Myocardial Protection Strategy: Reducing Cardiac Arrest Time to Improve Myocardial Protection in Patients Undergoing Mitral Valve Replacement Accompanying Coronary Artery Bypass Grafting

Background: Compared with isolated mitral valve replacement (MVR) or isolated coronary artery bypass grafting (CABG), MVR + CABG surgery is associated with higher mortality and complication rate. This study investigated the safety and efficacy of the myocardial protection technique to short cardioplegic arrest time in patients who underwent MVR + CABG. Methods: This study enrolled patients diagnosed with mitral valve disease and coronary artery disease who underwent MVR + CABG between January 2014 and January 2022. The patients were divided into the CABG without cardioplegic arrest (CA) group (novel group) and CABG with CA group (conventional group) according to surgical methods. The baseline data of the two groups of patients were corrected by the propensity score matching (PSM) method. Endpoints assessed were operative mortality (OM), major morbidity (MM)and 5-year follow-up clinical outcomes. Results: 810 patients (256 in the novel group and 554 in the conventional group) were enrolled in this study. PSM resulted in a total of 460 patients (230 pairs). There was no significant difference in OM between the two groups (6.5% vs 10.8%, P= 0.098). The MM was significantly lower in the novel group than the conventional group (24.3% vs 33.9%, P= 0.024). Mean operation time (285 ± 55 vs 298 ± 60 minutes, P= 0.016), cardiopulmonary bypass (CPB) time (115 ± 33 vs 139 ± 38 minutes, P < 0.001), CA time (66 ± 11 vs 85 ± 16 minutes, P < 0.001), intensive care unit stay time (33.6 ± 12.3 vs 36.6 ± 14.5 hours, P = 0.017) and post-operative length of stay (11.1 ± 3.6 vs 11.9 ± 4.1 days, P = 0.027) were significantly shorter in the novel group than in the conventional group. There was no significant difference between the novel group and the conventional group in terms of death from any cause, valve-related complications, myocardial infarction and any repeat revascularisation in 5 years follow-up. Conclusions: The novel group is associated with excellent short-term outcomes and comparable medium-term outcomes for patients undergoing MVR + CABG. Myocardial protection strategy to short cardioplegic arrest time in patients undergoing MVR + CABG was surgically feasible, reproducible, and safe.