title: Comparison of Hemodynamics After Aortic Root Replacement Using Valve-Sparing or Bioprosthetic Valved Conduit.
abstract: BACKGROUND
  The purpose of this study is to compare aortic hemodynamics and blood flow patterns using in-vivo four-dimensional (4D) flow magnetic resonance imaging (MRI) in patients after valve-sparing aortic root replacement (VSARR) and aortic root replacement with bioprosthetic valves (BIO-ARR).
  
  
  METHODS
  In-vivo 4D flow MRI was performed in 11 patients after VSARR (47 ± 18 years, 6 bicuspid aortic valves, 5 trileaflet aortic valves), 16 patients after BIO-ARR (52 ± 14 years), and 10 healthy controls (47 ± 16 years). Analysis included three-dimensional blood flow visualization and grading of helix flow in the ascending aorta (AAo) and arch. Peak systolic velocity was quantified in 9 analysis planes in the AAo, aortic arch, and descending aorta. Flow profile uniformity was evaluated in the aortic root and ascending aorta.
  
  
  RESULTS
  Peak systolic velocity (2.0 to 2.5m/second) in the aortic root and AAo in both VSARR and BIO-ARR were elevated compared with controls (1.1 to 1.3m/second, p < 0.005). Flow asymmetry in BIO-ARR was increased compared with VSARR, evidenced by more AAo outflow jets (9 of 16 BIO-ARR, 0 of 11 in VSARR). The BIO-ARR exhibited significantly (p < 0.001) increased helix flow in the AAo as a measure of increased flow derangement. Finally, peak systolic velocities were elevated at the aortic root for BIO-ARR (2.5 vs 2.0m/second, p < 0.05) but lower in the distal AAo when compared with VSARR.
  
  
  CONCLUSIONS
  The VSARR results in improved hemodynamic outcomes when compared with BIO-ARR, as indicated by reduced peak velocities in the aortic root and less helix flow in the AAo by 4D flow MRI. Longitudinal research assessing the clinical impact of these differences in hemodynamic outcomes is warranted.
authors.affiliation: Department of Radiology, Northwestern University, Chicago, Illinois.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Collins
authors.affiliation: Department of Radiology, Northwestern University, Chicago, Illinois.
authors.forename: Edouard
authors.initials: E
authors.lastname: Semaan
authors.affiliation: Department of Radiology, Northwestern University, Chicago, Illinois.
authors.forename: Alex
authors.initials: A
authors.lastname: Barker
authors.affiliation: Division of Cardiac Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: McCarthy
authors.affiliation: Department of Radiology, Northwestern University, Chicago, Illinois.
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.affiliation: Department of Radiology, Northwestern University, Chicago, Illinois; Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.affiliation: Division of Cardiac Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois. Electronic address: malaisrie@northwestern.edu.
authors.forename: S Chris
authors.initials: SC
authors.lastname: Malaisrie
mesh_terms: D000328:Adult; D001011:Aorta / Q000601:surgery*; D001021:Aortic Valve / Q000002:abnormalities* / Q000503:physiopathology / Q000601:surgery*; D000082882:Bicuspid Aortic Valve Disease; D001705:Bioprosthesis; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies