Myocardial cytoprotective efficacy of azapropazone in a canine heart model of regional ischemia and reperfusion.

The present study assessed the efficacy of azapropazone (AZA) in pentobarbital-anesthetized dogs subjected to 120 min of regional ischemia [left anterior descending coronary artery (LAD) ligation] followed by 5 h of reperfusion. Azapropazone was given 30 min prior to LAD occlusion (100 mg/kg i.v.), 35 min prior to LAD release (50 mg/kg, i.v.), and at 2.5 h postreperfusion (50 mg/kg i.v.). Regional myocardial blood flow (RMBF) and area at risk (AAR) were determined with radiolabeled microspheres. The degree and extent of ischemia (anaerobic metabolism) and necrosis were delineated with 14C-deoxy-2-D-glucose (14C-DG) and 111In-antimyosin, respectively, in control (n = 7) and AZA (n = 7)-treated groups. In mild (60-80% normal RMBF) and moderate (30-60% normal RMBF) flow-restricted areas, AZA resulted in a significant decrease in the degree and extent of ischemia (p less than 0.01) with the limitation of infarct size (p less than 0.01). However, AZA did not produce a significant infarct size limitation in the severe flow-restricted area (0-30% of normal RMBF). The effect of AZA is expressed primarily in moderate flow-restricted myocardium with the subsequent infarct size limitation.