Prognostic value of the hyperdense middle cerebral artery sign in patients undergoing mechanical thrombectomy.

The hyperdense middle cerebral artery sign (HMCAS) is a well-established computed tomography marker of arterial thrombus in acute ischemic stroke (AIS); however, its prognostic value in the modern mechanical thrombectomy (MT) era remains uncertain. This study aimed to evaluate whether HMCAS predicts recanalization success, functional outcome, and hemorrhagic transformation (HT) following MT. We retrospectively analyzed 149 patients with anterior circulation large vessel occlusion who underwent MT between May 2018 and July 2023. Clinical, imaging, and procedural parameters were compared between patients with and without HMCAS on baseline non-contrast computed tomography. The primary outcomes were successful recanalization, defined as modified thrombolysis in cerebral infarction (mTICI) 2b-3, and favorable 90-day functional outcome, defined as a modified Rankin Scale score of 2 or less. Secondary outcomes included HT and mortality. HMCAS was identified in 101 patients (67.8%). Patients with HMCAS were older (73.4 ± 12.2 vs 68.7 ± 14.2 years, P = .039) and had a higher prevalence of diabetes mellitus (39.5% vs 21.4%, P = .047). Baseline National Institutes of Health Stroke Scale scores were lower in the HMCAS group (median, 13 vs 15.5, P = .005). There were no significant differences between the groups in successful recanalization, functional independence, or mortality (P > .05 for all). However, HMCAS was significantly associated with HT (P < .001). In multivariable analysis, clot length (odds ratio [OR] = 1.10, P = .043) and shorter procedure duration (OR = 0.98, P = .003) independently predicted successful recanalization, whereas older age (OR = 0.96, P = .028), lower Alberta Stroke Program Early CT Score, HT (OR = 0.67, P = .003), and a higher number of passes (OR = 0.61, P = .024) predicted poor functional outcome. HMCAS was not an independent predictor of successful recanalization or favorable 90-day functional outcome after MT, but it was significantly associated with hemorrhagic transformation, suggesting that its presence on baseline non-contrast computed tomography may warrant closer periprocedural attention.