Wilson, Matthew D.

The RIKEN-RAL facility provides a source of negative muons that can be used to non-destructively determine the elemental composition of bulk samples. A negative muon can replace an electron in an atom and subsequently transition to lower orbital positions. As with conventional X-ray fluorescence, an X-ray photon is emitted with a characteristic energy to enable the transition between orbitals of an atom. As the mass of a negative muon is much greater than that of an electron, a higher energy X-ray photon is emitted when the negative muon transitions between orbitals compared to conventional X-ray fluorescence. The higher energy muonic X-rays are able to escape large samples even when they are emitted from lower Z atoms, making muonic X-rays fluorescence a unique method to characterize the elemental content of a sample. In a typical experiment a section of a sample will be probed with negative muons with the muon momentum tuned to interact at a desired depth in the sample. A small number of single element high purity Ge detectors are positioned to capture up to one photon each from each of the forty muon pulses per second at the RIKEN-RAL facility. This can provide a high resolution and high dynamic range X-ray energy spectrum when collected for several hours but can only provide a spatial average or single point elemental distribution per collection. Here, an STFC developed CdTe detector with 80 × 80 energy resolving channels has been used to demonstrate the ability to image the elemental distribution of a test sample. A test sample of C, Al, and Fe2O3 was positioned close to the detector surface and each of the 250 µm pitch pixels recorded a muonic X-ray energy spectrum. Results are presented to show the principal of this new technique and potential improvements to provide higher resolution and larger area elemental imaging using muonic X-rays are discussed.

Standardized methodology for transfemoral transcatheter aortic valve replacement with the Edwards Sapien XT valve under fluoroscopy guidance.

PubMed

Kasel, Albert M; Shivaraju, Anupama; Schneider, Stephan; Krapf, Stephan; Oertel, Frank; Burgdorf, Christof; Ott, Ilka; Sumer, Christian; Kastrati, Adnan; von Scheidt, Wolfgang; Thilo, Christian

2014-09-01

To provide a simplified, standardized methodology for a successful transfemoral transcatheter aortic valve replacement (TAVR) procedure with the Sapien XT valve in patients with severe aortic stenosis (AS). TAVR is currently reserved for patients with severe, symptomatic AS who are inoperable or at high operative risk. In many institutions, TAVR is performed under general anesthesia with intubation or with conscious sedation. In addition, many institutions still use transesophageal echo (TEE) during the procedure for aortic root angulations and positioning of the valve prior to implantation. Methods. We enrolled 100 consecutive patients (mean age, 80 ± 7 years; range, 50-94 years; female n=59) with severe symptomatic AS. Annulus measurements were based on computed tomography angiograms. All patients underwent fluoroscopy-guided transfemoral TAVR with little to no sedation and without simultaneous TEE. TAVR was predominantly performed with the use of local and central analgesics; only 36% of our cohort received conscious sedation. Procedural success of TAVR was 99%. Transthoracic echocardiography before discharge excluded aortic regurgitation (AR) >2 in all patients (AR >1; n=6). In-hospital stroke rate was 6%. The vessel closure system was successfully employed in 96%. Major vascular complication rate was 1%. The 30-day mortality was 2%. Fluoroscopy-guided TAVR with the use of just analgesics with or without conscious sedation is safe and effective, and this potentially enables a more time-effective and cost-effective procedure. This paper provides simplified, stepwise guidance on how to perform transfemoral TAVR with the Sapien XT valve.

Planar biaxial testing of heart valve cusp replacement biomaterials: Experiments, theory and material constants.

PubMed

Labrosse, Michel R; Jafar, Reza; Ngu, Janet; Boodhwani, Munir

2016-11-01

Aortic valve (AV) repair has become an attractive option to correct aortic insufficiency. Yet, cusp reconstruction with various cusp replacement materials has been associated with greater long-term repair failures, and it is still unknown how such materials mechanically compare with native leaflets. We used planar biaxial testing to characterize six clinically relevant cusp replacement materials, along with native porcine AV leaflets, to ascertain which materials would be best suited for valve repair. We tested at least six samples of: 1) fresh autologous porcine pericardium (APP), 2) glutaraldehyde fixed porcine pericardium (GPP), 3) St Jude Medical pericardial patch (SJM), 4) CardioCel patch (CC), 5) PeriGuard (PG), 6) Supple PeriGuard (SPG) and 7) fresh porcine AV leaflets (PC). We introduced efficient displacement-controlled testing protocols and processing, as well as advanced convexity requirements on the strain energy functions used to describe the mechanical response of the materials under loading. The proposed experimental and data processing pipeline allowed for a robust in-plane characterization of all the materials tested, with constants determined for two Fung-like hyperelastic, anisotropic strain energy models. Overall, CC and SPG (respectively PG) patches ranked as the closest mechanical equivalents to young (respectively aged) AV leaflets. Because the native leaflets as well as CC, PG and SPG patches exhibit significant anisotropic behaviors, it is suggested that the fiber and cross-fiber directions of these replacement biomaterials be matched with those of the host AV leaflets. The long-term performance of cusp replacement materials would ideally be evaluated in large animal models for AV disease and cusp repair, and over several months or more. Given the unavailability and impracticality of such models, detailed information on stress-strain behavior, as studied herein, and investigations of durability and valve dynamics will be the best surrogates

[Papillary muscle rupture complicating acute myocardial infarction--treatment with mitral valve replacement and coronary bypass surgery in acute phase].

PubMed

Kyo, S; Miyamoto, N; Yokote, Y; Ueda, K; Takamoto, S; Omoto, R

1996-06-01

Complete rupture of a papillary muscle following acute myocardial infarction is a severe complication that is typically associated with acute left ventricular failure, pulmonary edema, and relentless clinical deterioration. The reported mortality rates without surgical intervention is almost 90%, therefore, prompt operation without prolonged attempts at medical stabilization is the key to decrease operative mortality. Although the complete coronary revascularization in conjunction with mitral valve replacement is advocated in the western medical academic society, there is only a few case of conjunct surgery has been reported in Japan. Three successful cases of conjunct surgery of mitral valve replacement and coronary complete revascularization in acute phase within one week from the onset of acute myocardial infarction (AMI) are described. There were one male and two female patients with an average age of 60-year-old (range 48-67), who developed cardiogenic shock and admitted to our hospital. The average interval between onset of AMI and the appearance of mitral regurgitation (MR) was 38 hours, and that of the appearance of MR and admission was 40 hours. Surgeries were performed within 26 hours (average 13 hours) after admission. The mitral valve was replaced with a mechanical valve (St. Jude Medical Valve) and a complete coronary revasculatization was done using saphenous vein graft. The average period of operation time and aortic cross clamping time were 6 hours 22 minutes and 109 minutes respectively. The average number of coronary grafting was 2.3 (range 1-3). Postoperative recovery from cardiogenic shock was uneventful in all three patients. The average periods of ICU stay and hospital stay were 5 days and 43 days respectively. All patients have regained their social activities with mean follow up period of 52 months. Since ischemic heart disease remains the leading cause of death in such patients, it is suggested that complete coronary revascularization

From lows to highs: using low-resolution models to phase X-ray data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuart, David I.; Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot; Abrescia, Nicola G. A., E-mail: nabrescia@cicbiogune.es

2013-11-01

An unusual example of how virus structure determination pushes the limits of the molecular replacement method is presented. The study of virus structures has contributed to methodological advances in structural biology that are generally applicable (molecular replacement and noncrystallographic symmetry are just two of the best known examples). Moreover, structural virology has been instrumental in forging the more general concept of exploiting phase information derived from multiple structural techniques. This hybridization of structural methods, primarily electron microscopy (EM) and X-ray crystallography, but also small-angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR) spectroscopy, is central to integrative structural biology. Here,more » the interplay of X-ray crystallography and EM is illustrated through the example of the structural determination of the marine lipid-containing bacteriophage PM2. Molecular replacement starting from an ∼13 Å cryo-EM reconstruction, followed by cycling density averaging, phase extension and solvent flattening, gave the X-ray structure of the intact virus at 7 Å resolution This in turn served as a bridge to phase, to 2.5 Å resolution, data from twinned crystals of the major coat protein (P2), ultimately yielding a quasi-atomic model of the particle, which provided significant insights into virus evolution and viral membrane biogenesis.« less

A cost-utility analysis of transcatheter versus surgical aortic valve replacement for the treatment of aortic stenosis in the population with intermediate surgical risk.

PubMed

Tam, Derrick Y; Hughes, Avery; Fremes, Stephen E; Youn, Saerom; Hancock-Howard, Rebecca L; Coyte, Peter C; Wijeysundera, Harindra C

2018-05-01

Although transcatheter aortic valve implantation has been shown to be noninferior to surgical aortic valve replacement in patients with severe aortic stenosis at intermediate surgical risk, the cost-effectiveness of this strategy in this population is unknown. Our objective was to conduct a cost-utility analysis comparing transcatheter aortic valve implantation with surgical aortic valve replacement in the population with intermediate risk severe aortic stenosis. A fully probabilistic Markov model with 30-day cycles was constructed from the Canadian third-party payer's perspective to estimate the difference in cost and effectiveness (measured as quality-adjusted life years) of transcatheter aortic valve implantation versus surgical aortic valve replacement for intermediate-risk patients over a lifetime time horizon, discounted at 1.5% per annum. Clinical trial data from The Placement of Aortic Transcatheter Valve 2 informed the efficacy inputs. Costs (adjusted to 2016 Canadian dollars) were obtained from the Canadian Institute of Health Information and the Ontario Schedule of Benefits. Incremental cost-effectiveness ratios were calculated. In the base-case analysis, total lifetime costs for transcatheter aortic valve implantation were $10,548 higher than surgical aortic valve replacement but added 0.23 quality-adjusted life years, for an incremental cost-effectiveness ratio of $46,083/quality-adjusted life-years gained. Deterministic 1-way analyses showed that the incremental cost-effectiveness ratio was sensitive to rates of complications and cost of the transcatheter aortic valve implantation prosthesis. There was moderate-to-high parameter uncertainty; transcatheter aortic valve implantation was the preferred option in only 52.7% and 55.4% of the simulations at a $50,000 and $100,000 per quality-adjusted life years willingness-to-pay thresholds, respectively. On the basis of current evidence, transcatheter aortic valve implantation may be cost-effective for the

Mid- to long-term outcome comparison of the Medtronic Hancock II and bi-leaflet mechanical aortic valve replacement in patients younger than 60 years of age: a propensity-matched analysis.

PubMed

Wang, Yin; Chen, Si; Shi, Jiawei; Li, Geng; Dong, Nianguo

2016-03-01

This study aims to compare mid-long-term clinical outcomes between patients younger than 60 years of age undergoing bioprosthetic and mechanical aortic valve replacement. From January 2002 to December 2009, patients younger than 60 years of age who received Medtronic Hancock II porcine bioprostheses were selected and compared with those who received mechanical bi-leaflet valves in the aortic position. A stepwise logistic regression propensity score identified a subset of 112 evenly matched patient-pairs. Mid-long-term outcomes of survival, valve-related reoperations, thromboembolic events and bleeding events were assessed. The follow-up was only 95.1% complete. Fourteen measurable variables were statistically similar for the matched cohort. Postoperative in-hospital mortality was 3.6% (bioprosthetic valves) and 2.7% (mechanical valves) (P = 0.700). Survival at 5 and 10 years was 96.3 and 88.7% for patients receiving bioprosthetic valve replacement versus 96.3 and 87.9% for patients receiving mechanical valve replacement (P = 0.860), respectively. At 5 and 10 years after operations, freedom from valve-related reoperation was 97.2 and 94.8% for patients receiving mechanical valve replacement, and 96.3 and 90.2% for patients receiving bioprosthetic valve replacement (P = 0.296), respectively. There was no difference between freedom from thromboembolic events (P = 0.528) and bleeding events (P = 0.128) between the matched groups during the postoperative 10 years. In patients younger than 60 years of age undergoing aortic valve replacement, mid-long-term survival rate was similar for patients receiving bioprosthetic versus mechanical valve replacement. Bioprosthetic valves were associated with a trend for a lower risk of anticoagulation treatment and did not have significantly greater likelihood of a reoperation. These findings suggest that a bioprosthetic valve may be a reasonable choice for AVR in patients younger than 60 years of age. © The Author 2015. Published by

Pannus overgrowth after mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis.

PubMed

Oda, Takeshi; Kato, Seiya; Tayama, Eiki; Fukunaga, Shuji; Akashi, Hidetoshi; Aoyagi, Shigeaki

2009-01-01

A Carpentier-Edwards pericardial (CEP) bioprosthesis was explanted from an 81-year-old woman due to nonstructural dysfunction 9 years after mitral valve replacement. The nonstructural dysfunction produced severe regurgitation in the mitral position. During the surgery, excessive pannus overgrowth was seen on the left ventricular side of the CEP bioprosthesis. Pannus overgrowth was prominent on one leaflet. That leaflet was stiff and shortened due to the excessive overgrowth of pannus. In this patient, the distortion of one leaflet was the main reason for transvalvular leakage of the CEP bioprosthesis in the mitral position. A new CEP bioprosthesis was implanted in the mitral position. Pathological analysis revealed fibrotic pannus with a small amount of cellular material over the leaflets of the resected CEP valve. This change was marked on the distorted leaflet.

Effects of tranexamic acid on coagulation indexes of patients undergoing heart valve replacement surgery under cardiopulmonary bypass

PubMed Central

Liu, Fei; Xu, Dong; Zhang, Kefeng; Zhang, Jian

2016-01-01

This study aims to explore the effects of tranexamic acid on the coagulation indexes of patients undergoing heart valve replacement surgery under the condition of cardiopulmonary bypass (CPB). One hundred patients who conformed to the inclusive criteria were selected and divided into a tranexamic acid group and a non-tranexamic acid group. They all underwent heart valve replacement surgery under CPB. Patients in the tranexamic acid group were intravenously injected with 1 g of tranexamic acid (100 mL) at the time point after anesthesia induction and before skin incision and at the time point after the neutralization of heparin. Patients in the non-tranexamic acid group were given 100 mL of normal saline at corresponding time points, respectively. Then the coagulation indexes of the two groups were analyzed. The activated blood clotting time (ACT) of the two groups was within normal scope before CPB, while four coagulation indexes including prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), and fibrinogen (FIB) had significant increases after surgery; the PT and INR of the tranexamic acid group had a remarkable decline after surgery. All the findings suggest that the application of tranexamic acid in heart valve replacement surgery under CPB can effectively reduce intraoperative and postoperative blood loss. PMID:27694613

Purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies of great cormorant (Phalacrocorax carbo) haemoglobin.

PubMed

Jagadeesan, G; Malathy, P; Gunasekaran, K; Harikrishna Etti, S; Aravindhan, S

2014-11-01

Haemoglobin is the iron-containing oxygen-transport metalloprotein that is present in the red blood cells of all vertebrates. In recent decades, there has been substantial interest in attempting to understand the structural basis and functional diversity of avian haemoglobins. Towards this end, purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies have been carried out on cormorant (Phalacrocorax carbo) haemoglobin. Crystals were grown by the hanging-drop vapour-diffusion method using PEG 3350, NaCl and glycerol as precipitants. The crystals belonged to the trigonal system P3₁21, with unit-cell parameters a=b=55.64, c=153.38 Å, β=120.00°; a complete data set was collected to a resolution of 3.5 Å. Matthews coefficient analysis indicated that the crystals contained a half-tetramer in the asymmetric unit.

[Evaluation of the antithrombotic strategy in low thrombotic risk patients who underwent aortic valve replacement with a bioprosthesis].

PubMed

Aceves-Velázquez, Eduardo; Vieyra-Herrera, Gerardo; Rodríguez-Chávez, Laura; Herrera-Alarcón, Valentín

2017-07-16

According to current guidelines, in patients without additional risk factors who have undergone aortic valve replacement with a bioprosthesis, anticoagulation in the first 3 months after surgery is still a matter of debate. According to current evidence, aspirin in low doses is a reasonable alternative to vitamin K antagonists (VKA). A comparison is made between the incidence of thrombotic and haemorrhagic complications in patients with low thrombotic risk who underwent aortic valve replacement with a bioprosthesis in the National Institute of Cardiology of Ignacio Chávez of Mexico. The hypothesis: aspirin as monotherapy has a beneficial effect compared to VKA. The studied patients were the low thrombotic risk patients who underwent aortic valve replacement with a bioprosthesis in the National Institute of Cardiology of Ignacio Chávez of Mexico from 2011 to 2015. The groups studied were: aspirin only, VKA only, and the combination of VKA plus aspirin. The patients were retrospectively followed-up for 12 months, and the thrombotic and haemorrhagic complications were documented. Of the 231 patients included in the study, only one patient in the VKA only group presented with a haemorrhagic complication. No thrombotic complications were observed. In the present study no thrombotic complications were observed in patients who did not receive anticoagulation in the first 3 months after an aortic valve replacement with a bioprosthesis after a follow up period of 12 months. This suggests that the use of aspirin only is safe during this period. Copyright © 2017 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

[Aortic Valve Replacement after Balloon Valvuloplasty for Aortic Valve Stenosis in a Dialysis Patient with Cardiogenic Shock;Report of a Case].

PubMed

Takamatsu, Masanori; Hirotani, Takashi; Ohtsubo, Satoshi; Saito, Sumikatsu; Takeuchi, Shigeyuki; Hasegawa, Tasuku; Endo, Ayaka; Yamasaki, Yu; Hayashida, Kentaro

2015-06-01

A 67-year-old man on chronic hemodialysis was admitted with worsening congestive heart failure due to critical aortic stenosis. Echocardiography showed severe aortic stenosis with a valve area of 0.67 cm2 and an ejection fraction of 0.31. Cardiac catheterization revealed severe pulmonary hypertension with pulmonary artery pressures of 62/32 mmHg. In the middle of cardiac catheterization, the systolic pressure declined to 60 mmHg due to cardiogenic shock. Dopamine hydrochloride and dobutamine hydrochloride infusions were necessary to maintain a systolic pressure greater than 80 mmHg. Balloon aortic valvuloplasty was urgently performed. The patient's symptoms rapidly resolved except for angina on exertion. One month later, elective aortic valve replacement was performed. The postoperative course was uneventful and the he was discharged on the 60th postoperative day. A follow-up echocardiogram 6 months postoperatively revealed normal prosthetic valve function and an ejection fraction of 0.6.

X-ray beamsplitter

DOEpatents

Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

1989-01-01

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

Aortic valve replacement in a dialysis-dependent Jehovah's Witness: successful use of a minicircuit, microplegia, and multimodality blood conservation technique

PubMed Central

Sutton, Steve W.; Marcel, Randy

2007-01-01

We present the first reported case of an aortic valve replacement operation without blood transfusion in a 62-year-old Jehovah's Witness with dialysis-dependent chronic renal failure, severe anemia, severe aortic stenosis, and symptomatic angina with minimal exertion after an accident in which she suffered fractures of both her right arm and leg. She underwent successful valve replacement surgery after preoperative stabilization of her fractures and high-dose erythropoietin and iron supplement therapy preoperatively and postoperatively. The intraoperative blood conservation technique included a novel approach with a miniature cardiopulmonary bypass circuit and microplegia with limited hemodilution. High-risk valve surgery in patients who are Jehovah's Witnesses can be successful with a carefully planned multimodality blood conservation strategy. PMID:17256040

Search for Hard X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Astrophysics Data System (ADS)

Harmon, B. A.; Zhang, S. N.; Paciesas, W. S.; Tavani, M.; Kaaret, P.; Ford, E.

