Enhanced risk of infection with device-associated thrombi

Thrombosis and infection are two well-recognized risks with prosthetic devices that contact blood. Many of the currently used biomaterials may present an attractive surface for thrombus development as well as bacterial adhesion and colonization. Clinical experience with vegetative endocarditis patients has suggested that thrombosis may lead to enhanced risk of infection, and the possibility that adherent bacteria may enhance the risk of thrombosis has been noted by several investigators. To investigate the correlation between thrombosis and infection, a series of tests were conducted to assess the affinity of pathogen with surfaces in the absence and presence of blood components. Coronary stents were used as a model device to attract thrombi in a recirculating loop in vitro. Fresh heparinized blood was used to investigate thrombus development and bacterial interaction. (111)Indium-labeled Staphylococcus epidermidis and (111)Indium-labeled platelets were utilized to quantify bacterial interaction with thrombi under various test conditions. Anticoagulants, antiplatelet agents, and antibiotics were utilized in attempts to selectively influence bacteria, platelets, or thrombosis. The results suggest that under appropriate conditions, bacteria may preferentially adhere to platelet rich thrombus. These observations also suggest that by reducing the risk of thrombosis, the risk of device-associated infection may also be reduced.