Long-Term Follow-Up in Patients With Stable Angina and Unobstructed Coronary Arteries Undergoing Intracoronary Acetylcholine Testing

OBJECTIVES The aim of this study was to investigate the prognosis of a large cohort of patients with stable angina and unobstructed coronaries undergoing acetylcholine spasm testing. BACKGROUND Coronary artery spasm can be found in up to 60% of patients with symptoms of myocardial ischemia despite unobstructed coronary arteries. METHODS Consecutive symptomatic patients with unobstructed coronary arteries undergoing acetylcholine testing to detect epicardial or microvascular coronary spasm were prospectively enrolled. After a median follow-up period of 7.2 years (6.5 to 7.9 years), data regarding mortality, nonfatal myocardial infarction, stroke, repeat coronary angiography, recurrent symptoms, and quality of life were obtained in 736 patients (57% women, mean age 62 +/- 12 years). RESULTS In total, 55 deaths (7.5%), 8 nonfatal myocardial infarctions (1.4%), and 12 strokes (2.2%) occurred during the follow-up period. Recurrent symptoms were reported by 64% of patients, and repeat coronary angiography was per-formed in 12% of cases. Multivariate analysis revealed epicardial spasm as a predictor of nonfatal myocardial infarction (hazard ratio: 14.469; 95% confidence interval: 1.735 to 120.646) and repeat angiography (hazard ratio: 1.703; 95% confidence interval: 1.062 to 2.732), whereas patients with microvascular spasm more often had recurrent angina at follow-up (hazard ratio: 1.311; 95% confidence interval: 1.013 to 1.697). CONCLUSIONS In this long-term follow-up study, the overall prognosis of patients with coronary spasm was favor-able. Patients with epicardial spasm were at increased risk for myocardial infarction and repeat angiography, while microvascular spasm was associated with recurrent angina. Acetylcholine testing may help identify patients at increased risk for adverse cardiac events among this overall low-risk population. (C) 2020 by the American College of Cardiology Foundation.