1994-12-01

We are investigating the possibility of hard x-ray emission from the recurrent soft x-ray transient and x-ray burst source Aquila X-1 (Aql X-1). Outbursts of this source are relatively frequent with a spacing of ~ 4-10 months (Kitamoto, S. et al. 1993, ApJ, 403, 315). The recent detections of hard tails (\\(>\\)20 keV) in low luminosity x-ray bursters (Barret, D. & Vedrenne, G. 1994, ApJ Supp. S. 92, 505) suggest that neutron star transient systems such as Aql X-1 can produce hard x-ray emission which is detectable by BATSE. We are correlating reported optical and soft x-ray observations since 1991 of Aql X-1 with BATSE observations in order to search for hard x-ray emission episodes, and to study their temporal and spectral evolution. We will present preliminary results of this search in the 20-1000 keV band using the Earth occultation technique applied to the large area detectors. If this work is successful, we hope to alert the astronomical community for the next Aql X-1 outburst expected in 1995. Simultaneous x-ray/hard x-ray and optical observations of Aql X-1 during outburst would be of great importance for the modeling of soft x-ray transients and related systems.

[Anesthesia for total and descending aorta replacement and aortic valve replacement for post-repair aneurysm of coarctation of aorta and aortic stenosis].

PubMed

Furuichi, Yuko; Shimizu, Jun; Sakamoto, Atsuhiro

2012-04-01

We experienced anesthesia for total arch and descending aorta replacement and aortic valve replacement for post-repair aneurysm of coarctation of aorta and aortic stenosis. Because there was possibility that post coarctectomy syndrome would occur after repair of coarctation of aorta, administration of depressor that acts on renin-angiotensin-aldosterone and careful observation were needed postoperatively. In consideration of the development of collateral vessels, preoperative imaging evaluation was added and operative method in cardiopulmonary bypass was adjusted. Careful preoperative evaluation is very important in cardiac anesthesia.

X-ray beamsplitter

DOEpatents

Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

1987-08-07

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

Aortic valve replacement and repair of left ventricular pseudoaneurysm in a Jehovah’s Witness

PubMed Central

Perrotti, Andrea; Vaislic, Claude; Chocron, Sidney

2013-01-01

The preoperative and surgical management of a giant left ventricular pseudoaneurysm(LVP) associated with aortic valve replacement in a 76 year old male Jehovah’s Witness patient is reported. The satisfactory recovery observed in this patient demonstrates the feasibility of this complex surgical procedure even in this particular patient population. PMID:25478494

Can X-ray spectrum imaging replace backscattered electrons for compositional contrast in the scanning electron microscope?

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2011-01-01

The high throughput of the silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS) enables X-ray spectrum imaging (XSI) in the scanning electron microscope to be performed in frame times of 10-100 s, the typical time needed to record a high-quality backscattered electron (BSE) image. These short-duration XSIs can reveal all elements, except H, He, and Li, present as major constituents, defined as 0.1 mass fraction (10 wt%) or higher, as well as minor constituents in the range 0.01-0.1 mass fraction, depending on the particular composition and possible interferences. Although BSEs have a greater abundance by a factor of 100 compared with characteristic X-rays, the strong compositional contrast in element-specific X-ray maps enables XSI mapping to compete with BSE imaging to reveal compositional features. Differences in the fraction of the interaction volume sampled by the BSE and X-ray signals lead to more delocalization of the X-ray signal at abrupt compositional boundaries, resulting in poorer spatial resolution. Improved resolution in X-ray elemental maps occurs for the case of a small feature composed of intermediate to high atomic number elements embedded in a matrix of lower atomic number elements. XSI imaging strongly complements BSE imaging, and the SDD-EDS technology enables an efficient combined BSE-XSI measurement strategy that maximizes the compositional information. If 10 s or more are available for the measurement of an area of interest, the analyst should always record the combined BSE-XSI information to gain the advantages of both measures of compositional contrast. Copyright © 2011 Wiley Periodicals, Inc.

Assessment of Hemodynamic Conditions in the Aorta Following Root Replacement with Composite Valve-Conduit Graft.

PubMed

Cheng, Zhuo; Kidher, Emaddin; Jarral, Omar A; O'Regan, Declan P; Wood, Nigel B; Athanasiou, Thanos; Xu, Xiao Yun

2016-05-01

This paper presents the analysis of detailed hemodynamics in the aortas of four patients following replacement with a composite bio-prosthetic valve-conduit. Magnetic resonance image-based computational models were set up for each patient with boundary conditions comprising subject-specific three-dimensional inflow velocity profiles at the aortic root and central pressure waveform at the model outlet. Two normal subjects were also included for comparison. The purpose of the study was to investigate the effects of the valve-conduit on flow in the proximal and distal aorta. The results suggested that following the composite valve-conduit implantation, the vortical flow structure and hemodynamic parameters in the aorta were altered, with slightly reduced helical flow index, elevated wall shear stress and higher non-uniformity in wall shear compared to normal aortas. Inter-individual analysis revealed different hemodynamic conditions among the patients depending on the conduit configuration in the ascending aorta, which is a key factor in determining post-operative aortic flow. Introducing a natural curvature in the conduit to create a smooth transition between the conduit and native aorta may help prevent the occurrence of retrograde and recirculating flow in the aortic arch, which is particularly important when a large portion or the entire ascending aorta needs to be replaced.

Triple valve surgery: a 25-year experience.

PubMed

Yilmaz, Mustafa; Ozkan, Murat; Böke, Erkmen

2004-09-01

Surgical treatment of rheumatic valvular disease still constitutes a significant number of cardiac operations in developing countries. Despite improvements in myocardial protection and cardiopulmonary bypass techniques, triple valve operations (aortic, mitral and tricuspid valves) are still challenging because of longer duration of cardiopulmonary bypass and higher degree of myocardial decompensation. This study was instituted in order to assess results of triple valve surgery. Between 1977 and 2002, 34 patients underwent triple valve surgery in our clinic by the same surgeon (EB). Eleven patients underwent triple valve replacement (32.4%) and 23 underwent tricuspid valve annuloplasty with aortic and mitral valve replacements (67.6%). There was no significant difference between the two groups of patients who underwent triple valve replacement and aortic and mitral valve replacement with tricuspid valve annuloplasty. There were 4 hospital deaths (11.8%) occurring within 30 days. The duration of follow-up for 30 survivors ranged from 6 to 202 months (mean 97 months). The actuarial survival rates were 85%, 72%, and 48% at 5, 10, and 15 years respectively. Actuarial freedom from reoperation rates at 5, 10, and 15 years was 86.3%, 71.9%, and 51.2%, respectively. Freedom from cerebral thromboembolism and anticoagulation-related hemorrhage rates, expressed in actuarial terms was 75.9% and 62.9% at 5 and 10 years. Major cerebral complications occurred in 10 of the 30 patients. We prefer replacing, if repairing is not possible, the tricuspid valve, with a bileaflet mechanical prosthesis in a patient with valve replacement of the left heart who will be anticoagulated in order to avoid unfavorable properties of bioprosthesis like degeneration and of old generation mechanical prosthesis like thrombosis and poor hemodynamic function. In recent years, results of triple valve surgery either with tricuspid valve conservation or valve replacement in suitable cases have become

Transcatheter aortic valve replacement

MedlinePlus

... fully will restrict blood flow. This is called aortic stenosis. If there is also a leak, it is ... TAVR is used for people with severe aortic stenosis who aren't ... valve . In adults, aortic stenosis usually occurs due to calcium ...

X-Ray Polarization from High Mass X-Ray Binaries

NASA Technical Reports Server (NTRS)

Kallman, T.; Dorodnitsyn, A.; Blondin, J.

2015-01-01

X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. A class of potential targets for future X-ray polarization observations is the high mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature which depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

Be/X-ray Binary Science for Future X-ray Timing Missions

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2011-01-01

For future missions, the Be/X-ray binary community needs to clearly define our science priorities for the future to advocate for their inclusion in future missions. In this talk, I will describe current designs for two potential future missions and Be X-ray binary science enabled by these designs. The Large Observatory For X-ray Timing (LOFT) is an X-ray timing mission selected in February 2011 for the assessment phase from the 2010 ESA M3 call for proposals. The Advanced X-ray Timing ARray (AXTAR) is a NASA explorer concept X-ray timing mission. This talk is intended to initiate discussions of our science priorities for the future.

Abdomen X-Ray (Radiography)

MedlinePlus

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive ...

The Dram As An X-Ray Sensor

NASA Astrophysics Data System (ADS)

Jacobs, Alan M.; Cox, John D.; Juang, Yi-Shung

1987-01-01

A solid-state digital x-ray detector is described which can replace high resolution film in industrial radiography and has potential for application in some medical imaging. Because of the 10 micron pixel pitch on the sensor, contact magnification radiology is possible and is demonstrated. Methods for frame speed increase and integration of sensor to a large format are discussed.

Effects of tranexamic acid on coagulation indexes of patients undergoing heart valve replacement surgery under cardiopulmonary bypass.

PubMed

Liu, Fei; Xu, Dong; Zhang, Kefeng; Zhang, Jian

2016-12-01

This study aims to explore the effects of tranexamic acid on the coagulation indexes of patients undergoing heart valve replacement surgery under the condition of cardiopulmonary bypass (CPB). One hundred patients who conformed to the inclusive criteria were selected and divided into a tranexamic acid group and a non-tranexamic acid group. They all underwent heart valve replacement surgery under CPB. Patients in the tranexamic acid group were intravenously injected with 1 g of tranexamic acid (100 mL) at the time point after anesthesia induction and before skin incision and at the time point after the neutralization of heparin. Patients in the non-tranexamic acid group were given 100 mL of normal saline at corresponding time points, respectively. Then the coagulation indexes of the two groups were analyzed. The activated blood clotting time (ACT) of the two groups was within normal scope before CPB, while four coagulation indexes including prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), and fibrinogen (FIB) had significant increases after surgery; the PT and INR of the tranexamic acid group had a remarkable decline after surgery. All the findings suggest that the application of tranexamic acid in heart valve replacement surgery under CPB can effectively reduce intraoperative and postoperative blood loss. © The Author(s) 2016.

A search for X-ray polarization in cosmic X-ray sources. [binary X-ray sources and supernovae remnants

NASA Technical Reports Server (NTRS)

Hughes, J. P.; Long, K. S.; Novick, R.

1983-01-01

Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission.

X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Technical Reports Server (NTRS)

Tavani, Marco

1998-01-01

Aquila X-1 is the most prolific of soft X-ray transients. It is believed to contain a rapidly spinning neutron star sporadically accreting near the Eddington limit from a low-mass companion star. The interest in studying the repeated X-ray outbursts from Aquila X-1 is twofold: (1) studying the relation between optical, soft and hard X-ray emission during the outburst onset, development and decay; (2) relating the spectral component to thermal and non-thermal processes occurring near the magnetosphere and in the boundary layer of a time-variable accretion disk. Our investigation is based on the BATSE monitoring of Aquila X-1 performed by our group. We observed Aquila X-1 in 1997 and re-analyzed archival information obtained in April 1994 during a period of extraordinary outbursting activity of the source in the hard X-ray range. Our results allow, for the first time for this important source, to obtain simultaneous spectral information from 2 keV to 200 keV. A black body (T = 0.8 keV) plus a broken power-law spectrum describe accurately the 1994 spectrum. Substantial hard X-ray emission is evident in the data, confirming that the accretion phase during sub-Eddington limit episodes is capable of producing energetic hard emission near 5 x 10(exp 35) ergs(exp -1). A preliminary paper summarizes our results, and a more comprehensive account is being written. We performed a theoretical analysis of possible emission mechanisms, and confirmed that a non-thermal emission mechanism triggered in a highly sheared magnetosphere at the accretion disk inner boundary can explain the hard X-ray emission. An anticorrelation between soft and hard X-ray emission is indeed prominently observed as predicted by this model.

Robot-assisted real-time magnetic resonance image-guided transcatheter aortic valve replacement.

PubMed

Miller, Justin G; Li, Ming; Mazilu, Dumitru; Hunt, Tim; Horvath, Keith A

2016-05-01

Real-time magnetic resonance imaging (rtMRI)-guided transcatheter aortic valve replacement (TAVR) offers improved visualization, real-time imaging, and pinpoint accuracy with device delivery. Unfortunately, performing a TAVR in a MRI scanner can be a difficult task owing to limited space and an awkward working environment. Our solution was to design a MRI-compatible robot-assisted device to insert and deploy a self-expanding valve from a remote computer console. We present our preliminary results in a swine model. We used an MRI-compatible robotic arm and developed a valve delivery module. A 12-mm trocar was inserted in the apex of the heart via a subxiphoid incision. The delivery device and nitinol stented prosthesis were mounted on the robot. Two continuous real-time imaging planes provided a virtual real-time 3-dimensional reconstruction. The valve was deployed remotely by the surgeon via a graphic user interface. In this acute nonsurvival study, 8 swine underwent robot-assisted rtMRI TAVR for evaluation of feasibility. Device deployment took a mean of 61 ± 5 seconds. Postdeployment necropsy was performed to confirm correlations between imaging and actual valve positions. These results demonstrate the feasibility of robotic-assisted TAVR using rtMRI guidance. This approach may eliminate some of the challenges of performing a procedure while working inside of an MRI scanner, and may improve the success of TAVR. It provides superior visualization during the insertion process, pinpoint accuracy of deployment, and, potentially, communication between the imaging device and the robotic module to prevent incorrect or misaligned deployment. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Enhancement of valve metal osteoconductivity by one-step hydrothermal treatment.

PubMed

Zuldesmi, Mansjur; Waki, Atsushi; Kuroda, Kensuke; Okido, Masazumi

2014-09-01

In this study, we produced super-hydrophilic surfaces of valve metals (Ti, Nb, Ta and Zr) by one-step hydrothermal treatment. Their surface characteristics and osteoconductivity using an in vivo test were then assessed. These data were compared with that of as-polished, as-anodized and both anodized+hydrothermally treated samples. Changes in surface chemistry, surface morphology and structure were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffractometry. The results revealed that the water contact angles of valve metals were decreased by hydrothermal treatment and continued to reduce dramatically until lower than 10° after being immersed in phosphate buffered solution. By producing super-hydrophilic surfaces, the osteoconductivity of these hydrothermally treated valve metals was enhanced by up to 55%. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of the structure of the aortic valve and ascending aorta in adults having aortic valve replacement for aortic stenosis versus for pure aortic regurgitation and resection of the ascending aorta for aneurysm.

PubMed

Roberts, William Clifford; Vowels, Travis James; Ko, Jong Mi; Filardo, Giovanni; Hebeler, Robert Frederick; Henry, Albert Carl; Matter, Gregory John; Hamman, Baron Lloyd

2011-03-01

There is debate concerning whether an aneurysmal ascending aorta should be replaced when associated with a dysfunctioning aortic valve that is to be replaced. To examine this issue, we divided the patients by type of aortic valve dysfunction-either aortic stenosis (AS) or pure aortic regurgitation (AR)-something not previously undertaken. Of 122 patients with ascending aortic aneurysm (unassociated with aortitis or acute dissection), the aortic valve was congenitally malformed (unicuspid or bicuspid) in 58 (98%) of the 59 AS patients, and in 38 (60%) of the 63 pure AR patients. Ascending aortic medial elastic fiber loss (EFL) (graded 0 to 4+) was zero or 1+ in 53 (90%) of the AS patients, in 20 (53%) of the 38 AR patients with bicuspid valves, and in all 12 AR patients with tricuspid valves unassociated with the Marfan syndrome. An unadjusted analysis showed that, among the 96 patients with congenitally malformed valves, the 38 AR patients had a significantly higher likelihood of 2+ to 4+ EFL than the 58 AS patients (crude odds ratio: 8.78; 95% confidence interval: 2.95, 28.13). These data strongly suggest that the type of aortic valve dysfunction-AS versus pure AR-is very helpful in predicting loss of aortic medial elastic fibers in patients with ascending aortic aneurysms and aortic valve disease.

"X-Ray Transients in Star-Forming Regions" and "Hard X-Ray Emission from X-Ray Bursters"

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Kaaret, Philip

1999-01-01

This grant funded work on the analysis of data obtained with the Burst and Transient Experiment (BATSE) on the Compton Gamma-Ray Observatory. The goal of the work was to search for hard x-ray transients in star forming regions using the all-sky hard x-ray monitoring capability of BATSE. Our initial work lead to the discovery of a hard x-ray transient, GRO J1849-03. Follow-up observations of this source made with the Wide Field Camera on BeppoSAX showed that the source should be identified with the previously known x-ray pulsar GS 1843-02 which itself is identified with the x-ray source X1845-024 originally discovered with the SAS-3 satellite. Our identification of the source and measurement of the outburst recurrence time, lead to the identification of the source as a Be/X-ray binary with a spin period of 94.8 s and an orbital period of 241 days. The funding was used primarily for partial salary and travel support for John Tomsick, then a graduate student at Columbia University. John Tomsick, now Dr. Tomsick, received his Ph.D. from Columbia University in July 1999, based partially on results obtained under this investigation. He is now a postdoctoral research scientist at the University of California, San Diego.

Pericardial tissue valves and Gore-Tex conduits as an alternative for right ventricular outflow tract replacement in children.

PubMed

Allen, Bradley S; El-Zein, Chawki; Cuneo, Betina; Cava, Joseph P; Barth, Mary Jane; Ilbawi, Michel N

2002-09-01

There is still no perfect conduit for reconstruction of the right ventricular outflow tract (RVOT) in children. Homografts are not always available in the appropriate size, and degenerate in a few years. This study evaluates the pericardial valve with Gore-Tex conduit as an alternative for RVOT construction. From January 1, 1993, to September 30, 1999, a pericardial tissue valve was inserted in all patients undergoing RVOT reconstruction or pulmonary valve replacement (PVR) who were large enough to accommodate a tissue valve. In patients without a native main pulmonary artery, a new technique was used to construct an RV-PA conduit out of a flat sheet of Gore-Tex, as Dacron frequently leads to stenosis. Data were collected by retrospective review, follow-up echocardiograms, and assessment by a single cardiologist. There were 48 patients, 22 undergoing a PVR alone and 26 a RV-PA valved Gore-Tex conduit. Diagnosis included tetralogy of Fallot (n = 25); truncus arteriosis (n = 9); ventricular septal defect with PA (n = 5); DORV (n = 4); D-TGA with PS (n = 2); and 1 each IAA with sub AS, VSD with PI, and PS s/p Ross procedure. Patient age ranged from 3 to 33 years and 98% were reoperations. The valve sizes ranged from 19 to 33 mm and the median hospital length of stay was 4 days. There were 2 (4.2%) perioperative and 1 (2.1%) late deaths, none related to the valve or Gore-Tex conduit. At a follow-up of 15 to 86 months (mean 43 +/- 16 months), all remaining 45 patients are New York Heart Association class I, all valves are functional, and no patient has required valve or conduit replacement or revision; more importantly, echocardiogram revealed no significant valve or conduit stenosis (mean gradient 16 +/- 8 mm Hg) and no evidence of regurgitation or structural degeneration. A pericardial tissue valve and Gore-Tex conduit provides a reliable alternative for RVOT reconstruction in pediatric patients. It is readily available, molds in the limited retrosternal space, and

Long-term results after aortic valve replacement with the Biocor PSB stentless xenograft in the elderly.

