The effect of remote ischaemic preconditioning on myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery

In several recent clinical trials on cardiac surgery patients, remote ischaemic preconditioning (RIPC) showed a powerful myocardial protective effect. However, the effect of RIPC has not been studied in patients undergoing off-pump coronary artery bypass graft surgery. We evaluated whether RIPC could induce myocardial protection in off-pump coronary artery bypass graft surgery patients. Patients undergoing elective off-pump coronary artery bypass graft surgery were randomly allocated to the RIPC (n=65) or control group (n=65). After induction of anaesthesia, RIPC was induced by four cycles of five-minute ischaemia and reperfusion on the upper limb using a pneumatic cuff Anaesthesia was maintained with sevoflurane, remifentanil and vecuronium. Myocardial injury was assessed by troponin I before surgery and 1, 6, 12, 24, 48 and 72 hours after surgery. There were no statistical differences in troponin I levels between RIPC and control groups (P=0.172). Although RIPC reduced the total amount of troponin I (area under the curve of troponin increase) by 26%, it did not reach statistical significance (RIPC group 53.2 +/- 72.9 hours.ng/ml vs control group 67.4 +/- 97.7 hours.neml, P=0.281). In this study, RIPC by upper limb ischaemia reduced the postoperative myocardial enzyme elevation in off pump coronary artery bypass graft surgery patients, but this did not reach statistical significance. Further study with a larger number of patients may be needed to fully evaluate the clinical effect of RIPC in off-pump coronary artery bypass graft surgery patients.