Differences between MINOCA and type 2 myocardial infarction: An ITALIAN observational study.

Background: Myocardial infarction with non-obstructive coronary arteries (MINOCA) and type 2 myocardial infarction (MI), both presenting as non-ST-elevation MI (NSTEMI), are often grouped together due to overlapping symptoms. The aim of our study is to compare their characteristics and prognosis to distinguish between them.

Methods: Among 7815 patients with NSTEMI who underwent coronary angiography between 2005 and 2022 we identified 538 patients with diagnosis of MINOCA (n = 301; 3,9 %) and type 2 MI (n = 237; 3 %). The outcome was a composite of all-cause mortality, non-fatal MI, hospitalisation for heart failure (HF) and transitory ischemic attack or non-fatal stroke.

Results: The mean age of the entire cohort was 68 (11.5) years, with women being the most frequently represented group (65 %). Comparing the sub-cohorts, MINOCA patients were younger (66.3 (11.7) Vs. 70.6 (11) years, p < 0.01), and less likely to have typical cardiovascular risk than type 2 MI patients. At multivariable analysis different clinical (age, heart rate, typical chest pain, palpitations, postmenopausal status), and instrumental (cardiac rhythm, ST-segment changes, diastolic dysfunction, hypo/akinesia with non-coronary distribution) variables were independent predictors of MINOCA with AUC of 0.83 [95 % CI, 0.78-0.88], p < 0.01 at ROC analysis. At a median follow-up of 61 (IQR 34-100) months, MINOCA patients had significantly lower rate of the composite endpoint compared to type 2 MI (20 % Vs. 32 %, p < 0.01).

Conclusions: MINOCA cohort was associated with different characteristics compared to type 2 MI and had a better prognosis despite the number of events was not negligible.