PubMed

Luciani, G B; Santini, F; Auriemma, S; Barozzi, L; Bertolini, P; Mazzucco, A

2001-05-01

This study seeks to define the long-term results after Biocor PSB stentless aortic valve replacement (AVR) in elderly patients, including the effects of No-React treatment. We reviewed the outcomes of 106 consecutive patients, aged 70+/-6 years, having Biocor PSB (93 standard, 13 No-React) AVR between October 1992 and October 1996. There were three early deaths (3%) and 15 late deaths (15%), during a mean follow-up of 5.8+/-1.6 years. At 8 years, survival was 82%+/-4% and freedom from cardiac death was 94%+/-3%. Freedom from valve failure was 92%+/-4% at 8 years (No-React: 92%+/-8% at 4 years). Replacement of the xenograft was required in 5 patients. Freedom from reoperation was 91%+/-4% at 8 years (No-React: 92%+/-8% at 4 years). Four bleeding and two embolic events were recorded: overall valve-related event-free survival was 81%+/-7% at 8 years (No-React: 76%+/-12% at 4 years). Age of long-term survivors averaged 77+/-5 years and their New York Heart Association status was 1.3+/-0.6 (versus 2.9+/-0.6 preoperatively, p = 0.01). Satisfactory freedom from cardiac events and from valve deterioration added to uniform improvement in functional status despite advanced age and high prevalence of comorbid conditions make AVR with the Biocor PSB xenograft a valid long-term therapy for the elderly. No-React treatment does not influence xenograft durability.

Lumbosacral spine x-ray

MedlinePlus

X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray ...

X-ray ptychography

NASA Astrophysics Data System (ADS)

Pfeiffer, Franz

2018-01-01

X-ray ptychographic microscopy combines the advantages of raster scanning X-ray microscopy with the more recently developed techniques of coherent diffraction imaging. It is limited neither by the fabricational challenges associated with X-ray optics nor by the requirements of isolated specimen preparation, and offers in principle wavelength-limited resolution, as well as stable access and solution to the phase problem. In this Review, we discuss the basic principles of X-ray ptychography and summarize the main milestones in the evolution of X-ray ptychographic microscopy and tomography over the past ten years, since its first demonstration with X-rays. We also highlight the potential for applications in the life and materials sciences, and discuss the latest advanced concepts and probable future developments.

Valve-sparing aortic root replacement in patients with Marfan syndrome enrolled in the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions.

PubMed

Song, Howard K; Preiss, Liliana R; Maslen, Cheryl L; Kroner, Barbara; Devereux, Richard B; Roman, Mary J; Holmes, Kathryn W; Tolunay, H Eser; Desvigne-Nickens, Patrice; Asch, Federico M; Milewski, Rita K; Bavaria, Joseph; LeMaire, Scott A

2014-05-01

The long-term outcomes of aortic valve-sparing (AVS) root replacement in Marfan syndrome (MFS) patients remain uncertain. The study aim was to determine the utilization and outcomes of AVS root replacement in MFS patients enrolled in the Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC). At the time of this analysis, 788 patients with MFS were enrolled in the GenTAC Registry, of whom 288 had undergone aortic root replacement. Patients who had undergone AVS procedures were compared to those who had undergone aortic valve replacement (AVR). AVS root replacement was performed in 43.5% of MFS patients, and the frequency of AVS was increased over the past five years. AVS patients were younger at the time of surgery (31.0 versus 36.3 years, p = 0.006) and more likely to have had elective rather than emergency surgery compared to AVR patients, in whom aortic valve dysfunction and aortic dissection was the more likely primary indication for surgery. After a mean follow up of 6.2 +/- 3.6 years, none of the 87 AVS patients had required reoperation; in contrast, after a mean follow up of 10.5 +/- 7.6 years, 11.5% of AVR patients required aortic root reoperation. Aortic valve function has been durable, with 95.8% of AVS patients having aortic insufficiency that was graded as mild or less. AVS root replacement is performed commonly among the MFS population, and the durability of the aortic repair and aortic valve function have been excellent to date. These results justify a continued use of the procedure in an elective setting. The GenTAC Registry will be a useful resource to assess the long-term durability of AVS root replacement in the future.

Stacked, filtered multi-channel X-ray diode array

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacNeil, Lawrence; Dutra, Eric; Raphaelian, Mark

2015-08-01

There are many types of X-ray diodes used for X-ray flux or spectroscopic measurements and for estimating the spectral shape of the VUV to soft X-ray spectrum. However, a need exists for a low-cost, robust X-ray diode to use for experiments in hostile environments on multiple platforms, and for experiments that utilize forces that may destroy the diode(s). Since the typical proposed use required a small size with a minimal single line-of-sight, a parallel array could not be used. So, a stacked, filtered multi-channel X-ray diode array was developed, called the MiniXRD. To achieve significant cost savings while maintaining robustnessmore » and ease of field setup, repair, and replacement, we designed the system to be modular. The filters were manufactured in-house and cover the range from 450 eV to 5000 eV. To achieve the line-of-sight accuracy needed, we developed mounts and laser alignment techniques. We modeled and tested elements of the diode design at NSTec Livermore Operations (NSTec / LO) to determine temporal response and dynamic range, leading to diode shape and circuitry changes to optimize impedance and charge storage. The authors fielded individual and stacked systems at several national facilities as ancillary "ride-along" diagnostics to test and improve the design usability. This paper presents the MiniXRD system performance, which supports consideration as a viable low-costalternative for multiple-channel low-energy X-ray measurements. This diode array is currently at Technical Readiness Level (TRL) 6.« less

Minimally invasive aortic valve replacement in high risk patient groups

PubMed Central

Lewis, Harriet; Benedetto, Umberto; Caputo, Massimo; Angelini, Gianni; Vohra, Hunaid A.

2017-01-01

Minimally invasive aortic valve replacement (AVR) aims to preserve the sternal integrity and improve postoperative outcomes. In low risk patients, this technique can be achieved with comparable mortality to the conventional approach and there is evidence of possible reduction in intensive care and hospital length of stay, transfusion requirement, renal dysfunction, improved respiratory function and increased patient satisfaction. In this review, we aim to asses if these benefits can be transferred to the high risk patient groups. We therefore, discuss the available evidence for the following high risk groups: elderly patients, re-operative surgery, poor lung function, pulmonary hypertension, obesity, concomitant procedures and high risk score cohorts. PMID:28740685

Late outcomes for aortic valve replacement with the Carpentier-Edwards pericardial bioprosthesis: up to 17-year follow-up in 1,000 patients.

PubMed

McClure, R Scott; Narayanasamy, Narendren; Wiegerinck, Esther; Lipsitz, Stuart; Maloney, Ann; Byrne, John G; Aranki, Sary F; Couper, Gregory S; Cohn, Lawrence H

2010-05-01

This study reviews a single institution experience with the Carpentier-Edwards pericardial aortic valve bioprosthesis, concentrating on late outcomes. From December 1991 to June 2002, 1,000 patients underwent aortic valve replacement with the Carpentier-Edwards pericardial valve (mean follow-up 6.01 +/- 3.56 years). The institutional database was reviewed. Follow-up data were acquired through telephone interviews and mail-in questionnaires. Time-to-event analyses were performed by the Kaplan-Meier method. Mean age was 74.1 years; 545 patients (54.5%) were male. Mean preoperative ejection fraction was 52.5%. Isolated aortic valve replacement occurred in 372 cases (37.2%). Combined aortic valve replacement with coronary artery bypass grafting occurred in 443 cases (44.3%). The remaining 185 patients (18.5%) underwent complex procedures with concomitant mitral, tricuspid, or arch repair. One hundred forty patients (14.0%) had prior aortic valve surgery. Follow-up was 99.4% complete. Overall operative mortality was 7.2% (72 of 1,000). There were 503 late deaths (50.3%). Age-stratified survival at 15 years was 43.7% for patients less than 65 years of age; 18.2% for patients aged 65 to 75; and 9.4% for patients aged more than 75 years. There were 26 failed bioprostheses (2.6%) requiring reoperation. Structural valve deterioration was the cause in 13 of 26 cases (50%), endocarditis in 11 of 26 (42%), and perivalvular leak in 2 of 26 (7.6%). Age-stratified freedom from reoperation due to structural valve deterioration at 15 years was 34.7% for patients less than 65 years of age; 89.4% for patients aged 65 to 75; and 99.5% for patients aged more than 75 years. The Carpentier-Edwards pericardial bioprosthesis shows long-term durability with low rates of structural failure. Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

UNDERSTANDING X-RAY STARS:. The Discovery of Binary X-ray Sources

NASA Astrophysics Data System (ADS)

Schreier, E. J.; Tananbaum, H.

2000-09-01

The discovery of binary X-ray sources with UHURU introduced many new concepts to astronomy. It provided the canonical model which explained X-ray emission from a large class of galactic X-ray sources: it confirmed the existence of collapsed objects as the source of intense X-ray emission; showed that such collapsed objects existed in binary systems, with mass accretion as the energy source for the X-ray emission; and provided compelling evidence for the existence of black holes. This model also provided the basis for explaining the power source of AGNs and QSOs. The process of discovery and interpretation also established X-ray astronomy as an essential sub-discipline of astronomy, beginning its incorporation into the mainstream of astronomy.

Thoracic spine x-ray

MedlinePlus

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

Structural characterization of nano-oxide layers in PtMn based specular spin valves

NASA Astrophysics Data System (ADS)

Zhou, Min; Chen, Lifan; Diao, Zhitao; Park, Chang-Man; Huai, Yiming

2005-05-01

A systematic structure characterization of nano-oxide layers (NOLs) and specular spin valves using x-ray diffraction and high-resolution transmission electron microscopy (HRTEM) has been studied. High-angle x-ray diffraction data show almost identical fcc textures for both natural and plasma NOL spin-valves. Low-angle x-ray reflectivity spectrum shows more deteriorated Kiessig fringes at high incident angles for natural oxide sample, indicating rougher interfaces in natural oxidation than in plasma oxidation. Oxygen exposure plays an important role in NOLs process. Fabricating NOLs without any crystal structure degradation is critical to obtain high MR ratio. HRTEM reveals that oxide clusters mixing with insufficiently oxidized CoFe layers prevailed in natural NOL, and the natural oxidation was inhomogeneous. In contrast, plasma NOL has a thinner, more homogeneously oxidized CoFe layers with sharp interfaces. In plasma NOLs, the structures still maintain CoFe crystal structure. The structures and magnetic correlation of the NOL specular spin valves are discussed.

Transcatheter Aortic Valve Replacement by a Novel Suprasternal Approach.

PubMed

Codner, Pablo; Pugliese, Daniel; Kouz, Rémi; Patel, Amisha; Chen, Cheng-Han; Terre, Juan; Eudailey, Kyle W; Nazif, Tamim; Vahl, Torsten P; George, Isaac; Khalique, Omar K; Hahn, Rebecca T; Leon, Martin B; Kodali, Susheel; Borger, Michael

2018-04-01

Transcatheter aortic valve replacement (TAVR) provides therapy for patients with severe aortic stenosis at extreme, high, or intermediate surgical risk. Transfemoral access has been the preferred access route; however, this approach is not suitable for many TAVR candidates. A suprasternal approach may allow for earlier ambulation and shorter hospital stay as compared with other, nontransfemoral approaches. A total of 11 patients with unsuitable transfemoral access underwent suprasternal TAVR. Propensity matching was used to compare suprasternal patients to patients undergoing transaortic, transapical, and trans-subclavian TAVR. Groups were well matched for baseline characteristics. A self-expanding valve device was used in 6 (54.5%) and a balloon-expandable valve in 5 (45.5%) of the 11 patients treated by the suprasternal route. Suprasternal and trans-subclavian patients were able to ambulate earlier than patients treated by the transaortic route, a median 1.6 days (interquartile range [IQR]: 0.9 to 1.8), 1.6 days (IQR: 0.9 to 2.7), and 3.9 days (IQR: 1.9 to 4.5) after the procedure for suprasternal, trans-subclavian, and transaortic patients, respectively (p = 0.001). Length of hospitalization was shorter for patients treated by suprasternal or trans-subclavian access in comparison with patients treated by the transaortic or transapical approach: median 4 days (IQR: 3 to 8) and 4 days (IQR: 4 to 8) versus 8 days (IQR: 6 to 14) and 6 days (IQR: 7 to 11) for suprasternal and trans-subclavian versus transaortic and transapical, respectively (p = 0.01). Suprasternal and trans-subclavian access are associated with earlier ambulation and shorter hospitalization than other nontransfemoral TAVR routes, without an increase in complications. Further study is required to determine if suprasternal is the alternative access of choice for TAVR patients with poor transfemoral vasculature. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights

X-ray binaries

NASA Technical Reports Server (NTRS)

1976-01-01

Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

X-Ray Measurements Of A Thermo Scientific P385 DD Neutron Generator

NASA Astrophysics Data System (ADS)

Wharton, C. J.; Seabury, E. H.; Chichester, D. L.; Caffrey, A. J.; Simpson, J.; Lemchak, M.

2011-06-01

Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium-252 radioisotopic neutron sources in its PINS prompt gamma-ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x-ray output of the Thermo Scientific P385 deuterium-deuterium neutron generator. X rays are a normal byproduct from neutron generators, but depending on their intensity and energy, x rays can interfere with gamma rays from the object under test, increase gamma-spectrometer dead time, and reduce PGNAA system throughput. The P385 x-ray energy spectrum was measured with a high-purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x-ray emission points, the generator also was rotated 60° between measurements. The scans show the primary source of x-ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x-ray count rate, and its x-ray emission appears to be axially symmetric. A thin lead shield, 3.2 mm (1/8 inch) thick, reduced the 70-keV generator x rays to negligible levels.

Blocking Filters with Enhanced Throughput for X-Ray Microcalorimetry

NASA Technical Reports Server (NTRS)

Grove, David; Betcher, Jacob; Hagen, Mark

2012-01-01

New and improved blocking filters (see figure) have been developed for microcalorimeters on several mission payloads, made of high-transmission polyimide support mesh, that can replace the nickel mesh used in previous blocking filter flight designs. To realize the resolution and signal sensitivity of today s x-ray microcalorimeters, significant improvements in the blocking filter stack are needed. Using high-transmission polyimide support mesh, it is possible to improve overall throughput on a typical microcalorimeter such as Suzaku s X-ray Spectrometer by 11%, compared to previous flight designs. Using polyimide to replace standard metal mesh means the mesh will be transparent to energies 3 keV and higher. Incorporating polyimide s advantageous strength-to-weight ratio, thermal stability, and transmission characteristics permits thinner filter materials, significantly enhancing through - put. A prototype contamination blocking filter for ASTRO-H has passed QT-level acoustic testing. Resistive traces can also be incorporated to provide decontamination capability to actively restore filter performance in orbit.

Skull x-ray

MedlinePlus

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... Chernecky CC, Berger BJ. Radiography of skull, chest, and cervical spine - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. ...

Full-field transmission x-ray imaging with confocal polycapillary x-ray optics

PubMed Central

Sun, Tianxi; MacDonald, C. A.

2013-01-01

A transmission x-ray imaging setup based on a confocal combination of a polycapillary focusing x-ray optic followed by a polycapillary collimating x-ray optic was designed and demonstrated to have good resolution, better than the unmagnified pixel size and unlimited by the x-ray tube spot size. This imaging setup has potential application in x-ray imaging for small samples, for example, for histology specimens. PMID:23460760

X-ray generator

DOEpatents

Dawson, John M.

1976-01-01

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

X-ray lithography masking

NASA Technical Reports Server (NTRS)

Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

1998-01-01

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

Transcatheter aortic valve replacement using a self-expanding bioprosthesis in patients with severe aortic stenosis at extreme risk for surgery.

PubMed

Popma, Jeffrey J; Adams, David H; Reardon, Michael J; Yakubov, Steven J; Kleiman, Neal S; Heimansohn, David; Hermiller, James; Hughes, G Chad; Harrison, J Kevin; Coselli, Joseph; Diez, Jose; Kafi, Ali; Schreiber, Theodore; Gleason, Thomas G; Conte, John; Buchbinder, Maurice; Deeb, G Michael; Carabello, Blasé; Serruys, Patrick W; Chenoweth, Sharla; Oh, Jae K

2014-05-20

This study sought to evaluate the safety and efficacy of the CoreValve transcatheter heart valve (THV) for the treatment of severe aortic stenosis in patients at extreme risk for surgery. Untreated severe aortic stenosis is a progressive disease with a poor prognosis. Transcatheter aortic valve replacement (TAVR) with a self-expanding bioprosthesis is a potentially effective therapy. We performed a prospective, multicenter, nonrandomized investigation evaluating the safety and efficacy of self-expanding TAVR in patients with symptomatic severe aortic stenosis with prohibitive risks for surgery. The primary endpoint was a composite of all-cause mortality or major stroke at 12 months, which was compared with a pre-specified objective performance goal (OPG). A total of 41 sites in the United States recruited 506 patients, of whom 489 underwent attempted treatment with the CoreValve THV. The rate of all-cause mortality or major stroke at 12 months was 26.0% (upper 2-sided 95% confidence bound: 29.9%) versus 43.0% with the OPG (p < 0.0001). Individual 30-day and 12-month events included all-cause mortality (8.4% and 24.3%, respectively) and major stroke (2.3% and 4.3%, respectively). Procedural events at 30 days included life-threatening/disabling bleeding (12.7%), major vascular complications (8.2%), and need for permanent pacemaker placement (21.6%). The frequency of moderate or severe paravalvular aortic regurgitation was lower 12 months after self-expanding TAVR (4.2%) than at discharge (10.7%; p = 0.004 for paired analysis). TAVR with a self-expanding bioprosthesis was safe and effective in patients with symptomatic severe aortic stenosis at prohibitive risk for surgical valve replacement. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement; NCT01240902). Copyright © 2014 American College of Cardiology Foundation. Published by

The Melody® valve and Ensemble® delivery system for transcatheter pulmonary valve replacement

PubMed Central

McElhinney, Doff B; Hennesen, Jill T

2013-01-01

The Melody® transcatheter pulmonary valve (TPV) is a percutaneous valve system designed for the treatment of obstruction and/or regurgitation of prosthetic conduits placed between the right ventricle and pulmonary arteries in patients with congenital heart disease. In 2000, Melody TPV became the first transcatheter valve implanted in a human; in 2006 it became the first transcatheter valve commercially available anywhere in the world; and in 2010 it was launched as the first commercially available transcatheter valve in the United States. In this review, we present the clinical background against which the Melody valve was developed and implemented, introduce the rationale for and challenges of transcatheter valve technology for this population, outline the history and technical details of its development and use, and summarize currently available data concerning the performance of the device. PMID:23834411

Sinus x-ray

MedlinePlus

Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

X-Ray Data Booklet

Science.gov Websites

X-RAY DATA BOOKLET Center for X-ray Optics and Advanced Light Source Lawrence Berkeley National Laboratory Introduction X-Ray Properties of Elements Electron Binding Energies X-Ray Energy Emission Energies Table of X-Ray Properties Synchrotron Radiation Characteristics of Synchrotron Radiation History of X

Simulated Solar Flare X-Ray and Thermal Cycling Durability Evaluation of Hubble Space Telescope Thermal Control Candidate Replacement Materials

NASA Technical Reports Server (NTRS)

deGroh, Kim K.; Banks, Bruce A.; Sechkar, Edward A.; Scheiman, David A.

