title: A low-volume tester for the thrombogenic potential of mechanical heart valve prostheses.
abstract: OBJECTIVE
  During the development of a mechanical heart valve prosthesis, many studies are conducted to guarantee its correct function. Currently, investigations into the thrombogenic potential of a valve after its replacement are conducted with expensive and time-consuming chronic animal trials. Hence, the study aim was to develop and test an alternative system to resolve such thrombogenic issues.
  
  
  METHODS
  The Thrombosis Tester of the Helmholtz Institute Aachen (THIA II) has a reasonably small priming volume (220-270 ml) that allows analysis of the thrombogenic potential of two valves, using one human blood bottle.
  
  
  RESULTS
  Hydrodynamic evaluation demonstrated an absolutely stable physiological pressure and flow progression at the aortic and pulmonary positions. A sinus geometry of the human aortic root is implemented downstream of the valve in order to guarantee physiological leaflet motion. The tester remained absolutely thrombus-free during several tests carried out with minimally anticoagulated porcine blood, while the valves showed reproducible thrombus formation in reasonable locations. Tests with fully heparinized porcine blood showed that a soft silicon fixture for the valve could reduce hemolysis in the THIA II.
  
  
  CONCLUSIONS
  This in-vitro test protocol can enable the optimization of a valve design during the early stages of its research and development. The system can provide a unique and suitable supplement to animal trials for testing thrombogenic performance, under constant and reproducible boundary conditions, including considerable physiological and pathological circumstances such as the influence of valve position (aortic, pulmonic), and a comparison of different valve types.
authors: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany. linde@hia.rwth-aachen.de
authors: Torsten
authors: T
authors: Linde
authors: Kathrin F
authors: KF
authors: Hamilton
authors: Daniel L
authors: DL
authors: Timms
authors: Thomas
authors: T
authors: Schmitz-Rode
authors: Ulrich
authors: U
authors: Steinseifer
mesh_terms: D000826:Animal Testing Alternatives / Q000295:instrumentation*; D001777:Blood Coagulation; D004867:Equipment Design; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D057446:Hydrodynamics; D008422:Materials Testing; D013927:Thrombosis / Q000209:etiology* / Q000517:prevention & control