Relapsing bacteremia in patients with ventricular assist device: an emergent complication of extended circulatory support

Management and outcomes of left ventricular assist device-associated endocarditis: a systematic review

Background

Left ventricular assist device (LVAD)-associated endocarditis remains poorly studied, especially in newer continuous-flow LVADs (CF-LVADs). The aim of this review was to assess outcomes of patients with LVAD-associated endocarditis, as stratified by CF-LVAD and pulsatile LVAD (P-LVAD) use as well as by different interventions and pathogen types.

Methods

An electronic search was performed to identify studies in the English literature on LVAD-associated endocarditis.

Results

Overall, 16 articles with 26 patients were included; seven had CF-LVADs and 19 had P-LVADs; time to development of endocarditis was 91 days (152 vs. 65 days, respectively, P=0.05). Eleven of 25 patients were treated with antibiotics only. Remaining 14 patients received antibiotics, however, they also underwent additional surgical intervention. One patient was treated with embolization alone for mycotic aneurysm and was therefore excluded. At a median follow-up time of 344 days post implant, there was no difference in overall mortality between CF-LVAD and P-LVAD-associated endocarditis patients (57.9% vs. 42.9%, P=0.81). Patients who underwent additional surgical intervention had higher overall survival compared to those treated with antibiotics alone (71.4% vs. 27.3%, P=0.07); with no difference in outcomes amongst those who underwent surgical device exchange as compared to heart transplantation (80.0% vs. 66.7%; P=0.23).

Conclusions

Compared to patients with P-LVADs, CF-LVAD patients appeared to be resistant to early development of LVAD-associated endocarditis. There was a trend towards high survival observed amongst patients who underwent additional surgical intervention as compared to those treated with antibiotics alone, with no difference amongst surgical device exchange as compared to heart transplantation. Advantages of additional surgical intervention vs. medical therapy alone deserves further exploration to determine its applicability in CF-LVADs.

Ventricular assist device-related infections and solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

The Infectious Diseases Community of Practice of the American Society of Transplantation has published evidenced-based guidelines on the prevention and management of infectious complications in SOT recipients since 2004. This updated guideline reviews the epidemiology of ventricular assist device (VAD) infections and provides recommendations for the management and prevention of these infections. Almost one half of those awaiting heart transplantation are supported with VADs. Despite advances in device technologies, VAD infections commonly complicate mechanical circulatory support and remain typified by common components and anatomic locations. These infections have important implications for transplant candidates, most notably increased wait-list mortality. Strategic management of these infections is crucial for successful transplantation. Coincidentally, explantation of all VAD components at the time of transplantation is often the definitive cure for the device-associated infection. Highlighted in this updated guideline is the reported success of transplantation in patients with a variety of pre-existing VAD infections and guidance on post-transplant management strategies.

Successful heart transplantation in patients with active Staphylococcus bloodstream infection and suspected mechanical circulatory support device infection

BACKGROUND

An active bloodstream infection (BSI) is typically considered a contraindication to heart transplantation (HT). However, in some patients with Staphylococcus bacteremia and mechanical circulatory support device infection, positive blood cultures may persist until removal of the infected device, and eradicating the infection prior to HT may not be possible. We report the outcomes of six patients with active Staphylococcus BSI at the time of HT.

METHODS

All cases of HT performed at The Mount Sinai Hospital from 2009 through 2015 were reviewed. All patients with a mechanical circulatory support device and an active Staphylococcus BSI at the time of HT were included.

RESULTS

Six patients with active Staphylococcus bacteremia and suspected mechanical circulatory support device infection underwent HT. All patients were bacteremic with Staphylococcus species at the time of HT. All were managed with antimicrobial therapy, radical debridement at the time of HT, and limited use of immunosuppression, and all survived until hospital discharge with no evidence of relapsed Staphylococcus infection.

CONCLUSION

These results suggest that some carefully selected patients with active Staphylococcus bacteremia and suspected mechanical circulatory support device infection may safely undergo HT, and that HT may effectively eliminate the underlying infection.

Prevention and Infection Management in Mechanical Circulatory Support Device Recipients

There are currently no guidelines for the management of infection and its prevention in mechanical circulatory support (MCS) device recipients. The International Society of Heart and Lung Transplantation (ISHLT) has initiated a multidisciplinary collaboration for the creation of a consensus document to guide clinicians in infection prevention and management in MCS patients. Most medical centers use local protocols that are based on expert opinion. MCS recipients are debilitated and have some immunological dysfunction. Over the years there have been technical advancements with smaller devices and drivelines with improved durability. The pulsatile devices have been replaced with newer-generation continuous-flow devices. Patient are living longer with MCSs for bridge to transplant (BTT) and destination therapy (DT). MCS centers have improved patient management by introducing standardized driveline protocols, leading to reduced infection rates among MCS recipients.