1998-01-01

During the Hubble Space Telescope (HST) second servicing mission (SM2), astronauts noticed that the multilayer insulation (MLI) covering the telescope was damaged. Large pieces of the outer layer of MLI (aluminized Teflon fluorinated ethylene propylene (Al-FEP)) were torn in several locations around the telescope. A piece of curled up Al-FEP was retrieved by the astronauts and was found to be severely embrittled, as witnessed by ground testing. Goddard Space Flight Center (GSFC) organized a HST MLI Failure Review Board (FRB) to determine the damage mechanism of FEP in the HST environment, and to recommend replacement insulation material to be installed on HST during the third servicing mission (SM3) in 1999. Candidate thermal control replacement materials were chosen by the FRB and tested for environmental durability under various exposures and durations. This paper describes durability testing of candidate materials which were exposed to charged particle radiation, simulated solar flare x-ray radiation and thermal cycling under load. Samples were evaluated for changes in solar absorptance and tear resistance. Descriptions of environmental exposures and durability evaluations of these materials are presented.

What Is Heart Valve Surgery?

MedlinePlus

... working correctly. Most valve replacements involve the aortic Tricuspid valve and mitral valves. The aortic valve separates ... where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t ...

What Is Heart Valve Disease?

MedlinePlus

... and replacing it with a man-made or biological valve. Biological valves are made from pig, cow, or human ... the valve. Man-made valves last longer than biological valves and usually don’t have to be ...

Low permanent pacemaker rates following Lotus device implantation for transcatheter aortic valve replacement due to modified implantation protocol.

PubMed

Krackhardt, Florian; Kherad, Behrouz; Krisper, Maximilian; Pieske, Burkert; Laule, Michael; Tschöpe, Carsten

2017-01-01

Conduction disturbances requiring permanent pacemaker implantation following transcatheter aortic valve replacement (TAVR) are a common problem. Pacemaker implantation rates after TAVR appear to be higher compared to conventional aortic valve replacement. The aim of this study was to analyze whether a high annulus implantation conveys the benefit of a decreased rate of permanent pacemaker implantation while being safe and successful according to Valve Academic Research Consortium 2 (VARC2)-criteria. A total of 23 patients with symptomatic severe aortic valve stenosis, an aortic annulus of 19-27 mm and at high risk for surgery were treated with the Lotus valve. In all patients the valve was implanted in a high annulus position via femoral access. The primary device performance endpoint was VARC2-defined device success after 30 days and the primary safety endpoint was the need for permanent pacemaker implantation. The mean age was 73.23 ± 7.65 years, 46% were female, 38% were New York Heart Association class III/IV at baseline. Thirty-day follow-up data were available for all patients. The VARC2-defined device success rate after 30 days was 22/23 (96%). 2/21 (10%) patients required a newly implanted pacemaker due to 3rd degree atrioventricular block. 25% of the patients developed a new left bundle branch block after valvuloplasty or device implantation. 21 of the 23 patients (96%) had no other signs of conduction disturbances after 30 days. The approach of the modified implantation technique of Lotus TAVR device was safe and effective. The incidence of need for a permanent pacemaker following TAVR could be significantly reduced due to adopted implantation protocol.

Recent X-ray Variability of Eta Car Approaching The X-ray Eclipse

NASA Technical Reports Server (NTRS)

Corcoran, M.; Swank, J. H.; Ishibashi, K.; Gull, T.; Humphreys, R.; Damineli, A.; Walborn, N.; Hillier, D. J.; Davidson, K.; White, S. M.

2002-01-01

We discuss recent X-ray spectral variability of the supermassive star Eta Car in the interval since the last X-ray eclipse in 1998. We concentrate on the interval just prior to the next X-ray eclipse which is expected to occur in June 2003. We compare the X-ray behavior during the 2001-2003 cycle with the previous cycle (1996-1998) and note similarities and differences in the temporal X-ray behavior. We also compare a recent X-ray observation of Eta Car obtained with the Chandra high energy transmission grating in October 2002 with an earlier observation from Nov 2002, and interpret these results in terms of the proposed colliding wind binary model for the star. In addition we discuss planned observations for the upcoming X-ray eclipse.

Vancouver Transcatheter Aortic Valve Replacement Clinical Pathway: Minimalist Approach, Standardized Care, and Discharge Criteria to Reduce Length of Stay.

PubMed

Lauck, Sandra B; Wood, David A; Baumbusch, Jennifer; Kwon, Jae-Yung; Stub, Dion; Achtem, Leslie; Blanke, Philipp; Boone, Robert H; Cheung, Anson; Dvir, Danny; Gibson, Jennifer A; Lee, Bobby; Leipsic, Jonathan; Moss, Robert; Perlman, Gidon; Polderman, Jopie; Ramanathan, Krishnan; Ye, Jian; Webb, John G

2016-05-01

We describe the development, implementation, and evaluation of a standardized clinical pathway to facilitate safe discharge home at the earliest time after transfemoral transcatheter aortic valve replacement. Between May 2012 and October 2014, the Heart Team developed a clinical pathway suited to the unique requirements of transfemoral transcatheter aortic valve replacement in contemporary practice. The components included risk-stratified minimalist periprocedure approach, standardized postprocedure care with early mobilization and reconditioning, and criteria-driven discharge home. Our aim was to reduce variation in care, identify a subgroup of patients suitable for early discharge (≤48 hours), and decrease length of stay for all patients. We addressed barriers related to historical practices, complex multidisciplinary stakeholder engagement, and adoption of length of stay as a quality indicator. We retrospectively reviewed the experiences of 393 consecutive patients; 150 (38.2%) were discharged early. At baseline, early discharge patients had experienced less previous balloon aortic valvuloplasty, had higher left ventricular ejection fraction, better cognitive function, and were less frail than the standard discharge group (>48 hours). Early discharge was associated with the use of local anesthesia, implantation of balloon expandable device, avoidance of urinary catheter, and early removal of temporary pacemaker. Median length of stay was 1 day for early discharge and 3 days for other patients; 97.7% were discharged home. There were no differences in 30-day mortality (1.3%), disabling stroke (0.8%), or readmission (10.7%). The implementation of a transcatheter aortic valve replacement clinical pathway shifted the program's approach to combine standardized processes and individual risk stratification. The Vancouver transcatheter aortic valve replacement clinical pathway requires a rigorous assessment to determine its efficacy, safety, and reproducibility. �

Can glenoid wear be accurately assessed using x-ray imaging? Evaluating agreement of x-ray and magnetic resonance imaging (MRI) Walch classification.

PubMed

Kopka, Michaela; Fourman, Mitchell; Soni, Ashish; Cordle, Andrew C; Lin, Albert

2017-09-01

The Walch classification is the most recognized means of assessing glenoid wear in preoperative planning for shoulder arthroplasty. This classification relies on advanced imaging, which is more expensive and less practical than plain radiographs. The purpose of this study was to determine whether the Walch classification could be accurately applied to x-ray images compared with magnetic resonance imaging (MRI) as the gold standard. We hypothesized that x-ray images cannot adequately replace advanced imaging in the evaluation of glenoid wear. Preoperative axillary x-ray images and MRI scans of 50 patients assessed for shoulder arthroplasty were independently reviewed by 5 raters. Glenoid wear was individually classified according to the Walch classification using each imaging modality. The raters then collectively reviewed the MRI scans and assigned a consensus classification to serve as the gold standard. The κ coefficient was used to determine interobserver agreement for x-ray images and independent MRI reads, as well as the agreement between x-ray images and consensus MRI. The inter-rater agreement for x-ray images and MRIs was "moderate" (κ = 0.42 and κ = 0.47, respectively) for the 5-category Walch classification (A1, A2, B1, B2, C) and "moderate" (κ = 0.54 and κ = 0.59, respectively) for the 3-category Walch classification (A, B, C). The agreement between x-ray images and consensus MRI was much lower: "fair-to-moderate" (κ = 0.21-0.51) for the 5-category and "moderate" (κ = 0.36-0.60) for the 3-category Walch classification. The inter-rater agreement between x-ray images and consensus MRI is "fair-to-moderate." This is lower than the previously reported reliability of the Walch classification using computed tomography scans. Accordingly, x-ray images are inferior to advanced imaging when assessing glenoid wear. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights

Combined low-dose aspirin and warfarin anticoagulant therapy of postoperative atrial fibrillation following mechanical heart valve replacement.

PubMed

Wang, Jian-tang; Dong, Ming-feng; Song, Guang-min; Ma, Zeng-shan; Ma, Sheng-jun

2014-12-01

The safety and efficacy of combined low dose aspirin and warfarin therapy in patients with atrial fibrillation after mechanical heart valve replacement were evaluated. A total of 1016 patients (620 females, mean age of 36.8±7.7 years) admitted for cardiac valve replacement and complicated with atrial fibrillation after surgery were randomly divided into study (warfarin plus 75-100 mg aspirin) or control (warfarin only) groups. International normalized ratio (INR) and prothrombin time were maintained at 1.8-2.5 and 1.5-2.0 times the normal values, respectively. Thromboembolic events and major bleedings were registered during the follow-up period. Patients were followed up for 24±9 months. The average dose of warfarin in the study and control groups was 2.91±0.83 mg and 2.88±0.76 mg, respectively (P>0.05). The incidence of overall thromboembolic events in study group was lower than that in control group (2.16% vs. 4.35%, P=0.049). No statistically significant differences were found in hemorrhage events (3.53% vs. 3.95%, P=0.722) or mortality (0.20% vs. 0.40%, P=0.559) between the two groups. Combined low dose aspirin and warfarin therapy in the patients with atrial fibrillation following mechanical heart valve replacement significantly decreased thromboembolic events as compared with warfarin therapy alone. This combined treatment was not associated with an increase in the risk of major bleeding or mortality.

Profiling illness perceptions to identify patients at-risk for decline in health status after heart valve replacement.

PubMed

Kohlmann, Sebastian; Rimington, Helen; Weinman, John

2012-06-01

Identification of risk factors for decline in health status by profiling illness perceptions before and one year after heart valve replacement surgery. Prospective data from N=225 consecutively admitted first time valve replacement patients was assessed before and one year after surgery. Patients were asked about their illness perceptions (Illness Perception Questionnaire-Revised) and mood state (Hospital Anxiety and Depression Scale). Health status was defined by quality of life (Short-Form 36) and New York Heart Association (NYHA) class. Cluster analyses were conducted to identify illness perception profiles over time. Predictors of health status after surgery were analyzed with multivariate methods. Patients were grouped according to the stability and nature (positive, negative) of their illness perception profile over one year. One year after surgery patients holding a negative illness perception profile showed a lower physical quality of life and were diagnosed in a higher New York Heart Association class than patients changing to positive and patients with stable positive illness perceptions (P<.001). Over and above biological determinants, post-surgery physical quality of life and NYHA class were both predicted by pre-surgery illness perception profiles (P<.05). Patients going for heart valve replacement surgery can be easily categorized into illness perception profiles that predict health status one year after surgery. These patients could benefit from early screening as negative illness perceptions are modifiable risk factors. Copyright © 2012 Elsevier Inc. All rights reserved.

Large area soft x-ray collimator to facilitate x-ray optics testing

NASA Technical Reports Server (NTRS)

Espy, Samuel L.

1994-01-01

The first objective of this program is to design a nested conical foil x-ray optic which will collimate x-rays diverging from a point source. The collimator could then be employed in a small, inexpensive x-ray test stand which would be used to test various x-ray optics and detector systems. The second objective is to demonstrate the fabrication of the x-ray reflectors for this optic using lacquer-smoothing and zero-stress electroforming techniques.

Concomitant Transapical Transcatheter Valve Implantations: Edwards Sapien Valve for Severe Mitral Regurgitation in a Patient with Failing Mitral Bioprostheses and JenaValve for the Treatment of Pure Aortic Regurgitation.

PubMed

Aydin, Unal; Gul, Mehmet; Aslan, Serkan; Akkaya, Emre; Yildirim, Aydin

2015-04-28

Transcatheter valve implantation is a novel interventional technique, which was developed as an  alternative therapy for surgical aortic valve replacement in inoperable patients with severe aortic stenosis. Despite limited experience in using transcatheter valve implantation for mitral and aortic regurgitation, transapical transcatheter aortic valve implantation and valve-in-valve implantation for degenerated mitral valve bioprosthesis can be performed in high-risk patients who are not candidates for conventional replacement surgery. In this case, we present the simultaneous transcatheter valve implantation via transapical approach for both degenerated bioprosthetic mitral valve with severe regurgitation and pure severe aortic regurgitation.

Development of x-ray laminography under an x-ray microscopic condition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa

2011-07-15

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatialmore » resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.« less

Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

DOE PAGES

Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; ...

2015-03-02

We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~10 6 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10 7 laser pulses, wemore » also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

Subprosthetic Pannus after Aortic Valve Replacement Surgery: Cardiac CT Findings and Clinical Features.

PubMed

Han, Kichang; Yang, Dong Hyun; Shin, So Youn; Kim, Namkug; Kang, Joon-Won; Kim, Dae-Hee; Song, Jong-Min; Kang, Duk-Hyun; Song, Jae-Kwan; Kim, Joon Bum; Jung, Sung-Ho; Choo, Suk Jung; Chung, Cheol Hyun; Lee, Jae Won; Lim, Tae-Hwan

2015-09-01

To investigate the cardiac computed tomographic (CT) findings and clinical implications of subprosthetic pannus in patients who have undergone aortic valve replacement. The institutional review board approved this retrospective study, and the need to obtain written informed consent was waived. From April 2011 to March 2012, 88 patients (mean age, 63 years; 45 men) with a prosthetic aortic valve who underwent cardiac CT were retrospectively selected. Dynamic cardiac CT images were analyzed by using a multiplanar reformatted technique. The presence or absence of subprosthetic pannus and its extent were evaluated at cardiac CT. The geometric orifice area and the effective orifice area of each prosthetic valve were measured to enable analysis of the pannus encroachment ratio in the systolic phase. Hemodynamic parameters at echocardiography, including mean transprosthetic pressure gradient (MTPG), were compared between patients with and those without pannus. The encroachment ratio and the MTPG were correlated by using the Spearman test to evaluate the relationship between the two variables. Seventeen patients (19%) had subprosthetic pannus at cardiac CT. In patients with subprosthetic pannus, MTPG, peak pressure gradient, transvalvular peak velocity, and left ventricular ejection fraction (LVEF) were significantly higher than in patients without pannus (MTPG: 28.1 mm Hg ± 19.8 [standard deviation] vs 14.0 mm Hg ± 6.5, P = .004; peak pressure gradient: 53.1 mm Hg ± 38.4 vs 26.1 mm Hg ± 11.4, P = .004; transvalvular peak velocity: 3.3 m/sec ± 1.3 vs 2.5 m/sec ± 0.5; and LVEF: 64.7% ± 7.4 vs 56.8% ± 10.5, P = .004). A high MTPG (≥40 mm Hg) was observed in four patients at echocardiography, and subprosthetic panni were identified at CT in all four patients. In patients with increased MTPGs, the encroachment ratio by subprosthetic pannus at CT was significantly higher than that in patients with MTPGs of less than 40 mm Hg (42.7 ± 13.3 vs 7.6 ± 3, P = .012

Panoramic Dental X-Ray

MedlinePlus

... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

Calcification Characteristics of Low-Flow Low-Gradient Severe Aortic Stenosis in Patients Undergoing Transcatheter Aortic Valve Replacement

PubMed Central

Stähli, Barbara E.; Nguyen-Kim, Thi Dan Linh; Gebhard, Cathérine; Frauenfelder, Thomas; Tanner, Felix C.; Nietlispach, Fabian; Maisano, Francesco; Falk, Volkmar; Lüscher, Thomas F.; Maier, Willibald; Binder, Ronald K.

2015-01-01

Low-flow low-gradient severe aortic stenosis (LFLGAS) is associated with worse outcomes. Aortic valve calcification patterns of LFLGAS as compared to non-LFLGAS have not yet been thoroughly assessed. 137 patients undergoing transcatheter aortic valve replacement (TAVR) with preprocedural multidetector computed tomography (MDCT) and postprocedural transthoracic echocardiography were enrolled. Calcification characteristics were assessed by MDCT both for the total aortic valve and separately for each leaflet. 34 patients had LFLGAS and 103 non-LFLGAS. Total aortic valve calcification volume (p < 0.001), mass (p < 0.001), and density (p = 0.004) were lower in LFLGAS as compared to non-LFLGAS patients. At 30-day follow-up, mean transaortic pressure gradients and more than mild paravalvular regurgitation did not differ between groups. In conclusion, LFLGAS and non-LFLGAS express different calcification patterns which, however, did not impact on device success after TAVR. PMID:26435875

Ferumoxytol MRA for transcatheter aortic valve replacement planning with renal insufficiency.

PubMed

Kallianos, Kimberly; Henry, Travis S; Yeghiazarians, Yerem; Zimmet, Jeffrey; Shunk, Kendrick A; Tseng, Elaine E; Mahadevan, Vaikom; Hope, Michael D

2017-03-15

Computed tomography angiography (CTA) is the test of choice for pre-procedure imaging of transcatheter aortic valve replacement (TAVR) candidates. The iodinated contrast required, however, increases the risk of renal dysfunction in patients with pre-existing renal failure. Ferumoxytol is a magnetic resonance imaging (MRI) contrast agent that can be used with renal failure. Its long vascular resonance time allows gated MRA sequences that approach CTA in image quality. We present respiratory and cardiac gated MRA enabled by ferumoxytol that can be post-processed in an analogous fashion to CTA. Seven patients with renal failure presenting for TAVR were imaged with respiratory and cardiac gated MRA at 3T using ferumoxtyol for contrast. Aortic annulus, root and peripheral access dimensions were calculated in a fashion identical to that used for CTA. Of these, 6 patients underwent a TAVR procedure and 5 had intraoperative valve assessment with transesophageal echocardiograph (TEE) using standard clinical protocols that employed both two- and three-dimensional techniques. Good correlation between MRA aortic annulus measurements and those from TEE were shown in 5 patients with mean annulus area of 392.4mm 2 (290-470 range) versus 374.1mm 2 (285-440 range), with a pairwise correlation coefficient of 0.92, p=0.029. All patients received Sapien valve implants (one 20mm, three 23mm, and two 26mm valves). Access decisions were guided by MRA with no complications. Annulus sizing resulted in no greater than trace/mild aortic regurgitation in all patients. Ferumoxytol MRA is a safe alternative to CTA in patients with renal failure for pre-TAVR analysis of the aortic root and peripheral access. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Computed Tomography Helps to Plan Minimally Invasive Aortic Valve Replacement Operations.

PubMed

Stoliński, Jarosław; Plicner, Dariusz; Grudzień, Grzegorz; Kruszec, Paweł; Fijorek, Kamil; Musiał, Robert; Andres, Janusz

2016-05-01

This study evaluated the role of multidetector computed tomography (MDCT) in preparation for minimally invasive aortic valve replacement (MIAVR). An analysis of 187 patients scheduled for MIAVR between June 2009 and December 2014 was conducted. In the study group (n = 86), MDCT of the thorax, aorta, and femoral arteries was performed before the operation. In the control group (n = 101), patients qualified for MIAVR without receiving preoperative MDCT. The surgical strategy was changed preoperatively in 12.8% of patients from the study group and in 2.0% of patients from the control group (p = 0.010) and intraoperatively in 9.9% of patients from the control group and in none from the study group (p = 0.002). No conversion to median sternotomy was necessary in the study group; among the controls, there were 4.0% conversions. On the basis of the MDCT measurements, optimal access to the aortic valve was achieved when the angle between the aortic valve plane and the line to the second intercostal space was 91.9 ± 10.0 degrees and to the third intercostal space was 94.0 ± 1.4 degrees, with the distance to the valve being 94.8 ± 13.8 mm and 84.5 ± 9.9 mm for the second and third intercostal spaces, respectively. The right atrium covering the site of the aortotomy was present in 42.9% of cases when MIAVR had been performed through the third intercostal space and in 1.3% when through the second intercostal space (p = 0.001). Preoperative MDCT of the thorax, aorta, and femoral arteries makes it possible to plan MIAVR operations. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Aortic valve repair leads to a low incidence of valve-related complications.

