Rafik Ouared1, Ignacio Larrabide2, Olivier Brina1, Pierre Bouillot1, Gorislav Erceg1, Hasan Yilmaz1, Karl-Olof Lovblad1, Vitor Mendes Pereira1,3,4. 1. Interventional Neuroradiology Unit, Service of Neuroradiology, University of Geneva Hospitals and Faculty of Medicine, Geneva, Switzerland. 2. PLADEMA-CONICET, Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina. 3. Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada. 4. Division of Neurosurgery, Department of Surgery, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Abstract
BACKGROUND AND PURPOSE: Flow-diverter stents (FDSs) have been used effectively to treat large neck and complex saccular aneurysms on the anterior carotid circulation. Intra-aneurysmal flow reduction induces progressive aneurysm thrombosis in most patients. Understanding the degree of flow modification necessary to induce complete aneurysm occlusion among patients with considerable hemodynamics variability may be important for treatment planning. MATERIALS AND METHODS: Patients with incidental intracranial saccular aneurysms who underwent FDS endovascular procedures were included and studied for a 12 months' follow-up period. We used computational fluid dynamics on patient-specific geometries from 3D rotational angiography without and with virtual stent placement and thus compared intra-aneurysmal hemodynamic problems. Receiver operating characteristic analysis was used to estimate the stent:no-stent minimum hemodynamic ratio thresholds that significantly (p≤0.05) determined the condition necessary for long-term (12 months) aneurysm occlusion. RESULTS: We included 12 consecutive patients with sidewall aneurysms located in the internal carotid or vertebral artery. The measured porosity of the 12 deployed virtual FDSs was 83±3% (mean±SD). Nine aneurysms were occluded during the 12 months' follow-up, whereas three were not. A significant (p=0.05) area under the curve (AUC) was found for spatiotemporal mean velocity reduction in the aneurysms: AUC=0.889±0.113 (mean±SD) corresponding to a minimum velocity reduction threshold of 0.353 for occlusion to occur. The 95% CI of the AUC was 0.66 to 1.00. The sensitivity and specificity of the method were ∼99% and ∼67%, respectively. For both wall shear stress and pressure reductions in aneurysms no thresholds could be determined: AUC=0.63±0.16 (p=0.518) and 0.67±0.165 (p=0.405), respectively. CONCLUSIONS: For successful FDS treatment the post-stent average velocity in sidewall intracranial aneurysms must be reduced by at least one-third from the initial pre-stent conditions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
BACKGROUND AND PURPOSE: Flow-diverter stents (FDSs) have been used effectively to treat large neck and complex saccular aneurysms on the anterior carotid circulation. Intra-aneurysmal flow reduction induces progressive aneurysm thrombosis in most patients. Understanding the degree of flow modification necessary to induce complete aneurysm occlusion among patients with considerable hemodynamics variability may be important for treatment planning. MATERIALS AND METHODS:Patients with incidental intracranial saccular aneurysms who underwent FDS endovascular procedures were included and studied for a 12 months' follow-up period. We used computational fluid dynamics on patient-specific geometries from 3D rotational angiography without and with virtual stent placement and thus compared intra-aneurysmal hemodynamic problems. Receiver operating characteristic analysis was used to estimate the stent:no-stent minimum hemodynamic ratio thresholds that significantly (p≤0.05) determined the condition necessary for long-term (12 months) aneurysm occlusion. RESULTS: We included 12 consecutive patients with sidewall aneurysms located in the internal carotid or vertebral artery. The measured porosity of the 12 deployed virtual FDSs was 83±3% (mean±SD). Nine aneurysms were occluded during the 12 months' follow-up, whereas three were not. A significant (p=0.05) area under the curve (AUC) was found for spatiotemporal mean velocity reduction in the aneurysms: AUC=0.889±0.113 (mean±SD) corresponding to a minimum velocity reduction threshold of 0.353 for occlusion to occur. The 95% CI of the AUC was 0.66 to 1.00. The sensitivity and specificity of the method were ∼99% and ∼67%, respectively. For both wall shear stress and pressure reductions in aneurysms no thresholds could be determined: AUC=0.63±0.16 (p=0.518) and 0.67±0.165 (p=0.405), respectively. CONCLUSIONS: For successful FDS treatment the post-stent average velocity in sidewall intracranial aneurysms must be reduced by at least one-third from the initial pre-stent conditions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Authors: Ronak J Dholakia; Ari D Kappel; Andrew Pagano; Henry H Woo; Baruch B Lieber; David J Fiorella; Chander Sadasivan Journal: Interv Neuroradiol Date: 2017-12-14 Impact factor: 1.610
Authors: T Su; P Reymond; O Brina; P Bouillot; P Machi; B M A Delattre; L Jin; K O Lövblad; M I Vargas Journal: AJNR Am J Neuroradiol Date: 2020-02-13 Impact factor: 3.825
Authors: O Brina; P Bouillot; P Reymond; A S Luthman; C Santarosa; M Fahrat; K O Lovblad; P Machi; B M A Delattre; V M Pereira; M I Vargas Journal: AJNR Am J Neuroradiol Date: 2019-11-14 Impact factor: 3.825
Authors: P Bouillot; O Brina; H Yilmaz; M Farhat; G Erceg; K-O Lovblad; M I Vargas; Z Kulcsar; V M Pereira Journal: AJNR Am J Neuroradiol Date: 2016-06-30 Impact factor: 3.825
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