Work

Collateral status predicts functional outcome in early-treated large-core anterior circulation stroke

Year: 2026

Type: article

Abstract: Background and purpose Endovascular therapy (EVT) is increasingly offered to patients with large-core acute ischemic stroke (AIS), yet outcomes remain highly heterogeneous. Collateral circulation may be a key determinant of infarct evolution and recovery, but its role in early-window large-core stroke is not fully defined. Methods We retrospectively analyzed consecutive adults from a prospective stroke registry who presented within 6 h with anterior-circulation large-vessel occlusion, NIHSS ≥6, and a large ischemic core (MRI core >50 mL or CT perfusion core >70 mL, up to 150 mL). All patients received reperfusion therapy (intravenous thrombolysis, EVT, or both). Collateral status on baseline single-phase CTA was graded using the Tan scale (0–3); no patients had grade 3. The primary outcome was 90-day modified Rankin Scale (mRS); secondary outcome was NIHSS at discharge. Results Fifty-four patients met inclusion criteria (Tan 0: n = 24; Tan 1: n = 14; Tan 2: n = 16). Baseline NIHSS, ASPECTS, and core volume were similar across groups. Patients without collaterals (Tan 0) had worse 90-day outcomes (median mRS 4 [IQR 3–6]) compared with those with Tan 1 (2 [IQR 1–3]) or Tan 2 (1 [IQR 1–2]) collaterals (both p < 0.001), whereas Tan 1 and Tan 2 did not differ significantly ( p = 0.27). NIHSS at discharge showed a similar gradient. In proportional-odds logistic regression, each one-grade increase in collateral status was associated with lower odds of worse 90-day mRS (adjusted per-grade OR 0.32; 95% CI 0.15–0.68; p = 0.003). Conclusion In early-treated large-core AIS, even simple CTA-based collateral assessment strongly predicts recovery. Patients with absent collaterals follow a distinctly poorer trajectory, while those with any collateral filling behave more favorably. Incorporating collateral status into routine evaluation may improve prognostic accuracy and support treatment decisions in this challenging subgroup.

Source: Frontiers in Stroke

DOI: 10.3389/fstro.2026.1755828

Authors: Andrés Gallardo, Pablo M. Lavados, Pablo Albiña-Palmarola, Gabriel Cavada, Andrés Roldán, Verónica V. Olavarría