Factors for heterogeneous outcomes of angina and myocardial ischemia with non-obstructive coronary atherosclerosis

BACKGROUND AND OBJECTIVES: Absence of obstructive coronary artery disease (CAD) in patients with angina is common, but its prognosis debated. We investigated outcomes of such patients to identify predictors of cardiovascular events.

METHODS: We selected 1,014 patients with angina, evidence of myocardial ischemia at the electrocardiogram (ECG) exercise test or imaging stress tests, and non-obstructive CAD (absence of lumen diameter reduction ≥50%) at coronary angiography between 1999 and 2015. 1,905 age- and risk factors-matched asymptomatic subjects served as "real-world" comparators. The primary endpoint was the occurrence of all-cause death or myocardial infarction.

RESULTS: At 6-years median follow-up (IQR 3-9 years), the primary endpoint occurred in 53 patients (5.5%, 0.92/100 person-years). Besides similar event rates compared with asymptomatic subjects (hazard ratio, HR 0.85, 95% CI 0.62-1.15, P = 0.28), the index population showed a very heterogeneous prognosis. Patients with non-obstructive CAD (HR 1.85, 95% CI 1.02-3.37, P = 0.04, compared with "normal" coronary arteries) and with ischemia at imaging tests (HR 2.11, 95% CI 1.07-4.14, P = 0.03, compared with ischemia detected only at the ECG exercise test) were at higher risk, and those with both these components showing even >10-fold event rates as compared with the absence of both. 325 patients (34%) continued to experience angina, 69 (7.2%) underwent repeat coronary angiography, and 14 (1.5%) had a consequent coronary revascularization for atherosclerosis progression.

CONCLUSION: Apart from impaired quality of life, angina without obstructive CAD has an overall benign but very heterogeneous prognosis. Non-obstructive CAD and myocardial ischemia at imaging tests both confer a higher risk. This article is protected by copyright. All rights reserved.