Prevalence and prognostic relevance of perioperative myocardial injury/infarction 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 major adverse cardiac events (MACE) (cardiovascular death, acute myocardial infarction, life-threatening arrhythmia and acute heart failure), analysed using Fine-Grey hazard regression. All models were adjusted for prespecified confounders with PMI as a time-varying exposure. RESULTS: Amongst 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 < .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 amongst 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.