Preoperative ECG Signs of Ischemia Increase the Risk of Perioperative Myocardial Injury: An Observational Cohort Study

Abstract Background: Perioperative myocardial injury (PMI) is associated with increased postoperative mortality. To date, many different definitions have been used to define PMI. There is a scarcity of studies that have explored the association between ischemic findings on preoperative ECG and PMI. We aimed to explore the association between preoperative ECG signs of ischemia and perioperative myocardial injury in high-risk patients undergoing vascular surgery. Methods: The patients included in this retrospective single-center cohort study were recruited from a patient cohort recruited for a different prospective cohort study. High-sensitivity cardiac troponin T (hs-cTnT) was measured preoperatively and at 4 to 6, 24 and 48 hours postoperatively. Preoperative ECG was acquired within seven days prior to index surgery. Preoperative ECG signs of ischemia were defined as one or more of ST-elevation, ST-depression, T-wave inversion or pathological Q-wave. The primary outcome was PMI defined both solely according to the guidelines presented by the European Society of Cardiology (PMI1) and in combination with the older definition presented in the Fourth Universal Definition of Myocardial infarction (PMI2). Logistic regression and multiple regression were used to analyze the aim of the study. Results: In total 474 patients undergoing vascular surgery were included in this study. The primary outcomes of PMI1 and PMI2 occurred in 50 (10.5 %) and 103 (20.7 %) patients, respectively. A significant adjusted association was found between preoperative ECG signs of ischemia and PMI1 (OR, 2.42; 95% CI, 1.32-4.45; P = 0.004). However, the adjusted association with PMI2 was not significant (OR, 1.58; 95% CI, 0.99-1.91; P = 0.056). Conclusions: Among patients with preoperative ECG signs of ischemia we found a more than doubled risk of PMI1, the definition that required a larger perioperative elevation in hs-cTnT. Large multicenter randomized clinical trials are needed to evaluate if the outcome of patients with preoperative ECG signs of ischemia can be modified.