Proximal hyperdense middle cerebral artery sign is associated with increased risk of asymptomatic hemorrhagic transformation after endovascular thrombectomy: a multicenter retrospective study.

Objective: To investigate whether hyperdense middle cerebral artery sign (HMCAS) on pretreatment no-contrast CT (NCCT) is associated with hemorrhagic transformation (HT) after endovascular thrombectomy (EVT).

Methods: Patients with acute middle cerebral artery (MCA) occlusion who received EVT in three comprehensive hospitals were retrospectively evaluated. They were divided into four groups based on the presence or absence of HMCAS and corresponding CTA findings, among whom differences were compared. Univariate and multivariate logistic regression analyses were performed to investigate the association between HMCAS and HT and its subtypes.

Results: 318 patients were included, among whom 149 (46.9%) had HMCAS. Patients in the proximal positive HMCAS group had higher National Institute of Health Stroke Scale scores and lower Alberta Stroke Program Early CT Scores (ASPECTS) than those in the proximal negative HMCAS group. The rate of HT was higher in the proximal positive HMCAS group than that in the proximal negative HMCAS group. In multivariate logistic regression analysis, the proximal HMCAS were independently associated with HT (adjusted OR = 2.073, 95% CI 1.211-3.551, p = 0.008) and aHT (adjusted OR = 2.271, 95% CI 1.294-3.986, p = 0.004), but not with sHT. Patients who developed HT, including aHT and sHT, had a lower rate of good outcome.

Conclusion: Proximal HMCAS on initial NCCT was independently associated with aHT in patients who received EVT for acute MCA occlusion. Both aHT and sHT had a detrimental effect on clinical outcome.