Advanced or end-stage heart failure is an increasingly frequent sequela, as progressively more effective palliation for the earlier stages of heart disease and prevention of sudden death associated with heart disease become more widely recognized and employed (Chap. 234). When patients with end-stage or refractory heart failure are identified, the physician is faced with the decision of advising compassionate end-of-life care or choosing to recommend extraordinary life-extending measures. For the occasional patient who is relatively young and without serious comorbidities, the latter may represent a reasonable option. Current therapeutic options are limited to cardiac transplantation (with the option of mechanical cardiac assistance as a “bridge” to transplantation) or (at least in theory) the option of permanent mechanical assistance of the circulation. In the future, it is possible that genetic modulation of ventricular function or cell-based cardiac repair will be options for such patients. Currently, both approaches are considered to be experimental.
Surgical techniques for orthotopic transplantation of the heart were devised in the 1960s and taken into the clinical arena in 1967. The procedure did not gain widespread clinical acceptance until the introduction of “modern” and more effective immunosuppression in the early 1980s. By the 1990s, the demand for transplantable hearts met, and then exceeded, the available donor supply and leveled off at about 4,000 heart transplants annually worldwide, according to data from the Registry of the International Society for Heart and Lung Transplantation (ISHLT). Subsequently, heart transplant activity in the United States has remained stable at ∼2,200/year, but worldwide activity reported to this registry has decreased somewhat. This apparent decline in numbers may be a result of the fact that reporting is legally mandated in the United States, but not elsewhere, and several countries have started their own databases.
Donor and recipient hearts are excised in virtually identical operations with incisions made across the atria and atrial septum at the midatrial level (leaving the posterior walls of the atria in place) and across the great vessels just above the semilunar valves. The donor heart is generally “harvested” in an anatomically identical manner by a separate surgical team and transported from the donor hospital in a bag of iced saline solution and then is reanastomosed into the waiting recipient in the orthotopic or normal anatomic position. The only change in surgical technique since this method was first described has been a movement in recent years to move the right atrial anastamosis back to the level of the superior and inferior vena cavae to better preserve right atrial geometry and prevent atrial arrhythmias. Both methods of implantation leave the recipient with a surgically denervated heart that does not respond to any direct sympathetic or parasympathetic stimuli but does respond to circulating catecholamines. The physiologic responses of the denervated heart to the demands of exercise are atypical but quite adequate to carry on normal physical activity.
In the United States the allocation of donor organs is accomplished under the supervision of the United Network for Organ Sharing (UNOS), a private organization under contract to the federal government. The United States is divided geographically into eleven regions for donor heart allocation. Allocation of donor hearts within a region is decided according to a system of priority that takes into account (1) the severity of illness, (2) geographic distance from the donor, and (3) patient time on the waiting list. A physiologic limit of ∼3 h of “ischemic” (out-of-body) time for hearts precludes a national sharing of hearts. This allocation system design is reissued annually and is responsive to input from a variety of constituencies, including both donor families and transplant professionals.
At the current time, highest priority according to severity of illness is assigned to patients requiring hospitalization at the transplant center for IV inotropic support with a pulmonary artery catheter in place for hemodynamic monitoring or to patients requiring mechanical circulatory support [i.e., intra-aortic balloon pump (IABP), right or left ventricular assist device (RVAD, LVAD), extracorporeal membrane oxygenation (ECMO), or mechanical ventilation]. Second highest priority is given to patients requiring ongoing inotropic support, but without a pulmonary artery catheter in place. All other patients have priority according to their time accrued on the waiting list, and matching is achieved only according to ABO blood group compatibility and gross body size compatibility, although some patients who are “pre-sensitized” and have preexisting anti-HLA antibodies (commonly multiparous women or patients previously multiply transfused) undergo prospective cross-matching with the donor. While HLA matching of donor and recipient would be ideal, the relatively small numbers of patients, as well as the time constraints involved, make such matching impractical.
Heart failure is an increasingly common cause of death, particularly in the elderly. Most patients who reach what has recently been categorized as stage D, or refractory end-stage heart failure, are appropriately treated with compassionate end-of-life care. A subset of such patients who are younger and without significant comorbidities can be considered as candidates for heart transplantation. Exact criteria vary in different centers but generally take into consideration the patient's physiologic age and the existence of comorbidities such as peripheral or cerebrovascular disease, obesity, diabetes, cancer, or chronic infection.
A registry organized by the ISHLT has tracked worldwide and U.S. survival rates after heart transplantation since 1982. The most recent update reveals 83% and 76% survival 1 and 3 years posttransplant, or a posttransplant “half-life” of 10.00 years (Fig. 235-1). The quality of life in these patients is generally excellent, with well over 90% of patients in the registry returning to normal and unrestricted function following transplantation.
Survival was calculated using the Kaplan-Meier method, which incorporates information from all transplants for whom ...
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