Effect of Body Mass Index on Outcomes of Mechanical Thrombectomy in Acute Ischemic Stroke

Background: Obesity is an established risk factor for the development of acute ischemic stroke. However, its effect on clinical outcomes after acute ischemic stroke has remained controversial. In the present study, we evaluated the association of body mass index (BMI) on outcomes after mechanical thrombectomy (MT) for large vessel occlusion acute ischemic stroke (LVOS). Methods: We reviewed our prospective endovascular database for patients who had undergone MT for LVOS from 2015 to 2018. The BMI was analyzed as a continuous and categorical variable, with the latter defined as BMI, <18.5 kg/m² (underweight); BMI, 18.5–24.9 kg/m² (normal); BMI, 25–29.9 kg/m² (overweight), and BMI, >30 kg/m² (obese). Multivariate analysis was used to determine the outcome predictors. Results: A total of 335 patients had undergone MT, with 7 (2.1%) classified as underweight, 107 (31.9%) normal, 141 (42.1%) overweight, and 80 (23.9%) obese. The procedural times, techniques, and reperfusion success (treatment in cerebral infarction score >2b) were not significantly different among the BMI categories. A significant inverse linear correlation was found between the BMI and symptomatic hemorrhagic. For patients with successful reperfusion (treatment in cerebral infarction score >2b), we also found a significant bell-shaped relationship between the BMI and functional independence (modified Rankin scale score <3), with high and low BMIs associated with worse outcomes. For patients without post-MT symptomatic hemorrhage, a significant linear correlation was found between BMI and inpatient mortality. Conclusion: For LVOS patients treated with MT, a high BMI will not affect procedural success. However, it was independently associated with lower rates of functional independence in recanalized patients. Thus, the obesity paradox does not appear to pertain to MT, although larger prospective studies are necessary.