Hahnemann University Hospital: A Single-Center Experience with Ventricular Assist Device Infections

Background: Because supply of donor hearts worldwide is limited, ventricular assist devices (VADs) have become an effective treatment option for many patients with end-stage heart disease as bridge to recovery, bridge to transplant, or destination therapy. Infections in VADs occur in 14–50% of patients and have been associated with high morbidity and mortality, as well as longer wait periods for heart transplants. We reviewed our center’s experience in recent years as it associates with outcome.

Objective: To determine the incidence of infection among VAD recipients at Hahnemann University Hospital (HUH) and to characterize the microbiology of these infections with a thorough review of sites of infections, pathogens isolated, associated risk factors and device type, and relation to clinical outcome.

Methods: A retrospective chart review of VAD recipients at HUH between August 2005 and February 2009 was conducted and data were collected on patient demographics, comorbidities, indication for VAD and VAD type, infection site, microbiology, antibiotic prophylaxis, treatment, and clinical outcomes.

Results: Overall attack rate was 29.4% (10/34) in the study period, with an incidence of infection of 1.82 per 1000 VAD-days using 5490 as the total VAD-days-at-risk, a figure that is lower than in previous studies. Bloodstream infections occurred in 4/34 patients evaluated (11.8%) or an incidence of 0.73 per 1000 VAD-days. All but one of the patients with VAD-related infections had other comorbidities, most commonly diabetes or chronic kidney disease. Longer hospitalization prior to implantation not surprisingly seems to favor infections, as does a longer total duration of eventual VAD support (350.4 days on average vs 147 days for those without infection). Average time to onset of infection in our series was 182.7 days (range 33–632 days). Of 10 patients with VAD-related infections, 4 eventually received transplantation, though with a longer wait time (mean of 377 days vs 83 days in the noninfected group). HeartMate II recipients had a 30% infection rate compared with almost 64% for recipients of the older HeartMate I. The majority of the isolates were gram positive (70%), mostly appearing singly except for a driveline infection, which had 2 coexisting gram-negative isolates at the site of infection. All patients with VAD-related infections received a long course of antibiotics usually until transplant or indefinitely.

Conclusions: A smaller device like HeartMate II can lead to a reduction in VAD-related infections, which otherwise can delay a patient’s chance at transplantation. Although the majority of our isolates were gram positive, prophylaxis should still cover gram-negatives, which predominated among our driveline-related infections. Onset of infections at our institution was at least a month from device placement and generally not immediately postoperatively.