Sex Difference in Coronary Artery Spasm Tested by Intracoronary Acetylcholine Provocation Test in Patients with Nonobstructive Coronary Artery Disease

Introduction. Cardiovascular diseases manifest differently in men and women. The purpose of this study is to compare the sex difference in the characteristics of coronary artery spasm (CAS) in patients with nonobstructive cardiovascular disease (NOCVD) and the clinical outcomes in accordance with sex in CAS patients. Methods. The study analysed 5,491 patients with NOCVD who underwent an acetylcholine provocation test from November 2004 to May 2014 for evaluation of chest pain. CAS was defined as greater than 70% of luminal narrowing of the artery during the acetylcholine provocation test. Results. The patients were divided into men (n = 2,506) and women (n = 2,985). Mean follow-up days were 1,218 ± 577 days. To adjust for confounding factors, the propensity score matching (PSM) analysis was performed in all patients and among the CAS patients. After PSM analysis, a total of 1,201 pairs in all patients and a total of 713 pairs in CAS patients were generated. In all patients, women showed significantly less incidence of CAS compared with men (62.3% vs 50.9%, P < 0.01). Myocardial bridge (MB) and moderate stenosis were less prevalent in women, while transient ST elevation and ischemic chest pain during provocation were more frequent in women. In CAS patients, men had a higher incidence of multivessel spasm than women (35.7% vs. 29.7%, P < 0.01). Old age, dyslipidemia, and MB were independent risk factors of CAS in both men and women. In CAS patients, there was no statistical differences for various individual and composite major outcomes up to five years in either men or women. In men with CAS, old age was a risk factor of a 5-year major adverse cardiac event (MACE), and moderate stenosis was a risk factor of both 5-year MACE and 5-year recurrent angina. In women with CAS, mild stenosis was a risk factor of 5-year MACE, while myocardial bridge was a risk factor of 5-year recurrent angina. Conclusions. In this study, there were sex differences in the angiographic and clinical parameters during the acetylcholine provocation test, incidence of CAS, risk factors of CAS, 5-year MACE, and recurrent angina. Old age, dyslipidemia, and MB were independent risk factors of CAS in both sexes. However, major clinical outcomes up to five years in CAS patients were not different according to sex.