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Systematic review and meta-analysis of current rates of first pass effect by thrombectomy technique and associations with clinical outcomes
  1. Mehdi Abbasi1,
  2. Yang Liu1,
  3. Seán Fitzgerald2,3,
  4. Oana Madalina Mereuta2,3,
  5. Jorge L Arturo Larco4,
  6. Asim Rizvi1,
  7. Ramanathan Kadirvel1,
  8. Luis Savastano4,
  9. Waleed Brinjikji1,
  10. David F Kallmes1
  1. 1 Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
  2. 2 CÚRAM–SFI Research Centre for Medical Devices, National University of Ireland Galway, Galway, Ireland
  3. 3 Physiology Department, National University of Ireland Galway, Galway, Ireland
  4. 4 Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, USA
  1. Correspondence to Dr Mehdi Abbasi, Mayo Clinic, Rochester, Minnesota, USA; Abbasi.Mehdi{at}


Background First pass effect (FPE) in mechanical thrombectomy is thought to be associated with good clinical outcomes.

Objective To determine FPE rates as a function of thrombectomy technique and to compare clinical outcomes between patients with and without FPE.

Methods In July 2020, a literature search on FPE (defined as modified Thrombolysis in Cerebral Infarction (TICI) 2c–3 after a single pass) and modified FPE (mFPE, defined as TICI 2b–3 after a single pass) and mechanical thrombectomy for stroke was performed. Using a random-effects meta-analysis, we evaluated the following outcomes for both FPE and mFPE: overall rates, rates by thrombectomy technique, rates of good neurologic outcome (modified Rankin Scale score ≤2 at day 90), mortality, and symptomatic intracerebral hemorrhage (sICH) rate.

Results Sixty-seven studies comprising 16 870 patients were included. Overall rates of FPE and mFPE were 28% and 45%, respectively. Thrombectomy techniques shared similar FPE (p=0.17) and mFPE (p=0.20) rates. Higher odds of good neurologic outcome were found when we compared FPE with non-FPE (56% vs 41%, OR=1.78) and mFPE with non-mFPE (57% vs 44%, OR=1.73). FPE had a lower mortality rate (17% vs 25%, OR=0.62) than non-FPE. FPE and mFPE were not associated with lower sICH rate compared with non-FPE and non-mFPE (4% vs 18%, OR=0.41 for FPE; 5% vs 7%, OR=0.98 for mFPE).

Conclusions Our findings suggest that approximately one-third of patients achieve FPE and around half of patients achieve mFPE, with equivalent results throughout thrombectomy techniques. FPE and mFPE are associated with better clinical outcomes.

  • stroke
  • thrombectomy

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  • Contributors MA, YL, SF, JLAL, AR, WB, LS, RK, and DFK made substantial contributions to the conception or design of the work or the acquisition, analysis, or interpretation of data for the work; and drafting of the work or revising it critically for important intellectual content. MA, YL, JLAL, and OMM made substantial contributions to data collection. All authors provided final approval of the version to be published. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding This work was supported by the National Institutes of Health grant number (R01 NS105853).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.