Risk of cardiac events after elective versus urgent or emergent noncardiac surgery: Implications for quality measurement and improvement

Introduction: Patient populations differ for elective vs urgent and emergent surgery. The effect of this difference on surgical outcome is not well understood and may be important for improving surgical safety. Our primary hypothesis was that there is an association of surgical acuity with risk of postoperative cardiac events. Secondarily, we examined elective vs urgent and emergent patients separately to understand patient characteristics that are associated with postoperative cardiac events.

Methods: We performed a retrospective cohort study of patients ≥65 years undergoing noncardiac elective or urgent/emergent surgery. Logistic regression estimated the association of surgical acuity with a postoperative cardiac event, which was defined as myocardial infarction or cardiac arrest within 30 days of surgery. For the secondary analysis, we modeled the outcome after stratifying by acuity.

Results: The study included 161,177 patients with 1014 cardiac events. The unadjusted risk of a postoperative cardiac event was 3.2 per 1000 among elective patients and 28.7 per 1000 among urgent and emergent patients (adjusted odds ratio 4.10, 95% confidence interval 3.56-4.72). After adjustment, increased age, higher baseline cardiac risk, peripheral vascular disease, hypertension, worse American Society of Anesthesiologist (ASA) physical classification, and longer operative time were associated with a postoperative cardiac event. Higher baseline cardiac risk was more strongly associated with postoperative cardiac events in elective patients. In contrast, worse ASA physical classification was more strongly associated with postoperative cardiac events in urgent and emergent patients. Black patients had higher odds of a postoperative cardiac event only in urgent and emergent patients compared to White patients.

Conclusions: Quality measurement and improvement to address postoperative cardiac risk should consider patients based on surgical acuity.