957-111 Time Course of Impaired Coronary Vasodilatory Reserve After Reperfusion in Acute Myocardial Infarction

We have previously reported that coronary vasodilatory reserve is severely impaired immediately after reperfusion in patients with acute myocardial infarction. To investigate the time course of impaired coronary vasodilatory reserve after reperfusion, we studied 11 patients with a first acute anterior myocardial infarction who underwent coronary angioplasty (PTCA) within 6 hours after the onset of symptom. After PTCA, a coronary Doppler guide wire was positioned beyond the infarct related coronary lesion. Dipyridamole 10.56mg/kg) was administered intravenously over 4 minutes and coronary flow velocity was measured for 10 minutes. Coronary vasodilatory reserve was calculated as the ratio of hyperemic average peak velocity (APV)/resting APV These measurements were repeated at 2 weeks (n=9) and 6 months (n=6) after PTCA. Additional 10 patients with normal angiograms served as control.ResultsAfter PTCA (n=11)2 weeks (n=9)6 months (n=6)Control (n=10)resting APV (cm/s)27±1724±729±920±4hyperemic APV (cm/s)35±22#46±13#69±19#61±11#vasodilatory reserve1.36±0.28&1.89±0.31&2.46±0.36&3.02±0.25*#P<0.01 vs resting APV&p<001 vs control*p < 0.01ConclusionCoronary vasodilatory reserve is severely impaired immediately after reperfusion. The coronaryvasodilatory reserve gradually improves over 2 weeks but the impairement persists at 6 months after acute myocardial infarction