Outcomes of adults with restrictive cardiomyopathy after heart transplantation

Background: Restrictive cardiomyopathy (RCM) represents a spectrum of disorders with a common physiology but divergent etiologies. RCM commonly leads to progressive heart failure and the need for heart transplantation (HTx). Pediatric RCM is a more homogeneous disorder with post-HTx outcomes comparable to those for non-RCM patients. However, post-HTx outcomes in adult RCM patients have not been studied to date.

Methods: Demographic, clinical and survival outcomes of 38,190 adult HTx-only recipients from 1987 to 2010 were acquired from the registry of the United Network of Organ Sharing. The study population included 544 RCM patients (1.4%) and 37,646 non-RCM patients (98.6%). RCM diagnoses included idiopathic (n = 227, 42%), amyloid (n = 142, 26%), sarcoid (n = 81, 15%), radiation/chemotherapy (XRT) (n = 35, 6%) and other (n = 59, 11%).

Results: Follow-up began at the time of HTx (74±64 months). During the follow-up period, 224 (41%) patients in the RCM group died, whereas 18,791 (50%) in the non-RCM group died. Crude 1-, 5- and 10-year survival for RCM patients was 84%, 66% and 45%, and for non-RCM patients was 85%, 70% and 50%, respectively. The overall unadjusted hazard ratio of RCM vs non-RCM for all-cause mortality was 1.07 (confidence interval [CI] 0.93 to 1.22). Multivariate Cox proportional hazards regression analysis yielded a hazard ratio of 1.06 (CI 0.91 to 1.25). RCM subgroup analysis showed decreased survival at 1, 5 and 10 years in the XRT (71%, 47% and 32%) and amyloid (79%, 47% and 28%) patient groups. The unadjusted hazard ratio for the XRT and amyloid subgroups vs RCM for all-cause mortality was 1.81 (p = 0.002) and 1.85 (p = 0.0004), respectively.

Conclusions: Outcomes for RCM patients post-HTx are comparable to those of non-RCM patients. However, RCM subgroup analysis suggests increased mortality for XRT and amyloid subgroups. Further analysis is warranted to understand the contributing factors.