Left Ventricular Assist Device Infection Research Articles

LVAD bloodstream infections: therapeutic rationale for transplantation after LVAD infection

Introduction Patients who have ventricular assist devices (VADs) and experience bloodstream infection (BSI) have high mortality. We addressed 2 questions raised by the United Network for Organ Sharing (UNOS) priority policy for this problem: 1) Are organs wasted on this ultra-high-risk group? 2) Can device-related BSI be differentiated from transient BSI? Methods Patients with VADs who underwent heart transplantation from 1987 to 2001, who had BSI during VAD support, and who had positive cultures at VAD explant (device-related BSI, n = 10) were compared with those with negative cultures at explant (non–device-related BSI, n = 11). Results Patients with device-related BSI had an 80% (8/10) rate of persistent bacteremia; 30 days and 1 year after transplantation, mortality was 14% and 26%, respectively. Non–device-related BSI ( n = 11) persisted in 18% (2/11); peri-operative and 1-year mortalities were 9% and 13%. Duration of VAD support predicted infection (132 vs 48 days, p < 0.001); hypo-albuminemia (2.9 ± 0.5 mg/dl vs 3.3 ± 0.8 mg/dl, p < 0.05), and a resistant organism predicted a device-related BSI. These patients had increased intubation requirements and had increased creatinine concentration during the first post-operative week, with no difference in liver function, blood loss, transfusions (packed red blood cells, fresh frozen plasma, or platelets), or hemodynamic stability vs patients with non-device BSI. Despite decreased immunosuppression, we found no difference in acute rejection events with device-related BSI. Re-infection with the pre-operative organism occurred in only 1 patient per group. Conclusions These data suggest that urgent (Status 1A) cardiac transplantation is effective in stable patients with device-related BSI, and these data support the current UNOS policy. However, an extra-device source of BSI should be excluded by considering the isolated organism, the baseline nutritional status, and other risk factors.

The use of muscle flaps to treat left ventricular assist device infections.

Left ventricular assist devices have become an important adjunct in the therapeutic armamentarium for patients with end-stage heart failure. Although they may provide a bridge to transplantation, they are prone to certain problems, expecially infection. Because these are life-sustaining devices, changing the device or simple explantation may be a risky, if not impossible, option. Therefore, we evaluated the effectiveness of a surgical alternative, namely, coverage of infected devices with muscle or myocutaneous flaps. Eighty-two consecutive patients who underwent the insertion of 88 left ventricular assist devices at our institution over a 6.5-year period were evaluated. Follow-up was provided for all patients and ranged from 1 to 7.5 years. The duration of ventricular support ranged from 0 to 434 days. All patients who demonstrated clinical evidence of infection were identified. Overall, 54 patients (66 percent) had infections locally at the device site, at distant sites, or systemically during support. Cultured organisms included gram-positive and -negative bacteria, fungi, and viruses. Of the 56 infections in these 54 patients, 21 (38 percent) were device-related, i.e., in the pocket created by the device, in the device itself, or from the driveline. Thus, 24 percent (21 of 88) of all ventricular support devices inserted demonstrated device infection during use. Therapeutic modalities used to combat device-related infection included both nonsurgical management with antibiotics alone and surgical procedures such as device change or relocation, device explant, and flap coverage. Eight of the 20 patients in whom the 21 device-related infections occurred underwent surgical intervention. Four of these eight patients undenwent local flap coverage of their infected left ventricular assist devices. All four patients also had evidence of systemic infection, or "device endocarditis." Coverage was successfully achieved in all cases with pedicled rectus abdominis flaps. There were no perioperative complications. Two patients later underwent successful transplantation; the other two died from causes unrelated to the flap. In conclusion, the treatment of infected left ventricular assist devices currently includes both nonsurgical and surgical alternatives. Of the latter, muscle flaps should be considered a first-line intervention to assist in eradicating infection by providing well-vascularized tissue. Although there were no perioperative complications, the 50 percent mortality rate is consistent with that reported for patients with "device endocarditis." It may be that flap coverage of infected ventricular assist devices, if instituted at an earlier stage in the therapeutic process, could help prevent systemic infection in these patients and, therefore, improve their overall outcome.

