Abstract TP151: Stroke Mechanisms and Their Correlation With Prognosis in Medullary Infarction

Abstract

Introduction: Prognosis in patients with medullary infarction (MI) has not sufficiently discussed, especially in terms of stroke mechanisms. Objective: To explore how underlying vascular lesions contribute to the prognosis of MI. Methods: We collected 81 consecutive patients with acute isolated MI including 50 patients with lateral MI (LMI), 30 with medial MI (MMI) and one with both LMI and MMI. The presumed stroke mechanisms were defined as follows: 1. Large artery occlusive disease (LAOD): infarcts with severe atherosclerotic stenosis or occlusion on the relevant arteries. 2. Penetrating branch disease (PBD): infarcts with normal to mild stenosis of the vertebral artery on the relevant side. 3. Dissection: infarcts with angiographic findings of the relevant arteries consistent with dissection. 4. Cardiogenic embolism: infarcts with abrupt onset with atrial fibrillation. We set the significant disability (SD) as a condition that includes the mRS ≥2 and/or dysphagia. Poor outcome was defined as SD at one year after onset. Results: There were 20 patients with PBD (40%), 18 with dissection (36.0%) and 11 with LAOD (22.0%) in LMI and 17 with PBD (56.6%), 10 with LAOD (33.3%) and 2 with dissection (6.6%) in MMI. The incidence of SD at discharge in LMI and MMI were not different between 3 stroke mechanisms. However, stroke mechanisms of LAOD and dissection compared with PBD were independently correlated with poor prognosis at one year after onset: (OR: 13.0, p=0.034 and OR: 10.7, p=0.029, respectively) after adjustment of lesion location in LMI. In MMI, LAOD compared with PBD significantly correlated with SD (OR: 13.4, p=0.014). Functional disability still improved after discharge especially in patients with PBD. Intensive treatment of combined use of antithrombotic agents in acute stage seemed to be effective. Conclusions: PBD was the most predominant stroke mechanism in MI and its prognosis was good despite the certain disability at discharge. Patients with LAOD or dissection may be predisposed to chronic hypo-perfusion over a long period of time. Underlying vascular lesions better predict outcome of MI than infarct extension or location in patients with MI.