Incidence of acetylcholine-induced spasm of coronary arteries subjected to balloon angioplasty.

To examine the vasospastic activity of coronary arteries which have been subjected to previous balloon angioplasty, we conducted an acetylcholine provocative test at diagnostic catheterization in 147 consecutive patients. All patients underwent successful elective angioplasty and had follow-up angiography 1 to 6 months after the procedure. Sixty-two patients had a history of prior myocardial infarction and 43 patients had multivessel coronary artery disease. Angioplasty was performed on 176 vessels. Incremental doses of acetylcholine (25 micrograms, 50 micrograms, 100 micrograms) were injected into the right and left coronary arteries over a period of 1 min. The incidence of coronary spasm of arteries which had been subjected to angioplasty was 44%. Angiographic restenosis was observed in 59 patients (40%). There was no correlation between the occurrence of coronary spasm and the presence of restenosis. The maximal dose of injected acetylcholine was smaller in patients with positive evidence of spasm than in patients with negative evidence of spasm (55 +/- 27 micrograms vs 82 +/- 28 micrograms, p < 0.01). In patients with single vessel coronary 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 angioplasty have enhanced vasospastic activity in response to acetylcholine.