Predictors of poor outcome in acute stroke patients with posterior cerebral artery occlusion and medical management

BACKGROUND AND AIMS: The clinical evolution of acute ischemic stroke patients with isolated proximal posterior cerebral artery (PCA) occlusion treated with medical management alone has been poorly described. We aimed to determine the clinical and radiological factors associated with poor functional outcome in this population. METHODS: We conducted a multicenter international retrospective study of consecutive stroke patients with isolated occlusion of the first (P1) or second (P2) segment of PCA admitted within 6hrs from symptoms onset in 26 stroke centers in France, Switzerland and the USA, treated with best medical management alone. Poor functional outcome was defined as a modified Rankin scale (mRS) ≥2 at 3-month or no return to pre-stroke mRS. The associations between pretreatment variables and poor outcome were studied in univariable then multivariable analyses, as well as the association between poor outcome and key follow-up radiological variables. RESULTS: Overall, 585 patients were included. Median age was 74 years (IQR, 63-83), median NIHSS was 6 (3-10), 80% received intravenous thrombolysis (IVT), 22% and 78% had P1 and P2 occlusion, respectively. Poor outcome occurred in 56% of patients. In multivariable analysis focusing on pretreatment variables, age (adjusted OR=1.12 per 5-year increase [95%CI 1.05-1.20]; P=0.001), NIHSS score (aOR=1.12 per each point increase [1.08-1.18]; P<0.001), infarct volume (aOR=1.16 per 5mL increase [1.07-1.25]; P<0.001), and the lack of IVT use (aOR=1.79 [1.10-2.94], P=0.020) were independently associated with poor outcome. Regarding 24-hr follow-up radiological variables, complete recanalization (defined as no clot in the vascular tree at or beyond the primary occlusive lesion, aOR=0.37 95%CI 0.21-0.65, P<0.001) and parenchymal hematoma occurence (aOR=2.37 95%CI 1.01-5.56, P=0.048) were independently associated with poor 3-month outcome. CONCLUSIONS: Poor outcome occurred in more than half of medically treated PCA-related acute stroke patients. Facilitating IVT use may improve functional outcome. Therapeutic approaches aimed at enhancing recanalization and reducing hemorrhagic transformation need to be studied in clinical trials.