title: Blood flow analysis of the aortic arch using computational fluid dynamics.
abstract: OBJECTIVE
  To obtain predictive information regarding aortic disease, we evaluated how blood flow inside the aortic arch was influenced by thoracic aortic aneurysms. In addition, to reveal the optimal intraoperative management in these cases, we examined blood flow during right subclavian arterial (rSCA) perfusion using computational fluid dynamics (CFD).
  
  
  METHODS
  Patient-specific models of the aortic arch were made with six different patterns based on the computed tomographic images. CFD models with finite volume methods were created to simulate the physiological pulsatile flow including the peripheral reflection wave, characteristic impedance and autonomous regulation system. Flow stream patterns, wall shear stress (WSS) and the oscillatory shear index (OSI) were calculated during one cardiac cycle. Furthermore, flow streamlines during rSCA perfusion were simulated under different perfusion flows.
  
  
  RESULTS
  Aortic dilatation caused vortical disturbed flow in a dilated space, resulting in turbulent flow not only inside the aneurysm but also in the proximal and/or distal normal aortic portion. In patients with a dilated thoracic aorta, there was a helical spiral flow with a circumferential vortex in systole. In patients with an arch aneurysm, turbulent flow inside the aneurysm caused a high OSI at the tip of the aneurysm. A high OSI was detected at the orifice of the supra-aortic branches, sinotubular junction, posterior lateral side of the ascending aorta and lesser curvature of the proximal descending aorta. rSCA perfusion revealed that the right common carotid artery was perfused by blood flow from rSCA throughout the cardiac cycle. With 75% of the flow from the rSCA, blood flow from the heart reached the left common carotid and subclavian artery only during a short period during the peak of systole.
  
  
  CONCLUSIONS
  A dilated aorta causes a turbulent flow pattern in the aortic arch. The high OSI site was similar to the favourite entry site for acute aortic dissection, indicating the causal relationship between mechanical stress and acute aortic dissection. rSCA cannulation might be cerebroprotective from ascending aortic plaque.
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan snumat@yahoo.co.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Numata
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Itatani
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kanda
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Doi
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Morimoto
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kaichiro
authors.initials: K
authors.lastname: Manabe
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Ikemoto
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yaku
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000784:Aortic Dissection / Q000503:physiopathology; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D017545:Aortic Aneurysm, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D002315:Cardiopulmonary Bypass; D017536:Carotid Artery, Common / Q000503:physiopathology; D000072226:Computed Tomography Angiography / Q000379:methods; D003198:Computer Simulation; D003331:Coronary Vessels / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011673:Pulsatile Flow / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D013314:Stress, Mechanical; D013348:Subclavian Artery
keywords: Aneurysm; Aortic dissection; Fluid dynamics; Oscillatory shear index; Wall shear stress