PubMed

Aicher, Diana; Fries, Roland; Rodionycheva, Svetlana; Schmidt, Kathrin; Langer, Frank; Schäfers, Hans-Joachim

2010-01-01

Aortic valve replacement for aortic regurgitation (AR) has been established as a standard treatment but implies prosthesis-related complications. Aortic valve repair is an alternative approach, but its mid- to long-term results still need to be defined. Over a 12-year period, 640 patients underwent aortic valve repair for regurgitation of a unicuspid (n=21), bicuspid (n=205), tricuspid (n=411) or quadricuspid (n=3) aortic valve. The mechanism of regurgitation involved prolapse (n=469) or retraction (n=20) of the cusps, and dilatation of the root (n=323) or combined pathologies. Treatment consisted of cusp repair (n=529), root repair (n=323) or a combination of both (n=208). The patients were followed clinically and echocardiographically; follow-up was complete in 98.5% (cumulative follow-up: 3035 patient years). Hospital mortality was 3.4% in the total patient cohort and 0.8% for isolated aortic valve repair. The incidences of thrombo-embolism (0.2% per patient per year) and endocarditis (0.16%per patient per year) were low. Freedom from re-operation at 5 and 10 years was 88% and 81% in bicuspid and 97% and 93% in tricuspid aortic valves (p=0.0013). At re-operation, 13 out of 36 valves could be re-repaired. Freedom from valve replacement was 95% and 90% in bicuspid and 97% and 94% in tricuspid aortic valves (p=0.36). Freedom from all valve-related complications at 10 years was 88%. Reconstructive surgery of the aortic valve is feasible with low mortality in many individuals with aortic regurgitation. Freedom from valve-related complications after valve repair seems superior compared to available data on standard aortic valve replacement. Copyright 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

In-flight calibration of Hitomi Soft X-ray Spectrometer. (3) Effective area

NASA Astrophysics Data System (ADS)

Tsujimoto, Masahiro; Okajima, Takashi; Eckart, Megan E.; Hayashi, Takayuki; Hoshino, Akio; Iizuka, Ryo; Kelley, Richard L.; Kilbourne, Caroline A.; Leutenegger, Maurice A.; Maeda, Yoshitomo; Mori, Hideyuki; Porter, Frederick S.; Sato, Kosuke; Sato, Toshiki; Serlemitsos, Peter J.; Szymkowiak, Andrew; Yaqoob, Tahir

2018-03-01

We present the result of the in-flight calibration of the effective area of the Soft X-ray Spectrometer (SXS) on board the Hitomi X-ray satellite using an observation of the Crab nebula. We corrected for artifacts when observing high count rate sources with the X-ray microcalorimeter. We then constructed a spectrum in the 0.5-20 keV band, which we modeled with a single power-law continuum attenuated by interstellar extinction. We evaluated the systematic uncertainty of the spectral parameters by various calibration items. In the 2-12 keV band, the SXS result is consistent with the literature values in flux (2.20 ± 0.08 × 10-8 erg s-1 cm-2 with a 1 σ statistical uncertainty) but is softer in the power-law index (2.19 ± 0.11). The discrepancy is attributable to the systematic uncertainty of about +6%/-7% and +2%/-5% respectively for the flux and the power-law index. The softer spectrum is affected primarily by the systematic uncertainty of the Dewar gate valve transmission and the event screening.

X-Ray Measurements Of A Thermo Scientific P385 DD Neutron Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wharton, C. J.; Seabury, E. H.; Chichester, D. L.

2011-06-01

Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium-252 radioisotopic neutron sources in its PINS prompt gamma-ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x-ray output of the Thermo Scientific P385 deuterium-deuterium neutron generator. X rays are a normal byproduct from neutron generators, but depending on their intensity and energy, x rays can interfere with gamma rays from the object under test, increase gamma-spectrometer dead time, and reduce PGNAA system throughput. The P385 x-ray energy spectrum wasmore » measured with a high-purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x-ray emission points, the generator also was rotated 60 deg. between measurements. The scans show the primary source of x-ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x-ray count rate, and its x-ray emission appears to be axially symmetric. A thin lead shield, 3.2 mm (1/8 inch) thick, reduced the 70-keV generator x rays to negligible levels.« less

Left ventricular mass regression after aortic valve replacement with the new Mitroflow 12A pericardial bioprosthesis.

PubMed

García-Bengochea, José; Sierra, Juan; González-Juanatey, José R; Rubio, José; Vega, Marino; Fernández, Angel L; Sánchez, Daniel

2006-05-01

The study aim was to evaluate the durability of the new Mitroflow 12A pericardial bioprosthesis and to assess ventricular mass regression after aortic valve replacement (AVR) in patients with small valves. A total of 326 Mitroflow 12A pericardial bioprostheses was implanted without any other associated valve procedure. The mean patient age was 73.5 +/- 6.1 years; 252 patients (78.0%) were in NYHA class III/IV. Small valves (19 and 21 mm) were implanted in 212 patients (65.6%). The total follow up period was 837.1 patient-years (pt-yr). A subset of 61 patients with preoperative stenosis was selected and submitted to conventional echo-Doppler assessment at a mean period of 11.1 months after surgery. Hospital mortality was 8.6%. At eight years of follow up, survival was 57.1%. Freedom from structural valve deterioration (SVD) was 86.5% per pt-yr. Mean gradients were significantly reduced postoperatively for each valve size (to 18 +/- 8 mmHg for 19-mm valves and 12 +/- 4 mmHg for 25-mm valves). The effective orifice area (EOA) was also increased significantly for all valve sizes (to 1.1 +/- 0.1 cm2 for 19-mm valves and 1.8 +/- 0.2 cm2 for 25-mm valves). The left ventricular mass index (LVMI) decreased significantly, from 177 +/- 29 to 136 +/- 22 g/m2 for the 19-mm valve, and from 200 +/- 42 to 132 +/- 22 g/m2 for the 25-mm valve. The EOA index (EOAI) showed mismatch for the 19- and 21-mm valves (0.74 and 0.82 cm2/m2, respectively). The diagrammatic calculation between LVMI and relative wall thickness after surgery showed that 29.7% of patients achieved a normal pattern of remodeling (including 19- and 21-mm valves), despite various degrees of mismatch. The new Mitroflow 12A pericardial bioprosthesis showed an absence of mechanical failure after an eight-year follow up, with a satisfactory rate of SVD. Significant reductions in LVMI and improved ventricular geometry were observed, despite the small valve sizes implanted.

Note: Development of target changeable palm-top pyroelectric x-ray tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imashuku, Susumu; Kawai, Jun

2012-01-15

A target changeable palm-top size x-ray tube was realized using pyroelectric crystal and detachable vacuum flanges. The target metals can be exchanged easily by attaching them on the brass stage with carbon tape. When silver and titanium palates (area: 10 mm{sup 2}) were used as targets, silver L{alpha} and titanium K lines were clearly observed by bombarding electrons on the targets for 90 s. The intensities were the same or higher than those of previously reported pyroelectric x-ray tubes. Chromium, iron, nickel, copper, and zinc K lines in the x-ray tube (stainless steel and brass) disappeared by replacing the brassmore » stage and the stainless steel vacuum flange with a carbon stage and a glass tube, respectively.« less

Long-Wavelength X-Ray Diffraction and Its Applications in Macromolecular Crystallography.

PubMed

Weiss, Manfred S

2017-01-01

For many years, diffraction experiments in macromolecular crystallography at X-ray wavelengths longer than that of Cu-K α (1.54 Å) have been largely underappreciated. Effects caused by increased X-ray absorption result in the fact that these experiments are more difficult than the standard diffraction experiments at short wavelengths. However, due to the also increased anomalous scattering of many biologically relevant atoms, important additional structural information can be obtained. This information, in turn, can be used for phase determination, for substructure identification, in molecular replacement approaches, as well as in structure refinement. This chapter reviews the possibilities and the difficulties associated with such experiments, and it provides a short description of two macromolecular crystallography synchrotron beam lines dedicated to long-wavelength X-ray diffraction experiments.

X-ray Spectral Formation In High-mass X-ray Binaries: The Case Of Vela X-1

NASA Astrophysics Data System (ADS)

Akiyama, Shizuka; Mauche, C. W.; Liedahl, D. A.; Plewa, T.

2007-05-01

We are working to develop improved models of radiatively-driven mass flows in the presence of an X-ray source -- such as in X-ray binaries, cataclysmic variables, and active galactic nuclei -- in order to infer the physical properties that determine the X-ray spectra of such systems. The models integrate a three-dimensional time-dependent hydrodynamics capability (FLASH); a comprehensive and uniform set of atomic data, improved calculations of the line force multiplier that account for X-ray photoionization and non-LTE population kinetics, and X-ray emission-line models appropriate to X-ray photoionized plasmas (HULLAC); and a Monte Carlo radiation transport code that simulates Compton scattering and recombination cascades following photoionization. As a test bed, we have simulated a high-mass X-ray binary with parameters appropriate to Vela X-1. While the orbital and stellar parameters of this system are well constrained, the physics of X-ray spectral formation is less well understood because the canonical analytical wind velocity profile of OB stars does not account for the dynamical and radiative feedback effects due to the rotation of the system and to the irradiation of the stellar wind by X-rays from the neutron star. We discuss the dynamical wind structure of Vela X-1 as determined by the FLASH simulation, where in the binary the X-ray emission features originate, and how the spatial and spectral properties of the X-ray emission features are modified by Compton scattering, photoabsorption, and fluorescent emission. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

The Midterm Outcomes of Bioprosthetic Pulmonary Valve Replacement in Children.

PubMed

Shinkawa, Takeshi; Lu, Chiajung K; Chipman, Carl; Tang, Xinyu; Gossett, Jeffrey M; Imamura, Michiaki

2015-01-01

The purpose of this study was to assess the outcomes of bioprosthetic pulmonary valve replacement (PVR) in children. This is a retrospective review of all bioprosthetic PVR in children (≤ 20-year old) between 1992 and 2013 at a single institution. Most outcomes studied included pulmonary valve reintervention and bioprosthetic valve function. A total of 136 bioprosthetic PVRs were identified for 123 patients. The median age and body weight at the time of operation were 13.2 years and 48.4 kg. There were 1 early death and 3 late deaths during the median follow-up of 7.2 years (0-22.0 years). The actuarial transplant-free survival was 97.6% at 10 years. There were 43 bioprosthesis reinterventions with 29 reoperations and 14 catheter-based interventions. The freedom from bioprosthesis reintervention was 89.6% and 55.0% at 5 and 10 years, respectively. Echocardiographic bioprosthesis dysfunction (≥ moderate bioprosthesis insufficiency, ≥ 50 mmHg peak gradient through bioprosthesis, or bioprosthesis endocarditis with vegetation) was found in 57 bioprostheses. The freedom from bioprosthesis dysfunction was 74.0% and 32.8% at 5 and 10 years, respectively. Results from the Cox proportional hazards models showed that age had significant association with freedom from bioprosthesis reintervention and freedom from bioprosthesis dysfunction (P < 0.001 and P = 0.03), whereas bioprosthesis type had nonsignificant association with freedom from bioprosthesis dysfunction (P = 0.068). Bioprosthetic PVR in children had excellent early outcomes but rapidly deteriorating midterm outcomes. Careful and close follow-up are necessary for children with bioprosthesis in the pulmonary position. Copyright © 2015 Elsevier Inc. All rights reserved.

X-ray beam finder

DOEpatents

Gilbert, H.W.

1983-06-16

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

PubMed

O' Sullivan, Katie E; Casserly, Ivan; Hurley, John

2015-04-01

We report the first case of transcatheter aortic valve replacement implantation using JenaValve™ in a patient with mechanical mitral valve prosthesis. We believe that the design features of this valve may be particularly suited for use in this setting. © 2014 Wiley Periodicals, Inc.

X-ray driven channeling acceleration in crystals and carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Young-Min; Still, Dean A.; Shiltsev, Vladimir

2013-12-01

Acceleration of particles channeling in a crystal by means of diffracted x-rays via Bormann anomalous transmission was conceived for heavy ions and muons by Tajima and Cavenago [Phys. Rev. Lett. 59, 1440 (1987)], which potentially offers an appreciably high field gradient on the order of GV/cm. The theoretical model of the high gradient acceleration has been studied in two kinds of atomic structure, crystals and carbon nanotubes (CNTs), with analytic calculations and electromagnetic eigenmode simulations. A range of acceleration gradients and cutoffs of the x-ray power (the lowest power limit to overcome the Bremsstrahlung radiation losses) are characterized in termsmore » of the lattice constants, unit cell sizes, and photon energies. The parametric analysis indicates that the required x-ray power can be reduced to an order of megawatt by replacing crystals with CNTs. Eventually, the equivalent dielectric approximation of a multi-wall nanotube shows that 250–810 MeV muons can be synchronously coupled with x-rays of 0.65–1.32 keV in the accelerating structure.« less

X-ray and gamma ray astronomy detectors

NASA Technical Reports Server (NTRS)

Decher, Rudolf; Ramsey, Brian D.; Austin, Robert

1994-01-01

X-ray and gamma ray astronomy was made possible by the advent of space flight. Discovery and early observations of celestial x-rays and gamma rays, dating back almost 40 years, were first done with high altitude rockets, followed by Earth-orbiting satellites> once it became possible to carry detectors above the Earth's atmosphere, a new view of the universe in the high-energy part of the electromagnetic spectrum evolved. Many of the detector concepts used for x-ray and gamma ray astronomy were derived from radiation measuring instruments used in atomic physics, nuclear physics, and other fields. However, these instruments, when used in x-ray and gamma ray astronomy, have to meet unique and demanding requirements related to their operation in space and the need to detect and measure extremely weak radiation fluxes from celestial x-ray and gamma ray sources. Their design for x-ray and gamma ray astronomy has, therefore, become a rather specialized and rapidly advancing field in which improved sensitivity, higher energy and spatial resolution, wider spectral coverage, and enhanced imaging capabilities are all sought. This text is intended as an introduction to x-ray and gamma ray astronomy instruments. It provides an overview of detector design and technology and is aimed at scientists, engineers, and technical personnel and managers associated with this field. The discussion is limited to basic principles and design concepts and provides examples of applications in past, present, and future space flight missions.

X-ray imaging crystal spectrometer for extended X-ray sources

DOEpatents

Bitter, Manfred L.; Fraenkel, Ben; Gorman, James L.; Hill, Kenneth W.; Roquemore, A. Lane; Stodiek, Wolfgang; von Goeler, Schweickhard E.

2001-01-01

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Latest evidence on transcatheter aortic valve implantation vs. surgical aortic valve replacement for the treatment of aortic stenosis in high and intermediate-risk patients.

PubMed

Praz, Fabien; Siontis, George C M; Verma, Subodh; Windecker, Stephan; Jüni, Peter

2017-03-01

The goal of this review is to summarize the current evidence supporting the use of transcatheter aortic valve implantation (TAVI) in high and intermediate-risk patients. The focus is on the five randomized controlled trials comparing TAVI with surgical aortic valve replacement (SAVR) published to date, as well as two recent meta-analyses. TAVI has profoundly transformed the treatment of elderly patients presenting with symptomatic severe aortic stenosis. In experienced hands, the procedure has become well tolerated and the results more predictable. So far, two trials using two different devices [Placement of Aortic Transcatheter Valve (PARTNER) 1A and US CoreValve High Risk] have shown that TAVI is able to compete in terms of mortality with SAVR in high-risk patients. These findings have been extended to the intermediate-risk population in two recently published randomized controlled trials [PARTNER 2 and Nordic Aortic Valve Intervention (NOTION)]. The two meta-analyses suggested improved survival in both high and intermediate-risk patients during the first 2 years following the intervention. The survival benefit was only found in patients treated via the transfemoral access, and appeared more pronounced in women. Individual randomized trials enrolling high and intermediate-risk patients have established the noninferiority of TAVI in comparison with SAVR, whereas subsequent meta-analyses suggest superiority of transfemoral TAVI in terms of a sustained survival benefit 2 years after valve implantation irrespective of the surgical risk category. The benefit of TAVI appears more pronounced in women than in men.

X-ray lithography source

DOEpatents

Piestrup, M.A.; Boyers, D.G.; Pincus, C.

1991-12-31

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

X-ray lithography source

DOEpatents

Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

1991-01-01

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

Bone cartilage imaging with x-ray interferometry using a practical x-ray tube

NASA Astrophysics Data System (ADS)

Kido, Kazuhiro; Makifuchi, Chiho; Kiyohara, Junko; Itou, Tsukasa; Honda, Chika; Momose, Atsushi

2010-04-01

The purpose of this study was to design an X-ray Talbot-Lau interferometer for the imaging of bone cartilage using a practical X-ray tube and to develop that imaging system for clinical use. Wave-optics simulation was performed to design the interferometer with a practical X-ray tube, a source grating, two X-ray gratings, and an X-ray detector. An imaging system was created based on the results of the simulation. The specifications were as follows: the focal spot size was 0.3 mm of an X-ray tube with a tungsten anode (Toshiba, Tokyo, Japan). The tube voltage was set at 40 kVp with an additive aluminum filter, and the mean energy was 31 keV. The pixel size of the X-ray detector, a Condor 486 (Fairchild Imaging, California, USA), was 15 μm. The second grating was a Ronchi-type grating whose pitch was 5.3 μm. Imaging performance of the system was examined with X-ray doses of 0.5, 3 and 9 mGy so that the bone cartilage of a chicken wing was clearly depicted with X-ray doses of 3 and 9 mGy. This was consistent with the simulation's predictions. The results suggest that X-ray Talbot-Lau interferometry would be a promising tool in detecting soft tissues in the human body such as bone cartilage for the X-ray image diagnosis of rheumatoid arthritis. Further optimization of the system will follow to reduce the X-ray dose for clinical use.

Bandpass x-ray diode and x-ray multiplier detector

DOEpatents

Wang, C.L.

1982-09-27

An absorption-edge of an x-ray absorption filter and a quantum jump of a photocathode determine the bandpass characteristics of an x-ray diode detector. An anode, which collects the photoelectrons emitted by the photocathode, has enhanced amplification provided by photoelectron-multiplying means which include dynodes or a microchannel-plate electron-multiplier. Suppression of undesired high frequency response for a bandpass x-ray diode is provided by subtracting a signal representative of energies above the passband from a signal representative of the overall response of the bandpass diode.

X-ray astronomical spectroscopy

NASA Technical Reports Server (NTRS)

Holt, Stephen S.

