Prosthetic Heart Valves

About

Summary: It is well established that adverse events (such as blood element or cell damage, thrombus formation, and platelet activation) can be caused by flow-induced shear stresses. These factors may seriously limit the performance of a broad range of devices used to transport biological fluids. By way of non-limiting example, such devices include cardiovascular hardware, prosthetic valves, stents, bypass pumps, and flow-assist devices as well as conduits for transporting such fluids. In particular, there exists a large body of scientific literature that has emphasized the significant risk associated when blood elements are subjected to non-physiological hemodynamic shear stresses in in-vivo devices (heart valves, flow assist devices etc.), and the severe limitations of non in-vivo devices (bypass pumps, dialysis machines, heart-lung instruments, or syringe needles, etc.).  Implanted ventricular assist devices (VADs) have also been implicated in thromboembolic events. Other known examples of blood damage in cardiovascular systems include centrifugal blood pumps that are used during bypass surgery and have been shown to cause hemolysis and platelet activation, which can lead to thromboembolism. Also, blood flow over surfaces of vascular stents (coronary or peripheral stents) can induce shear stress resulting in thrombus formation.  There exists a need for systems and methods for flow control devices that can minimize the magnitude of shear stresses experienced by blood elements This invention consists of various devices for use in combination with a fluid flow having a biologic component and subject to an adverse response to shear stress. The device includes a surface in contact with the flow of the fluid. The surface has a longitudinal direction extending from a leading end toward a trailing end and aligned with a direction of the flow. The device is susceptible to fluid flow phenomena including boundary layer formation within the flow sufficient for a resulting shear stress to induce the thrombogenic response, or free shear flow formation such as jet, separation zones of sufficient characteristic to induce the thrombogenic response. The surface includes a surface feature sufficient to alter the fluid flow such as to reduce the overall shear stress that the biologic components may encounter while transiting through the device.