Progress versus precision: challenges in clinical trial design for left ventricular assist devices.

New left ventricular assist devices promise fewer adverse events but, currently, only minor improvements in survival. Small (survival) treatment effects, limited patient populations, and the increasing number of left ventricular assist devices in development challenge the efficient conduct of premarketing trials (especially in destination therapy) and, maybe more importantly, hamper innovation. Novel trial designs would facilitate this process. Among a range of trial designs, we opt for small randomized trials, which would preserve the advantages of randomization and also allow for a shorter enrollment period. We also advocate an evidence shift toward postmarketing studies, with the Interagency Registry of Mechanically Assisted Circulatory Support providing a robust infrastructure.