Implantation of pipeline flow-diverting stents reduces aneurysm inflow without relevantly affecting static intra-Aneurysmal pressure

摘要

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 (R = 0.81, P < .001) and delay until maximum contrast (R = 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 stentMAP, mean arterial pressurePED, Pipeline Embolization Device