Differential Impact of Diagnostic Criteria of Intracoronary Acetylcholine Provocation Testing on Clinical Characteristics and Outcomes.

Background: Intracoronary acetylcholine (ACh) provocation testing is a guideline-recommended invasive standard for diagnosing vasospastic angina (VSA)/coronary spastic angina. A positive ACh test is usually defined as significant epicardial vasospasm accompanied by signs of ischemia, namely chest symptoms and/or electrocardiographic (ECG) changes. However, the differential impact of diagnostic ACh test criteria on clinical characteristics and outcomes is unclear.

Methods and results: From 2012 to 2024, 973 patients underwent ACh provocation testing for VSA diagnosis. Patients were divided into 3 groups: negative ACh test; and positive ACh test (2 groups), defined as significant epicardial vasospasm with either narrow (both chest symptoms and ECG changes) or broad (chest symptoms or ECG changes) definitions of signs of ischemia. Clinical characteristics and adverse outcomes during ACh testing and follow-up were compared among the 3 groups. In all, 356 (36.6%), 166 (17.1%), and 451 (46.4%) had positive ACh tests with narrow and broad definitions of ischemia and negative ACh tests, respectively. Among patients with positive ACh tests, there were no significant differences in baseline characteristics and adverse outcomes between those with narrow and broad definitions of ischemia.

Conclusions: In patients undergoing ACh provocation testing, there were no significant differences in clinical characteristics and outcomes between those diagnosed as having VSA using narrow and broad definitions of signs of ischemia, suggesting that either sign can be used as a criterion of ischemia.