Large bore catheters with surface treatments versus untreated catheters for vascular access in hemodialysis.

Infection, thrombosis, and stenosis are among the most frequent complications associated with blood-contacting catheters. Complications resulting from infection remain a major problem for hemodialysis catheters, with significant numbers of catheters being removed due to catheter-related sepsis. Numerous strategies have been employed to reduce the occurrence of infection and im-prove long-term outcomes, with varying degrees of success. The most important is the careful and sterile handling by the attending staff of the catheters during hemodialysis treatments to minimize or stop a microbial colonization of the skin and the catheter. Another approach is coating the external surface of the catheters with substances which are antibacterial like silver and/or substances with low thrombogenicity like silicone. This investigation reviews results of animal and clinical experiments conducted to assess the efficacy and biocompatibility of silver and silicone coated dialysis catheters. It is concluded that silver coatings can reduce bacterial colonization and occurrence of infection associated with these devices. The catheters employing ion implantation of silicone rubber showed low thrombogenicity. Results of the studies indicate that ion beam based processes can be used to improve thrombus and infection resistance of blood contacting catheters. A new development is the microdomain structured surface (PUR-SMA coated catheters). Preliminary results with these catheters are very encouraging.

Long-term catheters for apheresis and dialysis with surface treatment with infection resistance and low thrombogenicity.

Infection, thrombosis, and stenosis are among the most frequent complications associated with blood-contacting catheters. These problems are usually related to surface properties of the base catheter material. Surface treatment processes, such as ion implantation and ion beam assisted deposition (IBAD) and microdomain structured surfaces, can be used to mitigate such complications. This study evaluated silver coated and implanted large bore catheters used for extracorporeal detoxification. In a 186 patient prospective study, 225 large bore catheters were inserted into the internal jugular or subclavian veins. Eighty-five surface-treated catheters (Spi-Argent, Spire Corporation, Bedford, MA, USA) and 28 catheters with surface treatment (Spi-Silicone, Spire Corporation) were inserted in 90 patients. One hundred and twelve untreated catheters placed in 96 patients served as controls, After removal, the catheters were cultured for bacterial colonization using standard microbiologic assays. They also were examined using a scanning electron microscope (SEM). Bacterial colonization was observed in 8% of the treated catheter compared with 46.4% of untreated catheters. The SEM investigations showed all treated catheters to possess low thrombogenicity. Catheters with microdomain structured surfaces showed same results in preliminary observation. The surface treatments of the large bore catheters can be used to improve thrombus and infection resistance of blood contacting catheters.