Dynamic Impact of Leptomeningeal Collateral Status for Hemorrhagic Transformation in Patients with Acute Ischemic Stroke with Endovascular Treatment: A Prospective Study.

BACKGROUND

Hemorrhagic transformation (HT) remains a common and serious complication after endovascular treatment (EVT) for acute ischemic stroke (AIS). Limited data exist on how dynamic status of leptomeningeal collaterals influence HT in AIS. This study aims to investigate the impact of dynamic status of leptomeningeal collaterals on postoperative HT in patients with AIS undergoing EVT.

METHODS

A prospective cohort study was performed between January 2019 and June 2023. Only patients with middle cerebral artery occlusion who received EVT were included. Preoperative leptomeningeal collaterals were evaluated using the regional leptomeningeal collateral (rLMC) score, and postoperative collaterals were assessed using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology score.

RESULTS

A total of 342 patients with middle cerebral artery occlusion were included in this study. Multivariate analysis demonstrated that patients with good rLMC scores (˃ 10) experienced fewer HT events compared with those with poor rLMC scores (≤ 10) (adjusted odds ratio [aOR] 0.46, 95% confidence interval [CI] 0.28-0.76, P = 0.002). Further subgroup analysis based on intravenous thrombolysis showed that good leptomeningeal collaterals were significantly associated with reduced risk of HT in patients receiving bridging therapy (aOR 0.12, 95% CI 0.03-0.38, p < 0.001). Among 75 patients with incomplete recanalization, analysis of collateral changes indicated that patients with consistently good preoperative and postoperative collateral had the lowest risk of HT (aOR 0.19, 95% CI 0.04-0.95, P = 0.043). However, no significant correlation was detected between symptomatic intracranial hemorrhage and preoperative and postoperative collateral or its dynamic evolution.

CONCLUSIONS

Good preoperative leptomeningeal collateral status is associated with reduced risk of HT and better 90-day functional outcomes after EVT, possibly due to its role in maintaining cerebral perfusion and slowing infarct growth. Although our findings suggest that collateral-dependent infarct growth may be a potential mechanism for HT and unfavorable outcomes, this hypothesis requires further investigation.