Etiological Patterns, Clinical Spectrum, and Prognostic Outcomes in Ischemic Posterior Circulation Stroke

Abstract

Background: Posterior circulation stroke (PCS) constitutes a substantial proportion of ischemic strokes in India and frequently presents with heterogeneous symptoms that may delay diagnosis. Detailed evaluation of its clinical characteristics and etiological mechanisms is essential for improving prognostication and patient outcomes. Aims & objectives: To evaluate the clinical profile, etiological spectrum, and 90-day functional outcomes of patients with ischemic PCS, and to identify predictors of poor prognosis. Materials and Methods: A prospective observational study was conducted at a tertiary care centre in South India from January 2024 to October 2025. Consecutive adult patients with MRI-confirmed ischemic PCS (n = 150) were included. Demographic variables, vascular risk factors, mode of presentation, stroke severity (NIHSS), vascular territory involvement, and TOAST etiological classification were recorded. All patients underwent vascular imaging and cardiac evaluation. Functional outcome was assessed at discharge and at 90 days using the modified Rankin Scale (mRS). Good outcome was defined as mRS ≤2. Predictors of poor outcome (mRS >2) were analyzed using multivariate logistic regression. Results: Of 150 patients (mean age 60.8 ± 13.2 years; 62% male), the most frequent presenting symptoms were vertigo (60%), gait ataxia (45%), dysarthria (40%), and visual disturbances (35%). Large-artery atherosclerosis was the predominant etiology (40%), followed by cardioembolism (25%) and small-vessel disease (15%). Basilar artery involvement was noted in 30% of cases. At 90 days, 65.3% of patients achieved good functional outcome. Independent predictors of poor outcome included age ≥65 years (OR 2.4; p = 0.012), NIHSS >8 at admission (OR 3.6; p < 0.001), cardioembolic etiology (OR 2.2; p = 0.045), and basilar artery involvement (OR 2.7; p = 0.006). Conclusion: Ischemic PCS demonstrates diverse clinical presentations, with large-artery atherosclerosis being the leading etiology in this South Indian cohort. Age, initial stroke severity, cardioembolic mechanism, and basilar artery involvement significantly influence short-term prognosis. Early recognition and targeted etiological evaluation are crucial for optimizing outcomes.