Hyperdense Middle Cerebral Artery Sign on Admission CT Scan – Prognostic Significance for Ischaemic Stroke Patients Treated with Intravenous Thrombolysis in the Safe Implementation of Thrombolysis in Stroke International Stroke Thrombolysis Register

Abstract

Background: Hyperdense middle cerebral artery sign (HMCAS) on CT scan before stroke thrombolysis is associated with increased risk for haemorrhage and unfavourable outcome in several small studies. Methods: We examined baseline characteristics, intracranial haemorrhage and outcomes of intravenous thrombolysis in patients with and without HMCAS using the internet-based Safe Implementation of Thrombolysis in Stroke-International Stroke Thrombolysis Register. Symptomatic intracerebral haemorrhage (SICH) was defined as a National Institute of Health Stroke Scale (NIHSS) score decrease of ≥4 points plus type 2 parenchymal haemorrhage on imaging [Safe Implementation of Thrombolysis in Stroke Monitoring Study (SITS-MOST) definition], or any haemorrhage on follow-up imaging combined with a decrease of at least 1 point on the NIHSS [randomized controlled trial (RCT) definition]. Three-month outcomes were mortality and independence (modified Rankin scale score = 0–2). Results: 1,905 of 10,023 (19.0%) patients had HMCAS. Patients with HMCAS (vs. no HMCAS) were younger (median age 68 vs. 70 years, p < 0.001), had severer stroke (baseline NIHSS score 17 vs. 11, p < 0.05), higher mortality [23% (95% CI 20.0–25.1) vs. 13% (95% CI 12.1–13.7)] and lower independence [31% (95% CI 28.5–33.0) vs. 56% (95% CI 54.8–57.2)]. SICH rates per the SITS-MOST were 1.3% (95% CI 0.8–1.9) versus 1.8% (95% CI 1.5–2.1) and per the RCT definition 10.3% (95% CI 9.0–11.8) versus 6.8% (95% CI 6.2–7.3). In multivariable analysis, HMCAS was not an independent predictor of SICH but of mortality and independence per the SITS-MOST. Conclusions: HMCAS patients had severer stroke and a worse 3-month outcome. The risk for SICH per the SITS-MOST definition was similar compared to non-HMCAS patients, although increased per the RCT definition. There is not sufficient evidence to exclude these patients from intravenous thrombolysis. Combined treatment approaches might be considered in the perspective of the severe outcome and evaluated in RCTs.