Evolution and impact of drive-line infection in a large cohort of continuous-flow ventricular assist device recipients

Background: Drive-line infections (DLIs) frequently complicate ventricular assist device (VAD) support. We sought to describe the detailed effects of DLIs over time in patients with continuous-flow VADs, including the onset, risk factors, organisms involved, association with invasive infections, and outcomes.

Methods: We reviewed data for patients with HeartMate II VADs (HMII) who were implanted at the Cleveland Clinic from October 2004 to September 2011 and followed through December 2011. DLIs were defined according to published criteria.

Results: DLIs developed in 45 of 194 HMII VADs over a median period of 232 days (range 22 to 883 days). Hazard for DLI was 2.0%/month, but transiently peaked at 11%/month at 7.5 months after implant. Pseudomonas aeruginosa accounted for 31%, 42% and 55% of initial, final and deep DLIs, respectively. Of the 40 superficial DLIs, 13 (32.5%) became deep. DLI-associated bacteremia and hospitalization occurred in 14 of 45 (31%) and 30 of 45 (67%), respectively. All patients received antibiotics (median 171 days), but only 3 of 44 (6.8%) developed an antibiotic complication. DLIs increased the risk for death while on VAD support (HR 2.20, 95% CI 1.20 to 4.05; p = 0.01). Six and 12 months after DLI, mortality was 9.8% and 31%, but the competing event of transplantation occurred successfully in 20% and 28%, respectively.

Conclusions: Most DLIs begin superficially with peak hazard at 7.5 months after implant. Depth of infection and infecting organism may evolve over months on support, with Pseudomonas becoming more prominent. Although effectively managed for prolonged periods, DLIs are associated with reduced survival on VAD support. Earlier transplantation is the most successful approach to treatment.