Remote Ischemic Preconditioning for Cardiac Surgery: Reflections on Evidence of Efficacy.

Abstract

Ever since its discovery more than two decades ago, remote ischemic preconditioning (RIPC) has generated tremendous interest among scientists and clinicians alike. However, two recent large, well-conducted, randomized controlled trials (RCTs) have failed to identify any significant benefit of RIPC during cardiac surgery. A reconciliatory yet objective review of cumulative evidence with regard to cardiac surgery reveals that RIPC in preclinical studies reduced infarct size after experimental myocardial infarction, which is different from cardiac surgery; improved release of biomarkers, but not hard clinical end-points, in proof-of-concept clinical trials with discordant results; and failed to produce significant improvement in outcomes in meta-analyses. This difficult journey of RIPC across the valley of death underscores the importance of scientific rigor and exercise of caution in interpreting data at every step of the way until efficacy of a purported therapy is proven conclusively in large RCTs.