Involvement of Subinsular Territory Stroke as Predictor of Outcome after Successful Endovascular Recanalization of Left Middle Cerebral Artery Occlusion

Subinsular stroke (subIS) can occur between the penetrating middle cerebral artery (MCA) branches, which clinical and radiological findings sometimes encounter in patients after the recanalization of left proximal MCA occlusion. However, no supportive data are available to clarify this relationship. This study investigated whether the involvement of subIS can impact outcomes after successful reperfusion therapy. Data from 152 consecutive patients who underwent endovascular thrombectomy between 2019 and 2023 were collected. A 3-month functional independence defined as a modified Rankin Scale 0-2 (primary outcome) and influencing factors were analyzed retrospectively. Recanalization was achieved in 35 patients, of whom 11 (31%) developed subIS. Patients with subIS were older in age (81 vs. 75; p < 0.05), had lower apparent diffusion coefficient (ADC) values on admission (0.52 vs. 0.62; p < 0.001), and higher modified Rankin Scale (mRS) scores (4 vs. 2; p < 0.001) than those without subIS. In a multivariate analysis, subIS was independently associated with a worse functional outcome (odds ratio: 10.5, p = 0.02). The cut-off value of the ADCs was 0.52 with a sensitivity and specificity of 70% and 64%, respectively. Subinsular ischemic lesions contribute to poor functional independence in patients after the successful recanalization of left MCA occlusion. The attenuation of the ADC value in these territories could be a valuable predictor of the outcome.