An endovascular model of carotid stenosis for the evaluation of thrombolysis and angioplasty

Purpose: To develop a porcine carotid artery thrombosis model using a novel stent-graft device to evaluate the efficacy of thrombolytic therapy and an gioplasty procedures. Methods: An endovascular device made from a tapered polytetrafluoroethylene graft inverted in a self-expanding nitinol stent was delivered to bilatera l carotid arteries via a right femoral approach in 16 pigs. Carotid thrombo tic occlusion ensued from flow stasis created by the intrastent stenosis. V ia selective carotid catheterization from a femoral approach, urokinase (25 0,000 IU) was pulse-sprayed in one carotid artery while a control saline so lution was infused in the contralateral vessel; delivery times were 1 hour, 8 hours, 3 days, or 6 days after carotid occlusion (4 animals per time per iod). After thrombolysis, balloon angioplasty was performed to maintain car otid patency. Arteriography and intravascular ultrasound were used to evalu ate the efficacy of thrombolysis. Light microscopy was used for histologica l analysis of the thrombus. Results: Carotid artery occlusion occurred in 15 +/- 8 minutes after stent- graft placement in all animals. Urokinase was effective in recanalizing all occluded arteries in the 1-hour, 4-hour, and 3-day groups (100%) but was e ffective in only 2 of 4 animals in the 6-day group (p < 0.05). Overall thro mbolytic efficacy was 78% +/- 7%. Control saline solution showed no thrombo lytic effect (p < 0.001). Angioplasty successfully restored normal luminal diameter in all fully lysed arteries (100%). Histological analysis showed f ibrin-predominant thrombus with a varying degree of platelet deposition. Conclusions: This endovascular approach, which creates a carotid stenosis u sing this novel stent-graft device, is reliable in producing carotid thromb osis. In our model, thrombolytic therapy was effective in restoring luminal patency, and the intraluminal stenosis is amenable to balloon angioplasty. The model is useful for the evaluation of antithrombotic therapy and adjun ctive endovascular interventions.