Remote Ischemic Preconditioning is a Safe Adjuvant Technique to Myocardial Protection But Adds No Clinical Benefit After On-Pump Coronary Artery Bypass Grafting

Background: To evaluate the impact of remote ischemic preconditioning (RIPC) on clinical outcome, biological markers of myocardial injury, and its safety in patients undergoing on-pump coronary artery bypass grafting (CABG). Material and Methods: This study was conducted at Ch. Pervaiz Elahi Institute of Cardiology (CPEIC) in Multan. The study took place from March 2012 to June 2013. Patients were randomly placed into two groups. Group A (N = 32) did not undergo RIPC; Group B (N = 35) received RIPC after induction of anesthesia. Similar standard general anesthesia, cardiopulmonary technique, myocardial protection strategies, and surgical techniques were used in both groups except the protocol for RIPC. Following postoperative outcome, i.e. cardiac defibrillation after removal of aortic cross clamp during the period of rewarming, demand for intra-aortic balloon pump (IABP), demand for antiarrhythmic before leaving the operation room, postoperative creatine kinase-myocardial band (CK-MB) level (at 1h, 12h, 24h, and 48h after surgery), postoperative serum creatinine level on first postoperative day, postoperative ejection fraction (EF) on third postoperative day, in-hospital mortality, and one-year mortality were noted, prospectively. Safety of protocol of RIPC was estimated by limb ischemia monitored by pulse oximetry during and after procedure of RIPC and postoperative neurapraxia by nerve examination of right upper limb. Results: Post aortic cross clamp release cardiac defibrillation, demand for IABP, demand for high inotropes, and use of antiarrhythmic in the operation room were statistically insignificant in the non-RIPC and RIPC group with P values of .54, .78, .16, and .16, respectively. Mean postoperative CK-MB level (IU/L) showed the following results: At 1h (Group A 20.94 + 1.66, Group B 20.57 + 1.54, P = .35), at 12h (Group A 27.13 + 1.85, Group B 28.05 + 3.04, P = .135), at 24h (Group A 27.63 + 1.7, Group B 27.85 + 2.2, P = .63), and at 48h (Group A 22.95 + 2.76, Group B 23.27 + 3.6, P = .69). First postoperative day serum creatinine (Group A 1.29 + 0.395, Group B 1.33 + 0.57, P = .77) and postoperative ejection fraction percentage on the third postoperative day (Group A 50.78 + 8.72, Group B 50.57 + 8.38, P = .92) showed no statistical difference between two groups. Postoperative low cardiac output state, in-hospital mortality, and one-year mortality also were statistically insignificant between the groups with P values of .93, .29, and .33, respectively. None of the patients in either group showed evidence of limb ischemia and neurapraxia of the right upper limb. Conclusion: RIPC is a safe technique, but it does not have additional clinical benefit after on-pump CABG surgery in the presence of a standard myocardial protective strategy.