title: Effect of mechanical aortic valve orientation on coronary artery flow: comparison of tilting disc versus bileaflet prostheses in pigs.
abstract: OBJECTIVE
  Orientation for optimal systolic performance of tilting disc and bileaflet aortic valves was defined in previous studies. The present study investigates the influence of valve orientation on coronary artery flow in an animal model.
  
  
  METHODS
  A rotation device holding either a Medtronic Hall tilting disc (n = 4; Medtronic, Inc, Minneapolis, Minn), a St Jude Medical bileaflet (n = 4; St Jude Medical, Inc, St Paul, Minn), or a Medtronic Advantage bileaflet (n = 3) aortic valve was implanted. The device allowed rotation of the valve without reopening the aorta. Flow through the left anterior descending coronary artery was measured preoperatively and at normal versus high cardiac output after weaning from extracorporeal circulation. Measurements were performed at the best and worst hemodynamic position, as defined previously.
  
  
  RESULTS
  Coronary flow rates were similar in all animals preoperatively (26 +/- 4.1 mL/min). After aortic valve replacement, left anterior descending flow increased significantly to 58.2 +/- 10.6 mL/min. Highest flow rates at normal cardiac output were found in the optimum orientation, especially for the Medtronic valves (Medtronic Hall, 64 +/- 8.7 mL/min; Medtronic Advantage, 64.6 +/- 11.6 mL/min; St Jude Medical, 48.3 +/- 10.3 mL/min), whereas the worst position demonstrated significantly lower left anterior descending flow, with no differences among valves (Medtronic Hall, 37.5 +/- 1.3 mL/min; St Jude Medical, 35.7 +/- 10.7 mL/min; Medtronic Advantage, 39.8 +/- 10 mL/min). Left anterior descending artery flow increased significantly with higher cardiac output.
  
  
  CONCLUSIONS
  Coronary blood flow was significantly influenced by mechanical aortic valve implantation and the orientation of prostheses. For both valve designs, the previously defined optimum orientation with respect to pressure gradients and turbulence demonstrated the highest left anterior descending flow rates. Even in its optimum orientation, the St Jude Medical valve showed significantly lower coronary flow than the other valves.
authors.affiliation: Department of Thoracic & Cardiovascular Surgery and the Department of Biomedical Statistics, Johann-Wolfgang-Goethe University, Frankfurt/Main, Germany. P.Klien@em.uni-frankfurt.de
authors.forename: Peter
authors.initials: P
authors.lastname: Kleine
authors.forename: Mirella
authors.initials: M
authors.lastname: Scherer
authors.forename: Ulf
authors.initials: U
authors.lastname: Abdel-Rahman
authors.forename: Armin A
authors.initials: AA
authors.lastname: Klesius
authors.forename: Hans
authors.initials: H
authors.lastname: Ackermann
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000502:physiology* / Q000601:surgery*; D001158:Arteries / Q000737:chemistry* / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003331:Coronary Vessels / Q000737:chemistry* / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D005858:Germany; D006339:Heart Rate / Q000502:physiology; D019918:Heart Valve Prosthesis Implantation; D023421:Models, Animal; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D012016:Reference Values; D013552:Swine; D013599:Systole / Q000502:physiology; D016896:Treatment Outcome