IT 11 laboratory andanimal investigations Effects of Hydralazine and Increased Cardiac Output on Recombinant Tissue Plasminogen Activator- Induced Thrombolysis in Canine Pulmonary Embolism*

We employed a canine model of pulmonary embolism, induced by injection ofautologous radiolabelled blood clots, to investigate effects of hydralazine and an increase in cardiac output per se on recombinant tissue plasminogen activator-induced thrombolysis. Emboli increased pulmonary artery pressure (PAP) and decreased CO from 2.7 to 1.8 L/min . Following embolization, dogs were randomly divided into three groups. Group 1 received .5 mg/kg of I-IPA over 30 minutes. Group 2 received the same dose of rtPA and were pretreated with hydralazine to increase CO approximately 50 percent. In the group 3 dogs, CO was increased by opening a systemic A-V fistula. Following embolization, CO remained low in group 1, the mean 2 h time-averaged CO was 1 .9 L/min ‘ . The CO was 2.9 and