A Flow-Diverting Stent Is Not a Pressure-Diverting Stent

Abstract

The approach for treatment of large and fusiform intracranial aneurysms has evolved from stent-assisted coiling to treatment with flow-diverting stents. The treatment results for these stents are promising; however, early postprocedural aneurysm rupture has been described. The exact cause of rupture is unknown but might be related to intra-aneurysmal flow and pressure changes. We measured intra-aneurysmal pressure before, during, and after placement of a flow-diverting stent by using a dual-sensor guidewire. The pressure inside the aneurysm momentarily decreased during placement but was restored to baseline values within minutes. The flow-diverting stent does not seem to protect the aneurysm from the stress induced by pressure or pressure changes within the lumen.

Intra-Aneurysmal Pressure and Flow Changes Induced by Flow Diverters: Relation to Aneurysm Size and Shape

“…The dynamic pressure, which is a function of the velocity, is 2 orders of magnitude smaller than the static pressure, so the change in total pressure can be expected to be Ͻ3% of the pulse pressure (Ͻ2 mm Hg), as observed. This is in accordance with results by Schneiders et al, 24 who showed that the placement of FDs does not imply an early reduction of intra-aneurysmal pressure. Recent clinical findings by Cebral et al 5 also supported by computational simulations, suggest that placement of FDs leads to an increased intra-aneurysmal pressure.…”

Pipeline Embolization Device in Aneurysmal Subarachnoid Hemorrhage

“…McAuliffe and Wenderoth 8 reported their series of 11 recently ruptured aneurysms treated with the PED, with 3 giant aneurysms, 2 of which rebled, resulting in death. The reason for this failure may be that flow-diverting stents do not seem to act as pressure diverters 49 and the aneurysmal wall still has to endure hemodynamic stresses caused by the cardiac pulse wave. Given these unfavorable outcomes, FDSs should be used with extreme caution in acutely ruptured giant aneurysms or as a second-stage treatment if parent vessel occlusion is not possible.…”

Complications associated with the use of flow-diverting devices for cerebral aneurysms: a systematic review and meta-analysis

“…Moreover, Schneiders et al 68 argue that the wall of the still-perfused aneurysm has to endure hemodynamic stress caused by the cardiac pulse wave, which again might contribute to rupture in a later phase. In our analysis, the reported incidence of delayed ruptures is slightly higher with the Silk FDD than with the PED (3.6% vs 3.3%).…”