Cardiac Transplantation

Cardiac Transplantation

Preoperative Considerations

Cardiac transplantation is the treatment of choice for otherwise healthy patients with end-stage heart disease so severe that they are unlikely to survive the next 6–12 months. The procedure is generally asso-ciated with 80–90% postoperative survival at 1 year and 60–90% survival at 5 years. Transplantation improves the quality of life and most patients are able to resume a relatively normal lifestyle. Unfortunately, the number of cardiac transplants performed is limited by the supply of donor hearts, which are obtained from brain-dead patients, most commonly following intracranial hemorrhage or head trauma.Patients with intractable heart failure have an ejection fraction of less than 20% and fall into NYHA functional class IV  and heart failure class D. For most patients, the pri-mary diagnosis is cardiomyopathy. Intractable heart failure may be the result of a severe con-genital lesion, ischemic cardiomyopathy, viral cardiomyopathy, peripartum cardiomyopathy, a failed prior transplantation, or valvular heart dis-ease. Medical therapy should include the standard drugs used for heart failure, including angioten-sin-converting enzyme inhibitors (or angiotensin receptor blockers, or both) and β blockade (usu-ally with carvedilol). Other drugs may include diuretics, vasodilators, and even oral inotropes; oral anticoagulation with warfarin may also be necessary. Patients may not be able to survive without intravenous inotropes while awaiting transplantation. Intraaortic balloon counterpulsa-tion, an LVAD, or even a total mechanical heart may also be necessary.

Transplant candidates must not have suffered extensive end-organ damage or have other major systemic illnesses. Reversible renal and hepatic dysfunction are common because of chronic hypo-perfusion and venous congestion. PVR must be normal or at least responsive to oxygen or vasodi-lators. Irreversible pulmonary vascular disease is usually associated with a PVR of more than 6–8 Wood units (1 Wood unit = 80 dyn·s·cm^–5), and is a contraindication to orthotopic cardiac transplan-tation because right ventricular failure is a major cause of early postoperative mortality. Patients with long-standing pulmonary hypertension may, however, be candidates for combined heart–lung transplantation.

Tissue cross-matching is generally not per-formed. Donor–recipient compatibility is based on size, ABO blood-group typing, and cytomegalovirus serology. Donor organs from patients with hepatitis B or C or HIV infections are excluded.