Management of Left Ventricular Assist Device Infection With Heart Transplantation

Background. Left ventricular assist devices (LVADs) are being used as bridges to heart transplantation (HT). Infection of the LVAD in this patient population represents a serious complication, as simple LVAD removal or delaying HT may result in death. To improve outcomes in this group of patients, we performed HT in the presence of LVAD infection. Methods. Eighteen patients underwent LVAD implantation followed by HT. Ten underwent HT in the absence of LVAD infection (group 1); and 8, in the presence of LVAD infection (group 2). All patients were treated similarly except for modification of immunosuppression in group 2 patients. Results. Infectious and noninfectious complications were equivalent between the two groups. There was no difference between groups in regard to intraoperative deaths (one versus none), long-term survival (8/10 versus 7/8), wound complications (three versus none), and mean length of hospital stay after HT (21 versus 26 days). Conclusions. Patients with LVAD infection are too seriously ill to allow LVAD removal or delay of HT. Transplantation in the face of infection is an effective treatment option.

Left Ventricular Assist Device Infection Is Associated With Increased Mortality but Is Not a Contraindication to Transplantation

Left ventricular assist devices (LVADs) are increasingly used as a bridge to transplantation. Infection is a frequent and major complication associated with the use of these devices, however, the correlation of infection and outcome has not yet been evaluated in a prospective fashion. Twenty-five patients (24 male, 1 female) with end-stage cardiac failure and resulting organ dysfunction were included. Patients were bridged with the Novacor N100 portable LVAD (median duration of support, 55 days) and were evaluated prospectively by device surface cultures on explantation, molecular typing of isolates, and correlation of infection with survival to transplant. Twelve (48%) of 25 patients had LVAD infection as defined by recovery of multiple isolates of identical genotype from the device surface. Whereas only 5 (42%) of 12 patients with LVAD infection survived until transplantation, 11 (85%) of 13 patients without infection were successfully transplanted (P < .05). Death of the 7 patients with proven LVAD infection was associated with multiple organ failure or other signs of acute infection. LVAD infection is associated with a significantly decreased survival probability. It does not preclude successful bridging but rather may pose an indication for urgent transplantation.

Implantable LVAD infections: Implications for permanent use of the device

Infection in implantable left ventricular assist device (LVAD) patients is common and has serious implications regarding permanent use of the LVAD. Thirty-three patients had HeartMate LVAD insertion as a bridge to heart transplantation. The mean length of hospital stay was 8 days before LVAD insertion. Before insertion 6 patients (18%) had positive pulmonary cultures and 5 patients (15%) had bacteremia. During LVAD support 18 patients (55%) had bloodstream infection. Of 24 patients (73%) successfully bridged to transplantation, 12 (50%) had positive blood cultures including Staphylococcus species (n = 9), Candida (n = 3), Pseudomonas (n = 2), and Enterococcus (n = 2). Infectious complications encountered in this series included driveline infection requiring surgical revision, septic embolus, "cleared" device infection, "suppressed" device infection, and LVAD infection treated by device removal in 1 patient and device exchange in another. Infection in implantable LVAD patients is common, especially in patients in whom multiple organ failure develops, requiring prolonged stay in the intensive care unit. Strategies are needed to prevent these infections in recipients of the permanent LVADs because treatment of an established infection is difficult and expensive.

Chemical reactivity factor for metallic sulphide lubricants: Thelen, E. and Devine, M. J. Transactions of the American Society of Lubrication Engineers, Vol 10, No 4 (October–December 1967) p386

Left ventricular assist device (LVAD) infections including drivelines, pump pockets, and bacteremia are difficult to manage and conservative treatments may not be effective as the infected foreign material remains.We performed a retrospective analysis of all 170 HeartMate II (Thoratec, Pleasanton, CA) implantations as bridge to transplant (BTT) between 2004 and 2012 at our institution. Sixty-one patients (36%) developed a culture positive driveline infection, pump pocket infection, bacteremia, or a combination of these. Twenty-six out of 61 patients with an infection and 49 out of 109 patients without an infection went on to receive a heart transplant.The 1- and 3-year freedom from LVAD infection was 60% and 32%, respectively. While early infection tends to first present as driveline infections, late infections tend to present initially as bacteremia. The 1-year likelihood of receiving a transplant in the patients with an LVAD infection group was 37%, compared with 43% in patients without an infection (p = 0.36). One-year survival to transplantation was 76% in patients with LVAD infection compared with 81% without (p = 0.33). The 1- and 3-year posttransplant survival in patients with a LVAD infection was 96% and 91%, respectively, compared with 92% and 88% in patients without an infection (p = 0.48) .In this nonmatched cohort of LVAD patients with and without infection, selected patients with controlled LVAD infection have an equal chance of getting transplanted with excellent early and late post-transplant survival.