In Vitro Thrombogenicity Testing of Artificial Organs

Abstract

Thromboembolic complications remain as one of the main problems for blood contacting artificial organs such as heart valves, bloodpumps and others. In vitro evaluation of thrombogenesis in prototypes has not previously been part of the standard evaluation of these devices. In comparison to hemolysis testing, evaluation of the thrombogenic potential is more difficult to perform because of the complexity of the blood coagulation system. We present an in vitro testing procedure that allows the accelerated examination of the thrombogenic potential of different types of blood pumps. Additionally, first results are presented that indicate the reliability of the accelerated clotting test for mechanical heart valves. Results for the centrifugal pump BioMedicus and two microaxial pumps have shown typical thrombus formation at locations such as bearings. The results indicate that the accelerated clotting test is an excellent addition to the much more expensive animal testing of artificial organs or assist devices. In vitro testing permits studies of thrombus formation to be performed at an early stage and at low costs and also facilitates a more precise investigation of device areas known to be potential hot spots for thrombus formation.

Comparison of Symmetric Hemodialysis Catheters Using Computational Fluid Dynamics

“…Historically, the development of blood recirculating devices has focused on hemolysis as an indicator of flow-induced blood trauma (25). More recent work (26) has shown that device thrombogenicity is largely driven by platelet activation.…”

Platelet Activation Due to Hemodynamic Shear Stresses: Damage Accumulation Model and Comparison to In Vitro Measurements

“…42 It was indicated that the functional relationship could be fine-tuned by readjusting the coefficients in the formula according to in vitro data. It was concluded that the coefficients in the trauma prediction equations were not universal, rather depending on the flow conditions and may be valid only for predominantly laminar flows.…”

Influence of the Opening Mode of the Mitral Valve Orifice on Intraventricular Hemodynamics

“…1 The performance of these valves is evaluated in engineering terms, i.e., the noise level, 26 energy loss, 6,33 and regurgitation, 17 as well as biologically, i.e., hemolysis and the thrombogenicity of the valve itself. 9,23 These factors are linked mainly to the fluid dynamics near the valve. In contrast, relatively few studies have examined the hemodynamics downstream from the valve, despite the fact that if stagnation occurs in the ventricular cavity, the risk of thrombosis increases.…”