You could be reading the full-text of this article now if you...

If you have access to this article through your institution,
you can view this article in

Implantation of Pipeline Flow-Diverting Stents Reduces Aneurysm Inflow Without Relevantly Affecting Static Intra-aneurysmal Pressure

Kerl, Hans U. MD*; Boll, Hanne DVM*; Fiebig, Teresa DVM*; Figueiredo, Giovanna MD*; Förster, Alex MD*; Nölte, Ingo S. MD*; Nonn, Andrea DVM; Groden, Christoph MD*; Brockmann, Marc A. MD*,‡

doi: 10.1227/NEU.0000000000000253

BACKGROUND: Flow-diverting stent (FDS) implantation is an endovascular treatment option for intracranial aneurysms. However, little is known about the hemodynamic effects.

OBJECTIVE: To assess the effect of stent compression on FDS porosity, to evaluate the influence of single and overlapping implantation of FDS on intra-aneurysmal flow profiles, and to correlate stent porosity with changes in static mean intra-aneurysmal pressure.

METHODS: Intra-aneurysmal time-density curves were recorded in a pulsatile in vitro flow model before and after implantation of FDSs (Pipeline Embolization Device; ev3) in 7 different types of aneurysm models. Reductions in the maximum contrast inflow and time to maximum intra-aneurysmal contrast were calculated. Micro--computed tomography was performed, and compression-related FDS porosity was measured. The influence of FDS placement on mean static intra-aneurysmal pressure was measured.

RESULTS: FDS compression resulted in an almost linear reduction in stent porosity. Stent porosity (struts per 1 mm) correlated significantly with the reduction of aneurysm contrast inflow (R2 = 0.81, P < .001) and delay until maximum contrast (R2 = 0.34, P = .001). Circulating intra-aneurysmal high-velocity flow was terminated in all sidewall models after implantation of a single stent. Superimposition of 2 stents reduced maximum intra-aneurysmal contrast by 69.1 ± 3.1% (mean ± SD) in narrow-necked sidewall aneurysm models, whereas no substantial reduction in maximum intra-aneurysmal contrast was observed in wide-necked sidewall aneurysm models. Intra-aneurysmal mean static pressure did not correlate with FDS porosity or number of implanted stents.

CONCLUSION: Implantation of FDS effectively reduces aneurysm inflow in a porosity-dependent way without relevantly affecting static mean intra-aneurysmal pressure.

ABBREVIATIONS: FDS, flow-diverting stent

MAP, mean arterial pressure

PED, Pipeline Embolization Device

Author Information

*University of Heidelberg, Medical Faculty Mannheim, Department of Neuroradiology, Mannheim, Germany;

University Hospital of the RWTH Aachen, Department of Diagnostic and Interventional Neuroradiology, Aachen, Germany

Correspondence: Marc A. Brockmann, MD, University Hospital of the RWTH Aachen, Department of Diagnostic and Interventional Neuroradiology, Pauwelsstrasse 30, 52074 Aachen, Germany. E-mail:

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (

Received February 07, 2013

Accepted November 12, 2013

Copyright © by the Congress of Neurological Surgeons