Characteristics and Outcomes of Type 1 versus Type 2 Perioperative Myocardial Infarction After Noncardiac Surgery.

ABSTRACT

BACKGROUND: Perioperative myocardial infarction is frequently attributed to type 2 myocardial infarction, a mismatch in myocardial oxygen supply-demand without unstable coronary artery disease. Our aim was to identify characteristics, management, and outcomes of perioperative type 1 versus type 2 myocardial infarction among surgical inpatients. METHODS: Adults age ≥45 years hospitalized for noncardiac surgery were identified in the United States. Perioperative myocardial infarction were identified using International Classification of Diseases, 10th revision (ICD-10) codes. Clinical characteristics, invasive myocardial infarction management, mortality, and readmissions were assessed by myocardial infarction subtype. RESULTS: Among 4,755,382 surgical hospitalizations, we identified 38,975 perioperative myocardial infarctions (0.82%), with type 2 infarction in 42%. Patients with type 2 myocardial infarction were older, more likely to be women, and less likely to have cardiovascular comorbidities compared with type 1 myocardial infarction. Fewer patients with type 2 myocardial infarction underwent invasive management than type 1 myocardial infarction (6.7% vs 28.8%, P < .001). Type 2 myocardial infarction mortality was lower than type 1 myocardial infarction mortality (12.1% vs 17.4%, P < .001; adjusted odds ratio [aOR] 0.51, 95% confidence interval [CI] 0.45-0.59). Invasive management of perioperative myocardial infarction was associated with lower mortality in type 1 (aOR 0.56, 95% CI 0.49-0.74) but not type 2 (aOR 1.19, 95% CI 0.77-1.85) myocardial infarction. Among survivors, there was no difference in 90-day hospital readmission between type 2 and type 1 perioperative myocardial infarction (36.5% vs 36.1%, P = .72). CONCLUSIONS: Type 2 myocardial infarctions account for approximately 40% of perioperative myocardial infarctions. Patients with type 2 perioperative myocardial infarction are less likely to undergo invasive management and have lower mortality compared with those with type 1 perioperative myocardial infarction.