Prevalence and prognostic relevance of perioperative myocardial infarction/injury after major noncardiac surgery in older patients

Background The prognostic relevance of perioperative myocardial injury/infarction (PMI) in older patients undergoing major noncardiac surgery remains unclear, as high comorbidity burden may lessen its impact. Methods Older patients (defined as age ≥70 years with ≥3 comorbidities, or ≥80 years) enrolled in a multicentre, prospective study of patients at increased cardiovascular risk undergoing major noncardiac surgery were analysed. The primary endpoint, all-cause mortality at 1 year, was analysed using Cox proportional hazards regression. Secondary endpoints included MACE (cardiovascular death, acute myocardial infarction, life-threatening arrhythmia, and acute heart failure), analysed using Fine–Gray hazard regression. All models were adjusted for prespecified confounders with PMI as a time-varying exposure. Results Among 4634 older patients (median age 80 years; 42.9% women), PMI occurred in 892 patients (19.2%), which was higher than in younger patients (P < 0.0001). The distribution of PMI aetiologies was comparable between groups. At 1 year, all-cause mortality was 26.2% in patients with PMI and 13.2% in patients without PMI, and MACE occurred in 30% versus 13%, respectively. After multivariable adjustment, the hazard ratio of PMI was highest on postoperative day 1 (all-cause mortality: 10.5 [95% CI 4.5–24.5]; MACE: 4.4 [95% CI 3.2–5.9]), declined by day 90 (1.4 [95% CI 1.0–1.9] and 2.2 [95% CI 1.7–2.7], respectively), and persisted through 1 year. Conclusions PMI was very common among older patients and associated with substantially higher 1-year risks of all-cause mortality and MACE, with greatest vulnerability observed during the initial 90 postoperative days.