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Original research
Predictive value of platelet reactivity unit (PRU) value for thrombotic and hemorrhagic events during flow diversion procedures: a meta-analysis
  1. Ebunoluwa Ajadi1,
  2. Shaowli Kabir2,
  3. Aaron Cook3,
  4. Stephen Grupke8,
  5. Abdulnasser Alhajeri4,8,
  6. Justin F Fraser4,5,8,9
  1. 1University of Kentucky College of Medicine, Lexington, Kentucky, USA
  2. 2Department of Statistics, College of Arts and Sciences, University of Kentucky, Lexington, Kentucky, USA
  3. 3Department of Pharmacy Practice and Science, University of Kentucky College of Pharmacy, Lexington, Kentucky, USA
  4. 4Department of Neurology, University of Kentucky, Lexington, KY, USA
  5. 5Department of Neurological Surgery, University of Kentucky, Lexington, Kentucky, USA
  6. 8Department of Radiology, University of Kentucky, Lexington, KY, USA
  7. 9Department of Neuroscience, University of Kentucky, Lexington, KY, USA
  1. Correspondence to Dr Justin F Fraser, Neurological Surgery, University of Kentucky, Lexington 40536, USA; Jfr235{at}


Background and purpose Platelet function testing prior to flow diversion procedures, although initially heavily debated, has seen a substantial increase in its adoption to assess the risk of operative and perioperative thrombotic and hemorrhagic events. This meta-analysis was conducted to assess platelet function testing, particularly the VerifyNow Platelet Reactivity Unit (PRU) assay, for a relationship between the reported assay PRU value and thrombotic and hemorrhagic events.

Materials and methods The currently available literature (2013–2018) was surveyed with PubMed and Google Scholar searches. Included studies were those for which there were at least 30 cases during the study period, for which VerifyNow platelet reactivity unit values were obtained prior to the procedures and for which intraoperative and perioperative adverse events were noted. PRU value cut-offs ranging from >200 to >240 comprised the hyporesponse group while values ranging from <60 to <70 comprised the hyper-response group. The data were subject to statistical analysis to assess the relationship between PRU values and thrombotic and hemorrhagic events. The collected data were subsequently statistically analyzed to assess for publication bias.

Results The searches yielded 27 studies, of which 12 met the inclusion criteria for the meta-analysis. The meta-analysis included data from 1464 reported Pipeline cases. The study included 273 men and 1177 women with a mean age across the analyzed procedures of 58 years (range 25–85). After loading with antiplatelet medications, preprocedural platelet hyper-responsiveness was associated with a greater incidence of hemorrhagic events with an increased absolute risk of 12%, but showed no relationship with thrombotic events. Preprocedural platelet hyporesponsiveness was associated with a greater incidence of thrombotic events with an absolute risk of 15%, but showed no relationship with hemorrhagic events.

Conclusions VerifyNow PRU values that correspond to platelet hyporesponse or hyper-response to dual antiplatelet therapy are associated with a higher risk of thrombotic and hemorrhagic events, respectively. Thus, the PRU value may offer some predictive value for these events.

  • aneurysm
  • blood flow
  • device
  • flow diverter
  • stent
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  • Contributors EA: collected, cleaned and analysed the data, designed the data collection tools and drafted and revised the paper. SK: designed the key statistical analysis tools and analyzed the data. AC, SG, AE: analysed the data and revised the draft paper. JFF: monitored and oversaw data collection and statistical analysis, drafted and revised the paper.

  • 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 JFF is an equity interest holder for Fawkes Biotechnology and a consultant for Stream Biomedical and Medtronic Neurovascular.

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

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