Comparable Clinical Characteristics and Outcomes between Patients with Total and Subtotal Coronary Occlusion during Intracoronary Acetylcholine Provocation Testing

Background Intracoronary acetylcholine (ACh) provocation testing is a guideline-recommended diagnostic procedure for vasospastic angina (VSA). Although significant ACh-induced vasospasm is usually defined as either total or subtotal coronary occlusion, the differential prognostic impact of total and subtotal occlusion remains unclear. Methods This study included 1143 patients who underwent ACh provocation testing to diagnose VSA. Patients were divided into three groups according to the pattern of ACh-induced vasoreactivity: no spasm, subtotal occlusion, and total occlusion. The primary endpoint was major adverse cardiovascular events (MACE), a composite of death, myocardial infarction, stroke, coronary revascularization, admission for heart failure and unstable angina, and resuscitated ventricular arrhythmia. Intraoperative complications were also evaluated. Results Of the 1143 patients, 474 (41.5%), 576 (50.4%), and 93 (8.1%) were categorized into the no spasm, subtotal occlusion, and total occlusion groups, respectively. The proportion of men and current smokers was significantly higher in the total occlusion group than that in the other two groups. Cardiogenic shock and ventricular arrhythmia during ACh testing were more frequent in the total occlusion group. During the median follow-up of 810 days, MACE occurred in 74 (15.6%), 73 (12.7%), and 22 (23.7%) patients in the no spasm, subtotal occlusion, and total occlusion groups, respectively (P=0.017). A multivariable analysis identified ACh-induced total occlusion as a factor associated with MACE. Conclusions Among the patients undergoing intracoronary ACh tests for diagnosing VSA, total coronary occlusion was induced during the provocation procedure in less than 10% of patients, but it was associated with worse clinical outcomes.