Blood Flow Considerations to Minimize Thrombosis.

摘要

The report describes the investigation of the effects of flow on thrombus formation on artificial surfaces and assesses the significance of these effects to the design of artificial kidney systems. Experiments have been performed using two flow configurations: (1) separated flow regions forming within the stagnation point flow,and (2) pipe flow having a constant shear over its entire length. Results of these experiments have indicated that aggregation on foreign surfaces in the separated flow is limited primarily by the diffusion of platelets to the surface in the separated flow region. Surface aggregation downstream from the separated flow proceeds fastest where the degree of aggregation in the separated flow or stagnation flow directly upstream is greatest. Thus possibly indicating that the propagation of aggregation is due to the release of ADP or other activating agents from aggregating platelets. In low shear rate test chambers,surface aggregation occurs on the surface in the stagnation region and downstream from the step producing the separated region. Within the separated region, microemboli composed of platelet aggregates and white cells have been observed to form within the flow.