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Microcatheter contrast injection in stent retriever neurothrombectomy is safe and useful: insights from SWIFT PRIME
  1. Radoslav Raychev1,
  2. Reza Jahan2,
  3. Jeffrey L Saver1,
  4. Raul G Nogueira3,4,
  5. Mayank Goyal5,
  6. Vitor M Pereira6,7,
  7. Elad Levy8,
  8. Dileep R Yavagal9,
  9. Christophe Cognard10,
  10. David Liebeskind11
  1. 1 Department of Neurology and Comprehensive Stroke Center, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
  2. 2 Division of Interventional Neuroradiology, University of California Los Angeles Medical Center, Los Angeles, California, USA
  3. 3 Grady Memorial Hospital Marcus Stroke & Neuroscience Center, Atlanta, Georgia, USA
  4. 4 Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
  5. 5 Departments of Radiology and Clinical Neurosciences, University of Calgary, Calgary, Canada
  6. 6 Division of Neuroradiology, Department of Medical Imaging, University Health Network - Toronto Western Hospital, Toronto, Canada
  7. 7 Division of Neurosurgery, Department of Surgery, University Health Network - Toronto Western Hospital, Toronto, Canada
  8. 8 Department of Neurosurgery, State University of New York, Buffalo, New York, USA
  9. 9 University of Miami and Jackson Memorial Hospitals, Miami, Florida, USA
  10. 10 Department of Diagnostic and Therapeutic Neuroradiology, University Hospital of Toulouse, Toulouse, France
  11. 11 Department of Neurology, University of California Los Angeles, Neurovascular Imaging Research Core, Los Angeles, California, USA
  1. Correspondence to Dr Radoslav Raychev, Department of Neurology and Comprehensive Stroke Center, University of California Los Angeles David Geffen School of Medicine, Los Angeles 92868, California, USA; rudoray{at}


Microcatheter contrast injection (MCI) prior to stent retriever deployment for the treatment of acute ischemic stroke may be useful for evaluation of distal anatomy and flow patterns beyond the occlusion. However, prior data from intra-arterialthrombolysis suggested that MCI increases the risk of intracranial hemorrhage (ICH). The safety and utility of MCI has not been investigated in the setting of thrombectomy.

Methods We analyzed the Solitaire With the Intention For Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME) trial to correlate pre-intervention MCI flow with collateral flow, and to investigate its impact on ICH and clinical outcome after thrombectomy with the Solitaire device.

Results MCI was noted in 52% (n=51) of patients with a prevalence for the M2 location of 71% (n=36). Dichotomized correlation demonstrated a strong inverse relationship for partial collaterals with good MCI flow (p=0.004; OR 8.25). None of the MCI variables (presence, number, or grades) correlated with ICH and clinical outcome. The most significant predictors of non-disabled outcome were higher Alberta Stroke Program early CT Score (ASPECTS) (OR 1.61; p=0.0361) and younger age (OR 0.922; p = 0.0109). Higher ASPECTS was also a strong predictor of lower ICH risk (OR 0.501, p=0.0078).

Conclusions Collateral flow inversely correlated with MCI flow in the endovascular arm of the SWIFT PRIME trial. This finding warrants further validation in larger cohorts as MCI may be influenced by individual operator’s technique and choice of syringe size. Evaluation of flow and distal anatomy with MCI prior to stent retriever deployment is safe with no evidence of an impact on ICH or clinical outcome.

Clinical trial registration NCT01657461: Post- results

  • stroke
  • thrombectomy
  • hemorrhage
  • catheter

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  • Contributors The main author (RR) interpreted the data, drafted the original manuscript version, reviewed all suggestions provided by all co-authors, approved the final version, and agreed 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 co-authors provided substantial contribution to the interpretation of the provided data. All co-authors also contributed with revisions to the original draft, approved the final version of the manuscript, and agreed to be accountable for all aspects of the work.

  • Funding The SWIFT PRIME study was funded by Medtronic Neurovascular.

  • Competing interests The main author has no competing interest. All co-authors are consultants for Medtronic Neurovascular.

  • Ethics approval The institutional review board at each site approved the trial.

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