Background: Donor availability remains a limiting factor for heart transplantation while transplant waiting time entails significant morbidity and mortality. This study was designed to assess the efficacy and safety of long-term beta blockade as optimization of therapy in patients with severe congestive heart failure already receiving digoxin, diuretics, and converting enzyme inhibitors awaiting transplantation.
Methods: The beta-1 antagonist metoprolol was given to 19 patients with moderate to severe congestive heart failure. Hemodynamic, clinical, and neurohormonal measurements were obtained before drug therapy and after 3 months of treatment. Patients initially received 6.25 mg of metoprolol orally twice daily which was increased to a target dose of 50 mg twice daily over several weeks.
Results: Metoprolol produced significant clinical, exercise, and hemodynamic benefits. Long-term therapy was associated with improvements in New York Heart Association class, ejection fraction, 6-minute walk, and peak maximal oxygen consumption. There were significant decreases in heart rate, pulmonary arterial systolic pressure, and left ventricular filling pressure with significant increases in stroke volume index and stroke work index. Four patients were removed from the transplant list after improving to New York Heart Association I. Only one patient required hospitalization during the first 6 months of therapy. There were no deaths caused by progressive heart failure; however, one patient died suddenly.
Conclusions: Beta blockade with metoprolol can be safely administered to patients awaiting heart transplantation producing clinical, exercise, and hemodynamic improvements. Thus, beta blockade may prove to be a safe and cost-effective bridge to transplantation.