ALTERNATION IN THE CORONARY BLOOD-FLOW VELOCITY PATTERN IN PATIENTS WITH NO-REFLOW AND REPERFUSED ACUTE MYOCARDIAL-INFARCTION

Background Experimental and clinical evidence indicates that myocardia l ischemia often damages the coronary microvasculature (''no-reflow'' phenomenon). In this study, we examined the effect of this phenomenon on the coronary blood how velocity pattern in patients with reperfused acute myocardial infarction. Methods and Results We measured coronary blood flow velocity after coronary angioplasty in 42 patients with ac ute myocardial infarction using a Doppler guidewire. Myocardial contra st echocardiography (MCE) was also performed before and after angiopla sty. Thirty-one patients showed good contrast reperfusion (MCE reflow) , whereas the other 11 showed no reflow (MCE no reflow). Peak velocity and duration of systolic coronary flow were significantly less in pat ients with MCE no reflow than in those with MCE reflow (8+/-4 versus 1 7+/-10 cm/s and 207+/-79 versus 289+/-55 ms, respectively; P<.01). Ear ly systolic retrograde how was frequently observed in patients with MC E no reflow, whereas it was observed in only 1 patient among those wit h MCE reflow (95% versus 3%; P<.001). Although peak diastolic how velo city was similar between the two subsets, diastolic deceleration rate was significantly higher in patients with MCE no reflow than in those with MCE reflow (107+/-76 versus 56+/-31 cm/s(2); P<.01). Conclusions The coronary flow velocity pattern in patients with the no-reflow phen omenon was characterized by the appearance of systolic retrograde flow , diminished systolic antegrade how, and rapid deceleration of diastol ic how. Thus, the Doppler guidewire allows us to assess the presence o f microvascular dysfunction in AMI.