Adjunctive Methylprednisolone After Thrombectomy: A Secondary Analysis Stratified by Admission White Blood Cell Count

Background Leukocyte‐driven inflammation may contribute to reperfusion–outcome mismatch after thrombectomy. We tested whether admission white blood cell (WBC) count may identify reperfused patients more likely to benefit from adjunctive methylprednisolone. Methods This post hoc secondary analysis of the MARVEL randomized, placebo‐controlled trial was conducted with a prospectively finalized statistical analysis plan. We included patients with anterior‐circulation large‐vessel occlusion stroke who achieved successful reperfusion after thrombectomy and received intravenous methylprednisolone or placebo. The analysis included 1201 patients stratified by admission WBC count (< 10 × 10 9 /L, n = 808; ≥ 10 × 10 9 /L, n = 393). The primary outcome was 90‐day modified Rankin Scale (mRS 0–6) using covariate‐adjusted ordinal logistic regression. Secondary outcomes included mRS 0–3 and 0–4, early NIHSS, mortality, symptomatic intracranial hemorrhage (sICH), any intracranial hemorrhage, pneumonia, and gastrointestinal bleeding. Results The treatment × WBC interaction reached nominal statistical significance ( p = 0.04). In patients with WBC ≥ 10 × 10 9 /L, methylprednisolone was associated with a more favorable 90‐day ordinal mRS distribution (adjusted common OR, 1.59; 95% CI, 1.11–2.28), higher odds of mRS 0–3 and 0–4, and lower mortality (aOR, 0.60; 95% CI, 0.37–0.96) and pneumonia (aOR, 0.61; 95% CI, 0.40–0.93), without an apparent increase in hemorrhage or gastrointestinal bleeding. No clear benefit was observed in patients with WBC < 10 × 10 9 /L. Conclusions Higher admission WBC was associated with more favorable estimated treatment effects from adjunctive methylprednisolone after thrombectomy, warranting prospective validation. Trial Registration: Chinese Clinical Trial Registry ( ChiCTR.org.cn ); ChiCTR2100051729; https://www.chictr.org.cn/