Background: Myocardial infarction and stroke after non-cardiac surgery are two ominous cardiovascular complications believed to share similar pathophysiological processes. However, the differences in the temporal distribution between them have not been adequately investigated in a large cohort of patients.
Methods and results: The preoperative clinical features and daily occurrence of myocardial infarction and stroke were routinely recorded in 36 634 consecutive patients following elective non-cardiac, non-carotid surgery. The preoperative characteristics and postoperative daily distribution of postoperative myocardial infarction and stroke were compared using exponential and linear regressions models. Myocardial infarction and stroke occurred in 122 (0.33%) and 126 (0.34%) patients, respectively, during the first 30 days after surgery. More patients with myocardial infarction had diabetes mellitus and cardiac disease (P = 0.041 and <0.0001, respectively) whereas more patients with stroke were older and female (P = 0.003 and 0.038, respectively). The peak incidence of myocardial infarction was on the day of surgery (43%) and declined exponentially thereafter (F = 725.4, P < 0.0001). However, postoperative stroke best fitted a linear regression with almost even daily distribution (F = 15.9, P = 0.0004). The median time to myocardial infarction was one day [95% confidence interval (95% CI) = 0-2 days] compared with nine days (95% CI = 7-11 days) for stroke.
Conclusions: The peak incidence of postoperative myocardial infarction is early after non-cardiac surgery and declines exponentially thereafter, as opposed to stroke, which occurs at a constant rate during the postoperative period. Myocardial infarction and cerebrovascular accident following non-cardiac surgery differ in their preoperative risk factors, and in the postoperative time-line of their occurrence.