title: Velocity fields and turbulent stresses downstream of biological and mechanical aortic valve prostheses implanted in pigs.
abstract: Since detailed knowledge about velocity fields downstream of heart valve prostheses obtained from in vitro studies has not been followed up by similar detailed studies in vivo a pig model for acute velocity field studies downstream of aortic valve prostheses was established. Two mechanical and two bioprosthetic valves were studied and a dynamic three dimensional visualisation of velocity fields one diameter downstream performed under different haemodynamic conditions in a total of 22 pigs. The Ionescu-Shiley pericardial valve had velocity fields very similar to the normal native porcine aortic valve. The Edwards-Carpentier porcine valve caused a jet type flow, and the valve design of the St Jude Medical and Björk-Shiley Monostrut valves was reflected in the velocity profile. Normalised (mean(SEM] systolic Reynolds normal stresses in the total cross sectional area were: native porcine 15(1.5) Nm-2; St Jude Medical 24(3.4) Nm-2; Björk-Shiley Monostrut 25(1.6) Nm-2; Edwards-Carpentier Supra-annular 51(6.6) Nm-2; Ionescu-Shiley Pericardial 19(2.0) Nm-2. Reynolds normal stresses were higher in areas of rapidly changing or constantly high velocity gradients.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Aarhus Kommunehospital, Denmark.
authors.forename: J M
authors.initials: JM
authors.lastname: Hasenkam
authors.forename: E M
authors.initials: EM
authors.lastname: Pedersen
authors.forename: J H
authors.initials: JH
authors.lastname: Ostergaard
authors.forename: H
authors.initials: H
authors.lastname: Nygaard
authors.forename: P K
authors.initials: PK
authors.lastname: Paulsen
authors.forename: G
authors.initials: G
authors.lastname: Johannsen
authors.forename: B A
authors.initials: BA
authors.lastname: Schurizek
mesh_terms: D000818:Animals; D001021:Aortic Valve; D001705:Bioprosthesis; D001783:Blood Flow Velocity; D002302:Cardiac Output; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D008955:Models, Cardiovascular; D012212:Rheology; D013552:Swine; D013599:Systole