Thrombolytic Treatment with Brinase® of Dogs with Experimental Pulmonary Embolism

Abstract

Thrombolysis by means of Aspergillus oryzae protease was studied in mongrel dogs of both sexes with experimentally induced pulmonary emboli. Thirty-five animals were used. A new experimental model was employed. Pulmonary embolisms were produced by injection of auto-logous blood clots through a wide catheter in the inferior vena cava. Brinase® (Astra, Södertälje, Sweden), a pro-teolytic enzyme from Aspergillus oryzae, was administered during periods of 2–4 hours into a pulmonary artery to one group of dogs, and intravenously to another. The extent of embolization and the effect of the treatment were evaluated by pulmonary angiography. Rapid lysis was detected in all dogs which received 3 mg Brinase per kg b.w. or more. The enzyme attacks both fibrin, fibrinogen and coagulation factors. The rapidly performed Normo-test assay measuring factors II VII X (Nyegaard & Co., Oslo, Norway) was used as guideline to prevent irreversible toxic dosage to the dogs. The administration of Brinase was stopped, when Normotest values dropped to 50% of pre-infusion values, lysis of emboli was observed and the dogs survived.