Intracoronary streptokinase: effects on reperfusion hemorrhage and regional myocardial blood flow in the anesthetized dog.

The effects of intracoronary streptokinase on reperfusion-induced myocardial hemorrhage and regional myocardial blood flow were examined. Anesthetized dogs were reperfused for 2 h following 4 h of circumflex coronary occlusion. Fourteen animals received 250,000 IU intracoronary streptokinase during the reperfusion period and 13 received an equivalent volume of normal saline. Radioactive microspheres were injected 15 min before, 10 min after, and 2 h after reperfusion. Hemorrhage was quantitated by a scoring system and by measuring the hemoglobin content of the infarcted posterior papillary muscle as well as the total infarct. Infarct size was quantitated using nitroblue tetrazolium to demarcate the necrotic myocardium. Postmortem examination revealed that gross myocardial hemorrhage occurred within the borders of the infarct in both groups. The hemoglobin was 6.9 mg/g in normal myocardium. There was no statistical difference between the saline- and streptokinase-treated animals as regards posterior papillary muscle hemoglobin (12.8 vs. 15.8 mg/g) or total infarct hemoglobin (10.5 vs. 11.2 mg/g). Hemorrhagic scores in the two groups were also not statistically different. Reperfusion flows measured 10 min after reperfusion averaged 0.69 ml/min/g for the saline-treated animals and 0.55 ml/min/g for the streptokinase-treated animals (p greater than 0.05). Reperfusion flows measured 2 h after reperfusion were also not statistically different (0.49 vs. 0.44 ml/min/g). In this experimental preparation, streptokinase does not augment reperfusion hemorrhage or adversely affect reflow measured in the early hours following reperfusion.