Introduction Intracranial placement of flow-diverter (FD) stents provides a safe and effective treatment for aneurysms.¹ However, long-term angiographic follow-up is indicated, since in-stent stenosis and late thrombosis as a consequence of poor vessel wall apposition increase the risks of stroke-related complications.^1,2 In addition to conventional angiography, high-resolution contrast-enhanced cone-beam CT (VasoCT) may provide improved three-dimensional visualization of stent deployment and apposition.^2,3

Here we explored the use of VasoCT for the assessment of FD vessel wall apposition in comparison to concurrent optical coherence tomography (OCT) endoscopy. Catheter-based OCT delivers near-infrared images at a spatial resolution in the order of 10–50 μm, which enables superior intravascular tissue and device visualization.⁴ This work was performed in an experimental sidewall aneurysm model in canines.

Materials and methods Two sidewall aneurysms were created on each common carotid artery (CCA) in female canines by anastomosis of sections of the detached right external jugular vein, as described before.⁵ Under fluoroscopic guidance (Allura Xper FD20, Philips, Best, The Netherlands), FD stents (Pipeline Embolization Device, EV3-MTI, Irvine, CA; Surpass, Stryker, Fremont, CA) were placed and apposition was assessed bilaterally using VasoCT, and in the right CCA using OCT (C7 System/Dragonfly Catheter, St Jude Medical, Westford, MA).

Results Figure 1 shows an example of poor apposition, approximately 7.5 mm proximal to the aneurysm on the right CCA. With OCT (right), the distance between the FD and vessel wall measured 0.39 mm. The vessel diameter in this plane was 3.24–3.53 mm, and the area between the stent and the vessel wall was 15% of the lumen area. A similar distance 0.35 mm could be observed in a 67 μm VasoCT reconstruction (left), although lumen and stent struts are rendered more smoothly as compared to OCT.

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Abstract P-001 Figure 1

Conclusion Due to its superior in-plane resolution, OCT clearly visualised the distinction between the vessel wall and the FD stent struts. Nevertheless, our example showed that VasoCT enables identification of apposition distances in the order of 0.5mm. Although OCT is clinically used in interventional cardiology, its neurovascular application is currently limited to the experimental setting. Here we showed that OCT can provide a gold-standard for the validation of VasoCT assessments of FD apposition.

References

1. Pierot L, Wakhloo AK. Stroke 2013;44:2046–2054

2. Kizilkilic O, et al. J Neurosurg 2012;117:45–49

3. Flood TF, et al. J NeuroIntervent Surg 2014;doi:10.1136/neurintsurg-2013-010950

4. Bezerra HG, et al. J Am Coll Cardiol Intv 2009;2:1035–1046

5. Wakhloo AK, et al. Am J Neuroradiol 1994;15:493–502

Disclosures K. van der Marel: None. M. Gounis: 1; C; eV3/Covidien, Philips Healthcare, NIH, Silk Road, Stryker Neurovascular. 2; C; Stryker Neurovascular, Codman Neurovascular. R. King: None. A. Wakhloo: 1; C; NIH, Philips Healthcare. 2; C; Stryker Neurovascular. A. Puri: None.