Incidence of cerebral hemorrhage after antifibrinolytic treatment for embolic stroke in rabbits

We studied thrombolysis in an animal model of embolic stroke to determine the safety of tissue plasminogen activator and streptokinase. We occluded the middle cerebral arteries of 137 rabbits with radiolabeled blood clots and administered tissue plasminogen activator (n=49), streptokinase (n=40), or saline (n=48) at various times after embolization. We assessed the rate of thrombolysis and cerebral hemorrhage 24 hours later. Both drugs were very effective in producing thrombolysis. Compared with saline, streptokinase caused a significant increase in the rate of cerebral hemorrhage (p<0.05), but tissue plasminogen activator did not. We conclude that thrombolytic therapy for acute stroke should be safer with tissue plasminogen activator than with streptokinase.