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Original research
Direct thromboaspiration efficacy for mechanical thrombectomy is related to the angle of interaction between the aspiration catheter and the clot
  1. Gianmarco Bernava1,
  2. Andrea Rosi1,
  3. José Boto1,
  4. Olivier Brina1,
  5. Zsolt Kulcsar2,
  6. Christoph Czarnetzki3,
  7. Emmanuel Carrera4,
  8. Karl Schaller5,
  9. Karl-Olof Lovblad1,
  10. Paolo Machi1
  1. 1 Neuroradiology, University Hospitals of Geneva, Geneva, Switzerland
  2. 2 Neuroradiology, University Hospitals of Zurich, Zurich, Switzerland
  3. 3 Anesthesiology, Regional Hospital of Lugano, Lugano, Switzerland
  4. 4 Neurology, University Hospitals of Geneva, Geneva, Switzerland
  5. 5 Neurosurgery, University Hospitals of Geneva, Geneva, Switzerland
  1. Correspondence to Dr Paolo Machi, HUG, Geneva, Switzerland; paolo.machi{at}


Background Direct thromboaspiration has been reported as an effective mechanical treatment for acute ischemic stroke. We aimed to determine whether the angle of interaction between the aspiration catheter and the clot affects the success of clot removal in ischemic stroke patients with large vessel occlusion in the anterior and posterior circulation.

Methods All patients treated at our institution by direct thromboaspiration as a firstline technique between January 2016 and December 2017 were enrolled in the study. We retrospectively reviewed baseline and procedural characteristics, the angle of interaction formed between the aspiration catheter and the clot, the modified Thrombolysis in Cerebral Infarction score, and the 3 month modified Rankin Scale score.

Results 85 patients underwent direct thromboaspiration as the firstline treatment during the study period. 100 direct thromboaspiration passes were performed. An angle of interaction of ≥125.5° significantly influenced the success of clot removal (P<0.001) with good sensitivity and specificity, in particular for occlusion of the middle cerebral and basilar artery. The combination of aspiration with a stent retriever based thrombectomy was a valid rescue treatment in cases of standalone direct thromboaspiration failure.

Conclusions In our series, an angle of interaction between the aspiration catheter and the clot of ≥125.5° was significantly associated with successful clot removal. The prediction of the angle of interaction on pretreatment imaging may help operators to select the most adequate mechanical thrombectomy technique on a case by case basis.

  • Stroke
  • Thrombectomy
  • Catheter

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  • Contributors Substantial contributions to the conception or design of the work; acquisition, analysis, or interpretation of data for the work; drafting the work; revising it critically for important intellectual content; final approval of the version to be published; and agreement 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: all authors.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors.

  • Competing interests None declared.

  • Ethics approval Ethics approval was obtained from the local institutional review board.

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

  • Data sharing statement All the data are available upon request to the corresponding author.

  • Patient consent for publication Not required.

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