Remote Ischemic Preconditioning and Cardiac Surgery.

To the Editor: Remote ischemic preconditioning (RIPC) is an inexpensive technique that is used to reduce perioperative organ damage. High-quality randomized trials have shown cardiac1 and renal2 protection with a possible reduction in mortality when RIPC was used in addition to halogenated agents.3 However, two recent multicenter, randomized trials, the Remote Ischemic Preconditioning for Heart Surgery (RIPHeart) Study reported by Meybohm et al.4 and the Effect of Remote Ischemic Preconditioning on Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Graft Surgery (ERICCA) trial reported by Hausenloy et al.5 (Oct. 8 issue), suggest no difference between RIPC and sham treatment in patients with various conditions who underwent cardiac surgery. The most plausible way to explain the results of these studies is to focus on the hypnotic drug propofol,6 which was used as the primary anesthetic agent in most of the patients in these pragmatic trials but not in patients in previous studies that showed cardiac and renal protection and reduced mortality.1,2 Propofol inhibits the organ-protective properties of several agents and techniques, including RIPC, and a meta-analysis of randomized trials showed that propofol-based total intravenous anesthesia, as compared with halogenated agents, doubled mortality among patients who underwent cardiac surgery.7 We recommend that future studies of RIPC avoid the use of propofol. Furthermore, data are lacking from trials comparing propofol with other agents in the perioperative period and in critically ill patients. Giovanni Landoni, M.D. Martina Baiardo Redaelli, M.D. Carmine D. Votta, M.D.