Reduction of Flow-Induced Blood Damage in Bileaflet Mechanical Heart Valves Through Passive Flow Control

Abstract

Bileaflet mechanical heart valves (BMHVs), though a life-saving device in treating heart valve disease, are often associated with several complications including a high risk of hemolysis, platelet activation, and thromboembolism. To address this risk, patients must undergo prophylactic anticoagulation therapy. One likely cause of this hyper-coagulative state is the nonphysiologic levels of stress experienced by the erythrocytes and platelets flowing through the BMHVs. Research has shown that the combination of shear stress magnitude and exposure time found in the highly transient leakage jet emanating from the b-datum gap during valve closure is sufficient to cause hemolysis and platelet activation [1–3]. Reducing the shear stresses experienced by the blood flowing through the b-datum gap during valve closure may therefore reduce the prevalence of valve-related blood damage. Such shear stress reduction could be achieved by passive flow control, in particular vortex generators, incorporated onto the BMHV leaflet surface. Vortex generators have been used to control shear flows in various aerodynamic applications, and it is thus thought that their application to mechanical heart valve leaflet surfaces may reduce shear stresses by creating streamwise vortices that will serve to dissipate the regurgitant jet originating from the b-datum gap at the time of valve closure.