Development of an infection-resistant LVAD driveline: A novel approach to the prevention of device-related infections

Background: Infection remains the single most important challenge to extended left ventricular assist device (LVAD) use and often arises from the percutaneous driveline exit site. We evaluated the ability of an LVAD driveline prototype impregnated with chlorhexidine, triclosan, and silver sulfadiazine to resist bacterial and fungal colonization. Methods: The spectrum and duration of antimicrobial activity were evaluated in vitro by daily transfer of driveline segments embedded on agar plates inoculated with 10(8) colony-forming units (CFU) of Staphylococcus aureus (S. aureus), Staphlococcus epidermidis, Enterobacter aerogenes, Psuedomonas aeruginosa, and Candida albicans, and then measuring zones of inhibition around the sample subsequent to 24 hours of incubation at 37 degrees C. Antimicrobial activity was demonstrated against all organisms for greater than 14 days, and for over 21 days for gram-positive bacteria. To demonstrate in vivo efficacy of the treated driveline, 3-cm segments of driveline were implanted in the dorsal and ventral surface of rats. The exit site was inoculated with 10(6) CFU of S. aureus. After 7 days, driveline segments were aseptically explanted and assayed for bacterial colonization and retention of antimicrobial activity. One hundred percent of control segments were colonized (105 CFU S. aureus/cm) as against 13% of the test explants (less than or equal to 330 CFU/cm; p < 0.0001). Results: Subcultures of the insertion site and driveline pocket tissue resulted in 10(3) to 105 CFU per swab culture for control rats and 0 to 10(2) CFU/swab for test animals. Test drivelines retained 80% of anti-S. aureus activity. Gross and histological examination of the driveline and surrounding pocket revealed minimal tissue reactivity with positive signs,of tissue ingrowth. Conclusion: An antimicrobial driveline may prevent early infections and facilitate ingrowth of tissue to provide long-term stability and protection against late infection.