1987-01-01

The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

X-ray Measurements of a Thermo Scientific P385 DD Neutron Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

E.H. Seabury; D.L. Chichester; A.J. Caffrey

2001-08-01

Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium-252 radioisotopic neutron sources in its PINS prompt gamma-ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x-ray output of the Thermo Scientific P385 deuterium-deuterium neutron generator. X-rays are a normal byproduct from a neutron generator and depending on their intensity and energy they can interfere with gamma rays from the object under test, increase gamma-spectrometer dead time, and reduce PGNAA system throughput. The P385 x-ray energy spectrum was measuredmore » with a high-purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x-rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x-ray emission points, the generator also was rotated 60° between measurements. The scans show the primary source of x-ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x-ray count rate, and the x-ray emission appears to be axially symmetric within the neutron generator.« less

3D Printed Cardiac Phantom for Procedural Planning of a Transcatheter Native Mitral Valve Replacement

PubMed Central

Izzo, Richard L.; O’Hara, Ryan P.; Iyer, Vijay; Hansen, Rose; Meess, Karen M.; Nagesh, S.V. Setlur; Rudin, Stephen; Siddiqui, Adnan H.; Springer, Michael; Ionita, Ciprian N.

2017-01-01

3D printing an anatomically accurate, functional flow loop phantom of a patient’s cardiac vasculature was used to assist in the surgical planning of one of the first native transcatheter mitral valve replacement (TMVR) procedures. CTA scans were acquired from a patient about to undergo the first minimally-invasive native TMVR procedure at the Gates Vascular Institute in Buffalo, NY. A python scripting library, the Vascular Modeling Toolkit (VMTK), was used to segment the 3D geometry of the patient’s cardiac chambers and mitral valve with severe stenosis, calcific in nature. A stereolithographic (STL) mesh was generated and AutoDesk Meshmixer was used to transform the vascular surface into a functioning closed flow loop. A Stratasys Objet 500 Connex3 multi-material printer was used to fabricate the phantom with distinguishable material features of the vasculature and calcified valve. The interventional team performed a mock procedure on the phantom, embedding valve cages in the model and imaging the phantom with a Toshiba Infinix INFX-8000V 5-axis C-arm bi-Plane angiography system. Results After performing the mock-procedure on the cardiac phantom, the cardiologists optimized their transapical surgical approach. The mitral valve stenosis and calcification were clearly visible. The phantom was used to inform the sizing of the valve to be implanted. Conclusion With advances in image processing and 3D printing technology, it is possible to create realistic patient-specific phantoms which can act as a guide for the interventional team. Using 3D printed phantoms as a valve sizing method shows potential as a more informative technique than typical CTA reconstruction alone. PMID:28615797

3D Printed Cardiac Phantom for Procedural Planning of a Transcatheter Native Mitral Valve Replacement.

PubMed

Izzo, Richard L; O'Hara, Ryan P; Iyer, Vijay; Hansen, Rose; Meess, Karen M; Nagesh, S V Setlur; Rudin, Stephen; Siddiqui, Adnan H; Springer, Michael; Ionita, Ciprian N

2016-02-27

3D printing an anatomically accurate, functional flow loop phantom of a patient's cardiac vasculature was used to assist in the surgical planning of one of the first native transcatheter mitral valve replacement (TMVR) procedures. CTA scans were acquired from a patient about to undergo the first minimally-invasive native TMVR procedure at the Gates Vascular Institute in Buffalo, NY. A python scripting library, the Vascular Modeling Toolkit (VMTK), was used to segment the 3D geometry of the patient's cardiac chambers and mitral valve with severe stenosis, calcific in nature. A stereolithographic (STL) mesh was generated and AutoDesk Meshmixer was used to transform the vascular surface into a functioning closed flow loop. A Stratasys Objet 500 Connex3 multi-material printer was used to fabricate the phantom with distinguishable material features of the vasculature and calcified valve. The interventional team performed a mock procedure on the phantom, embedding valve cages in the model and imaging the phantom with a Toshiba Infinix INFX-8000V 5-axis C-arm bi-Plane angiography system. After performing the mock-procedure on the cardiac phantom, the cardiologists optimized their transapical surgical approach. The mitral valve stenosis and calcification were clearly visible. The phantom was used to inform the sizing of the valve to be implanted. With advances in image processing and 3D printing technology, it is possible to create realistic patient-specific phantoms which can act as a guide for the interventional team. Using 3D printed phantoms as a valve sizing method shows potential as a more informative technique than typical CTA reconstruction alone.

3D printed cardiac phantom for procedural planning of a transcatheter native mitral valve replacement

NASA Astrophysics Data System (ADS)

Izzo, Richard L.; O'Hara, Ryan P.; Iyer, Vijay; Hansen, Rose; Meess, Karen M.; Nagesh, S. V. Setlur; Rudin, Stephen; Siddiqui, Adnan H.; Springer, Michael; Ionita, Ciprian N.

2016-03-01

3D printing an anatomically accurate, functional flow loop phantom of a patient's cardiac vasculature was used to assist in the surgical planning of one of the first native transcatheter mitral valve replacement (TMVR) procedures. CTA scans were acquired from a patient about to undergo the first minimally-invasive native TMVR procedure at the Gates Vascular Institute in Buffalo, NY. A python scripting library, the Vascular Modeling Toolkit (VMTK), was used to segment the 3D geometry of the patient's cardiac chambers and mitral valve with severe stenosis, calcific in nature. A stereolithographic (STL) mesh was generated and AutoDesk Meshmixer was used to transform the vascular surface into a functioning closed flow loop. A Stratasys Objet 500 Connex3 multi-material printer was used to fabricate the phantom with distinguishable material features of the vasculature and calcified valve. The interventional team performed a mock procedure on the phantom, embedding valve cages in the model and imaging the phantom with a Toshiba Infinix INFX-8000V 5-axis Carm bi-Plane angiography system. Results: After performing the mock-procedure on the cardiac phantom, the cardiologists optimized their transapical surgical approach. The mitral valve stenosis and calcification were clearly visible. The phantom was used to inform the sizing of the valve to be implanted. Conclusion: With advances in image processing and 3D printing technology, it is possible to create realistic patientspecific phantoms which can act as a guide for the interventional team. Using 3D printed phantoms as a valve sizing method shows potential as a more informative technique than typical CTA reconstruction alone.

X-Ray

MedlinePlus

... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. Why it's done X-ray technology is used to examine many parts of the ...

Mitral valve replacement complicated by iatrogenic left ventricular outflow obstruction and paravalvular leak: case report and review of literature.

PubMed

Lee, Justin Z; Tey, Kai R; Mizyed, Ahmad; Hennemeyer, Charles T; Janardhanan, Rajesh; Lotun, Kapildeo

2015-10-09

Left ventricular outflow tract (LVOT) obstruction and paravalvular leak (PVL) are relatively uncommon, but are serious complications of prosthetic valve replacement. We present a case that displays the unique therapeutic challenges of treating a patient who developed both LVOT obstruction and mitral PVL after undergoing surgical aortic and mitral valve replacement (MVR). We also describe the use of alcohol septal ablation and albumin-glutaraldehyde (BioGlue) for septal ablation to percutaneously treat the patient's LVOT obstruction, followed by use of an Amplatzer vascular plug for percutaneous closure of an antero-medial mitral PVL associated with severe regurgitation. Percutaneous interventional management of these entities may be considered as an initial therapeutic option, especially in high-risk patients with significant morbidity and mortality of repeat surgical operations.

X-ray luminescence computed tomography using a focused x-ray beam.

PubMed

Zhang, Wei; Lun, Michael C; Nguyen, Alex Anh-Tu; Li, Changqing

2017-11-01

Due to the low x-ray photon utilization efficiency and low measurement sensitivity of the electron multiplying charge coupled device camera setup, the collimator-based narrow beam x-ray luminescence computed tomography (XLCT) usually requires a long measurement time. We, for the first time, report a focused x-ray beam-based XLCT imaging system with measurements by a single optical fiber bundle and a photomultiplier tube (PMT). An x-ray tube with a polycapillary lens was used to generate a focused x-ray beam whose x-ray photon density is 1200 times larger than a collimated x-ray beam. An optical fiber bundle was employed to collect and deliver the emitted photons on the phantom surface to the PMT. The total measurement time was reduced to 12.5 min. For numerical simulations of both single and six fiber bundle cases, we were able to reconstruct six targets successfully. For the phantom experiment, two targets with an edge-to-edge distance of 0.4 mm and a center-to-center distance of 0.8 mm were successfully reconstructed by the measurement setup with a single fiber bundle and a PMT. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Selenium single-wavelength anomalous diffraction de novo phasing using an X-ray-free electron laser

DOE PAGES

Hunter, Mark S.; Yoon, Chun Hong; DeMirci, Hasan; ...

2016-11-04

Structural information about biological macromolecules near the atomic scale provides important insight into the functions of these molecules. To date, X-ray crystallography has been the predominant method used for macromolecular structure determination. However, challenges exist when solving structures with X-rays, including the phase problem and radiation damage. X-ray-free electron lasers (X-ray FELs) have enabled collection of diffraction information before the onset of radiation damage, yet the majority of structures solved at X-ray FELs have been phased using external information via molecular replacement. De novo phasing at X-ray FELs has proven challenging due in part to per-pulse variations in intensity andmore » wavelength. Here we report the solution of a selenobiotinyl-streptavidin structure using phases obtained by the anomalous diffraction of selenium measured at a single wavelength (Se-SAD) at the Linac Coherent Light Source. Finally, our results demonstrate Se-SAD, routinely employed at synchrotrons for novel structure determination, is now possible at X-ray FELs.« less

Gait Speed Predicts 30-Day Mortality After Transcatheter Aortic Valve Replacement: Results From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

PubMed

Alfredsson, Joakim; Stebbins, Amanda; Brennan, J Matthew; Matsouaka, Roland; Afilalo, Jonathan; Peterson, Eric D; Vemulapalli, Sreekanth; Rumsfeld, John S; Shahian, David; Mack, Michael J; Alexander, Karen P

2016-04-05

Surgical risk scores do not include frailty assessments (eg, gait speed), which are of particular importance for patients with severe aortic stenosis considering transcatheter aortic valve replacement. We assessed the association of 5-m gait speed with outcomes in a cohort of 8039 patients who underwent transcatheter aortic valve replacement (November 2011-June 2014) and were included in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. We evaluated the association between continuous and categorical gait speed and 30-day all-cause mortality before and after adjustment for Society of Thoracic Surgeons-predicted risk of mortality score and key variables. Secondary outcomes included in-hospital mortality, bleeding, acute kidney injury, and stroke. The overall median gait speed was 0.63 m/s (25th-75th percentile, 0.47-0.79 m/s), with the slowest walkers (<0.5 m/s) constituting 28%, slow walkers (0.5-0.83 m/s) making up 48%, and normal walkers (>0.83 m/s) constituting 24% of the population. Thirty-day all-cause mortality rates were 8.4%, 6.6%, and 5.4% for the slowest, slow, and normal walkers, respectively (P<0.001). Each 0.2-m/s decrease in gait speed corresponded to an 11% increase in 30-day mortality (adjusted odds ratio, 1.11; 95% confidence interval, 1.01-1.22). The slowest walkers had 35% higher 30-day mortality than normal walkers (adjusted odds ratio, 1.35; 95% confidence interval, 1.01-1.80), significantly longer hospital stays, and a lower probability of being discharged to home. Gait speed is independently associated with 30-day mortality after transcatheter aortic valve replacement. Identification of frail patients with the slowest gait speeds facilitates preprocedural evaluation and anticipation of a higher level of postprocedural care. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01737528. © 2016 American Heart Association, Inc.

Intermediate results of isolated mitral valve replacement with a Biocor porcine valve.

PubMed

Rizzoli, Giulio; Bottio, Tomaso; Vida, Vladimiro; Nesseris, Georgios; Caprili, Luca; Thiene, Gaetano; Gerosa, Gino

2005-02-01

We analyzed the intermediate experience, survival, and prosthetic complications of patients who received the Biocor valve, a new-generation porcine valve, in the mitral position. At the University of Padua, between May 1992 and January 2004, 154 consecutive patients (102 female and 52 male patients; mean age, 72.3 +/- 6 years; age range, 37-86 years) received 158 mitral Biocor prostheses (Biocor Industria e Pesguisa Ltda, Belo Horizonte, Brazil). Thirty-five percent of the patients had previous mitral operations, 24% had coronary artery bypass grafting, and 34.6% had other procedures. Median preoperative New York Heart Association class was III. Echocardiography was performed in 75% of the long-term survivors. Follow-up included 609.4 patient-years and was 100% complete, with a median time of 4 patient-years (range, 0.02-11.3 years). At 8 years, 20 (14%) of 142 operative survivors were still at risk. Early mortality was 13.6%. According to univariate analysis, New York Heart Association class III to IV, ejection fraction of less than 40%, urgency, male sex, and coronary artery bypass grafting were significant perioperative risk factors. Eight- and 10-year actuarial survival was 51.1% +/- 5.6% (40 deaths). Eight-year actuarial freedom from valve-related death, thromboembolism, anticoagulant-related hemorrhage, endocarditis, paravalvular leak, and valve-related complications were 85.2% +/- 5%, 85.7% +/- 4.4%, 92.6% +/- 3.7%, 94.1% +/- 3%, 91.8% +/- 3%, and 70.2% +/- 5.7%, respectively. Freedom from structural valve deterioration was 100%. Actual freedom from reoperation was 93.2% +/- 2.2%. By Doppler echocardiography, the peak and mean transprosthetic gradients were 15 +/- 5 mm Hg and 6.3 +/- 3 mm Hg, respectively (mean follow-up, 4.2 +/- 2.7 years). At intermediate follow-up, the Biocor prosthesis in the mitral position showed excellent results in terms of valve durability when compared with other second-generation tissue valves.

X-ray Observations of Cosmic Ray Acceleration

NASA Technical Reports Server (NTRS)

Petre, Robert

2012-01-01

Since the discovery of cosmic rays, detection of their sources has remained elusive. A major breakthrough has come through the identification of synchrotron X-rays from the shocks of supernova remnants through imaging and spectroscopic observations by the most recent generation of X-ray observatories. This radiation is most likely produced by electrons accelerated to relativistic energy, and thus has offered the first, albeit indirect, observational evidence that diffusive shock acceleration in supernova remnants produces cosmic rays to TeV energies, possibly as high as the "knee" in the cosmic ray spectrum. X-ray observations have provided information about the maximum energy to which these shOCks accelerate electrons, as well as indirect evidence of proton acceleration. Shock morphologies measured in X-rays have indicated that a substantial fraction of the shock energy can be diverted into particle acceleration. This presentation will summarize what we have learned about cosmic ray acceleration from X-ray observations of supernova remnants over the past two decades.

3D echocardiographic analysis of aortic annulus for transcatheter aortic valve replacement using novel aortic valve quantification software: Comparison with computed tomography.

PubMed

Mediratta, Anuj; Addetia, Karima; Medvedofsky, Diego; Schneider, Robert J; Kruse, Eric; Shah, Atman P; Nathan, Sandeep; Paul, Jonathan D; Blair, John E; Ota, Takeyoshi; Balkhy, Husam H; Patel, Amit R; Mor-Avi, Victor; Lang, Roberto M

2017-05-01

With the increasing use of transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis (AS), computed tomography (CT) remains the standard for annulus sizing. However, 3D transesophageal echocardiography (TEE) has been an alternative in patients with contraindications to CT. We sought to (1) test the feasibility, accuracy, and reproducibility of prototype 3DTEE analysis software (Philips) for aortic annular measurements and (2) compare the new approach to the existing echocardiographic techniques. We prospectively studied 52 patients who underwent gated contrast CT, procedural 3DTEE, and TAVR. 3DTEE images were analyzed using novel semi-automated software designed for 3D measurements of the aortic root, which uses multiplanar reconstruction, similar to CT analysis. Aortic annulus measurements included area, perimeter, and diameter calculations from these measurements. The results were compared to CT-derived values. Additionally, 3D echocardiographic measurements (3D planimetry and mitral valve analysis software adapted for the aortic valve) were also compared to the CT reference values. 3DTEE image quality was sufficient in 90% of patients for aortic annulus measurements using the new software, which were in good agreement with CT (r-values: .89-.91) and small (<4%) inter-modality nonsignificant biases. Repeated measurements showed <10% measurements variability. The new 3D analysis was the more accurate and reproducible of the existing echocardiographic techniques. Novel semi-automated 3DTEE analysis software can accurately measure aortic annulus in patients with severe AS undergoing TAVR, in better agreement with CT than the existing methodology. Accordingly, intra-procedural TEE could potentially replace CT in patients where CT carries significant risk. © 2017, Wiley Periodicals, Inc.

Bismuth Passivation Technique for High-Resolution X-Ray Detectors

NASA Technical Reports Server (NTRS)

Chervenak, James; Hess, Larry

2013-01-01

The Athena-plus team requires X-ray sensors with energy resolution of better than one part in 3,000 at 6 keV X-rays. While bismuth is an excellent material for high X-ray stopping power and low heat capacity (for large signal when an X-ray is stopped by the absorber), oxidation of the bismuth surface can lead to electron traps and other effects that degrade the energy resolution. Bismuth oxide reduction and nitride passivation techniques analogous to those used in indium passivation are being applied in a new technique. The technique will enable improved energy resolution and resistance to aging in bismuth-absorber-coupled X-ray sensors. Elemental bismuth is lithographically integrated into X-ray detector circuits. It encounters several steps where the Bi oxidizes. The technology discussed here will remove oxide from the surface of the Bi and replace it with nitridized surface. Removal of the native oxide and passivating to prevent the growth of the oxide will improve detector performance and insulate the detector against future degradation from oxide growth. Placing the Bi coated sensor in a vacuum system, a reduction chemistry in a plasma (nitrogen/hydrogen (N2/H2) + argon) is used to remove the oxide and promote nitridization of the cleaned Bi surface. Once passivated, the Bi will perform as a better X-ray thermalizer since energy will not be trapped in the bismuth oxides on the surface. A simple additional step, which can be added at various stages of the current fabrication process, can then be applied to encapsulate the Bi film. After plasma passivation, the Bi can be capped with a non-diffusive layer of metal or dielectric. A non-superconducting layer is required such as tungsten or tungsten nitride (WNx).

Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, Daniel; Shenoy, Gopal; Wang, Jin

A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

X-ray monitoring optical elements

DOEpatents

Stoupin, Stanislav; Shvydko, Yury; Katsoudas, John; Blank, Vladimir D.; Terentyev, Sergey A.

2016-12-27

An X-ray article and method for analyzing hard X-rays which have interacted with a test system. The X-ray article is operative to diffract or otherwise process X-rays from an input X-ray beam which have interacted with the test system and at the same time provide an electrical circuit adapted to collect photoelectrons emitted from an X-ray optical element of the X-ray article to analyze features of the test system.

Dimension dependent immunity of X-ray irradiation on low-temperature polycrystalline-silicon TFTs

NASA Astrophysics Data System (ADS)

Wei, Yin-Chang; Li, Yi-Chieh; Lee, I.-Che; Cheng, Huang-Chung

2017-06-01

Typically, each element in a large-area flat-panel X-ray image sensor consists of a photodetector and amorphous silicon (a-Si) thin-film transistor (TFT) switches. In order to reduce noise, increase sensor dynamic range, and increase carrying capacity, the low-temperature polycrystalline-silicon (LTPS) TFTs have been proposed as a candidate to replace the a-Si TFTs. However, there are concerns regarding the impact of X-ray radiation in LTPS-TFTs, and several studies have been conducted to inquire into the same. In this paper, we show that LTPS TFTs with small channel length (<2 µm) are almost immune to X-ray radiation.

Quality of life in high-risk patients: comparison of transcatheter aortic valve implantation with surgical aortic valve replacement.

