The Antianginal Agent,Ranolazine,Reduces Myocardial Infarct Size but Does Not Alter Anatomic No-Reflow or Regional Myocardial Blood Flow in Ischemia/Reperfusion in the Rabbit

Abstract

It has been suggested that ranolazine protects the ischemic/reperfused heart by reducing diastolic wall pressure during ischemia. However, there is limited information regarding the effect of ranolazine on the anatomic zone of no-flow in a model of acute myocardial occlusion/reperfusion. Before coronary artery occlusion (CAO), open-chest anesthetized rabbits were assigned to vehicle or ranolazine. Hearts received 60 minutes of CAO and 3 hours reperfusion. Ischemic risk zone was comparable in the 2 groups. Ranolazine significantly reduced infarct size. There was a non-significant trend for the no-reflow defect to be smaller in the ranolazine group. Regional myocardial blood flow was similar in both groups in the risk zone during ischemia and at 3 hours reperfusion. Heart rates were similar in both groups, whereas mean arterial pressure was reduced in the ranolazine group. While ranolazine was effective in reducing myocardial infarct size, the mechanism by which it did this was independent of improving perfusion during either ischemia or reperfusion, suggesting that ranolazine's effect of reducing infarct size involves alternative mechanisms.