title: Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices: A Pilot Study.
abstract: BACKGROUND
  The effects of nonpulsatile flow on the aorta are unknown. Our aim was to examine the structure of the aorta from patients with continuous-flow left ventricular assist devices (LVADs) and directly measure aortic wall composition and stiffness.
  
  
  RESULTS
  Age-matched aortic wall samples were collected from consecutive patients with heart failure (HF) at the time of transplantation and compared with nonfailing donor hearts. An unbiased stereological approach was used to quantify aortic morphometry and composition, and biomechanical testing was performed to determine the stress-strain relationship of the vessel. Data were obtained from 4 patients without a left ventricular assist device (HF group: mean age, 58.3±8.0 years), 7 patients with a continuous-flow LVAD (HF+LVAD group: mean, 57.7±5.6 years), and 3 nonfailing donors (mean, 53.3±12.9 years). Compared with HF, the aortic walls from HF+LVAD had an increase in wall thickness, collagen, and smooth muscle content accompanied by a reduction in elastin and mucinous ground-substance content. Stress-strain curves from the aortas revealed increased vessel stiffness in HF+LVAD compared with HF and nonfailing. The physiological modulus of the aorta progressively stiffened from 74.3±5.5 kPa in the nonfailing to 134.4±35.0 kPa in the HF to 201.7±36.4kPa in the HF+LVAD groups (P<0.001).
  
  
  CONCLUSIONS
  Among continuous-flow LVAD patients without aortic valve opening, there are changes in the structure and composition of the aorta as well as an increase in aortic wall stiffness compared with age-matched HF patients and nonfailing donors. Further studies examining the role of nonpulsatile blood flow on aortic function and the potential resultant systemic sequelae are needed.
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.). Amrut.Ambardekar@ucdenver.edu.
authors.forename: Amrut V
authors.initials: AV
authors.lastname: Ambardekar
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
authors.forename: Kendall S
authors.initials: KS
authors.lastname: Hunter
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
authors.forename: Ashok N
authors.initials: AN
authors.lastname: Babu
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
authors.forename: Rubin M
authors.initials: RM
authors.lastname: Tuder
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
authors.forename: R Blair
authors.initials: RB
authors.lastname: Dodson
authors.affiliation: From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
authors.forename: JoAnn
authors.initials: J
authors.lastname: Lindenfeld
mesh_terms: D001013:Aorta, Thoracic / Q000473:pathology / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012189:Retrospective Studies; D059289:Vascular Stiffness / Q000502:physiology*; D016277:Ventricular Function, Left
keywords: aorta; collagen; elastin; heart failure; heart-assist devices; muscle, smooth; vascular stiffness