Factors affecting the angiographic recanalization and early clinical improvement in middle cerebral artery territory infarction after thrombolysis

Background: Factors affecting the angiographic recanalization (AR) and clinical improvement (CI) still remain unclear in patients receiving thrombolytic therapy. Objectives: To elucidate factors related to AR and early Cl in patients with middle cerebral artery (MCA) or internal carotid artery (ICA) occlusion. Designs: Retrospective study. Setting: Department of Neurology, Asan Medical Center, Seoul, South Korea. Patients: We studied 42 patients who (1) underwent diffusion-weighted magnetic resonance (MR) imaging and MR angiography within 6 hours after onset, (2) had MCA territory infarction, (3) had nonvisualization of the MCA or the ICA on initial MR angiography, (4) were treated with thrombolytics, and (5) underwent follow-up MR imaging and MR angiography at day 2 or 3. Results: Successful AR and CI were achieved in 31 and 16 patients, respectively. Angiographic recanalization was related to CI (P<.01), lower follow-up National Institutes of Health Stroke Scale scores (P<.05), the absence of a dominant ipsilateral posterior cerebral artery (P<.01) on initial MR angiography, and the sparing of the internal capsule on both initial (P<.05) and follow-up (P<.01) MR imaging. Clinical improvement was associated with the absence of ICA (vs MCA) flow signals'(P<.05), the sparing of the internal capsule (P<.01), and marginally, with the infarct volume change (P=.06). Conclusions: In patients with MCA or ICA occlusion, CI after thrombolysis is related to the AR and the sparing of the critical motor pathway. The presence of a dominant ipsilateral posterior cerebral artery may predict poor AR after thrombolysis.