Remote ischemic preconditioning and incidence of postoperative atrial fibrillation

Objectives. Although remote ischemic preconditioning (RIPC) has shown favorable effects on ischemia-reperfusion injury, much remains unknown of its mechanisms and clinical significance. We hypothesized that RIPC would reduce the incidence of postoperative atrial fibrillation (POAF) following coronary artery bypass graft (CABG) surgery. In addition, we investigated whether RIPC could induce alterations of circulating microRNA in blood plasma. Design. This is a single-center, double-blind, randomized controlled trial. 92 adult patients referred for first-time isolated CABG surgery were randomly assigned to either RIPC (n = 45) or control (n = 47). The RIPC-stimulus comprised three 5-min cycles of upper arm ischemia, induced by inflating a blood pressure cuff to 200 mmHg, with an intervening 5 min reperfusion. Heart rhythm was assessed by telemetry. MicroRNA expression was assessed in plasma by real-time polymerase chain reaction. Results. Of the 92 patients included in the study, 27 patients developed POAF (29%). 17 of these patients belonged to the RIPC group (38%), and 10 to the control group (21%). There were no significant alterations of microRNA expression. Conclusions. We did not observe a reduced incidence of POAF by RIPC before CABG surgery. Larger multi-center studies may be necessary to further clarify this issue.