Hyperdense Middle Cerebral Artery Sign as a Predictor of First-Pass Recanalization and Favorable Outcomes in Direct Thrombectomy Patients.

Background: The Hyperdense Middle Cerebral Artery Sign (HMCAS) is an early marker of acute MCA occlusion on non-contrast CT (NCCT), which has been linked with stroke type and thrombus composition.

Aims: To assess the prognostic value of HMCAS in M1 occlusion patients treated with endovascular thrombectomy and explore its predictive value across different patients.

Methods: Patients with M1 occlusion were selected from the ANGEL-ACT registry, which comprised 1793 individuals. Cohorts were divided based on the presence of HMCAS. The primary outcome was functional independence (mRS 0-2) at 90 days. Secondary outcomes included excellent outcome (mRS 0-1), good functional outcome (mRS 0-3), modified first pass effect (mFPE), successful recanalization, intracranial hemorrhage, and 90-day mortality. Propensity score matching (PSM) was employed to adjust for confounders, with 96 patients in each matched group. Subgroup analysis was performed to determine whether the effect of HMCAS on clinical outcomes differed between groups.

Results: Among 714 acute M1 occlusion patients, 96 (13.4%) had HMCAS. PSM analysis showed that HMCAS was independently associated with mFPE (OR: 1.97, 95% CI: 1.04-3.75, p = 0.038) but had no significant effects on other clinical outcomes. There was a significant association between HMCAS and functional independence for patients who underwent direct thrombectomy but not for patients who underwent bridging therapy (P for interaction = 0.033).

Conclusion: This study indicates that in patients with acute M1 occlusion undergoing EVT, HMCAS on pretreatment NCCT is not significantly associated with functional independence but is linked to a higher first-pass recanalization rate. Its clinical impact on outcomes depends on whether intravenous thrombolysis is administered before thrombectomy.