Computational fluid dynamics (CFD) analysis in a ruptured vertebral artery dissecting aneurysm implanted by Pipeline when recurrent after LVIS-assisted coiling treatment: Case report and review of the literatures

Abstract

Backgrounds: Hemodynamics plays an important role in the natural history of the process of rupture and recurrence of intracranial aneurysms. This study aimed to investigate the role of hemodynamics for recurrence in a vertebral artery dissecting aneurysm (VADA).

Methods: A patient with a ruptured VADA firstly treated by low-profile visualized intraluminal support (LVIS)-assisted coiling, and was implanted with a Pipeline Embolization Device (PED) after aneurysm recurrence. Finite element analysis and computational fluid dynamics simulations were conducted in 6 serial imaging procedures, and the calculated hemodynamics was correlated with aneurysm recurrence.

Results: Wall shear stress (WSS) was not effectively suppressed, resulting in aneurysm recurrence with initial entry tear to occur above the protuberance after 7 months of LVIS stent-assisted coiling. With the implantation of PED, WSS, inflow stream and velocity at the aneurysm neck significantly decreased. During the 3-month follow-up after PED deployment, there was significant shrinkage of the sac and the blood flow in the sac was reduced considerably. The 27-month follow-up after PED deployment indicated the aneurysm was stable.

Conclusions: The present case study suggests that insufficient suppression of high WSS and high inflow velocity at the neck of the parent artery, especially near the posterior inferior cerebellar artery, might be associated with aneurysm recurrence.

Keywords: aneurysm recurrence; compuational fluid dynamics; finite element analysis; vertebral artery dissecting aneurysm.

Figure 1.

DSA images and 3D reconstruction images of the same patient at different periods. (A1) Initial 3D reconstruction image of left VA. (A2) Immediate DSA image of left VA showing the ruptured fusiform artery aneurysm when first treated with LVIS-assisted coiling. (B1) First DSA follow-up of 3D reconstruction image of left VA aneurysm at 7 months. (B2) First follow-up DSA image of left VA aneurysm at 7 months. (C1) Image of 3D reconstruction of left VA aneurysm after 3 months with the PED implanted. (C2) DSA image of the same patient of left VA aneurysm after 3 months with the PED implanted. (D1) Image of 3D reconstruction of left VA aneurysm after 27 months with the PED implanted. (D2) DSA image of the same patient of left VA aneurysm after 27 months with the PED implanted.

Figure 2.

Morphological changes and deformations were colored by magnitude of the aneurysm. (A) Alignment of aneurysms by rigid registration. (2019.4: Grey, 2019.12: Blue); (B) Three-dimensional deformation contour characterizing aneurysm growing; (C) Alignment of aneurysms by rigid registration. (2019.12: Blue, 2020.3: Grey); (D) Three-dimensional deformation contour characterizing aneurysm growing after 3 months from 2019.12.

Figure 3.

Hemodynamic parameters of VA aneurysm. Aneurysm distribution of WSS, velocity streamline and high flow volume (v≥0.01 m/s): (A1-A3) before the first treatment; (B1-B3) Immediately after the first treatment; (C1-C3) before the second treatment after recurrence; (D1-D3) Immediately after the second treatment (PED implantation); (E1-E3) 3 months follow-up after the second treatment; (F1-F3) 27 months follow-up after the second treatment.

Figure 4.

Local hemodynamic results of the aneurysm. Distribution of WSS, streamline, high flow volume (v≥0.01 m/s) and velocity sectional view of blood velocity: (A1-A4) before the first treatment; (B1-B4) Immediately after the first treatment; (C1-C4) before the second treatment after recurrence; (D1-D4) Immediately after the second treatment (implantation of PED); (E1-E4) 3 months follow-up after the second treatment; (F1-F4) 27 months follow-up after the second treatment.