Chapter 71: Cardiac Transplantation

INTRODUCTION

Heart transplantation remains the ultimate treatment for congestive heart failure (CHF), a disease which carries a 50% five-year mortality and a ninefold increase in the risk of sudden death. Cardiomyopathy (54%) and coronary artery disease (37%) are the two main underlying causes of CHF in transplant recipients. Other causes include congenital heart disease (2.9%), valvular disease (2.8%), and retransplantation (2.5%).

Since the first successful transplant in 1963, suboptimal modulation of the immune response to control rejection prevented initial success of this procedure until the introduction of cyclosporin A in the 1970s. For all adult and pediatric heart transplants between 1982 and 2011, survival rates were 81% at 1 year and 69% at 5 years with a median survival time of 11 and 13 years for those surviving the first year. Outcomes have not significantly changed but likely reflect a widening of indications and higher risk recipients. Young age remains the sole most important determinant of survival.

PREOPERATIVE ASSESSMENT

Indications for cardiac transplantation include the following:

1. Hemodynamically unstable CHF

2. Refractory cardiogenic shock

3. Dependence on intravenous inotrope therapy

4. Recurrent untreatable angina

5. Recurrent symptomatic ventricular arrhythmias unresponsive to therapy

Absolute contraindications for cardiac transplantation include the following:

1. Systemic illness with life expectancy less than 2 years

2. Malignancy within the previous 5 years

3. AIDS or other opportunistic diseases

4. Systemic lupus erythematosis, sarcoidosis, or amyloidosis with multisystem involvement

5. Irreversible hepatic or renal failure in patients considered for heart transplant alone

6. Severe obstructive pulmonary disease

7. Fixed pulmonary hypertension

A multidisciplinary assessment of heart transplant recipients focuses on the following:

• Likelihood of surviving the surgery

• Compliance with postoperative medical treatment and follow up

• Identification of potentially reversible medical conditions

• Optimization of HF therapy

Once listed, the heart transplant recipient is given a code status based on the short-term prognosis. Status IA (highest priority) includes one of the following factors: dependency on intravenous inotropes, mechanical ventilation, mechanical circulatory support, or device-related complications. Patients with status IB are stable on mechanical circulatory support. All other patients are status II (lowest priority).

Heart failure commonly manifests with decreased stroke volume. This decline in cardiac output is initially compensated by ventricular dilatation and increased sympathetic drive. Progressive chamber dilatation will result in functional valvular abnormalities, alteration of myocardial mechanics, and pump failure. Chronic sympathetic activation will be counteracted by downregulation of the beta-adrenergic receptors.

The management of patients with end-stage CHF who are candidates for cardiac transplantation consists of the following:

• Angiotensin converting enzyme (ACE) inhibitors reduce left ventricular hypertrophy, provide relief of symptoms, and improve overall mortality.

• Beta-adrenergic receptor blockers counteract the elevated sympathetic tone, promote ventricular remodeling, and improve overall mortality.

• Loop diuretics are the first choice for mild heart failure. Spironolactone, a potassium-sparing aldosterone-antagonist, is the only diuretic associated with significant ...