Influence of hyaluronidase on infarct size following experimental coronary occlusion of short (90') or long (24 hrs) duration.

Abstract

The effect of hyaluronidase (HY) on myocardial infarct size after experimental coronary artery occlusion was studied in two groups of dogs. Group I received HY as a bolus of 500 IU/kg BW prior to occlusion of a medium-sized marginal or diagonal vessel during 90 minutes. Another 500 IU/kg of HY was infused at constant rate during coronary occlusion. Another artery of the same heart was occluded under comparable conditions without therapy. This artery was reperfused before the first dose of HY. In group II the LAD was occluded in a closed chest preparation after intracoronary injection of 500 IU/kg BW of HY. During the ensuing 24 hours occlusion period the dose of 200 IU/kg HY was repeated seven times in regularly spaced intervals. Neither collateral nor normal flow was altered in both groups by HY and hemodynamic conditions remained constant. Nevertheless in group I therapy led to a reduction of infarct size from 29% (control) to 14% necrosis of the perfusion area after HY, whereas after 24 hours of continuing therapy the size of the infarcted area did not differ from control. Thus HY was able to significantly postpone the transition of ischemia to necrosis but was unable to prevent it. Infarct size following 24 hours of occlusion was not different from a control group.