Early temporal changes in coronary flow velocity patterns in patients withacute myocardial infarction demonstrating the "no-reflow" phenomenon

Coronary flow velocity pattern in patients with acute myocardial infarction demonstrating no-reflow phenomenon is characterized with early systolic re trograde flow and rapid deceleration of diastolic flow velocity. In this st udy, we investigated the early temporal changes in microvascular function i n patients with the no-reflow phenomenon. Among 144 patients with a first a cute myocardial infarction, 33 exhibited sizable no-reflow phenomenon after coronary reperfusion with myocardial contrast echocardiography. We assesse d temporal changes in coronary how velocity patterns with the Doppler guide wire. The early systolic retrograde flow was observed less than or equal to 10 seconds after reperfusion in 16 patients (group A) or later in 17 patie nts (331 +/- 327 seconds, group B). Diastolic deceleration rate was higher in group A than in group B at 1 minute after reperfusion. It gradually incr eased in group B and showed comparable value to group A 10 minutes later. G roup A had longer elapsed time from symptom onset to reperfusion and a grea ter number of infarct Q waves before reperfusion than group B (14 +/- 13 vs 5 +/- 2 hours, p < 0.01; and 3 +/- 2 vs 2 +/- 1, p < 0.02). In contrast, t he incidence of transient ST reelevation shortly after reperfusion was high er in group B (76% vs 25%, p < 0.01). Thus, the characteristic coronary flo w velocity pattern is either established at the moment of coronary reperfus ion or progresses thereafter in patients with no-reflow phenomenon. This su ggests different mechanisms of developing ischemic microvascular injury, (C ) 1999 by Excerpta Medica, Inc.