A Novel Canine Model of Acute Vertebral Artery Occlusion

The extended time window and theoretic reduction in hemorrhage make mechanical strategies an attractive approach for the treatment of patients with ischemic stroke. However, a limited availability of suitable animal models of cerebrovascular thrombosis has hampered the study of novel endovascular interventions. The aim of the present study was to develop a new technique for site-specific placement of a thrombus in a canine model that would allow for the evaluation of mechanical thrombectomy and clot retrieval methods and the visualization of thrombus dislocation or fragmentation during angiographic manipulation.

Angiography and embolization with a preformed thrombus were performed in 12 canines. Under fluoroscopic guidance, an embolism protection device (EPD) was anchored to the middle segment of the left vertebral artery (VA) via the left femoral arterial sheath. A preformed radiopaque clot was injected through the guide catheter into the left VA, via the contralateral femoral artery, proximal to the EPD. After 15 min of occlusion, the EPD was removed and persistent occlusion of the VA was documented angiographically.

Angiography performed during the observation period confirmed the persistence of VA occlusion in each case, and displacement of the radiopaque clots did not occur during the 3-hour observation period. The technique allowed selective embolization of targeted vessels without thrombus fragmentation.

This study demonstrates, for the first time, a canine model of post-circulation embolism induced by autologous blood clot placement. This model can be rapidly formed and easily operated, and the site of thrombosis can be readily controlled.