Coronary vasomotor response to acetylcholine late after angioplasty.

To elucidate the changes in coronary vasomotion in a previously balloon-dilated segment, we examined the vasoconstricting response of previously balloon-dilated and non-dilated segments to acetylcholine. Acetylcholine was administered into coronary arteries cumulatively (left and right coronary artery: 10-100 micrograms) in 15 patients (age: 60 +/- 3 years, 12 males and 3 females) at 7.4 +/- 1.5 months after successful percutaneous transluminal coronary angioplasty (PTCA). In PTCA segments with no restenosis, does-dependent constriction in response to acetylcholine was observed in only 1 patient. In non-PTCA segments of PTCA and non-PTCA arteries, 12 patients showed dose-dependent vasoconstriction in response to acetylcholine. Coronary spasm, which was defined as a more than 75% reduction in coronary diameter compared with that after isosorbide dinitrate, was provoked in one PTCA segment (7%). In non-PTCA segments of PTCA and non-PTCA arteries, 15 of 44 arteries (34%) demonstrated coronary spasm in 9 of 15 patients (60%, p < 0.005 vs PTCA segment). In conclusion, PTCA segments free of restenosis showed no hyper-reactivity to acetylcholine, while non-PTCA segments showed hypercontractility in response to acetylcholine. Coronary balloon angioplasty may alter the coronary vasomotor reaction to acetylcholine several months after angioplasty.