ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Because of the lack of donor hearts, thousands of patients annually die with end-stage heart failure. Surgical alternatives to transplantation include partial left ventricular resection, dynamic cardiomyoplasty, and left ventricular assist devices. Partial left ventricular resection is an innovative procedure in which the heart is surgically reduced in size and cardiac function is dramatically improved immediately after surgery. Long-term follow-up is required to determine the success of this procedure. Dynamic cardiomyoplasty has been in use for 12 years. In properly selected patients, it results in significant amelioration of symptoms and improvement in quality of life. Improved survival and objective physiologic improvement have not been documented. A randomized trial is now in progress to evaluate survival with surgical therapy versus survival with medical therapy. Left ventricular assist devices have been shown to be extremely effective as a short- and long-term “bridge” to heart transplantation in mortally ill patients. They are not approved for long-term support as an alternative to transplantation in the United States, but a randomized trial is now underway to compare the efficacy of these devices with the efficacy of medical therapy in New York Heart Association functional class IV patients.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The severe shortage of human donor hearts has prompted several investigators to develop alternative strategies using cross-specie organs or xenografts. Unlike human allotransplantation, in which the important antigenic differences between donor and recipient are confined to the major histocompatibility and blood group antigens, xenotransplantation is confronted with the potential for multiple antigenic differences. In the pig-to-primate model of xenotransplantation, the primary obstacle to cross-species transplantation has been hyperacute rejection mediated by complement fixing antibodies directed against galactose α1,3-galactose (Gal α1,3-Gal) epitopes on the pig endothelium. Conventional immunosuppression is unable to overcome hyperacute rejection; however, recent efforts in molecular biology have focused on genetically engineering porcine donors to express human proteins in their tissue. Transgenic pigs that express human complement regulatory proteins on their endothelium have been developed. Heterotopic transplantation of these transgenic donor hearts have had only moderate success. Alternative approaches attempt to eliminate the Gal α 1,3-Gal epitopes by genetically “knocking out” the enzyme necessary for its synthesis, or to reduce the expression of Gal α 1,3-Gal epitopes by genetically inserting enzymes that redirect precursor molecules into alternative synthetic pathways. The technology to knock out the necessary enzymes in pigs is not yet available; however, pigs expressing the H-transferase gene have been developed and show reduced levels of Gal α1,3-Gal epitopes. Although this “new breed” of transgenic pigs may overcome the barrier of hyperacute rejection, special strategies will need to be developed that target the next barrier of xenograft rejection.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Chronic rejection is a complex syndrome with many inciting causes, both nonimmune and immune mediated. Therefore, prevention and treatment of this syndrome encompass a variety of approaches. Recent advances in the understanding and possible prevention of chronic rejection include the ability for early detection of those patients who are at high risk for the development of graft vascular disease, optimal use of currently available immunosuppressive drugs, the use of steroid-sparing immunosuppressive protocols, the use of hepatic hydroxy-methylglutaryl coenzyme A reductase inhibitors, development of immunosuppressive agents with the ability to inhibit growth factor actions, and the preemptive treatment of cytomegalovirus infection.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Diagnosis and treatment of acute cardiac rejection have evolved tremendously since the first human heart transplantation in the 1960s. The first truly accurate method for the diagnosis of cardiac allograft rejection has been the use of the routine surveillance endomyocardial biopsy. The turning point for the improvement of cardiac allograft survival was the introduction of cyclosporine as part of a triple immunosuppressive maintenance therapy. More recently, heart transplant centers have investigated the use of noninvasive methods to diagnose acute allograft rejection, such as enzymatic markers, electrocardiography, nuclear medicine, and echocardiography, with limited success. The treatment of acute allograft rejection with methotrexate, total lymphoid irradiation, and photopheresis has been shown to be successful in more recent reports for patients not responding to the usual therapy for acute cardiac allograft rejection.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The shortage of suitable donor hearts has made the selection of potential transplant recipients a critical step in the cardiac transplantation process. Appropriate patients for transplantation should have a high predicted short- and intermediate-term mortality rate despite aggressive medical therapy. Stratifying patients based on the etiology of the heart failure, left ventricular ejection fraction, functional capacity, hemodynamic measurements, the presence of arrhythmias, and neurohormonal activation is useful in defining a high-risk population. The transplant evaluation should focus on risk definition as well as on factors that increase posttransplant morbidity and mortality.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The role of mechanical support devices in patients with endstage heart disease has continued to increase over recent years. Currently available devices differ in configuration, anatomic location, flow characteristics, and durability. Therefore, an understanding of the available devices and evolving patient selection criteria are essential to optimize clinical results. Hemodynamically compromised patients should be considered for mechanical assistance prior to the onset of irreversible or multiple end-stage organ failure. The decrease in morbidity and mortality with the current generation of mechanical assist devices, along with the observed improvement in rehabilitation and posttransplant survival, has raised enthusiasm for the use of implantable devices as a chronic alternative to heart transplantation. Clinical trials are currently under way to evaluate this mode of therapy in both the United States and Europe. Future modifications will likely provide further improvements in clinical results and quality of life in both the adult and the pediatric population.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Outcomes analysis not only is important for individual patient decision making, but it is also one of the means by which our knowledge in cardiac transplantation can be advanced. Using retrospectively collected information on patients undergoing cardiac transplantation, hazard function analysis is able to 1) estimate the distribution of time to an event; 2) estimate the phases of hazard (instantaneous risk of the event); 3) determine risk factors associated with the event in each of the identified phases of hazard; 4) predict the time-related probability of an event for a specific patient based on the patient's risk-factor profile; and 5) compare the effectiveness of therapies by the process of risk adjustment.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The current supply of organs from brain-dead donors does not meet the continually increasing demand of patients awaiting cardiac transplantation. A donor heart that will support the circulation of the recipient must be selected and procured with care. In this regard, an understanding of the pathophysiology of brain death and its impact on organs potentially used for transplantation will permit the development of therapeutic strategies for preventing the multifactorial events that further potentiate organ injury in the donor. This article reviews the pathophysologic features of brain death, including the autonomic storm, electrocardiographic abnormalities, and hemodynamic, histopathologic, and endocrine changes. A discussion of donor management then follows, which covers hemodynamic support, donor heart assessment, and hormonal therapy, specifically focusing on the use of triiodothyronine, which promises to be of great benefit.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The medical community's acceptance of liver transplantation for patients with alcoholic liver disease has led to important medical and ethical questions regarding the selection and treatment of these patients. Recent studies from various centers regarding medical outcome in alcoholic transplantees suggest that 1) drinking after transplantation is common and increases with time after transplantation; 2) many patients may consume relatively modest amounts; and 3) overall survival is reasonable in the first 5 years after transplantation, but individual cases of death or illness in the setting of relapse to drinking occur over time. Patterns of return to drinking after transplantation are poorly understood at present. Research on outcome in alcoholic patients after transplantation has been hampered by small sample sizes, problems documenting sample selection methods, and difficulty in detecting and quantifying a return to drinking. Prospective multicenter studies are needed. Recommendations for clinical practice include psychiatric assessment for most, if not all, alcoholic applicants; prescription of pretransplant treatment of substance use disorder, if indicated; and careful attention to the structure of posttransplant care.

ISSN:1087-2418    

出版商:OVID    

年代:1998

数据来源: OVID