Differences Between Proximal and Distal M1 Occlusions after Mechanical Thrombectomy.

Purpose: Whether M1 occlusions proximal (pM1) and distal (dM1) to the lenticulostriate perforators result in different clinical outcomes after mechanical thrombectomy (MT) is unknown. We retrospec-tively compared the clinical outcomes and baseline characteristics of patients with these two types of occlusions. Methods: From March 2010 to May 2019, we performed MT for 141 M1 occlusions, including pM1 occlu-sions (n = 58) and dM1 occlusions (n = 83). Results: Good clinical outcomes (modified Rankin Scale score 0 to 2) were achieved in 28 out of 58 (48.3%) patients with pM1 occlusions and 46 out of 83 (55.4%) patients with dM1 occlusions without sig-nificance (p = 0.493). Cardioembolic occlusions represented 19 out of 58 (32.6%) pM1 occlusions and 53 out of 83 (63.9%) dM1 occlusions, and atherosclerotic occlusions represented 37 out of 58 (63.8%) pM1 occlusions and 27 out of 83 (32.5%) dM1 occlusions, with significance (p = 0.001). Rescue treatments, such as balloon angioplasty or stenting, were needed more for pM1 occlusions than dM1 occlusions (21 out of 58 (36.2%) vs. 8 out of 83 (9.8%), p < 0.001). The multivariable logistic regression analysis demonstrated that the need for rescue treatment was associated with pM1 occlusions (adjusted odds ratio; 3.804, 95% confidence interval; 1.306-11.082, p = 0.014). Conclusions: In our series, pM1 and dM1 occlusions did not significantly differ in good clinical outcomes. Our study also showed that pM1 occlusions were more strongly associated with atherosclerotic occlu-sions, while dM1 occlusions were more strongly associated with cardioembolic occlusions, and rescue treatments were needed more often for pM1 occlusions than dM1 occlusions. (c) 2021 Elsevier Ltd. All rights reserved.