title: Role of terminal and anastomotic circulation in the patency of arteries jailed by flow-diverting stents: animal flow model evaluation and preliminary results.
abstract: OBJECTIVE The authors describe herein the creation of an animal model capable of producing quantifiable data regarding blood flow rate and velocity modifications in terminal and anastomotic types of cerebrofacial circulation. They also present the preliminary results of a translational study aimed at investigating the role of terminal and anastomotic types of circulation in arterial branches jailed by flow-diverting stents as factors contributing to arterial patency or occlusion. METHODS Two Large White swine were used to validate a terminal-type arterial model at the level of the right ascending pharyngeal artery (APhA), created exclusively by endovascular means. Subsequently 4 Large White swine, allocated to 2 groups corresponding to the presence (Group B) or absence (Group A) of terminal-type flow modification, underwent placement of flow-diverting stents. Blood flow rates and velocities were quantified using a dedicated time-resolved 3D phase-contrast MRA sequence before and after stenting. Three months after stent placement, the stented arteries were evaluated with digital subtraction angiography (DSA) and scanning electron microscopy (SEM). Patent (circulating) ostia quantification was performed on the SEM images. RESULTS Terminal-type flow modification was feasible; an increase of 75.8% in mean blood velocities was observed in the right APhAs. The mean blood flow rate for Group A was 0.31 ± 0.19 ml/sec (95% CI -1.39 to 2.01) before stenting and 0.21 ± 0.07 ml/sec (95% CI -0.45 to 0.87) after stenting. The mean blood flow rate for Group B was 0.87 ± 0.32 ml/sec (95% CI -1.98 to 3.73) before stenting and 0.76 ± 0.13 ml/sec (95% CI -0.41 to 1.93) after stenting. Mean flow rates after stenting showed a statistically significant difference between Groups A and B (Welch test). Mean and maximal blood velocities were reduced in Group A cases and did not decrease in Group B cases. Control DSA and SEM findings showed near occlusion of the jailed APhAs in both cases of anastomotic circulation (mean patent ostium surface 32,776 μm2) and patency in both cases of terminal-type circulation (mean patent ostium surface 422,334 μm2). CONCLUSIONS Terminal-type arterial modification in swine APhAs is feasible. Sufficient data were acquired to perform an a priori analysis for further research. Flow diversion at the level of the APhA ostium resulted in significant stenosis in cases of anastomotic circulation, while sufficient patency was observed in terminal-type circulation.
authors.affiliation: Departments of 1 Interventional Neuroradiology and.|Applied Medical Research Team (ERMA).
authors.forename: Christina
authors.initials: C
authors.lastname: Iosif
authors.affiliation: Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guerike," Magdeburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Berg
authors.affiliation: Anesthesiology, Dupuytren University Hospital (CHU Limoges).
authors.forename: Sebastien
authors.initials: S
authors.lastname: Ponsonnard
authors.affiliation: Science of Ceramic Processes and Surface Treatments, CNRS, UMR 7315, European Ceramic Center, University of Limoges.
authors.forename: Pierre
authors.initials: P
authors.lastname: Carles
authors.affiliation: Departments of 1 Interventional Neuroradiology and.
authors.forename: Suzana
authors.initials: S
authors.lastname: Saleme
authors.affiliation: Departments of 1 Interventional Neuroradiology and.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pedrolo-Silveira
authors.affiliation: Departments of 1 Interventional Neuroradiology and.
authors.forename: Georges
authors.initials: G
authors.lastname: Mendes
authors.affiliation: Departments of 1 Interventional Neuroradiology and.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Waihrich
authors.affiliation: Science of Ceramic Processes and Surface Treatments, CNRS, UMR 7315, European Ceramic Center, University of Limoges.
authors.forename: Gilles
authors.initials: G
authors.lastname: Trolliard
authors.affiliation: Research and Analysis Laboratory, Haute-Vienne.
authors.forename: Claude-Yves
authors.initials: CY
authors.lastname: Couquet
authors.affiliation: Applied Medical Research Team (ERMA).|Department of Histology, Cytology, Cellular Biology and Cytogenetics, Mother and Child (HME) University Hospital, Limoges, France; and.
authors.forename: Catherine
authors.initials: C
authors.lastname: Yardin
authors.affiliation: Departments of 1 Interventional Neuroradiology and.|Applied Medical Research Team (ERMA).
authors.forename: Charbel
authors.initials: C
authors.lastname: Mounayer
mesh_terms: D000818:Animals; D001158:Arteries / Q000503:physiopathology*; D001783:Blood Flow Velocity; D003097:Collateral Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D023421:Models, Animal; D015607:Stents; D013552:Swine; D014652:Vascular Diseases / Q000503:physiopathology*; D014654:Vascular Patency
keywords: APhA = ascending pharyngeal artery; CCA = common carotid artery; CFD = computational fluid dynamics; DSA = digital subtraction angiography; ECA = external carotid artery; FDS = flow-diverting stent; PED = Pipeline embolization device; RM = rete mirabile; SEM = scanning electron microscopy; collateral arteries; embolization; endothelialization; flow diverting stent; magnetic resonance angiography; ostium; pcMRA = phase contrast MR angiography; vascular disorders