Patterns and outcomes of invasive management of type 2 myocardial infarction in the United States.

Background: Type 2 myocardial infarction (MI) occurs due to a mismatch in myocardial oxygen supply and demand without unstable coronary artery disease. We sought to identify patterns, predictors and outcomes of invasive management of type 2 MI in the USA.

Methods: Adults aged ≥18 years hospitalized with type 2 MI were identified in a cross-sectional study from the 2018 National Inpatient Sample. Invasive management was defined as invasive coronary angiography or revascularization. Patient, hospital and geographic characteristics associated with invasive management were identified by multivariable logistic regression. Propensity-matched cohorts were generated to evaluate associations between invasive vs. conservative management and mortality.

Results: We identified 268 850 admissions with type 2 MI in 2018. Type 2 MI patients had a high burden of comorbidities and were commonly admitted with diagnoses of circulatory (39.7%), infectious (23.1%) or respiratory (10.8%) illness. Only 11.2% of type 2 MI were managed invasively, of which 17.9% underwent coronary revascularization. Odds of invasive management were higher with commercial insurance [adjusted OR (aOR) 1.39; 95% confidence interval (CI), 1.27-1.52] and lower with Medicaid (aOR 0.86; 95% CI, 0.76-0.96) vs. Medicare. Significant heterogeneity in invasive management of type 2 MI was observed by geographic region (range 7.2-13.8%), independent of patient and hospital factors. Invasive management was associated with lower in-hospital mortality than conservative management overall (3.9 vs. 9.1%; P < 0.001) and in propensity-matched analyses (OR, 0.70; 95% CI, 0.59-0.84).

Conclusion: Invasive management of type 2 MI varies by insurance status and geography, highlighting uncertainty regarding optimal management and potential disparities in clinical care.