Association between collateral status and clinical outcomes in patients with acute basilar artery occlusion following endovascular therapy

Background: The correlation between the digital subtraction angiography (DSA)-based collateral status grading system and clinical outcomes in acute basilar artery occlusion (ABAO) patients has not been systematically evaluated. This study aims to assess the role of DSA-based collateral status in relation to 90-day functional outcomes, safety outcomes, and long-term outcomes among patients with ABAO undergoing endovascular therapy (EVT). Materials and methods: We used data of ABAO patients from the BASILAR (Assessment of Endovascular treatment for Acute Basilar Artery Occlusion via a nationwide Prospective Registry) Registry. Collateral status was assessed using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) criteria. Outcomes included 90-day functional outcomes, safety outcomes and long-term outcomes. Results: Among 647 patients who received EVT, 12.7% (82 of 647) achieved good collateral. Compared to patients with poor collateral, good collateral was associated with higher odds of 90-day and 1-year favorable functional outcome (adjusted OR: 3.167 and 3.478, 95% CI: 1.743-5.753 and 1.798-6.731, P < 0.001) and reduced rate of mortality within 90-day and 1-year (adjusted OR: 0.218 and 0.291, 95% CI: 0.099-0.482 and 0.145-0.585, P < 0.001). Collateral status was not associated with hemorrhagic complications. The SHAP value of collateral status for predicting 90-day favorable outcomes ranked third and rose to first for 1-year favorable outcomes. There was no interaction between collateral status and any factors association with favorable functional outcome. Conclusion: In patients with ABAO undergoing EVT, good collateral status was associated with favorable functional outcome, while no significant correlation was found between collateral status and hemorrhagic complications. Collateral status may be crucial for the long-term recovery of patients with ABAO undergoing thrombectomy.