title: The Ross procedure: biomechanical properties of the pulmonary artery according to aortic valve phenotype.
abstract: The aim of this study is to determine whether patients undergoing the Ross procedure with bicuspid aortic valves have pulmonary artery biomechanical properties different from those with tricuspid valves.
  
  
  
  Thirty-two pulmonary arteries and 20 aortas were obtained from patients undergoing the Ross procedure at the time of surgery, from a cohort of 32 patients. The aortic valve was tricuspid in 5 patients (16%), bicuspid in 18 patients (56%) and unicuspid in 9 patients (28%). Histological analysis and ex vivo equi-biaxial tensile testing completed within 8 hours of surgery were used to evaluate differences in patient groups and between the pulmonary artery and the ascending aorta.
  
  
  
  There was no difference in thickness among pulmonary arteries when compared according to aortic valve phenotype (P = 0.94). There was no difference in the tensile tissue properties among aortas and pulmonary arteries when compared according to aortic valve phenotype, in either the circumferential or longitudinal axis. When compared according to the main surgical indication, pulmonary artery walls from patients with pure aortic regurgitation were less stiff than their counterparts (aortic regurgitation: 0.055 ± 0.037 MPa, aortic stenosis: 0.103 ± 0.051 MPa, mixed disease: 0.110 ± 0.044 MPa and aortic valve endocarditis: 0.216 ± 0.033 MPa, P = 0.002). There was no difference in the number of elastic lamellae in pulmonary artery specimens from the three different aortic valve phenotypes, as well as in the aortic specimens.
  
  
  
  No significant differences were observed in the biomechanical properties of pulmonary arteries when compared according to aortic valve phenotype.
authors.affiliation: Division of Cardiac Surgery, Montreal Heart Institute and Université de Montréal, Montreal, Canada.
authors.forename: Pierre Olivier
authors.initials: PO
authors.lastname: Dionne
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, QC, Canada.
authors.forename: Evan
authors.initials: E
authors.lastname: Wener
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, QC, Canada.
authors.forename: Alexander
authors.initials: A
authors.lastname: Emmott
authors.affiliation: Division of Cardiac Surgery, Montreal Heart Institute and Université de Montréal, Montreal, Canada.
authors.forename: Raymond
authors.initials: R
authors.lastname: Cartier
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada.
authors.forename: Rosaire
authors.initials: R
authors.lastname: Mongrain
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, QC, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Leask
authors.affiliation: Division of Cardiac Surgery, Montreal Heart Institute and Université de Montréal, Montreal, Canada i.elhamamsy@icm-mhi.org.
authors.forename: Ismail
authors.initials: I
authors.lastname: El-Hamamsy
mesh_terms: D000328:Adult; D001021:Aortic Valve / Q000002:abnormalities* / Q000503:physiopathology / Q000601:surgery; D001022:Aortic Valve Insufficiency / Q000503:physiopathology* / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000503:physiopathology* / Q000601:surgery; D000082882:Bicuspid Aortic Valve Disease; D004548:Elasticity; D004696:Endocarditis / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006349:Heart Valve Diseases / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011651:Pulmonary Artery / Q000473:pathology / Q000503:physiopathology*; D014261:Tricuspid Valve / Q000503:physiopathology*
keywords: Biomechanics; Dilatation; Pulmonary artery; Ross procedure