Catheter coatings, blood flow, and biocompatibility

Thrombus forms on catheters and other indwelling synthetic materials. Systemic heparin infusion decreases, but does not eliminate thrombus formation. The day is approaching when systemic heparinization may no longer be indicated to suppress catheter thrombogenesis. Passivation of catheters by heparin immobilization is not yet perfected, but progress is being made. A clearer picture is emerging of the factors that influence the activation of host defenses at foreign surfaces. As this occurs, new materials and surface finishes that take advantage of specific steps in the blood-foreign material interaction are being developed. Surfaces that either inhibit general protein adsorption or promote albumin adsorption appear to possess substantially improved biocompatibility.