Leakage flow at mechanical heart valve prostheses: improved washout or increased blood damage?

摘要: BACKGROUND AND AIMS OF THE STUDY An essential problem of mechanical heart valve (MHV) prostheses is the risk thromboembolic events and consequent need lifetime anticoagulation due to unnatural hemodynamics that results in traumatization red blood cells platelets. The precise spatial tidal localization blood-damaging within flow poorly understood. present study addresses question whether leakage at MHV, which claimed improve washout hinge areas microthrombi platelet-activating agents, responsible for significant damage. METHODS This investigated vitro, primarily turbulent jets currently used valves. St. Jude Medical, Sorin Bicarbon, Duromedics-Edwards CarboMedics valves were analyzed mitral position a circulatory mock loop. Jet configuration was determined by echocardiography; velocity shear stress distributions measured using laser-Doppler anemometry (LDA). A damage index (BDI) developed terms lactate dehydrogenase release platelets hemoglobin (RBC), as function exposure time stresses field. BDIs validated direct measurement hemolysis caused flow, porcine blood. RESULTS All showed characteristic reproducible jet patterns, mainly emerging from areas. Maximum velocities up 1.7 m/s measured. > 80 Pa found. MHV revealed differences calculated BDIs. Bicarbon had significantly lower BDI RBC damage, well platelet damage; this measurements. CONCLUSIONS relevance leakage-induced demonstrated literature investigation type implant position.