α-Adrenergic Blockade Improves Recovery of Myocardial Perfusion and Function After Coronary Stenting in Patients With Acute Myocardial Infarction

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Abstract
Background —AMI reperfusion by thrombolysis does not improve TIMI flow and LV function. The role of infarct-related artery (IRA) stenosis and superimposed changes in coronary vasomotor tone in maintaining LV dysfunction must be elucidated. Methods and Results —Forty patients underwent diagnostic angiography 24 hours after thrombolysis. Seventy-two hours after thrombolysis, the culprit lesion was dilated with coronary stenting. During angioplasty, LV function was monitored by transesophageal echocardiography. Percent regional systolic thickening was quantitatively assessed before PTCA, soon after stenting, 15 minutes after stenting, and after phentolamine 12 μg/kg IC (n=10), the α 1 -blocker urapidil 600 μg/kg IV (n=10), or saline (n=10). Ten patients pretreated with β-blockers received urapidil 10 mg IC. Coronary stenting significantly improved thickening in IRA-dependent and in non–IRA-dependent myocardium (from 27±15% to 38±16% and from 40±15% to 45±15%, respectively). Simultaneously, TIMI frame count decreased from 39±11 and 40±11 in the IRA and non-IRA, respectively, to 23±10 and 25±7 ( P P Conclusions —Our finding that α-adrenergic blockade attenuates vasoconstriction and postischemic LV dysfunction supports the hypothesis of an important role of neural mechanisms in this phenomenon.