Hemodynamic impact of cerebral aneurysm endovascular treatment devices: coils and flow diverters

Abstract

Coils and flow diverters or stents are devices successfully used to treat cerebral aneurysms. Treatment aims to reduce intra-aneurysmal flow, thereby separating the aneurysmal sac from the blood circulation. The focus and this manuscript combining literature review and our original research is an analysis of changes in aneurysmal hemodynamics caused by endovascular treatment devices. Knowledge of post-treatment hemodynamics is a path to successful long-term treatment. Summarizing findings on hemodynamic impact of treatment devices, we conclude: coiling and stenting do not affect post-treatment intra-aneurysmal pressure, but significantly alter aneurysmal hemodynamics through flow reduction and a change in flow structure. The impact of treatment devices on aneurysmal flow depends, however, on a set of parameters including device geometry, course of placement, parent vessel and aneurysm geometry.

Keywords::

• cerebral aneurysms
• coils
• computational fluid dynamics
• endovascular treatment
• flow diverters
• flow visualization
• stents
• wall shear stress

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Flow diverters or stents and coils effectively and similarly reduce intra-aneurysmal flow (velocity and vorticity).

• Flow diverters and coils do not affect the post-treatment intra-aneurysmal pressure.

• Packing densities above 20% seem to lessen the influence of coil configuration on intra-aneurysmal hemodynamics.

• Recanalization after treatment seems to be dependent on hemodynamics at the neck remnant.

• Intra-aneurysmal flow reduction does not guarantee aneurysm occlusion.

• The post-treatment impact of coiling and stenting on intra-aneurysmal hemodynamics depends on many factors, including parent vessel flow, treatment device geometry and device placement. Some of these factors, like the post-treatment device structure, cannot yet be predicted or defined during the treatment procedure.

• Post-treatment intra-aneurysmal flow reduction is currently the only hemodynamic parameter associated with the success of the treatment.