Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location

A pilot study

Waleed Brinjikji, Bong Jae Chung, Carlos Jimenez, Christopher Putman, David F. Kallmes, Juan R. Cebral

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Background While clinical and angiographic risk factors for intracranial aneurysm instability are well established, it is reasonable to postulate that intra-aneurysmal hemodynamics also have a role in aneurysm instability. Objective To identify hemodynamic characteristics that differ between radiologically unstable and stable unruptured intracranial aneurysms. Materials and methods 12 pairs of unruptured intracranial aneurysms with a 3D rotational angiographic set of images and followed up longitudinally without treatment were studied. Each pair consisted of one stable aneurysm (no change on serial imaging) and one unstable aneurysm (demonstrated growth of at least 1 mm diameter or ruptured during follow-up) of matching size (within 10%) and locations. Patient-specific computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups using the paired Wilcoxon test. Results The area of the aneurysm under low wall shear stress (low shear stress area (LSA)) was 2.26 times larger in unstable aneurysms than in stable aneurysms (p=0.0499). The mean aneurysm vorticity was smaller by a factor of 0.57 in unstable aneurysms compared with stable aneurysms (p=0.0499). No statistically significant differences in geometric variables or shape indices were found. Conclusions This pilot study suggests there may be hemodynamic differences between unstable and stable unruptured cerebral aneurysms. In particular, the area under low wall shear stress was larger in unstable aneurysms. These findings should be considered tentative until confirmed by future larger studies.

Original languageEnglish
Pages (from-to)376-380
Number of pages5
JournalJournal of NeuroInterventional Surgery
Volume9
Issue number4
DOIs
StatePublished - 1 Apr 2017

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Aneurysm
Hemodynamics
Intracranial Aneurysm
Pulsatile Flow
Hydrodynamics
Growth

Keywords

  • Aneurysm
  • Subarachnoid

Cite this

Brinjikji, Waleed ; Chung, Bong Jae ; Jimenez, Carlos ; Putman, Christopher ; Kallmes, David F. ; Cebral, Juan R. / Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location : A pilot study. In: Journal of NeuroInterventional Surgery. 2017 ; Vol. 9, No. 4. pp. 376-380.
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Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location : A pilot study. / Brinjikji, Waleed; Chung, Bong Jae; Jimenez, Carlos; Putman, Christopher; Kallmes, David F.; Cebral, Juan R.

In: Journal of NeuroInterventional Surgery, Vol. 9, No. 4, 01.04.2017, p. 376-380.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location

T2 - A pilot study

AU - Brinjikji, Waleed

AU - Chung, Bong Jae

AU - Jimenez, Carlos

AU - Putman, Christopher

AU - Kallmes, David F.

AU - Cebral, Juan R.

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N2 - Background While clinical and angiographic risk factors for intracranial aneurysm instability are well established, it is reasonable to postulate that intra-aneurysmal hemodynamics also have a role in aneurysm instability. Objective To identify hemodynamic characteristics that differ between radiologically unstable and stable unruptured intracranial aneurysms. Materials and methods 12 pairs of unruptured intracranial aneurysms with a 3D rotational angiographic set of images and followed up longitudinally without treatment were studied. Each pair consisted of one stable aneurysm (no change on serial imaging) and one unstable aneurysm (demonstrated growth of at least 1 mm diameter or ruptured during follow-up) of matching size (within 10%) and locations. Patient-specific computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups using the paired Wilcoxon test. Results The area of the aneurysm under low wall shear stress (low shear stress area (LSA)) was 2.26 times larger in unstable aneurysms than in stable aneurysms (p=0.0499). The mean aneurysm vorticity was smaller by a factor of 0.57 in unstable aneurysms compared with stable aneurysms (p=0.0499). No statistically significant differences in geometric variables or shape indices were found. Conclusions This pilot study suggests there may be hemodynamic differences between unstable and stable unruptured cerebral aneurysms. In particular, the area under low wall shear stress was larger in unstable aneurysms. These findings should be considered tentative until confirmed by future larger studies.

AB - Background While clinical and angiographic risk factors for intracranial aneurysm instability are well established, it is reasonable to postulate that intra-aneurysmal hemodynamics also have a role in aneurysm instability. Objective To identify hemodynamic characteristics that differ between radiologically unstable and stable unruptured intracranial aneurysms. Materials and methods 12 pairs of unruptured intracranial aneurysms with a 3D rotational angiographic set of images and followed up longitudinally without treatment were studied. Each pair consisted of one stable aneurysm (no change on serial imaging) and one unstable aneurysm (demonstrated growth of at least 1 mm diameter or ruptured during follow-up) of matching size (within 10%) and locations. Patient-specific computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups using the paired Wilcoxon test. Results The area of the aneurysm under low wall shear stress (low shear stress area (LSA)) was 2.26 times larger in unstable aneurysms than in stable aneurysms (p=0.0499). The mean aneurysm vorticity was smaller by a factor of 0.57 in unstable aneurysms compared with stable aneurysms (p=0.0499). No statistically significant differences in geometric variables or shape indices were found. Conclusions This pilot study suggests there may be hemodynamic differences between unstable and stable unruptured cerebral aneurysms. In particular, the area under low wall shear stress was larger in unstable aneurysms. These findings should be considered tentative until confirmed by future larger studies.

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JF - Journal of NeuroInterventional Surgery

SN - 1759-8478

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