PubMed

Amonn, Kathrin; Stortecky, Stefan; Brinks, Henriette; Gahl, Brigitta; Windecker, Stephan; Wenaweser, Peter; Carrel, Thierry; Huber, Christoph

2013-01-01

To compare health-related quality of life (QoL) in patients undergoing transcatheter aortic valve implantation via transapical access (TA TAVI) with patients undergoing surgical aortic valve replacement (SAVR). One hundred and forty-four high-risk patients referred for aortic valve replacement underwent TAVI screening and were assigned to either TA TAVI (n = 51, age 79.7 ± 9.2 years, logistic EuroSCORE 26.5 ± 16.1%, 51% males) or SAVR (n = 93, age 81.1 ± 5.3 years, logistic EuroSCORE 12.1 ± 9.3%, 42% males) by the interdisciplinary heart team. QoL was assessed using the Short Form 36 (SF-36) Health Survey Questionnaire and the Hospital Anxiety and Depression Scale. Furthermore, current living conditions and the degree of independence at home were evaluated. Patients undergoing TA TAVI were at higher risk as assessed by EuroSCORE (26.5 ± 16 vs. 12.1 ± 9, P < 0.001) and STS score (6.7 ± 4 vs. 4.4 ± 3, P < 0.001) compared with SAVR patients. At the 30-day follow-up, the rate of mortality was similar and amounted to 7.8% for TA TAVI and 7.5% for SAVR patients and raised to 25.5% in TA TAVI and 18.3% in SAVR patients after a follow-up period of 15 ± 10 months. Assessment of QoL revealed no differences in terms of anxiety and depression between TA TAVI and SAVR patients. The SF-36 mental health metascore was similar in both groups (65.6 ± 19 vs. 68.8 ± 22, P = 0.29), while a significant difference was observed in the physical health metascore (49.7 ± 21 vs. 62.0 ± 21, P = 0.015). After adjustment for baseline characteristics, this difference disappeared. However, every added point in the preoperative risk assessment with the STS score decreased the SF-36 physical health dimension by two raw points at the follow-up assessment. Selected high-risk patients undergoing TAVI by using a transapical access achieve similar clinical outcomes and QoL compared with patients undergoing SAVR. Increased STS scores predict worse QoL outcomes.

Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

ClinicalTrials.gov

2017-04-26

Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

Optical and X-ray studies of Compact X-ray Binaries in NGC 5904

NASA Astrophysics Data System (ADS)

Bhalotia, Vanshree; Beck-Winchatz, Bernhard

2018-06-01

Due to their high stellar densities, globular cluster systems trigger various dynamical interactions, such as the formation of compact X-ray binaries. Stellar collisional frequencies have been correlated to the number of X-ray sources detected in various clusters and we hope to measure this correlation for NGC 5904. Optical fluxes of sources from archival HST images of NGC 5904 have been measured using a DOLPHOT PSF photometry in the UV, optical and near-infrared. We developed a data analysis pipeline to process the fluxes of tens of thousands of objects using awk, python and DOLPHOT. We plot color magnitude diagrams in different photometric bands in order to identify outliers that could be X-ray binaries, since they do not evolve the same way as singular stars. Aligning previously measured astrometric data for X-ray sources in NGC 5904 from Chandra with archival astrometric data from HST will filter out the outlier objects that are not X-ray producing, and provide a sample of compact binary systems that are responsible for X-ray emission in NGC 5904. Furthermore, previously measured X-ray fluxes of NGC 5904 from Chandra have also been used to measure the X-ray to optical flux ratio and identify the types of compact X-ray binaries responsible for the X-ray emissions in NGC 5904. We gratefully acknowledge the support from the Illinois Space Grant Consortium.

Preservation of the bicuspid aortic valve.

PubMed

Schäfers, Hans-Joachim; Aicher, Diana; Langer, Frank; Lausberg, Henning F

2007-02-01

Bicuspid anatomy of the aortic valve is a common reason for aortic regurgitation and is associated with aortic dilatation in more than 50% of patients. We have observed different patterns of aortic dilatation and used different approaches preserving the valve. Between October 1995 and February 2006, a regurgitant bicuspid valve was repaired in 173 patients. The aorta was normal in 57 patients who underwent isolated repair. Aortic dilatation mainly above commissural level (n = 38) was treated by separate valve repair plus supracommissural aortic replacement. In 78 patients, aortic dilatation involved the root and was treated by root remodeling. Hospital mortality and perioperative morbidity were low in all three groups. Myocardial ischemia was significantly shorter in repair plus aortic replacement than remodeling (p < 0.001). Freedom from aortic regurgitation II or greater at 5 years varied between 91% and 96%. Freedom from reoperation at 5 years was 97% after remodeling, but only 53% after repair plus aortic replacement (p = 0.33). Symmetric prolapse was the most frequent cause for reoperation. The long-term stability of bicuspid aortic valve repair is excellent in the absence of aortic pathology. In the presence of aortic dilatation, root remodeling leads to equally stable valve durability. In patients with less pronounced root dilatation, separate valve repair plus aortic replacement may be a less complex alternative. Symmetric prolapse should be avoided if the ascending aorta is replaced.

Streptococcus pneumoniae endocarditis on replacement aortic valve with panopthalmitis and pseudoabscess

PubMed Central

O’Brien, Stephen; Dayer, Mark; Benzimra, James; Hardman, Susan; Townsend, Mandie

2011-01-01

A 63-year-old woman with a previous episode of Streptococcus agalactiae endocarditis requiring a bioprosthetic aortic valve replacement presented with a short history of malaise, a right panopthalmitis with a Roth spot on funduscopy of the left eye and Streptococcus pneumoniae grown from vitreous and aqueous taps as well as blood cultures. She developed first degree heart block and her ECG was suggestive of an aortic root abscess. This gradually resolved over 6 weeks, during which she was treated with intravenous antibiotics. After careful consideration, it is likely that what was thought to be an aortic root abscess was instead an area of perivalvular inflammation. PMID:22678733

X-ray Spectropolarimetry of Z-pinch Plasmas with a Single-Crystal Technique

NASA Astrophysics Data System (ADS)

Wallace, Matt; Haque, Showera; Neill, Paul; Pereira, Nino; Presura, Radu

2017-10-01

When directed beams of energetic electrons exist in a plasma the resulting x-rays emitted by the plasma can be partially polarized. This makes plasma x-ray polarization spectroscopy, spectropolarimetry, useful for revealing information about the anisotropy of the electron velocity distribution. X-ray spectropolarimetry has indeed been used for this in both space and laboratory plasmas. X-ray polarization measurements are typically performed employing two crystals, both at a 45° Bragg angle. A single-crystal spectropolarimeter can replace two crystal schemes by utilizing two matching sets of internal planes for polarization-splitting. The polarization-splitting planes diffract the incident x-rays into two directions that are perpendicular to each other and the incident beam as well, so the two sets of diffracted x-rays are linearly polarized perpendicularly to each other. An X-cut quartz crystal with surface along the [11-20] planes and a paired set of [10-10] planes in polarization-splitting orientation is now being used on aluminum z-pinches at the University of Nevada, Reno. Past x-ray polarization measurements have been reserved for point-like sources. Recently a slotted collimating aperture has been used to maintain the required geometry for polarization-splitting enabling the spectropolarimetry of extended sources. The design of a single-crystal x-ray spectropolarimeter and experimental results will be presented. Work was supported by U.S. DOE, NNSA Grant DE-NA0001834 and cooperative agreement DE-FC52-06NA27616.

Structural valve deterioration in a starr-edwards mitral caged-disk valve prosthesis.

PubMed

Aoyagi, Shigeaki; Tayama, Kei-Ichiro; Okazaki, Teiji; Shintani, Yusuke; Kono, Michitaka; Wada, Kumiko; Kosuga, Ken-Ichi; Mori, Ryusuke; Tanaka, Hiroyuki

2013-01-01

The durability of the Starr-Edwards (SE) mitral caged-disk valve, model 6520, is not clearly known, and structural valve deterioration in the SE disk valve is very rare. Replacement of the SE mitral disk valve was performed in 7 patients 23-40 years after implantation. Macroscopic examination of the removed disk valves showed no structural abnormalities in 3 patients, in whom the disk valves were removed at <26 years after implantation. Localized disk wear was found at the sites where the disk abutted the struts of the cage, in disk valves excised >36 years after implantation in 4 patients. Disk fracture, a longitudinal split in the disk along its circumference at the site of incorporation of the titanium ring, was detected in the valves removed 36 and 40 years after implantation, respectively, and many cracks were also observed on the outflow aspect of the disk removed 40 years after implantation. Disk fracture and localized disk wear were found in the SE mitral disk valves implanted >36 years previously. The present results suggest that SE mitral caged-disk valves implanted >20 years previously should be carefully followed up, and that those implanted >30 years previously should be electively replaced with modern prosthetic valves

Retrograde transcatheter device closure of a complex paravalvular leak after bioprosthetic pulmonary valve replacement in a pediatric patient.

PubMed

Chikkabyrappa, Sathish; Mosca, Ralph S; McElhinney, Doff B

2016-06-01

We report a case of retrograde transcatheter device closure of a complex paravalvular leak (PVL) after bioprosthetic pulmonary valve replacement (PVR) in a 13-year-old patient with congenital pulmonary valve stenosis. There are prior reports of pulmonary PVL closure after PVR in adults (Seery and Slack, Congenit Heart Dis 2014;9:E19-F22), but indications for and technical considerations in PVL closure after bioprosthetic PVR, particularly in children, are not well defined. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

The Cambridge-Cambridge X-ray Serendipity Survey: I X-ray luminous galaxies

NASA Technical Reports Server (NTRS)

Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, M.

1994-01-01

We report on the first results obtained from a new optical identification program of 123 faint X-ray sources with S(0.5-2 keV) greater than 2 x 10(exp -14) erg/s/sq cm serendipitously detected in ROSAT PSPC pointed observations. We have spectroscopically identified the optical counterparts to more than 100 sources in this survey. Although the majority of the sample (68 objects) are QSO's, we have also identified 12 narrow emission line galaxies which have extreme X-ray luminosities (10(exp 42) less than L(sub X) less than 10(exp 43.5) erg/s). Subsequent spectroscopy reveals them to be a mixture of star-burst galaxies and Seyfert 2 galaxies in approximately equal numbers. Combined with potentially similar objects identified in the Einstein Extended Medium Sensitivity Survey, these X-ray luminous galaxies exhibit a rate of cosmological evolution, L(sub X) varies as (1 + z)(exp 2.5 +/- 1.0), consistent with that derived for X-ray QSO's. This evolution, coupled with the steep slope determined for the faint end of the X-ray luminosity function (Phi(L(sub X)) varies as L(sub X)(exp -1.9)), implies that such objects could comprise 15-35% of the soft (1-2 keV) X-ray background.

Compact X-ray sources: X-rays from self-reflection

NASA Astrophysics Data System (ADS)

Mangles, Stuart P. D.

2012-05-01

Laser-based particle acceleration offers a way to reduce the size of hard-X-ray sources. Scientists have now developed a simple scheme that produces a bright flash of hard X-rays by using a single laser pulse both to generate and to scatter an electron beam.

Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters

NASA Astrophysics Data System (ADS)

Guo, Yan-Jun; Dai, Shi; Li, Zhao-Sheng; Liu, Yuan; Tong, Hao; Xu, Ren-Xin

2015-04-01

Hard X-rays above 10 keV are detected from several anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system. Using data from Suzaku and INTEGRAL, we study the soft and hard X-ray spectra of four AXPs/SGRs: 1RXS J170849-400910, 1E 1547.0-5408, SGR 1806-20 and SGR 0501+4516. It is found that the spectra could be well reproduced by the bulk-motion Comptonization (BMC) process as was first suggested by Trümper et al., showing that the accretion scenario could be compatible with X-ray emission from AXPs/SGRs. Simulated results from the Hard X-ray Modulation Telescope using the BMC model show that the spectra would have discrepancies from the power-law, especially the cutoff at ˜200 keV. Thus future observations will allow researchers to distinguish different models of the hard X-ray emission and will help us understand the nature of AXPs/SGRs. Supported by the National Natural Science Foundation of China.

X-Ray Studies of Delphi Diesel Injection Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Christopher

2017-01-01

This CRADA explored the performance of two different models of Delphi diesel injectors. For each injector, the valve needle motion was imaged from two lines of sight at three different injection pressures to characterize its 3D motion. The needle lift was quite repeatable, and followed the expected trend of faster lift with higher injection pressure. In addition, it was observed that the maximum lift increased with injection pressure, even after the valve reached its mechanical limit, indicating that the increased fuel pressure was causing compression or bending of the needle. The off-axis motion of the needle was found to bemore » significant in both measurement planes, though it was very repeatable from one injection event to the next. The effect of ambient pressure on the needle motion was explored at an injection pressure of 400 bar, with ambient pressure up to 15 bar. No effect of the elevated ambient pressure on the needle lift was observed. High-speed x-ray imaging of the spray as it first emerges from the injector nozzle was performed in order to characterize the near-nozzle morphology and breakup of the spray. While imaging was successful at low ambient pressure, the contrast of the images was reduced at high ambient pressures, and quantitative measurements of the morphology were precluded. The near-nozzle fuel distributions were measured using time-resolved x-ray radiography for three injection pressures at an ambient pressure of 33 bar. Increasing injection pressure caused the fuel distribution to narrow, as measured by the Full Width at Half Maximum of the mass distributions. The fuel distributions were quantified for the two injectors at each measurement condition, quantifying the impact that each experimental parameter has on the near-nozzle fuel and air mixture preparation.« less

Quality of Life After Transcatheter Aortic Valve Replacement: Prospective Data From GARY (German Aortic Valve Registry).

PubMed

Lange, Rüdiger; Beckmann, Andreas; Neumann, Till; Krane, Markus; Deutsch, Marcus-André; Landwehr, Sandra; Kötting, Joachim; Welz, Armin; Zahn, Ralf; Cremer, Jochen; Figulla, Hans R; Schuler, Gerhard; Holzhey, David M; Funkat, Anne-Kathrin; Heusch, Gerd; Sack, Stefan; Pasic, Miralem; Meinertz, Thomas; Walther, Thomas; Kuck, Karl-Heinz; Beyersdorf, Friedhelm; Böhm, Michael; Möllmann, Helge; Hamm, Christian W; Mohr, Friedrich W

2016-12-26

This study sought to analyze health-related quality-of-life (HrQoL) outcomes of patients undergoing transcatheter aortic valve replacement (TAVR) based on data from GARY (German Aortic Valve Registry). Typically, patients currently referred for and treated by TAVR are elderly with a concomitant variable spectrum of multiple comorbidities, disabilities, and limited life expectancy. Beyond mortality and morbidity, the assessment of HrQoL is of paramount importance not only to guide patient-centered clinical decision-making but also to judge this new treatment modality in this high-risk patient population. In 2011, 3,875 patients undergoing TAVR were included in the GARY registry. HrQoL was prospectively measured using the EuroQol 5 dimensions questionnaire self-complete version on paper at baseline and 1 year. Complete follow-up EuroQol 5 dimensions questionnaire evaluation was available for 2,288 patients (transvascular transcatheter aortic valve replacement [TAVR-TV]: n = 1,626 and transapical TAVR [TAVR-TA]: n = 662). In-hospital mortality was 5.9% (n = 229) and the 1-year mortality was 23% (n = 893). The baseline visual analog scale score for general health status was 52.6% for TAVR-TV and 55.8% for TAVR-TA and, in parallel to an improvement in New York Heart Association functional class, improved to 59.6% and 58.5% at 1 year, respectively (p < 0.001). Between baseline and 1 year, the number of patients reporting no complaints increased by 7.8% (TAVR-TV) and by 3.5% within the mobility dimension, and by 14.1% (TAVR-TV) and 9.2% within the usual activity dimension, whereas only moderate changes were found for the self-care, pain or discomfort, and anxiety or depression dimensions. In a multiple linear regression analysis several pre- and post-operative factors were predictive for less pronounced HrQoL benefits. TAVR treatment led to improvements in HrQoL, especially in terms of mobility and usual activities. The magnitude of improvements was higher in the

X-ray crystallography

NASA Technical Reports Server (NTRS)

2001-01-01

X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

Practical considerations for optimizing cardiac computed tomography protocols for comprehensive acquisition prior to transcatheter aortic valve replacement.

PubMed

Khalique, Omar K; Pulerwitz, Todd C; Halliburton, Sandra S; Kodali, Susheel K; Hahn, Rebecca T; Nazif, Tamim M; Vahl, Torsten P; George, Isaac; Leon, Martin B; D'Souza, Belinda; Einstein, Andrew J

2016-01-01

Transcatheter aortic valve replacement (TAVR) is performed frequently in patients with severe, symptomatic aortic stenosis who are at high risk or inoperable for open surgical aortic valve replacement. Computed tomography angiography (CTA) has become the gold standard imaging modality for pre-TAVR cardiac anatomic and vascular access assessment. Traditionally, cardiac CTA has been most frequently used for assessment of coronary artery stenosis, and scanning protocols have generally been tailored for this purpose. Pre-TAVR CTA has different goals than coronary CTA and the high prevalence of chronic kidney disease in the TAVR patient population creates a particular need to optimize protocols for a reduction in iodinated contrast volume. This document reviews details which allow the physician to tailor CTA examinations to maximize image quality and minimize harm, while factoring in multiple patient and scanner variables which must be considered in customizing a pre-TAVR protocol. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Digital imaging with solid state x-ray image intensifiers

NASA Astrophysics Data System (ADS)

Damento, Michael A.; Radspinner, Rachel; Roehrig, Hans

1999-10-01

X-ray cameras in which a CCD is lens coupled to a large phosphor screen are known to suffer from a loss of x-ray signal due to poor light collection from conventional phosphors, making them unsuitable for most medical imaging applications. By replacing the standard phosphor with a solid-state image intensifier, it may be possible to improve the signal-to-noise ratio of the images produced with these cameras. The solid-state x-ray image intensifier is a multi- layer device in which a photoconductor layer controls the light output from an electroluminescent phosphor layer. While prototype devices have been used for direct viewing and video imaging, they are only now being evaluated in a digital imaging system. In the present work, the preparation and evaluation of intensifiers with a 65 mm square format are described. The intensifiers are prepared by screen- printing or doctor blading the following layers onto an ITO coated glass substrate: ZnS phosphor, opaque layer, CdS photoconductor, and carbon conductor. The total thickness of the layers is approximately 350 micrometers , 350 VAC at 400 Hz is applied to the device for operation. For a given x-ray dose, the intensifiers produce up to three times the intensity (after background subtracting) of Lanex Fast Front screens. X-ray images produced with the present intensifiers are somewhat noisy and their resolution is about half that of Lanex screens. Modifications are suggested which could improve the resolution and noise of the intensifiers.

Fluid mechanics of heart valves.

PubMed

Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S

2004-01-01

Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.

Ross procedure for ascending aortic replacement.

PubMed

Elkins, R C; Lane, M M; McCue, C

1999-06-01

Patients with aortic valve disease and aneurysm or dilatation of the ascending aorta require both aortic valve replacement and treatment of their ascending aortic disease. In children and young adults, the Ross operation is preferred when the aortic valve requires replacement, but the efficacy of extending this operation to include replacement of the ascending aorta or reduction of the dilated aorta has not been tested. We reviewed the medical records of 18 (5.9%) patients with aortic valve disease and an ascending aortic aneurysm and 26 (8.5%) patients with dilation of the ascending aorta, subgroups of 307 patients who had a Ross operation between August 1986 and February 1998. We examined operative and midterm results, including recent echocardiographic assessment of autograft valve function and ability of the autograft root and ascending aortic repair or replacement to maintain normal structural integrity. There was one operative death (2%) related to a perioperative stroke. Forty-two of 43 survivors have normal autograft valve function, with trace to mild autograft valve insufficiency, and one patient has moderate insufficiency at the most recent echocardiographic evaluation. None of the patients has dilatation of the autograft root or of the replaced or reduced ascending aorta. Early results with extension of the Ross operation to include replacement of an ascending aortic aneurysm or vertical aortoplasty for reduction of a dilated ascending aorta are excellent, with autograft valve function equal to that seen in similar patients without ascending aortic disease.

