Subarachnoid hemorrhage model in the rat: modification of the endovascular filament model

The present study describes modifications to the endovascular filament model of subarachnoid hemorrhage (SAH) in rats. Specifically, we sought to improve the percentage yield of SAH, reduce mortality rates and better simulate human cerebral aneurysmal rupture. Instead of using a 4-0 prolene suture to induce SAH in the existing endovascular filament model, a hollow and flexible polyetrafluoroethylene (PTFE) tube was maneuvered into the proximal anterior cerebral artery (ACA) to ensure that advancement occurred without producing trauma to the vessels. SAH was induced by advancing a tungsten wire through this tube, perforating the ACA at the desired location. These modifications produced significant improvements over the endovascular filament model. Mortality rate declined from 46 to 19%, and SAH was produced more frequently. With the prolene suture, only 48% of our attempts produced a SAH, and unsuccessful attempts typically resulted in an acute subdural hematoma (ASDH). In contrast, the wire/tubing technique was 90% successful at inducing SAH, and led to a significant reduction of ASDH incidence from 44 to 6%. Additionally, the modified technique produced vasospasm in basilar and middle cerebral arteries post-SAH as well as pseudoaneurysms in the proximal ACA which indicated the location of vessel perforation.