Digital angiographic quantification of blood flow dynamics in embolic stroke treated with tissue-type plasminogen activator

Abstract

Computer analysis of digital subtraction angiography (DSA) was utilized to quantify the effectiveness of tissue-type plasminogen activator (TPA) in a rabbit cerebroembolic stroke model. Fourteen animals underwent cannulation of the facial artery and a preembolus angiogram. Autologous blood clots were then injected, and occlusion of the internal carotid artery at the circle of Willis was documented with repeat angiogram. The experimental group received a 1-mg/kg intravenous infusion of TPA via a femoral catheter for 90 minutes. A control group received an equivalent volume of saline. Follow-up angiograms were performed every 15 minutes. The TPA-treated animals showed progressive improvement in flow through previously occluded vessels. Time-density curves of the contrast material over the middle cerebral artery trunk and brain parenchyma were generated. The best integrated curves for the two groups were compared at 30 minutes after occlusion and 90 minutes after treatment. Animals were then observed for 24 hours and their neurological status was documented. Premortem infusion of either Evans blue dye or neutral red dye was performed and the integrity of the blood-brain barrier and tissue perfusion were assessed by video planometry. Significant improvements were noted by DSA, and Evans blue and neutral red dye studies in animals treated with TPA.