Prevention of percutaneous driveline infection after left ventricular assist device implantation: prophylactic antibiotics are not necessary

Infection is a major source of morbidity and mortality after ventricular assist device (VAD) implantation. The percutaneous driveline is the most common site of infection in these patients and often serves as a portal to deeper pump infections. There are no data defining the role of prophylactic antibiotics in preventing these infections. We compared all patients who underwent primary HeartMate II VAD implantation at two different institutions employing two different driveline infection prevention strategies between February 2007 and September 2011. While all patients received perioperative antibiotics, driveline maintenance strategies included sterile dressing changes with Hibiclens application without continued prophylactic antibiotics (Abx) (Mayo Clinic, n = 141, No Abx) and sterile dressing changes with continued prophylactic antibiotics (University of Michigan Hospital, n = 144, Abx). Although gender was similar between cohorts (Abx: 79% male vs. No Abx: 84% male, p = 0.25), median age at implant (Abx: 59 vs. No Abx: 64, p = 0.001) and destination therapy as indication for VAD (Abx: 22% vs. No Abx: 60%, p < 0.001) were significantly different. Follow-up was available in all late survivors (Abx: 140 patients, No Abx: 127 patients). Median duration of support was similar between groups (Abx: 12.3 months vs. No Abx: 11 months, p = 0.44). Total patient-years of device support were 172 years for 140 patients in the Abx cohort and 146 years for 127 patients in the No Abx cohort. Driveline drainage/infection was observed in 25 of 140 patients (18%) in the Abx group and 16 of 127 (13%) in the No Abx group (p = 0.15). Device exchange for major driveline infection was performed in seven patients in the Abx group and 0 patients in the No Abx group. Total driveline infection events per patient-years of support were 0.15 for the Abx group and 0.11 in the No Abx group (p = 0.43). There was no significant difference in the raw incidence of major driveline infections or driveline infections per patient-years of support in patients who were maintained on prophylactic antibiotics compared with those who were not. These data suggest that other factors may be more important than prophylactic antibiotics in preventing driveline infections.

Laparoscopic cholecystectomy in patients with HeartMate II left ventricular assist devices

INTRODUCTION

With an expanding population of patients requiring ventricular assist devices, it is inevitable that these patients will require noncardiac surgery. Ventricular assist devices provide mechanical support for a failing heart either as a bridge to transplant or now as a long-term support if transplant is not available, so-called destination therapy. These devices can add significant technical challenges to abdominal surgery, in that the power supply and drivelines crossing the abdomen can potentially be damaged. The use of preoperative or intraoperative imaging may aid in locating these devices and increase patient safety.

MATERIALS AND METHODS

We describe a laparoscopic cholecystectomy in two patients supported with HeartMate(®) II (Thoratec Corp., Pleasanton, CA) left ventricular assist devices. Our use of fluoroscopic guidance in port placement is also described. A literature review was performed to assess the frequency of laparoscopic procedures performed on patients with similar ventricular assist devices and of complications associated with the device and other comorbidities.

RESULTS

Laparoscopic cholecystectomy was performed without significant intraoperative hemodynamic changes. The use of imaging, such as fluoroscopy, can identify the location of the ventricular assist device and its associated drive wires to assure they are not damaged intraoperatively.

CONCLUSIONS

Laparoscopic cholecystectomy can be performed safely on patients with ventricular assist devices. Complications due to damage to the device can be avoided with the assistance of fluoroscopy to identify the implanted abdominal portions of the ventricular assist device. Each laparoscopic procedure performed on these patients presents the surgeon with unique obstacles in which careful operative planning and intraoperative monitoring are essential.

Clinical manifestations and management of left ventricular assist device-associated infections

BACKGROUND

Infection is a serious complication of left ventricular assist device (LVAD) therapy. Published data regarding LVAD-associated infections (LVADIs) are limited by single-center experiences and use of nonstandardized definitions.

METHODS

We retrospectively reviewed 247 patients who underwent continuous-flow LVAD implantation from January 2005 to December 2011 at Mayo Clinic campuses in Minnesota, Arizona, and Florida. LVADIs were defined using the International Society for Heart and Lung Transplantation criteria.

RESULTS

We identified 101 episodes of LVADI in 78 patients (32%) from this cohort. Mean age (± standard deviation [SD]) was 57±15 years. The majority (94%) underwent Heartmate II implantation, with 62% LVADs placed as destination therapy. The most common type of LVADIs were driveline infections (47%), followed by bloodstream infections (24% VAD related, and 22% non-VAD related). The most common causative pathogens included gram-positive cocci (45%), predominantly staphylococci, and nosocomial gram-negative bacilli (27%). Almost half (42%) of the patients were managed by chronic suppressive antimicrobial therapy. While 14% of the patients had intraoperative debridement, only 3 underwent complete LVAD removal. The average duration (±SD) of LVAD support was 1.5±1.0 years. At year 2 of follow-up, the cumulative incidence of all-cause mortality was estimated to be 43%.

CONCLUSION

Clinical manifestations of LVADI vary on the basis of the type of infection and the causative pathogen. Mortality remained high despite combined medical and surgical intervention and chronic suppressive antimicrobial therapy. Based on clinical experiences, a management algorithm for LVADI is proposed to assist in the decision-making process.

