Five-Year Mortality of Patients with Perioperative Myocardial Infarction After On-Pump Isolated or Combined Coronary Artery Bypass Graft Surgery: A Retrospective Propensity Score-Weighted Analysis

<b>Background:</b> Coronary artery bypass grafting (CABG) is a widely used procedure to treat coronary artery disease, performed either alone or in conjunction with other cardiac procedures. Perioperative myocardial infarction (pMI) remains a major complication after on-pump CABG and negatively influences survival. Its reported incidence varies with the applied definition, and little is known about its prognostic effect in combined surgeries. <b>Objective:</b> The aim of this study was to investigate the impact of pMI on 5-year survival after isolated or combined on-pump CABG. <b>Methods:</b> We retrospectively reviewed adult patients undergoing urgent or elective CABG with cardiopulmonary bypass at Amiens University Hospital between 2013 and 2017. Diagnosis of pMI followed the Fourth Universal Definition of myocardial infarction. The primary outcome was all-cause death within 5 years. Logistic regression and Cox proportional hazards analyses were performed, and inverse probability weighting based on propensity scores was used to minimize confounding. <b>Results:</b> Out of 712 patients, 112 (16%) experienced pMI. Five-year mortality was 32% in the pMI subgroup compared with 11% in those without pMI (<i>p</i> < 0.001). Before adjustment, pMI was associated with higher long-term mortality (HR = 2.62, 95%CI [1.73-4.00], <i>p</i> < 0.001). This effect persisted after weighting (HR = 2.43, 95% CI [1.56-3.78], <i>p</i> = 0.041). A landmark analysis excluding the first 30 postoperative days showed no significant link with later mortality (HR = 1.13, 95%CI [0.54-2.34], <i>p</i> = 0.74). Independent predictors of pMI included active smoking (OR = 2.24, 95% CI [1.36-3.69], <i>p</i> = 0.001) and prolonged bypass duration (>180 min) (OR = 2.57, 95% CI [1.19-5.34], <i>p</i> = 0.015). <b>Conclusions:</b> When defined by the Fourth Universal Definition, pMI was independently related to increased 5-year mortality following CABG, explained mainly by deaths occurring early after surgery.