Experimental pulmonary embolism: effects of urokinase therapy on organizing thrombi.

Abstract

Abstract An experimented model was established which permitted embolization of multiple thrombi of varying age and degree of organization into the pulmonary circulation of a dog. The emboli were characterized as to size, shape, and histology prior to embolization and on recovery following an observation period. Serial angiography after insertion of each embolus and during the period of observation permitted its localization and assessment of changes occurring in it. The animals served as controls or were treated with therapeutic doses of urokinase. Results indicate that: (1) One and 2 week old partially organized thrombi underwent spontaneous lysis of 20 to 25 per cent within 24 hours after embolization to the pulmonary circulation; (2) thrombolytic therapy for short periods greatly accelerated the rate of lysis of aged thrombi; and (3) angiographic results often failed to provide quantitative estimation of these and led to both false positive and negative results.