title: Evaluation of Marfan patients status post valve-sparing aortic root replacement with 4D flow.
abstract: BACKGROUND
  Over the past two decades elective valve-sparing aortic root replacement (V-SARR) has become more common in the treatment of patients with aortic root and ascending aortic aneurysms. Currently there are little data available to predict complications in the post-operative population. The study goal was to determine if altered flow patterns in the thoracic aorta, as measured by MRI, are associated with complications after V-SARR.
  
  
  METHODS
  Time-resolved three-dimensional phase-contrast MRI (4D flow) was used to image 12 patients with Marfan syndrome after V-SARR. The patients were followed up for an average of 5.8 years after imaging and 8.2 years after surgery. Additionally 5 volunteers were imaged for comparison. Flow profiles were visualized during peak systole using streamlines. Wall shear stress estimates and normalized flow displacement were evaluated at multiple planes in the thoracic aorta.
  
  
  RESULTS
  During the follow-up period, a single patient developed a Stanford Type B aortic dissection. At initial imaging, prior to the development of the dissection, the patient had altered flow patterns, wall shear stress estimates, and increased normalized flow displacement in the thoracic aorta in comparison to the remaining V-SARR patients and volunteers.
  
  
  CONCLUSIONS
  This is the first follow-up study of patients after 4D flow imaging. An aortic dissection developed in one patient with altered flow patterns and hemodynamic stresses in the thoracic aorta. These results suggest that flow and altered hemodynamics may play a role in the development of post-operative intramural hematomas and dissections.
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA, USA. Electronic address: tomhope@stanford.edu.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Hope
authors.forename: John-Peder Escobar
authors.initials: JP
authors.lastname: Kvitting
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hope
authors.forename: D Craig
authors.initials: DC
authors.lastname: Miller
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Herfkens
mesh_terms: D000328:Adult; D000784:Aortic Dissection / Q000175:diagnosis / Q000473:pathology*; D001013:Aorta, Thoracic / Q000473:pathology; D017545:Aortic Aneurysm, Thoracic / Q000175:diagnosis / Q000473:pathology*; D001021:Aortic Valve / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008382:Marfan Syndrome / Q000175:diagnosis / Q000473:pathology*; D008875:Middle Aged; D033081:Shear Strength; D013314:Stress, Mechanical; D013599:Systole; D013997:Time Factors
keywords: Aortic dissection; Magnetic resonance imaging; Marfan syndrome; Phase contrast; Valve-sparing aortic root replacement