Thrombolytic activity of defibrotide against old venous thrombi

The age of the thrombus is probably a very important determinant of the outcome of thrombolysis. The clinical potential for rapidly dissolving thrombi by thrombolytic therapy is considerable because restoration of the blood flow can rescue the jeopardized district served by the occluded vessel such as for myocardial infarction, deep vein thrombosis, arterial thrombosis, pulmonary embolism, and occlusion of retinal vessels. Defibrotide was effective against 3-, 7-, or 10-day-old thrombi; its ED50s were 32, 65, or 118 mg/kg-1 hour-1, respectively, suggesting that the age of the thrombus could play a role in the outcome of thrombolysis. A similar pattern was also shown for urokinase.