DISPARITY BETWEEN SEROTONIN-PROVOKED AND ACETYLCHOLINE-PROVOKED CORONARY-ARTERY SPASM

Background and hypothesis: Intrinsic vasoactive substances, such as se rotonin and acetylcholine, are known to provoke coronary artery spasm in patients with vasospastic angina. It remains unclear, however, whet her these different agents, which activate different receptors, produc e spasms at the same sites in these patients. The present study was de signed to clarify the disparity of receptor agonist-induced coronary a rtery spasms in the same patients. Methods: We conducted sequential pr ovocative tests of coronary artery spasm by acetylcholine, serotonin, and ergonovine in 20 patients with rest angina examined with quantitat ive coronary angiography. Results: Coronary artery spasms were provoke d in all pa tients at 27 spastic sites. In 13 patients, ergonovine pro voked spasms and in 10 of 13 patients who were diagnosed with variant angina, both acetylcholine and serotonin provoked spasms at the same s ites where ergonovine also did. In 4 of 13 patients, spasms were provo ked by serotonin but not by acetylcholine. In the remaining seven pati ents, whose spasms were induced by ergonovine, spasms were produced by acetylcholine but not by serotonin. On coronary angiography, the spas tic sites for both acetylcholine and serotonin, and those for serotoni n alone, were located in the proximal segments of coronary arteries, w hereas the spastic sites for acetylcholine alone were located in the d istal segments. Conclusions: This study documented the disparity be tw een serotonin- and acetylcholine-induced spasms. Provocative tests usi ng agents that activate different receptors may produce coronary arter y spasms at the same and/or different sites, and this disparity may re flect the clinical heterogeneity of vasospastic ischemic syndrome.