Long-term outcomes in very young patients with myocardial infarction with non-obstructive coronary arteries

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) covers an expanding group of patients over recent years. Previous studies showed considerable risks of outcomes in this group. However, there is a lack of evidence in young patients with MINOCA. In this study, we aimed to investigate the long-term outcomes in very young patients with MINOCA. We retrospectively compared the features and predictors of 183 very young (<= 40-year-old) patients to >40-year-old patients with MINOCA. We compared the baseline characteristics and major adverse cardiac events (total MI, revascularization and mortality) rates between the groups during a median follow-up of 7.3 years. We performed the Cox regression analysis to investigate the risk factors for mortality. We found that the <= 40-year-old group with MINOCA had 12% mortality rates during the follow-up. They had significantly lower rates of diabetes and hypertension and higher rates of male gender and smoking compared to the older group. The very young group also had lower rates of CRF, previous MI and atrial fibrillation. The <= 40-year-old groups received significantly lower rates of medications. Ejection fraction (EF) <30% was independently associated with 6-fold increases in total mortality [hazard ratio (HR) = 6.23, 95% confidence interval (CI) 1.42-27.2, P = 0.02] in the <= 40-year-old group. In conclusion, the <= 40-year-old patients with MINOCA have substantial long-term mortality rates. EF <30% was independently associated with total mortality in this group. Moreover, the <= 40-year-old group also received less intense medical therapy compared to their older counterparts.