Response to Letter Regarding Article, “East Asian Variant of Aldehyde Dehydrogenase 2 Is Associated With Coronary Spastic Angina: Possible Roles of Reactive Aldehydes and Implications of Alcohol Flushing Syndrome”

We appreciate Brugaletta and colleagues for their interest in our article.1 In their opinion, it cannot be excluded that endothelial dysfunction contributes to vasospasm, being a confounding variable in the diagnosis of coronary spastic angina (CSA) by the acetylcholine test, and that use of ergonovine instead of acetylcholine could differentiate between CSA and vasospasm caused by endothelial dysfunction. Coronary spasm can be induced by various methods, including intracoronary injection of acetylcholine, ergonovine, histamine, or dopamine; hyperventilation; alcohol ingestion; cold pressure test; physical exercise; and mental stress.2 Various factors therefore may be involved in the pathogenesis of coronary spasm. However, it is generally accepted that hyperreactivity of coronary vascular smooth muscle is the common underlying mechanism of coronary spasm.2,3 The precise mechanisms underlying the hyperreactivity of coronary smooth muscle, however, …