Clinical characteristics and outcome in patients with ST-segment and non-ST-segment elevation myocardial infarction without obstructive coronary artery: an observation study from Chinese population

The disparity between ST-segment and non-ST-segment elevation myocardial infarction without obstructive coronary artery (STE-MINOCA and NSTE-MINOCA) are unclear. Our study aims to compare the clinical features and outcomes in patients with STE-MINOCA and NSTE-MINOCA.

This cross-sectional study consecutively enrolled patients diagnosed with acute myocardial infarction (AMI) from January 2013 to January 2020. MINOCA were identified as angiographic stenosis < 50%. Clinical characteristics, angiographic features, and clinical outcomes of STE-MINOCA and NSTE-MINCOA were documented. The primary endpoint was composite events in the different time periods.

A total of 1966 AMI patients were screened, 107 (5.4%) were diagnosed as MINOCA. Among, there were 34 (31.8%) of STE-MINOCA and 73 (68.2%) of NSTE-MINOCA. STE-MINOCA group were younger, had lower N-terminal pro-brain natriuretic peptide (NT-proBNP), and smaller left atrial diameter (P < 0.05). Dual antiplatelet therapy (DAPT) was more likely to be prescribed to STE-MINOCA patients (P = 0.015). During median follow-up time of 24.5 months, STE-MINOCA group also demonstrated lower risks for primary endpoint and cardiovascular-related (CVS) rehospitalization. In univariate Cox regression analyses, NSTE-MINOCA showed an increased risk of long-term primary endpoint (HR 2.57, 95 CI%: 1.10-6.02) and CVS-related rehospitalization (HR 3.14, 95% CI: 1.16-8.48). After adjusting for NT-proBNP and DAPT, NSTE-MINOCA remained an independent risk factor for CVS-related rehospitalization in long-term follow-up (HR 2.78, 95% CI: 1.03-7.49).

Although STE-MINOCA and NSTE-MINOCA patients showed similar clinical characteristics, NSTE-MINOCA group presented a worse long-term outcome mainly driven by CVS-related hospitalization which suggested that NSTE-MINOCA patients might also require prompt medical attention.