Introduction Multiple recent randomized clinical trials have demonstrated the efficacy of endovascular thrombectomy in patients with acute stroke involving the proximal anterior circulation, and multiple clinical factors influence the outcome of patients undergoing thrombectomy. Obesity, despite its adverse health effects in the general population, has been associated with improved clinical outcomes in cardiovascular disease, including stroke--this phenomenon has been referred to the “obesity paradox”.1–3 To our knowledge, this “obesity paradox” has not been studied in patients undergoing endovascular stroke treatment. This study examines the role of body mass index (BMI) in outcomes of patients with strokes involving the anterior circulation who undergo mechanical thrombectomy.
Materials and Methods The CT perfusion database was queried for all patients evaluated for thrombectomy at our comprehensive stroke center from 2012–2015; 133 patients with large vessel occlusions of the anterior circulation who underwent thrombectomy with BMI available in the electronic medical record were identified. Patients were stratified into 5 BMI categories: underweight (UW; BMI<18.5kg/m2), normal weight (NW; BMI 18.5–24.99 kg/m2), overweight (OW; BMI 25–29.99 kg/m2), obese (Ob; BMI 30–39.99 kg/m2), and morbidly obese (MO; BMI≥40 kg/m2). Univariate analysis was performed assessing the relationship between various BMI categories and discharge NIHSS and change in NIHSS after treatment.
Results MO had the lowest discharge NIHSS of all BMI groups with mean discharge NIHSS of 2.1. Both UW and MO patients had statistically lower discharge NIHSS than the cohort of NW, OW, and Ob patients (p=0.032 for UW and p=0.0045 for MO, respectively). MO had greater improvement in NIHSS after treatment compared to NW, OW, and Ob patients (NIHSS change 15.0 vs 6.5, p=0.021). UW patients had greater improvement in NIHSS after treatment than NW, OW, and OB patients, but this was not statistically significant.
Conclusion Extremes of BMI were associated with better clinical outcomes with a “reverse U-shaped relationship” in patients with large vessel occlusions of the anterior circulation undergoing endovascular treatment, as the best clinical outcomes were observed in the UW and MO. This paradox differs from the previously described “obesity paradox,” in which OW and mildly Ob typically have better outcomes than the NW, UW, and MO.1,2 The cause of and implications for these findings in acute stroke treatment is unclear. While these results may be secondary to patient selection bias, additional potential mechanisms include possible associations between body composition and stroke etiology, clot composition, and collateral vessels. Further investigation into this possible new paradox and potential associations between BMI and other factors influencing endovascular treatment outcomes is warranted.
. Lavie, Carl J., Richard V. Milani, and Hector O. Ventura. ”Obesity and cardiovascular disease.”Journal of the American College of Cardiology 53.21 (2009): 1925–1932.
. Andersen, Klaus Kaae, and Tom Skyhøj Olsen. ”The obesity paradox in stroke: lower mortality and lower risk of readmission for recurrent stroke in obese stroke patients.”International Journal of Stroke 10.1 (2015): 99–104.
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Disclosures J. Lavie: None. G. Bennett: None. S. Arndt: None. A. Albar: None. K. Wojcik: None. J. Milburn: None. G. Vidal: None.
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