Introduction: Remote ischemic preconditioning (RIPC) is a new noninvasive myocardial protection strategy that uses blood pressure cuf inflation to simulate transient non-fatal ischemia to protect the myocardium and reduce ischemia-reperfusion injury. Sulfonylureas may mask the effects of RIPC due to their cardioprotec-tive effect. This meta-analysis aimed to evaluate whether RIPC, in the absence of sulfonylureas, reduces troponin release in patients undergoing cardiac surgery.
Methods: We conducted a meta-analysis of randomized controlled clinical trials to determine whether RIPC can reduce postoperative troponin release in cardiac surgery patients undergoing cardiopulmonary bypass without treatment with sulfonylureas. The data were normalized to equivalent units prior to the analysis. A random-effects model was used to provide more conservative estimate of the effects in the presence of known or unknown heterogeneity.
Results: Six studies with a total of 570 participants were included. The analysis showed that troponin release was lower in the RIPC group than in the control group at six hours (test of standardized mean differences = 0, Z=3.64, P<0.001) and 48 hours (Z=2.72, P=0.007) postoperatively. When the mean of cross-clamping time was > 60 minutes, RIPC reduced troponin release at six hours (Z=2.84, P=0.005), 24 hours (Z=2.64, P=0.008), and 48 hours (Z=2.87, P=0.004) postoperatively.
Conclusion: In cardiac surgery patients who are not taking sulfonylureas, RIPC can reduce troponin release at six and 48 hours postoperatively; hence, RIPC may serve significant benefits in certain cardiac surgery patients.
Keywords: Blood Pressure; Cardiac Surgery; Cardiopulmonary Bypass; Meta-Analysis; Sulfonylureas; Troponin.