ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Methods for analyzing rates of events such as heart valve failure following surgery are important for comparing different techniques and devices; however, in patients undergoing major surgery, other risks such as mortality compete with the risk of heart valve failure to determine each patient’s final outcome. When multiple, mutually exclusive endpoints are possible, a situation known to statisticians as acompeting risksproblem arises. No single statistical technique that is currently available provides an entirely satisfactory solution to this problem. We argue that in order for valve failure incidences to be useful clinically, the overall patient outcome milieu from which these failures arise must be considered. In this article, we review recent work in the area of competing-risks analysis as it pertains to heart valve surgery outcome.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Replacement of the diseased aortic valve represents one of the triumphs of cardiac surgery; however, the perfect valve substitute continues to elude surgeons after almost four decades of clinical experience. The characteristics of the ideal valve substitute include the following: central flow capacity, low transvalvular gradient, low thrombogenicity, durability, easy availability, resistance to infection, non-immunogenicity, and easy implantability. The pulmonary autograft first performed by Ross (Lancet1967, 2:956–958) came closest to achieving these goals, but creates a double valve procedure for single valve disease. Aortic valve replacement (AVR) with homograft aortic valve was introduced by Ross in 1962 (Lancet1962, 2:487) and Barratt-Boyes in 1964 (Thorax1964, 19:131–150). Like the pulmonary autograft, homograft AVR results in an excellent hemodynamic outcome but suffers from limitations of graft availability, lack of durability, and difficulty with implantation. Mechanical valves and stented tissue valves allow “off the shelf” easy availability as well as easy implantability. These valves are unfortunately intrinsically obstructed to some extent because of the space occupied by the stent and sewing ring. Stent mounted tissue valves also continue to exhibit limited durability. Stentless xenograft aortic valves have been developed as a compromise between these ends of the valve spectrum to allow excellent hemodynamics and hopefully improved durability while allowing “off the shelf” availability in a variety of standard sizes. We examine the rationale for use of the stentless xenograft aortic valve, the clinical development of this valve, and the surgical techniques of implantation.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

During the 31 years since the initial Ross procedure, data have been collected that have been helpful in assessing long-term performance of the autograft. The ongoing study of the pulmonary autograft supports the use of the Ross procedure in young patients, in females of childbearing age, and in patients with congenital aortic stenosis and complex left ventricular outflow tract obstruction. We continue to see little or no thromboembolism despite no anticoagulation therapy. The remarkable ability of the autograft to grow in children is extremely beneficial. Additionally, excellent results have been obtained in some series for the treatment of endocarditis. Recently, the autograft has performed similarly to a normal aortic valve under high stress. Changes in implantation techniques transitioning from subcoronary to root replacement and performing annular narrowing has decreased the incidence of early regurgitation. A potential for an immune response with resulting pulmonary stenosis and possible early explantation of the pulmonary homograft exists; however, overall, results of the Ross procedure are excellent and highly reproducible.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Balloon mitral valvuloplasty (BMV) for mitral stenosis is a procedure that has evolved significantly since its introduction by Inoueet al.in 1984. This article reviews currently used techniques, advantages, and limitations as well as outcomes in comparison with surgical procedures. Included is a review of imaging techniques that facilitate BMV, such as transesophageal echocardiography and the recently developed tri-dimensional transthoracic echocardiography and intracardiac echocardiography. In a separate section, the application of BMV in specific clinical situations, such as in patients with multivalvular disease, during pregnancy, in children, in the presence of thrombi, and in patients with bioprostheses, is discussed.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

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.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The selection of patients for heart transplantation involves the use of multiple prognostic variables. Because of the complexity of the clinical syndrome of heart failure, central cardiac and peripheral maladaptations occur. Exercise capacity simultaneously assesses cardiovascular reserve and evaluates the peripheral maladaptations; accordingly, exercise testing has become an increasingly important tool in the risk stratification of these patients. Established prognostic indicators in heart failure are reviewed. The role exercise testing plays in selecting ambulatory patients for heart transplantation is emphasized.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

This review describes to date the experience with combined heart-kidney transplant (HNTx) from a single donor. HNTxs are very uncommon relative to single-organ transplants of the heart and kidney, as well as combined kidney-pancreas and combined kidney-liver transplants. Two groups of patients seem to be candidates for HNTx: 1) those with end-stage heart disease and fixed (nonreversible) renal disease, and 2) those with end-stage renal disease and severe cardiac disease unamenable to other treatment. In both groups, significant disease should be limited to the heart and kidney. Reports to date generally suggest decreased cardiac rejection in HNTx relative to heart-only transplants. Renal rejection in HNTx seems markedly reduced relative to kidney-only transplants. Simultaneous rejection of both organs is very uncommon, and, therefore, surveillance of both organs is necessary. Short-term patient survival seems to be acceptable in HNTx. Long-term patient and graft survival remains unknown, and further multicenter reports are needed.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Mixed bone marrow chimerism (mixed chimerism) is defined by the coexistence of two genetically different bone marrow stem cells in an individual. The chimeric immune system recognizes donor antigen as self, yet is capable of mounting a normal response to third-party antigens. In animal models, mixed chimerism confers donor-specific tolerance for solid-organ and cellular grafts: tissue from the bone marrow donor is permanently accepted by mixed chimeras in the absence of conventional immunosuppressive agents. Clinical application of mixed chimerism to induce transplantation tolerance requires novel approaches to safely and reliably achieve engraftment of donor bone marrow in transplant recipients. Recent advances offer potential solutions to these obstacles and suggest that the application of mixed chimerism to induce tolerance to transplanted organs may soon be a clinical reality.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID