[Endothelial dysfunction of the infarct-related coronary artery after reperfusion therapy].

The response of the infarct-related coronary artery to acetylcholine (20, 30, 50 micrograms) was investigated in 30 patients without restenosis during a 4-month follow-up period after direct percutaneous transluminal coronary angioplasty (PTCA) of the left proximal anterior descending coronary artery. The patients were divided into two groups according to wall motion as obtained by the centerline method from a left ventricular angiogram: moderate group (n = 10) with reduced wall motion with less than 20 abnormal contraction segments (moderate reduction at the infarcted site), severe group (n = 20) with reduced wall motion with 20 or more abnormal contraction segments (severe reduction). The acetylcholine-induced percentage changes in luminal diameter were assessed at the PTCA site and the distal portion of the coronary artery and the effect of acetylcholine was compared at the two sites. Coronary artery diameter in the moderate and severe groups displayed 8.1 +/- 24.9% and 7.4 +/- 30.8% contraction at the PTCA site and 38.3 +/- 46.3% and 72.5 +/- 28.2% contraction at the distal portion, respectively. Severe group had greater contraction at the distal portion than at the PTCA site. Vasoconstriction of the patent infarct-related coronary artery tended to occur in the infarcted area where wall motion was severely affected. In addition, endothelial dysfunction appears to be induced by a lengthy interruption of epicardial coronary blood flow and is present in the patent infarcted coronary artery without restenosis.