Risk of Postoperative Ischemic Stroke and Myocardial Infarction in Patients Operated for Cancer.

Abstract

Risk assessment for ischemic stroke (IS) and myocardial infarction (MI) is done routinely before surgery, but the increase in risks associated with surgery is not known. The aim of this study is to assess the risk of arterial ischemic events during the first year after oncological surgery. We used Swedish healthcare databases to identify 443,300 patients who underwent cancer surgery between 1987 and 2016 and 4,127,761 matched comparison subjects. We estimated odds ratios (ORs) for myocardial infarction and ischemic stroke during the hospitalization with logistic regression and calculated 1-year cumulative incidences and hazard ratios (HRs) with 95% confidence intervals (CIs) for the outcomes after discharge. The cumulative incidences of myocardial infarction and ischemic stroke during the first postoperative year were 1.33% and 1.25%, respectively. In the comparison cohort, the corresponding 1-year cumulative incidences were 1.04% and 1.00%. During the hospitalization, the OR for myocardial infarction was 8.81 (95% CI 8.24-9.42) and the OR for ischemic stroke was 6.71 (95% CI 6.22-7.23). After discharge, the average HR during follow-up for 365 days was 0.90 (95% CI 0.87-0.93) for myocardial infarction and 1.02 (95% CI 0.99-1.05) for ischemic stroke. We found an overall increased risk of IS and MI during the first year after cancer surgery that was attributable to events occurring during the hospitalization period. After discharge from the hospital, the overall risk of myocardial infarction was lower among the cancer surgery patients than among matched comparison subjects.