Effect of Remote Ischemic Preconditioning on Myocardial Injury in Noncardiac Surgery: the PRINCE Randomized Clinical Trial

Background: Major noncardiac surgery carries high rates of postoperative myocardial injury and other complications. Remote ischemic preconditioning (RIPC) was reported to decrease these complications. However, such supportive evidence lacks robustness. Methods: In a multinational, double-blind trial, we randomly assigned adult high-risk patients undergoing noncardiac surgical procedures to receive RIPC or sham-RIPC after the induction of general anesthesia and before surgery. RIPC involved three 5-minute ischemic cycles, each followed by 5 minutes of reperfusion, using a blood-pressure cuff inflated to 200 mmHg. The primary endpoint was the rate of myocardial injury defined by an increase in postoperative troponin levels above the highest 99th percentile of reference values. Secondary outcomes included myocardial infarction, stroke, acute kidney injury, need for intensive care unit, length of hospital stay and 30-day all-cause mortality. Results: We recruited 1213 patients in 25 hospitals and 8 countries. We randomly assigned 599 to RIPC and 614 to sham-RIPC. The most frequent surgical procedures were abdominal and intrathoracic surgeries (406 patients, 33.6%). RIPC was applied to the upper limb in 1,014 patients (84.8%) and to the lower limb in 182 patients (15.2%). Postoperative myocardial injury occurred in 215/566 patients (38.0%) in the RIPC group and in 223/596 patients (37.4%) in the sham-RIPC group (relative risk, 1.02; 95% confidence interval, 0.88 to 1.18; P=0.84). There were no significant differences in the rate of any secondary outcomes. We observed eleven episodes of limb petechiae (10 [1.7%] in the RIPC group vs 1 [0.2%] in the sham-RIPC group) and 34 (6.0%) hospital readmissions in the RIPC group vs 20 (3.5%) in the sham-RIPC group. Conclusions: Among adult patients undergoing noncardiac surgery, RIPC did not reduce myocardial injury or other postoperative complications.