Association Between Vasomotor Response to Ergonovine Provocation Test and Non-Severe Coronary Artery Stenosis

Background: Coronary artery spasm (CAS) causes vasospastic angina in patients without significant coronary artery stenosis. However, there has been limited investigation regarding the CAS patterns within this population. This study aims to evaluate the incidence and patterns of CAS in patients with non-severe coronary artery stenosis using intracoronary ergonovine (ERG) provocation test. Methods: A total of 884 patients experiencing angina with non-severe coronary artery stenosis who underwent intracoronary ERG provocation test between January 2018 and December 2022 were enrolled. Patients were categorized into two groups, based on the severity of coronary artery stenosis: the Non-group (stenosis < 30%, n = 732), and the Mild-to-moderate group (30%−69%, n = 152). Significant CAS was defined as arterial narrowing of ≥ 70%, and vasomotor responses were observed in each group. Results: The baseline clinical characteristics of the Mild-to-moderate group were worse than the Non-group. They were older with higher prevalence of hypertension, diabetes mellitus, dyslipidemia, and smokers. During the ERG test, CAS was observed in 37.7% of the overall population. The Mild-to-moderate group (54.6%) showed a higher incidence than the Non-group (34.2%, p < 0.001). The Mild-to-moderate group demonstrated odds ratio of 2.31 for CAS compared to the Non-group (95% CI: 1.60−3.33, p < 0.001) even after adjustment. Conclusions: A considerable number of patients experiencing angina with non-severe coronary artery stenosis were found to have CAS. Moreover, CAS was observed more frequently in patients with mild to moderate coronary artery stenosis compared to those without any fixed stenosis.