Outcome of patients with dissecting versus atherosclerotic tandem occlusion acute ischemic stroke

Background: The different pathophysiological mechanisms leading to tandem occlusion (TO), namely arterial dissection or atherosclerosis, may have an impact on the outcome of patients with acute ischemic stroke (AIS) undergoing endovascular thrombectomy (EVT). Methods: Consecutive AIS patients with occlusion of the cervical internal carotid artery and concomitant intracranial large vessel occlusion who received EVT between 2011 and 2023 as part of the Italian Registry of Endovascular Treatment in Acute Stroke (IRETAS) were deemed eligible. We compared clinical and radiological outcomes of patients with dissecting TO versus atherosclerotic TO by the propensity score matching approach. Results: Overall, 2148 patients (mean age 69.3±12.8 years; males 64.5%) qualified for the analysis. Of these, 236 (10.9%) had dissecting TO, and 1912 (89.1%) atherosclerotic TO. As expected, patients with dissecting TO stroke were younger and had a lower burden of major cardiovascular risk factors. In the matched cohort, we observed no difference between the two groups in either 90-day functional independence (OR 1.33; 95% CI 0.94 to 1.83; p=0.115) or in any of the secondary endpoints, except for a reduced risk of parenchymal hematoma type 2 (OR 0.37; 95% CI 0.14 to 0.98; p=0.046) in the group of patients with dissecting TO stroke, which, however, did not affect patient outcome. Conclusions: The outcome of patients undergoing EVT because of dissecting TO stroke does not differ from that of patients with atherosclerotic TO stroke. The etiology of the underlying vascular lesion should not be regarded as a contraindication to EVT procedures in these cases.