Abstract
BACKGROUND: Perioperative cardiovascular events are a leading cause of morbidity and mortality after noncardiac surgery. We propose a simplified method for perioperative risk stratification. METHODS: In a retrospective cohort study we identified patients who underwent noncardiac surgery between 2009 and 2015 in the US National Surgical Quality Improvement Program. Multivariable logistic regression models adjusted for age, sex, race, and surgery type were generated to estimate the effect of traditional cardiovascular risk factors (hypertension, diabetes mellitus, current smoking) on odds of perioperative myocardial infarction (MI). Time to event analysis was conducted using competing risk analysis, with MI as the outcome event and death as the competing risk. RESULTS: A total of 3,848,501 noncardiac surgeries were identified. Postoperative MI occurred in 0.37% of patients and 1.04% of patients died. The 30-day event rate of perioperative MI increased in a stepwise fashion with additional risk factors (0.42% for 1, 0.82% for 2, and 1.08% for 3; P for trend < 0.001) after accounting for the competing risk of death. Compared with those with no risk factors, patients with 1, 2, and 3 risk factors had increased odds of MI (adjusted odds ratio [aOR], 2.07 [95% confidence interval (CI), 1.96-2.19]; aOR, 3.63 [95% CI, 3.43-3.85]; and aOR, 5.54 [95% CI, 5.09-6.04], respectively). Perioperative MI was rare (0.10%) in patients without risk factors. CONCLUSIONS: Patients with cardiovascular risk factors are at increased risk of perioperative MI, those without risk factors are at low risk. Further evaluation is needed to determine the effect of a simplified risk score in the perioperative setting.