[Deformation of the tricuspid annulus by pericardial adhesions: a rare cause of early tricuspid regurgitation after mitral valve replacement].

PubMed

Tapia, M; Latrémouille, C; Chabert, J P; Fabiani, J N

1995-12-01

The authors report the case of major tricuspid regurgitation occurring early after mitral valve replacement. The mechanism was demonstrated at reoperation: the heart was deformed by a posterior pericardial effusion and cardiodiaphragmatic pericardial adhesions.

The Advanced X-Ray Astrophysics Facility. Observing the Universe in X-Rays

NASA Technical Reports Server (NTRS)

Neal, V.

1984-01-01

An overview of the Advanced X ray Astronophysics Facility (AXAF) program is presented. Beginning with a brief introduction to X ray astrophysics, the AXAF observatory is described including the onboard instrumentation and system capabilities. Possible X ray sources suitable for AXAF observation are identified and defined.

The Mapping X-ray Fluorescence Spectrometer (MapX)

NASA Astrophysics Data System (ADS)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1990-01-01

The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

Focusing X-Ray Telescopes

NASA Technical Reports Server (NTRS)

O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab;

Three-dimensional prototyping for procedural simulation of transcatheter mitral valve replacement in patients with mitral annular calcification.

PubMed

El Sabbagh, Abdallah; Eleid, Mackram F; Matsumoto, Jane M; Anavekar, Nandan S; Al-Hijji, Mohammed A; Said, Sameh M; Nkomo, Vuyisile T; Holmes, David R; Rihal, Charanjit S; Foley, Thomas A

2018-01-23

Three-dimensional (3D) prototyping is a novel technology which can be used to plan and guide complex procedures such as transcatheter mitral valve replacement (TMVR). Eight patients with severe mitral annular calcification (MAC) underwent TMVR. 3D digital models with digital balloon expandable valves were created from pre-procedure CT scans using dedicated software. Five models were printed. These models were used to assess prosthesis sizing, anchoring, expansion, paravalvular gaps, left ventricular outflow tract (LVOT) obstruction, and other potential procedure pitfalls. Results of 3D prototyping were then compared to post procedural imaging to determine how closely the achieved procedural result mirrored the 3D modeled result. 3D prototyping simulated LVOT obstruction in one patient who developed it and in another patient who underwent alcohol septal ablation prior to TMVR. Valve sizing correlated with actual placed valve size in six out of the eight patients and more than mild paravalvular leak (PVL) was simulated in two of the three patients who had it. Patients who had mismatch between their modeled valve size and post-procedural imaging were the ones that had anterior leaflet resection which could have altered valve sizing and PVL simulation. 3D printed model of one of the latter patients allowed modification of anterior leaflet to simulate surgical resection and was able to estimate the size and location of the PVL after inserting a valve stent into the physical model. 3D prototyping in TMVR for severe MAC is feasible for simulating valve sizing, apposition, expansion, PVL, and LVOT obstruction. © 2018 Wiley Periodicals, Inc.

Patient-prosthesis mismatch in aortic valve replacement: really tolerable?

PubMed

Fuster, Rafael García; Montero Argudo, José A; Albarova, Oscar Gil; Sos, Fernando Hornero; López, Sergio Cánovas; Codoñer, María Bueno; Buendía Miñano, José A; Albarran, Ignacio Rodríguez

2005-03-01

Several studies have demonstrated favorable results despite patient-prosthesis mismatch after aortic valve replacement with the use of third generation prostheses. Our aim was to determine whether this mismatch is always tolerable. A clinical-echocardiographic study has been performed in 339 consecutive patients who underwent aortic valve replacement because of aortic stenosis. In-hospital outcome and left ventricular mass index regression (1st month-1st year) were analyzed in the presence or absence of mismatch (indexed effective orifice area < or =0.85cm(2)/m(2)). The influence of high degrees of preoperative left ventricular mass on in-hospital mortality has also been evaluated. Left ventricular mass index was considered increased if the calculated value was over the superior quartile of the frequency distribution of all the values observed in both sexes. Mismatch was found in 38% of the patients. In the absence of mismatch, the absolute mass regression was proportional to the preoperative left ventricular mass. This regression was higher in patients with increased left ventricular mass indexed (vs not increased): -38.0+/-7.8 vs -8.8+/-4.7g/m(2), p<0.01 (1st month) and -67.7+/-16.9vs -23.5+/-6.7g/m(2), p<0.05 (1st year). Mass regression was impaired in the presence of mismatch, particularly, in patients with previously increased left ventricular mass: -8.2+/-11.6 vs -5.6+/-6.3g/m(2) (p=0.83) and -24.6+/-12.6 vs -11.7+/-10.5g/m(2) (p=0.54). This worse regression was reflected on a 100% incidence of residual hypertrophy at follow-up (1st month-1st year). In the presence of mismatch, increased ventricular mass was associated with higher mortality: 14.7% vs 2.1% (p<0.01). In the absence of mismatch, ventricular mass was not associated with mortality: 4.1 vs 2.5% (p=0.55). In patients with severe ventricular hypertrophy it may be important to elude patient-prosthesis mismatch to avoid a significant increase in mortality and improve ventricular mass regression

Patient selection for transcatheter aortic valve replacement: A combined clinical and multimodality imaging approach

PubMed Central

Cocchia, Rosangela; D’Andrea, Antonello; Conte, Marianna; Cavallaro, Massimo; Riegler, Lucia; Citro, Rodolfo; Sirignano, Cesare; Imbriaco, Massimo; Cappelli, Maurizio; Gregorio, Giovanni; Calabrò, Raffaele; Bossone, Eduardo

2017-01-01

Transcatheter aortic valve replacement (TAVR) has been validated as a new therapy for patients affected by severe symptomatic aortic stenosis who are not eligible for surgical intervention because of major contraindication or high operative risk. Patient selection for TAVR should be based not only on accurate assessment of aortic stenosis morphology, but also on several clinical and functional data. Multi-Imaging modalities should be preferred for assessing the anatomy and the dimensions of the aortic valve and annulus before TAVR. Ultrasounds represent the first line tool in evaluation of this patients giving detailed anatomic description of aortic valve complex and allowing estimating with enough reliability the hemodynamic entity of valvular stenosis. Angiography should be used to assess coronary involvement and plan a revascularization strategy before the implant. Multislice computed tomography play a central role as it can give anatomical details in order to choice the best fitting prosthesis, evaluate the morphology of the access path and detect other relevant comorbidities. Cardiovascular magnetic resonance and positron emission tomography are emergent modality helpful in aortic stenosis evaluation. The aim of this review is to give an overview on TAVR clinical and technical aspects essential for adequate selection. PMID:28400918

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

X-ray lasers

NASA Astrophysics Data System (ADS)

Elton, Raymond C.

Theoretical and practical aspects of X-ray lasers are discussed in an introduction emphasizing recent advances. Chapters are devoted to the unique optical properties of the X-ray spectral region, the principles of short-wavelength lasers, pumping by exciting plasma ions, pumping by electron capture into excited ionic states, pumping by ionization of atoms and ions, and alternative approaches. The potential scientific, technical, biological, and medical applications of X-ray lasers are briefly characterized.

International normalized ratio self-management lowers the risk of thromboembolic events after prosthetic heart valve replacement.

PubMed

Eitz, Thomas; Schenk, Soren; Fritzsche, Dirk; Bairaktaris, Andreas; Wagner, Otto; Koertke, Heinrich; Koerfer, Reiner

2008-03-01

Although prosthetic valves are durable and easy to implant, the need for lifetime warfarin-based anticoagulation restricts their exclusive usage. We investigated if anticoagulation self-management improves outcome in a single-center series. Between 1994 and 1998, 765 patients with prosthetic valve replacements were prospectively enrolled and randomized to receive conventional anticoagulation management by their primary physician (group 1, n = 295) or to pursue anticoagulation self-management (group 2, n = 470). A study head office was implemented to coordinate and monitor anticoagulation protocols, international normalized ratios (INR), and adverse events. Patients were instructed on how to obtain and test their own blood samples and to adjust warfarin dosages according to the measured INR (target range, 2.5 to 4). Mean INR values were slightly yet significantly smaller in group 1 than in group 2 (2.8 +/- 0.7 vs 3.0 +/- .6, p < 0.001). Moreover, INR values of patients with conventional INR management were frequently measured outside the INR target range, whereas those with anticoagulation self-management mostly remained within the range (35% vs 21%, p < 0.001). In addition, the scatter of INR values was smaller if self-managed. Freedom from thromboembolism at 3, 12, and 24 months, respectively, was 99%, 95%, and 91% in group 1 compared with 99%, 98%, and 96% in group 2 (p = 0.008). Bleeding events were similar in both groups. Time-related multivariate analysis identified INR self-management and higher INR as independent predictors for better outcome. Anticoagulation self-management can improve INR profiles up to 2 years after prosthetic valve replacement and reduce adverse events. Current indications of prosthetic rather than biologic valve implantations may be extended if the benefit of INR self-management is shown by future studies with longer follow-up.

The superslow pulsation X-ray pulsars in high mass X-ray binaries

NASA Astrophysics Data System (ADS)

Wang, Wei

2013-03-01

There exists a special class of X-ray pulsars that exhibit very slow pulsation of P spin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (P spin ~ 5560 s with Ṗ spin ~ 4.9 × 10-7 s s-1) and long-term spin-up trend for 2S 0114+65 (P spin ~ 9600 s with Ṗ spin ~ -1 × 10-6 s s-1) in the last 20 years. A Be X-ray transient, SXP 1062 (P spin ~ 1062 s), also showed a fast spin-down rate of Ṗ spin ~ 3 × 10-6 s s-1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system - accreting magnetars.

Mouse blood vessel imaging by in-line x-ray phase-contrast imaging

NASA Astrophysics Data System (ADS)

Zhang, Xi; Liu, Xiao-Song; Yang, Xin-Rong; Chen, Shao-Liang; Zhu, Pei-Ping; Yuan, Qing-Xi

2008-10-01

It is virtually impossible to observe blood vessels by conventional x-ray imaging techniques without using contrast agents. In addition, such x-ray systems are typically incapable of detecting vessels with diameters less than 200 µm. Here we show that vessels as small as 30 µm could be detected using in-line phase-contrast x-ray imaging without the use of contrast agents. Image quality was greatly improved by replacing resident blood with physiological saline. Furthermore, an entire branch of the portal vein from the main axial portal vein to the eighth generation of branching could be captured in a single phase-contrast image. Prior to our work, detection of 30 µm diameter blood vessels could only be achieved using x-ray interferometry, which requires sophisticated x-ray optics. Our results thus demonstrate that in-line phase-contrast x-ray imaging, using physiological saline as a contrast agent, provides an alternative to the interferometric method that can be much more easily implemented and also offers the advantage of a larger field of view. A possible application of this methodology is in animal tumor models, where it can be used to observe tumor angiogenesis and the treatment effects of antineoplastic agents.

Miniature x-ray source

DOEpatents

Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

2002-01-01

A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

CardiaMed mechanical valve: mid-term results of a multicenter clinical trial.

PubMed

Nazarov, Vladimir M; Zheleznev, Sergey I; Bogachev-Prokophiev, Alexandr V; Afanasyev, Alexandr V; Nemchenko, Eugene V; Jeltovskiy, Yuri V; Lavinyukov, Sergey O

2014-01-01

Prosthesis choice is a major concern in valvular surgery. A multicenter clinical trial was performed to assess the efficacy and safety of the CardiaMed prosthetic heart valve. The study enrolled 420 patients who underwent mitral (209) or aortic (211) valve replacement from 2003 to 2004 at 7 institutions in Russia, and who were followed up from 2006 to 2011. The mean age was 52.2 ± 10.2 years (range, 12-78 years), 47.4% were female, and 99.05% completed the study. The maximum observation term was 7.5 years (2188.5 patient-years); 1081.6 patient-years for aortic and 1106.9 patient-years for mitral valve replacement. The overall 7-year survival rate was 85.1%  ± 3.7%; 86.1%  ± 4.8% and 84.4%  ± 5.4% for aortic and mitral valve replacement, respectively. The 7-year freedom from valve-related death was 93.9%  ± 3.7% and 94.5%  ± 3.2% for aortic and mitral valve replacement, respectively. When early mortality (<30 days) was excluded, these rates were 94.8%  ± 3.1% and 93.8%  ± 3.82%, respectively. Linearized valve-dependent complication rates were determined for structural valve failure (0%/patient-year overall), thrombosis (0.63%/patient-year, all for mitral valve replacement), thromboembolic complications including transient neurologic deficits (0.13%/patient-year overall, 0.5%/patient-year for aortic valve replacement, 0.8%/patient-year for mitral valve replacement), hemorrhagic bleeding (0.64%/patient-year overall, 0.55%/patient-year for aortic valve replacement, 0.09%/patient-year for mitral valve replacement), prosthetic endocarditis (0.28%/patient-year overall, 0.28%/patient-year for aortic valve replacement, 0%/patient-year for mitral valve replacement), and hemolysis (0%/patient-year overall). The CardiaMed mechanical heart valve prostheses meets world standards of safety and efficacy.

Wide-area phase-contrast X-ray imaging using large X-ray interferometers

NASA Astrophysics Data System (ADS)

Momose, Atsushi; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

2001-07-01

Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mm×20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

Indication for percutaneous aortic valve implantation

PubMed Central

Akin, Ibrahim; Kische, Stephan; Rehders, Tim C.; Nienaber, Christoph A.; Rauchhaus, Mathias; Schneider, Henrik; Liebold, Andreas

2010-01-01

The incidence of valvular aortic stenosis has increased over the past decades due to improved life expectancy. Surgical aortic valve replacement is currently the only treatment option for severe symptomatic aortic stenosis that has been shown to improve survival. However, up to one third of patients who require lifesaving surgical aortic valve replacement are denied surgery due to high comorbidities resulting in a higher operative mortality rate. In the past such patients could only be treated with medical therapy or percutaneous aortic valvuloplasty, neither of which has been shown to improve mortality. With advances in interventional cardiology, transcatheter methods have been developed for aortic valve replacement with the goal of offering a therapeutic solution for patients who are unfit for surgical therapy. Currently there are two catheter-based treatment systems in clinical application (the Edwards SAPIEN aortic valve and the CoreValve ReValving System), utilizing either a balloon-expandable or a self-expanding stent platform, respectively. PMID:22371763

Progression of Tricuspid Regurgitation after Mitral Valve Replacement for Rheumatic Heart Disease.

PubMed

Q Tri, Ho H; Vinh, Pham N

2017-05-01

Progression of tricuspid regurgitation (TR) may occur after mitral valve replacement (MVR). The study aim was to define the independent predictors for new severe TR after MVR to treat rheumatic heart disease. A total of 413 patients (177 men, 236 women; mean age 40.9 ± 9.2 years) with rheumatic heart disease undergoing MVR without concomitant tricuspid valve repair at the authors' institute between 1995 and 2005, who did not have preoperative severe TR, were followed for at least one year postoperatively. Survival without severe TR was estimated using the Kaplan-Meier method. Independent predictors for new severe TR were identified using multiple Cox regression analysis. During a median follow up of 13 years there were two late deaths, and 46 patients (11.1%) had new severe TR. Survival without severe TR was 88.0 ± 1.7% at 10 years. Independent predictors for new severe TR were preoperative moderate TR (HR 2.401; p = 0.008) and atrial fibrillation (AF) (HR 2.119; p = 0.018). At the most recent follow up, furosemide was used in 23.9% patients with and 7.3% patients without new severe TR (p = 0.001). Patients with new severe TR had larger right ventricles and higher pulmonary artery pressures on echocardiography. Among patients with rheumatic heart disease undergoing MVR without concomitant tricuspid valve repair, independent predictors for new severe TR were preoperative moderate TR and AF. New severe TR was associated with increased furosemide use.

X-Pinch And Its Applications In X-ray Radiograph

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou Xiaobing; Wang Xinxin; Liu Rui

2009-07-07

An X-pinch device and the related diagnostics of x-ray emission from X-pinch were briefly described. The time-resolved x-ray measurements with photoconducting diodes show that the x-ray pulse usually consists of two subnanosecond peaks with a time interval of about 0.5 ns. Being consistent with these two peaks of the x-ray pulse, two point x-ray sources of size ranging from 100 mum to 5 mum and depending on cut-off x-ray photon energy were usually observed on the pinhole pictures. The x-pinch was used as x-ray source for backlighting of the electrical explosion of single wire and the evolution of X-pinch, andmore » for phase-contrast imaging of soft biological objects such as a small shrimp and a mosquito.« less

Evolution of X-ray astronomy

NASA Technical Reports Server (NTRS)

Rossj, B.

1981-01-01

The evolution of X-ray astronomy up to the launching of the Einstein observatory is presented. The evaluation proceeded through the following major steps: (1) discovery of an extrasolar X-ray source, Sco X-1, orders of magnitude stronger than astronomers believed might exist; (2) identification of a strong X-ray source with the Crab Nebula; (3) identification of Sco X-1 with a faint, peculiar optical object; (4) demonstration that X-ray stars are binary systems, each consisting of a collapsed object accreting matter from an ordinary star; (5) discovery of X-ray bursts; (6) discovery of exceedingly strong X-ray emission from active galaxies, quasars and clusters of galaxies; (7) demonstration that the principal X-ray source is a hot gas filling the space between galaxies.

Active x-ray optics for Generation-X, the next high resolution x-ray observatory

NASA Astrophysics Data System (ADS)

Elvis, Martin; Brissenden, R. J.; Fabbiano, G.; Schwartz, D. A.; Reid, P.; Podgorski, W.; Eisenhower, M.; Juda, M.; Phillips, J.; Cohen, L.; Wolk, S.

2006-06-01

X-rays provide one of the few bands through which we can study the epoch of reionization, when the first galaxies, black holes and stars were born. To reach the sensitivity required to image these first discrete objects in the universe needs a major advance in X-ray optics. Generation-X (Gen-X) is currently the only X-ray astronomy mission concept that addresses this goal. Gen-X aims to improve substantially on the Chandra angular resolution and to do so with substantially larger effective area. These two goals can only be met if a mirror technology can be developed that yields high angular resolution at much lower mass/unit area than the Chandra optics, matching that of Constellation-X (Con-X). We describe an approach to this goal based on active X-ray optics that correct the mid-frequency departures from an ideal Wolter optic on-orbit. We concentrate on the problems of sensing figure errors, calculating the corrections required, and applying those corrections. The time needed to make this in-flight calibration is reasonable. A laboratory version of these optics has already been developed by others and is successfully operating at synchrotron light sources. With only a moderate investment in these optics the goals of Gen-X resolution can be realized.

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

Chandra X-ray Observatory - NASA's flagship X-ray telescope

Science.gov Websites

astronomy, taking its place in the fleet of "Great Observatories." Who we are NASA's Chandra X-ray astronomy, distances are measured in units of light years, where one light year is the distance that light gravity? The answer is still out there. By studying clusters of galaxies, X-ray astronomy is tackling this

Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

DOEpatents