INCIDENCE OF ACETYLCHOLINE-INDUCED SPASM OF CORONARY-ARTERIES SUBJECTED TO BALLOON ANGIOPLASTY

To examine the vasospastic activity of coronary arteries which have be en subjected to previous balloon angioplasty, we conducted an acetylch oline provocative test at diagnostic catheterization in 147 consecutiv e patients. All patients underwent successful elective angioplasty and had follow-up angiography 1 to 6 months after the procedure. Sixty-tw o patients had a history of prior myocardial infarction and 43 patient s had multivessel coronary artery disease. Angioplasty was performed o n 176 vessels. Incremental doses of acetylcholine (25 mug, 50 mug, 100 mug) were injected into the right and left coronary arteries over a p eriod of 1 min. The incidence of coronary spasm of arteries which had been subjected to angioplasty was 44%. Angiographic restenosis was obs erved in 59 patients (40%). There was no correlation between the occur rence of coronary spasm and the presence of restenosis. The maximal do se of injected acetylcholine was smaller in patients with positive evi dence of spasm than in patients with negative evidence of spasm (55+/- 27 mug vs 82+/-28 mug, p<0.01). In patients with single vessel coronar y artery disease, the incidence of spasm of the contralateral artery, i.e. the artery without angioplasty, was lower than that of the artery subjected to angioplasty (22% vs 46%, p<0.01). Thus, the data suggest that coronary arteries which have been previously subjected to angiop lasty have enhanced vasospastic activity in response to acetylcholine.