Survival Benefit of the Implantable Cardioverter-Defibrillator in Patients on the Waiting List for Cardiac Transplantation

Abstract

Background The implantable cardioverter-defibrillator (ICD) effectively reduces sudden cardiac death in patients with severe LV dysfunction. Effect of ICD therapy on total mortality in patients on the waiting list for cardiac transplantation is still uncertain. Methods and Results We retrospectively analyzed 854 unselected consecutive patients (ICD therapy, n=102; 11.9%) on the waiting list for cardiac transplantation between January 1992 and March 2000. Actuarial 12-month total mortality rate on the waiting list was 24.2%; sudden cardiac death was the predominant mode of death (66.7% of total deaths). Kaplan-Meier analysis revealed improved survival for ICD (total mortality, 13.2%) compared with non-ICD (total mortality, 25.8%) patients (log rank, P =0.03). No event of sudden death occurred in ICD patients, whereas in non-ICD patients, 12-month sudden death rate was 20.1% ( P =0.0001). Nonsudden death rates did not differ between ICD and non-ICD patients ( P =0.16). A Cox proportional hazards model demonstrated that absence of an ICD was a powerful independent predictor of total mortality ( P =0.02; relative risk, 2.22; 95% confidence interval, 1.16 to 4.17) and sudden cardiac death ( P <0.0001; infinite relative risk) on the waiting list. Conclusions ICD therapy, because it prevents sudden cardiac death, significantly improves survival on the waiting list for cardiac transplantation. The present study supports the use of ICDs as a bridge to transplantation in patients who are at risk of sudden cardiac death. Prospective randomized trials are needed to evaluate the potential benefit of prophylactic ICD therapy as a bridge to transplantation in all patients on cardiac transplant waiting lists.