Background Flow diverters (FDs) are increasingly used in the treatment of intracranial aneurysms, and carry the risk of thromboembolic complications, even in patients treated with dual antiplatelet therapy. The effect of FDs on the downstream vascular is unknown. The aim of the study was to investigate vascular wall pulse wave velocity (PWV) and contractility changes following FD treatment in a rabbit model.
Methods FDs (Pipeline Embolic Device, Medtronic Inc., Irvine, California, USA) were implanted in the aorta of normal rabbits and sham-operated aorta were used as controls (n=6 per group). Pulse wave imaging with ultra-fast ultrasound at 1600 frames per second (Vantage, Verasonics, Inc., Kirkland, WA) was performed in the vessel wall distal to FD prior to device implantation and at 8- week follow-up to measure the PWV. Force contraction vascular reactivity studies were conducted in the aortic rings using an organ bath.
Results The difference in mean PWV in the follow-up compared with pre-implantation was significantly higher in the distal vessels compared with sham controls (1.18 m/s [SD=0.54] vs. 0.37 m/s [SD=1.09], P=0.03). Conversely, the aortic segments distal to the FD exhibited a 55% increase in vascular contractility compared with proximal segments (P=0.002). We observed a significant positive correlation between mean PWV and mean vascular contractility.
Conclusion Implantation of FD was associated with increased PWV and vascular contractility, suggesting that FD implantation causes changes to the vascular wall. Further studies are needed to understand the clinical implication of changes in vascular PWV and contractility.
- flow diverter
- vessel wall
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Contributors PKP and DD were involved in tissue harvesting, vascular contractility studies, and drafting of the manuscript. YHD was involved in FD deployment and sacrifice. MWU was involved in pulse wave velocity measurement and analysis. LM and SV were involved in conception and design of vascular contractility studies. DFK, JC ,and RK contributed to the conception and design of the study and to revision of the article critically for important intellectual content.
Funding This study was funded in part by National Institutes of Health under grant R01NS076491. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We would like to thank YS Prakash MD for allowing us to perform the vascular contractility studies in their laboratory. We would like to acknowledge Tina Gunderson for performing the statistics of the study. We would also like to acknowledge Radiology Internal Grant award program, Mayo Clinic for funding and to present the findings of the study ito the International Stroke conference 2018, Los Angeles, USA.
Competing interests None declared.
Patient consent None required.
Ethics approval Institutional Animal Care and Use Committee.
Provenance and peer review Not commissioned; externally peer reviewed.