Collateral status may modify the effect of methylprednisolone in endovascular treatment for acute ischemic stroke: a post-hoc analysis of the marvel randomized trial

Background: Collateral status is a predictor of clinical prognosis in acute ischemic stroke (AIS) patients undergoing endovascular treatment (EVT), but its role in guiding therapeutic decisions for adjunctive therapy remains unclear. To determine whether collateral status modifies the efficacy and safety of adjunctive methylprednisolone in AIS patients receiving EVT. Methods: The post-hoc analysis enrolled 1649 patients from the MARVEL trial, a multicenter, double-blind, randomized, placebo-controlled clinical trial of patients with large vessel occlusion received EVT. The trial was conducted at 82 stroke centers in China between 9 February 2022, and 30 June 2023. Collateral status was assessed using the American Society of Interventional and Therapeutic Neuroradiology/ Society of Interventional Radiology Collateral Flow Grading System grade (poor: 0–1; good: 2–4). The primary efficacy outcome was the ordinal modified Rankin Scale score at 90 days (range, 0 [no symptoms] to 6[death]). Safety outcomes included mortality within 90 days, and symptomatic intracranial hemorrhage. Results: Among 1649 patients (median age, 69.0 years [IQR, 59.0-76.0 years]; 713 women [43.2%]) enrolled, poor collateral status was present in 639 patients: 321 patients (50.2%) in the methylprednisolone group and 318 patients (49.8%) in the placebo group. The association of methylprednisolone with the primary outcome was modified by collateral status (P for interaction = 0.003). In the poor collateral status stratum, there was a shift in favor of better outcomes in patients randomized to methylprednisolone (adjusted common odds ratio [cOR], 1.43[95% CI: 1.17, 1.74]), whereas in the good collateral status stratum, there was no significant difference between the groups (adjusted cOR, 0.98 [95% CI: 0.84, 1.15]). Conclusions: Collateral status modifies the effect of methylprednisolone in AIS patients undergoing EVT. These hypothesis-generating findings suggest that patients with poor collaterals may derive benefit from methylprednisolone, potentially guiding adjunctive therapy decisions. Prospective validation is warranted before clinical application.