Abstract TP82: High Rate of Recanalization and Attenuated Poor Outcome After Intravenous Thrombolysis in “Top-of-the-basilar” Syndrome

Objective: The safety and efficacy of intravenous thrombolysis (IVT) in patients with “top-of-the-basilar” syndrome (TOBS) was not systematically investigated. We thus aim to evaluate the rate of recanalization, hemorrhagic transformation and long-term prognosis after IVT in TOBS in our consecutively collected thrombolytic patients. Methods: We retrospectively examined clinical and imaging data from consecutive acute ischemic stroke patients with basilar artery occlusion (BAO) who underwent multimodal CT or MRI before and 24 hours after IVT at our center. The presence of Hyperdense artery sign (HAS) on noncontrast CT or Susceptibility vessel sign (SVS) on susceptibility-weighted imaging were recorded. Recanalization, hemorrhagic transformation (HT), and clinical outcome were assessed by Arterial Occlusive Lesion (AOL) scale, ECASS II definition and modified Rankin Scale (mRS), respectively. Results: Among all 43 BAO patients with pre- and post-treatment angiongraphy, 24 (55.8%) were considered as TOBS based on either CTA (n = 18) or TOF-MRA (n = 6) before IVT. Follow-up imaging revealed recanalization (AOL ≥ 2) in 19 (79.2%) and HT in 6 (25%) of TOBS patients. This recanalization rate of TOBS was much higher than other LAO (56.2% for M1, 68.0% for M2, 12.8% for internal carotid artery, 50.0% for anterior cerebral artery, 58.3% for posterior cerebral artery, and 21.1% for other type of BAO). Cardioembolic stroke were considered in 18 (75%) of TOBS. The presence of HAS or SVS in TOBS with recanalization was higher than those without (89.5% verse 40%, p=0.042). The rate of poor clinical outcome (mRS ≥ 3) was lower in patients with recanalization than those without recanalization (36.8% verse 100%, p=0.037). 3-month mortality were also lower in patients with recanalization (15.8% verse 80.0%, p=0.014). Conclusions: Most (about 80%) of TOBS patients can achieve recanalization after IVT, leading to a dramatic recovery in Chinese population. The presence of HAS or SVS of basilar artery might indicate high rate of recanalization.