Differences between proximal and distal M1 occlusions after mechanical thrombectomy

Abstract

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 retrospectively 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 occlusions (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 significance (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 occlusions, while dM1 occlusions were more strongly associated with cardioembolic occlusions, and rescue treatments were needed more often for pM1 occlusions than dM1 occlusions.

Keywords: Acute ischemic stroke; Lenticulostriate perforators; Mechanical thrombectomy; Middle cerebral artery.