Long-term outcome of patients with NSTEMI and nonobstructive coronary arteries by different angiographic subtypes

Discordant data have been reported on the prognosis of myocardial infarction with nonobstructive coronary arteries (MINOCA). Moreover, few data are available on the impact of angiographic subtypes. The objectives of this study were to assess the prognostic impact on the long-term follow-up of the diagnosis of MINOCA and its angiographic subtypes.

We included 591 consecutive patients with non-ST-segment elevation myocardial infarction (NSTEMI) who underwent coronary angiography. MINOCA was classified according to angiographic findings as smooth coronary arteries, mild irregularities (< 30% stenosis), and moderate atherosclerosis (30%-49% stenosis). The primary endpoint was a composite of mortality, nonfatal myocardial infarction, and revascularization (MACE) at a median of 5 years of follow-up.

A total of 121 patients (20.5%) showed no obstructive lesions. MINOCA was associated with a lower occurrence of MACE (P=.014; HR, 0.63; 95%CI, 0.44-0.91) and was confirmed as an independent factor in the multivariate analysis (P=.018; HR, 0.63; 95%CI, 0.43-0.92). On analysis of the separate components of the main endpoint, MINOCA was significantly associated with a lower rate of myocardial infarction and revascularization, but not with mortality. Analysis of angiographic subtypes among MINOCA patients showed that smooth coronary arteries were a statistically significant protective factor on both univariate and multivariate analysis, while mild irregularities and 30% to 49% plaques were associated with a higher risk of MACE.

MINOCA is associated with a lower rate of MACE, driven by fewer reinfarctions and revascularizations. Within the angiographic subtypes of MINOCA, smooth arteries were independently associated with a lower number of MACE.