BackgroundIt has been amply demonstrated that endovascular procedures can be successful treatment for stroke, both in terms of revascularization and clinical outcome. There is not, however, a published comparison of any histological or ultrastructural damage to the vessels that may be caused by a direct aspiration first pass technique (ADAPT) or stent retrievers (SR) used in these procedures. This study analyses and compares acute damage to the arterial wall caused by ADAPT or SR.Material and methodsDamage to the walls of swine extracranial arteries was evaluated after ADAPT with the Penumbra system or thrombectomy with an SR (Solitaire 6×30). The procedures were performed after injecting thrombi into the selected arteries (arteries with diameters similar to those of the human internal carotid artery and first segment of the middle cerebral artery). After the procedures, the animal was euthanized and 12 arterial samples were obtained for analysis by optical and electronic microscopy.ResultsTissue samples from the vessels treated with SR showed almost complete loss of endothelium, thickening of the internal elastic lamina, and degeneration of the elastic fibers of the bordering lamina media and adventitia. In contrast, tissue samples of the vessels treated with ADAPT had a clear integral internal elastic lamina and uninterrupted endothelial lining, although cell alignment was altered and there were surface lacerations due to manipulation of the samples.ConclusionsBoth techniques caused acute damage to the vessel walls, however, thrombectomy with SR appeared to be more harmful to all layers of the arterial wall, particularly the endothelium.