Nonobstructive coronary atherosclerosis is associated with adverse prognosis among patients diagnosed with myocardial infarction without obstructive coronary arteries.

Background And Aims: The prognostic impact of nonobstructive coronary artery disease (CAD), as opposed to normal coronary arteries, on long-term outcomes of patients with myocardial infarction with no obstructive coronary arteries (MINOCA) is unclear. We aimed to address the association between nonobstructive-CAD and major adverse events (MAE) following MINOCA.

Methods: We conducted a retrospective cohort study of consecutive MINOCA patients admitted to a large referral medical center between 2005 and 2018. Patients were classified according to coronary angiography as having either normal-coronaries or nonobstructive-CAD. The primary outcome was MAE, defined as the composite of all-cause mortality and recurrent acute coronary syndrome (ACS).

Results: Of the 1544 MINOCA patients, 651 (42%) had normal coronaries, and 893 (58%) had CAD. The mean age was 61.2 ± 12.6 years, and 710 (46%) were females. Nonobstructive-CAD patients were older and less likely to be females, with higher rates of diabetes, hypertension, dyslipidemia, atrial fibrillation, and chronic renal-failure (p < 0.05). At a median follow-up of 7 years, MAE occurred in 203 (23%) patients and 67 (10%) patients in the nonobstructive-CAD and normal-coronaries groups, respectively (p < 0.01). In multivariable models, nonobstructive -CAD was significantly associated with long-term MAE [adjusted-hazard-ratio (aHR):1.67, 95% confidence-interval (95%CI):1.25-2.23; p < 0.001]. Other factors associated with a higher MAE-risk were older-age (aHR:1.05,95%CI:1.03-1.06; p < 0.001) and left ventricular ejection-fraction<40% (aHR:3.04,95%CI:2.03-4.57; p < 0.001), while female-sex (aHR:0.72, 95%CI: 0.56-0.94; p=0.014) and sinus rhythm at presentation (aHR:0.66, 95%CI: 0.44-0.98; p=0.041) were associated with lower MAE-risk.

Conclusions: In MINOCA, nonobstructive-CAD is independently associated with a higher MAE-risk than normal-coronaries. This finding may promote risk-stratification of patients with nonobstructive-CAD-MINOCA who require tighter medical follow-up and treatment optimization.