Lack of Class I Vasoreactivity Testing for Diagnosing Patients With Coronary Artery Spasm

ABSTRACT Background Vasoreactivity testing, such as intracoronary acetylcholine (ACh) or ergometrine (EM), is defined as Class I for the diagnosis of patients with vasospastic angina (VSA) according to recommendations from the Coronary Vasomotion Disorders International Study (COVADIS) group and guidelines from the Japanese Circulation Society (JCS). Hypothesis Although vasoreactivity testing is a clinically useful tool, it carries some risks and limitations in diagnosing coronary artery spasm. Methods Previous reports on vasoreactivity testing for diagnosing the presence of coronary spasm are summarized from the perspective of Class I. Results There are several problems such as reproducibility, underestimation, overestimation, and inconclusive/nonspecific results associated with daily spasm. Because provoked spasm caused by intracoronary ACh is not always similar to that caused by intracoronary EM, possibly due to different mediators, supplementary use of these vasoreactivity tests is necessary for cardiologists to diagnose VSA when a provoked spasm is not revealed by each vasoactive agent. Conclusions Cardiologists should understand the imperfection of these vasoreactivity tests when diagnosing patients with VSA.