Introduction DIRECT-SAFE and SWIFT DIRECT did not show noninferiority of mechanical thrombectomy(MT) alone compared with intravenous thrombolysis(IVT) plus MT. However, for isolated M2-occlusions, data is scarce.

Aim of Study This study aims to evaluate safety and efficiency of bridging-IVT+MT compared to MT only in M2-occlusions.

Methods All patients prospectively enrolled in the German Stroke Registry-ET (05/2015–12/2021; N=13082) were screened for isolated M2-occlusions. Primary endpoint was defined as functional independence(90d mRS≤2), secondary endpoints were excellent outcome(90d mRS≤1), increase in mRS-points pre-stroke to 90d and successful reperfusion(TICI≥2b). Safety outcomes were intracranial hemorrhage(ICH) during treatment and symptomatic intracranial hemorrhage (sICH) at 24h(ECASS II). Propensity-score-matched cohorts (age, pre-stroke-mRS, NHISS-admission, ASPECTS, time symptom onset to admission) of patients receiving IVT+MT vs. MT alone were compared using standard descriptive statistics and multivariable regression.

Results N=618 matched cases were analyzed (IVT+MT:309; MT:309). No differences were found in age (77y), pre-stroke-mRS (0.8), NIHSS-admission (10.8) and recanalization success (TICI≥2b 84%). IVT was not associated with higher probability of functional independence, however, 90d-mRS (2.9 vs. 3.4, p<0.01) and pre-stroke to 90d-mRS increase (+2.1 vs. +2.6, p<0.01) was lower in patients receiving MT+IVT. No significant differences were found for ICH (MT:4.9%, MT+IVT:6.1%, p=0.481) and sICH (MT:3.9%, MT+IVT:2.9%, p=0.506).

Conclusion In M2-occlusions, MT+IVT was not associated with increased risk of sICH. Patients receiving MT+IVT had lower 90d-mRS and a lower increase in mRS pre-stroke to 90d. However, probability of functional independence and rates of successful recanalization were similar compared to matched controls.

Disclosure of Interest HK has financial interest in Eppdata GmbH.

GT received fees as consultant and lecturer from Acandis, Alexion, Amarin, Boehringer Ingelheim, Bayer, BMS/Pfizer, Daiichii Sankyo and Portola. He serves in the board of the TEA Stroke Study and of ESO.

JF is consultant for Cerenovus, Medtronic, Microvention, Penumbra, Phenox, Roche, Stryker and Tonbridge. He is stock holder of Tegus Medical, Eppdata and Vastrax. He serves as Associate Editor at JNIS.

All other authors have nothing to disclose.