Supplementary Material for: Severe Leukoaraiosis Is Associated with Poor Outcome after Successful Recanalization of M1 Middle Cerebral Artery Occlusion Strokes

Background: Severe leukoaraiosis (LA) is an established risk factor for poor outcome after mechanical thrombectomy (MT) for large vessel occlusion stroke. There is uncertainty whether this association also applies to successfully recanalized patients with M1 segment middle cerebral artery (MCA) occlusions. Methods: A retrospective single-centre study of patients with successful reperfusion (thrombolysis in cerebral infarction, TICI 2b or 3) after MT for an M1 MCA occlusion was performed over a 7-year period. LA score (LAS) was assessed using the age-related white matter change scale on pre-interventional brain imaging. Results: A total of 209 patients (median age 75.0 years) were included. LAS was assessed on pre-interventional imaging by computed tomography in 177 (84.7%) patients and magnetic resonance imaging in 32 (15.3%) patients. The median LAS was 1 (IQR 0–8), and severe LA consisted of the top 25 percentile, ranging from 9 to 24. Multivariable analysis demonstrated an association of severe LA (OR 0.32, 95% CI 0.12–0.88, p = 0.023), higher NIHSS on admission (OR 0.89, 95% CI 0.84–0.94, p < 0.001), advanced age (OR 0.97, 95% CI 0.95–1.00, p = 0.039), good leptomeningeal collaterals (OR 3.65, 95% CI 1.46–8.15, p = 0.001), and TICI 3 score (OR 3.26, 95% CI 10.52–7.01) with good clinical outcome after 3 months as measured with the modified Rankin scale. Conclusion: Severe LA is associated with poor clinical outcome at 3 months in acute stroke patients undergoing MT due to emergent M1 MCA occlusion.