Angiographic collateral status predicts functional outcome and early neurological deterioration in large-vessel occlusion stroke treated with endovascular therapy.

Background: Despite successful recanalization with endovascular treatment (EVT) for acute ischemic stroke (AIS), many patients experience poor outcomes. While collateral circulation is a known prognostic factor, its dynamic assessment via digital subtraction angiography (DSA) and its relationship to outcomes post-EVT require further investigation. Methods: This single-center retrospective study analyzed 185 consecutive AIS patients with large vessel occlusion treated with EVT. Collateral status was graded on pre-treatment DSA using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale and categorized as poor, fair, or good. The primary outcome was functional independence (modified Rankin Scale [mRS] score 0-2) at 90 days. Secondary outcomes included early neurological deterioration (END) within 7 days and 90-day mortality. Results: Patients with good collaterals had significantly higher rates of functional independence (66.1%) compared to those with fair (45.9%) and poor collaterals (13.2%). Conversely, the incidences of END (1.8% vs. 8.2% vs. 23.5%) and 90-day mortality (1.8% vs. 11.5% vs. 27.9%) were progressively higher in the good, fair, and poor collateral groups, respectively. Multivariable logistic regression confirmed that a higher collateral score was an independent predictor of good functional outcome and was independently associated with a lower risk of END and mortality. Conclusion: DSA-assessed collateral status is a strong independent predictor of 90-day functional outcome, END, and mortality in AIS patients following EVT. Robust pretreatment collaterals are associated with markedly improved recovery and survival, highlighting the critical prognostic value of collateral assessment in guiding treatment and patient management.