Myocardial Infarction With No Obstructive Coronary Artery Disease: Angiographic and Clinical Insights in Patients With Premature Presentation

Abstract

BackgroundPremature myocardial infarction (MI) is an increasingly prevalent cause of morbidity and mortality worldwide. A subset of patients, predominantly young women, present with MI with no obstructive coronary artery disease (MINOCA), a nomenclature gaining recognition. However, few data exist on presentation and prognosis according to the severity of coronary artery disease (CAD). MethodsWe studied patients with premature (younger than 55 years of age) acute MI enrolled in a large cohort in 24 centres across Canada. Baseline clinical, psychosocial, and coronary anatomy characteristics as well as 12-month outcomes were compared between patients with MINOCA (< 50% stenosis) and patients with MI with obstructive CAD (≥ 50% stenosis; MICAD). ResultsFrom a cohort of 1210 patients with acute coronary syndrome, we examined 998 MI patients with available angiography core lab readings: 82 (8.2%) had a MINOCA and 916 (91.8%) had a MICAD. Forty percent of patients with MINOCA were women compared with one-third with MICAD. The prevalence of traditional risk factors and chest pain at presentation was lower in MINOCA patients, yet 37% had a ST-elevation MI and 10% presented with a cardiac arrest. No evident etiology was detected in > 70% of MINOCA, but 10% presented with either spontaneous coronary dissection or Takotsubo cardiomyopathy. Although combined major adverse cardiovascular events and all-cause readmission rate was lower in the MINOCA group (14% vs 25%; adjusted hazard ratio, 0.51; 95% confidence interval, 0.28-0.93), it was not negligible. ConclusionsPatients with MINOCA present with high-risk features despite the absence of obstructive CAD. A search for etiology and eventual treatment provides a rich avenue for improving prognosis in young women with premature MI.