BENEFICIAL EFFECT OF INTRACORONARY VERAPAMIL ON MICROVASCULAR AND MYOCARDIAL SALVAGE IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Objectives. We assessed the acute effect of intracoronary injection of verapamil on microvascular function after primary percutaneous transl umanal coronary angioplasty (PTCA) for acute myocardial infarction (AM I) with myocardial contrast echocardiography (MCE) in relation to func tional outcomes. Background. Recent clinical studies have documented t he potential of verapamil for possible increase in coronary blood flow after primary PTCA. Methods. Forty patients with a first AMI were ran domly assigned to the verapamil group (n = 20) or the control group (n = 20). In the verapamil group, verapamil (0.5 mg) was injected into t he infarct-related artery shortly after PTCA, followed by the oral adm inistration. We performed MCE with an intracoronary injection of sonic ated microbubbles before and after verapamil. To assess microvascular integrity, we determined the baseline subtracted peak intensity in the risk area and the ratio of the no reflow zone plus the low reflow zon e to the risk area (low reflow ratio). We determined the average wall motion score (dyskinesia/ akinesia = 3; normal = 0) in the risk area o n the day of AMI and a mean of 24 days later. Results. The low reflow zone was observed shortly after PTCA in 14 verapamil group patients, a nd the low reflow ratio decreased after verapamil (0.39 +/- 0.23 vs. 0 .29 +/- 0.17 [mean +/- SD], p < 0.05). Peak intensity significantly (p < 0.05) increased from 6 +/- 5 to 12 +/- 6 after verapamil. The reduc tion in wall motion score from the acute (day -1) to the late stage (d ay -24) was significantly greater in the verapamil group than in the c ontrol group (0.7 +/- 0.8 vs. 0.2 +/- 1.3, respectively, p < 0.05). Co nclusions. Intracoronary administration of verapamil after primary PTC A can attenuate microvascular dysfunction and thereby augment myocardi al blood flow in patients with AMI, leading to better functional outco me than with PTCA alone. (C) 1997 by the American College of Cardiolog y.