Introduction The first-pass effect (FPE) is complete or near-complete recanalization of a occluded blood vessel with a single pass of a mechanical thrombectomy (MT) device. Publications have shown FPE has been related to better clinical outcome compared to recanalization after more than one attempt.

Aim of Study We looked for FPE predictors and impact on clinical outcome after 90 days in patients with acute ishemic stroke (AIS)

Methods We present a monocentric cohort study of adult patients with anterior circulation occlusions in the first two years of performing the procedure (2018–2020).

Results In 82 included patients, FPE was achieved in 33 (40.2%), In the cohort, all recanalization time intervals have shown a statistically significant difference (p = 0.005). Distal occlusions were less prevalent in the group with FPE (12.1% vs. 34.7%, p = 0.022) where more frequent medial cerebral artery (ACM) occlusions were observed (58% vs. 45%). The clinical outcome after 90 days was almost identical in the group of patients with recanalization after 1 attempt compared with the group of 2+ attempts (42.4% vs. 42.9% and 27% vs. 30%). Age, sex, ASPECT score on admission, MT under local anesthesia were not predictors of the first-pass effect.

Conclusion Despite shorter time intervals and higher frequency of recanalization rate of the FPE group, no difference was observed in relation to clinical and safety outcomes after 90 days of AIS. In order to better understand the FPE and its predictors, further studies are needed in form of randomized controlled clinical studies.

Disclosure of Interest Nothing to disclose