Long-term Outcome of Patients With Perioperative Myocardial Infarction as Diagnosed by Troponin I After Routine Surgical Coronary Artery Revascularization

Objective: Diagnosis of perioperative myocardial infarction (P-MI) after coronary artery bypass graft (CABG) surgery traditionally relied on a combination of electrocardiographic and enzyme assay changes. Patients with Q-wave P-MIs who survive to hospital discharge have a poorer long-term prognosis. Troponin assays are more sensitive and specific for detecting minor P-MI, with an increased incidence of P-MI being reported. This study investigated if P-MI after CABG surgery, as defined by troponin-I isozyme (cTn-I), correlated with long-term outcome. Design: A prospective, observational study. Setting: A single-institution, cardiothoracic specialty hospital. Participants: Seventy patients undergoing elective CABG surgery. Interventions: Patients (n = 70) were stratified into low-risk and high-risk groups according to the absence (cTn-I Measurements and Main Results: Most patients felt that their quality of life and activity index had improved and that their symptoms of angina had lessened at 12-month follow-up. However, cardiovascular event-free survival was significantly less in patients with P-MI ( p = 0.01) 3 years postoperatively. The incidence for cardiovascular events was 0.24 versus 0.65 ( p = 0.049) in those patients without and with P-MI, respectively. The hazard ratio (2.9; 95% confidence interval, 1.3-9.4) for cardiovascular incidents was also significantly greater in patients with P-MI. More specifically, the incidence of arrhythmia was 2.4% versus 26.1% ( p p = 0.02) in patients without and with P-MI, respectively. Conclusions: It was shown that P-MI as defined by cTn-I is associated with an increased long-term incidence of adverse cardiovascular events. An elevated peak cTn-I level (≥15 μg/L) identified patients at increased risk but did not have a powerful positive predictive value for either cardiovascular (48%) or vascular (26%) complications. However, a peak cTn-I