Evaluate current evidence on prognostic models in posterior circulation stroke (PCS) and highlight future directions integrating clinical, vascular, and imaging predictors.

PCS represents approximately 20% of ischemic strokes, but outcome prediction remains less established than in anterior circulation stroke. Although prognostic models such as ASTRAL, THRIVE, and iScore were developed in acute ischemic stroke, they are limited in reflecting PCS-specific factors.

PRISMA–based PubMed search for PCS prognostic models and collateral scores identified 66 studies. Six met inclusion criteria after excluding intravenous thrombolysis (IVT)-only or endovascular thrombectomy (EVT)-only, or non-scoring-system studies.

Clinical predictors in PCS have been less systematically studied beyond general factors such as age, baseline NIHSS, and vascular risk factors. NIHSS underestimates bulbar, ocular, and gait abnormalities, leading to underrecognized “minor” PCS with poor outcomes. Imaging-based predictors included Posterior Circulation–Alberta Stroke Program Early CT Score (PC-ASPECT), which quantified infarct burden but not collateral or thrombus status, predicting functional independence (OR 1.6, 95%CI 1.1–2.2). Vascular models such as Basilar Artery on Computed Tomography Angiography Score (BATMAN), and posterior circulation ASPECT–Collaterals score (PC-ASCO) addressed these limitations but were validated only in basilar artery occlusion. BATMAN <7 was associated with poor 3-month outcomes in both derivation (OR 5.5, 95%CI 1.4–21; AUC 0.81) and validation cohorts (OR 6.9, 95%CI 1.4–33; AUC 0.74). PC-ASCO predicted functional independence and malignant cerebellar edema (aORs 1.91/0.71, 95%CIs 1.25–2.92/0.53–0.95, p=0.003/0.02). Posterior circulation ischemic stroke outcome score (PCISOS), integrating clinical and imaging variables and stratified in CHANCE-2, identified “minor” NIHSS patients with poor outcomes, as high-risk patients showed high 90-day stroke recurrence (18.5% vs 6.0%; aHR 3.02, 95%CI 1.52–6.02, P<0.001).

Integrating clinical, imaging, and vascular factors can enhance risk stratification and guide individualized treatment such as IVT and EVT. Future efforts should emphasize outcome measures reflecting PCS-specific symptoms/signs and vessel territory-based differences.