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 extend ed left ventricular assist device (LVAD) use and often arises from the perc utaneous driveline exit site. We evaluated the ability of an LVAD driveline prototype impregnated with chlorhexidine, triclosan, and silver sulfadiazi ne 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 i noculated with 10(8) colony-forming units (CFU) of Staphylococcus aureus (S . aureus), Staphlococcus epidermidis, Enterobacter aerogenes, Psuedomonas a eruginosa, and Candida albicans, and then measuring zones of inhibition aro und the sample subsequent to 24 hours of incubation at 37 degrees C. Antimi crobial activity was demonstrated against all organisms for greater than 14 days, and for over 21 days for gram-positive bacteria. To demonstrate in v ivo efficacy of the treated driveline, 3-cm segments of driveline were impl anted in the dorsal and ventral surface of rats. The exit site was inoculat ed with 10(6) CFU of S. aureus. After 7 days, driveline segments were asept ically explanted and assayed for bacterial colonization and retention of an timicrobial activity. One hundred percent of control segments were colonize d (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 resu lted in 10(3) to 105 CFU per swab culture for control rats and 0 to 10(2) C FU/swab for test animals. Test drivelines retained 80% of anti-S. aureus ac tivity. Gross and histological examination of the driveline and surrounding pocket revealed minimal tissue reactivity with positive signs,of tissue in growth. Conclusion: An antimicrobial driveline may prevent early infections and fac ilitate ingrowth of tissue to provide long-term stability and protection ag ainst late infection.