Outcomes of Restrictive and Hypertrophic Cardiomyopathies After LVAD: An INTERMACS Analysis

Background Patients with restrictive (RCM) and hypertrophic (HCM) cardiomyopathies are felt to be a difficult population to treat with left ventricular assist device (LVAD) therapy. Scarce data exist on outcomes of continuous-flow (CF) LVAD support in these challenging patient cohorts. Methods The Interagency Registry for Mechanically Assisted Circulatory Support Registry was queried for all patients with RCM (n = 94) and HCM (n = 104) who underwent CF LVAD implantation between March 2008 and March 2014. Survival, adverse event rates, baseline demographics, echocardiography parameters, and competing outcomes were compared with patients with dilated cardiomyopathy (DCM) (n = 8749). Results Left ventricular size was smaller and baseline EF was higher in RCM and HCM compared with DCM patients. Nonetheless, these parameters were not completely normal in the RCM and HCM groups, suggesting that most of these patients exhibited features of a DCM and represented a mixed phenotype. In these specific patient populations, survival up to 4 years was not different among the 3 groups (log rank 0.25) and competing outcomes at 1 year were similar. In the subgroup of patients with very small ventricles (ie, < 5.0 cm), survival was far inferior. Finally, overall rates of right ventricular assist device requirement, hemolysis, pump dysfunction, and cardiac arrhythmias were similar among the 3 groups. Conclusion Relatively few patients with HCM and RCM undergo CF LVAD implantation, and most that do display some features of a DCM. Overall survival and adverse event profiles of these patients were similar to traditional DCM patients; however, in those with very small ventricles, survival was inferior.