CORONARY VASOMOTOR RESPONSE TO ACETYLCHOLINE LATE AFTER ANGIOPLASTY

To elucidate the changes in coronary vasomotion in a previously balloo n-dilated segment, we examined the vasoconstricting response of previo usly balloon-dilated and non-dilated segments to acetylcholine. Acetyl choline was administered into the coronary arteries cumulatively (left and right coronary artery: 10-100 mu g) in 15 patients (age: 60+/-3 y ears, 12 males and 3 females) at 7.4+/-1.5 months after successful per cutaneous transluminal coronary angioplasty (PTCA). In PTCA segments w ith no restenosis, dose-dependent constriction in response to acetylch oline 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-PT CA segments of PTCA and non-PTCA arteries, 15 of 44 arteries (34%) dem onstrated coronary spasm in 9 of 15 patients (60%, p<0.005 vs PTCA seg ment). In conclusion, PTCA segments free of restenosis showed no hyper reactivity to acetylcholine, while non-PTCA segments showed hypercontr actility in response to acetylcholine. Coronary balloon angioplasty ma y alter the coronary vasomotor reaction to acetylcholine several month s after angioplasty.