Remote ischemic preconditioning in cardiac anesthesia: a review focusing on translation

Remote ischemic conditioning (RIC) is a powerful cardioprotective strategy. Its clinical application is simple, cheap and so far free from secondary side effects. Given the heterogeneous results of recent large-scale clinical trials, its clinical relevant benefit is still doubted. Following a MEDLINE-based search on all publications concerning RIC in experimental or clinical settings, this review focuses on the translation from bench to bedside. A short resume of mechanistic insights is followed by the presentation of current clinical evidence of beneficial effects of RIC and the critical assessment of the recently published large-scale trials. Strong experimental evidence suggests beneficial cardioprotective effects induced by RIC. The signal transmission is sought to be achieved by a combination of neuronal and humoral signaling pathways. The protective effects of RIC are not limited to the heart alone: kidney, brain, gut, liver and lung have been experimentally shown to benefit from RIC. Thirty-two randomized clinical trials (N.=5409 cardiac patients) with cardiac surgery patients were published in the last decade. Their results are as heterogeneous as their monitored outcome parameters or strategies to apply RIC. The impressive experimental and clinical evidence in favor of RIC is opposed by the neutral results of the latest large-scale trials. While the underlying reasons for these neutral results are matter of on-going debate and could not be answered by recent published sub-investigations, additional adequately designed studies are encouraged by the mentioned results of experimental and pilot studies to exclude any confounding factors.