Impact of adverse events on ventricular assist device outcomes

Left ventricular assist devices have been proven to be superior to medical therapy for advanced heart failure patients awaiting heart transplantation and viable alternatives to transplantation for destination therapy patients. Improvements in the design of ventricular assist devices have been rewarded by a decrease in adverse events and an increase in survival. Despite significant progress, even the latest generation left ventricular assist devices are burdened by a significant long-term adverse events profile that will increasingly challenge physicians as patients survive longer on implantable mechanical circulatory support. In this review, we analyze the impact of long-term adverse events on clinical outcomes in the major trials of continuous flow left ventricular assist devices. We discuss several of the more pertinent and interesting adverse events, examine their potential causes, and explore their future implications.

Feasibility of robotic-assisted laparoscopic nephroureterectomy in left ventricular assist device patient

Left ventricular assist devices (LVADs) have revolutionized management options for patients with advanced heart failure. It is not uncommon for patients treated with these devices to present with noncardiac surgical conditions including urologic problems. Maintaining perioperative hemodynamic and hematologic stability is a special challenge. The minimally invasive surgery provides well-documented advantages over the open approach including a less operative blood loss and faster convalescence. In carefully selected patients, robotic-assisted surgery can be utilized in the management of patients with complex urologic diseases in a dire need for these benefits. We present the first case of robotic-assisted laparoscopic nephroureterectomy (RANU) with retroperitoneal lymph node dissection for upper tract transitional cell carcinoma (TCC) in a patient treated with LVAD.

Infections occurring in adult patients receiving mechanical circulatory support: the two-year experience of an Italian National Referral Tertiary Care Center

OBJECTIVE

Infection during mechanical circulatory support is a frequent adverse complication. We analyzed infections occurring in this population in a national tertiary care center, and assessed the differences existing between the setting of extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs).

DESIGN, SETTING, AND PARTICIPANTS

An observational study was made of patients treated with ECMO or VAD in the San Raffaele Scientific Institute (Italy) between 2009 and 2011.

INTERVENTIONS

None.

RESULTS

Thirty-nine percent of the 46 patients with ECMO and 69% of the 15 patients with VAD developed infection. We observed a mortality rate of 36.1% during mechanical circulatory support and of 55.7% during the global hospitalization period. Although Gram-negative infections were predominant overall, patients with ECMO were more prone to develop Candida infection (29%), and patients with VAD tended to suffer Staphylococcus infection (18%). Patients with infection had longer ECMO support (p=0.03), VAD support (p=0.01), stay in the intensive care unit (p=0.002), and hospital admission (p=0.03) than patients without infection. Infection (regression coefficient=3.99, 95% CI 0.93-7.05, p=0.02), body mass index (regression coefficient=0.46, 95% CI 0.09-0.83, p=0.02), fungal infection (regression coefficient=4.96, 95% CI 1.42-8.44, p=0.009) and obesity (regression coefficient=10.47, 95% CI 1.77-19.17, p=0.02) were predictors of the duration of ECMO support. Stepwise logistic regression analysis showed the SOFA score at the time of implant (OR=12.33, 95% CI 1.15-132.36, p=0.04) and VAD (OR=1.27, 95% CI 1.04-1.56, p=0.02) to be associated with infection.

CONCLUSIONS

Infection is a major challenge during ECMO and VAD support. Each mechanical circulatory support configuration is associated with specific pathogens; fungal infections play a major role.

Role of biofilm in Staphylococcus aureus and Staphylococcus epidermidis ventricular assist device driveline infections

OBJECTIVE

Infections, especially those involving drivelines, are among the most serious complications that follow ventricular assist device implantation. Staphylococci are the most common causes of these infections. Once driveline infections are established, they can remain localized or progress as an ascending infection to cause metastatic seeding of other tissue sites. Although elaboration of biofilm appears to be critical in prosthetic device infections, its role as a facilitator of staphylococcal infection and migration along the driveline and other prosthetic devices is unclear.

METHODS

A murine model of driveline infection was used to investigate staphylococcal migration along the driveline. A biofilm-producing strain of Staphylococcus epidermidis and a Staphylococcus aureus strain and its intercellular adhesion gene cluster (ica)-negative (biofilm-deficient) isogenic mutant were used in these studies. Bacterial density on the driveline and the underlying tissue was measured over time. Scanning electron microscopy was used to examine the morphology of S epidermidis biofilm formation as the infection progressed.

RESULTS

The biofilm-deficient S aureus mutant was less effective at infecting and migrating along the driveline than the wild-type strain over time. However, the ica mutation had no effect on the ability of the strain to infect underlying tissue. S aureus exhibited more rapid migration than S epidermidis. Scanning electron microscopy revealed the deposition of host matrix on the Dacron material after implantation. This was followed by elaboration of a bacterial biofilm that correlated with more rapid migration along the driveline.

CONCLUSIONS

Biofilm formation is a critical virulence determinant that facilitates the progression of drivelines infections.

SdrF, a Staphylococcus epidermidis surface protein, contributes to the initiation of ventricular assist device driveline-related infections

Staphylococcus epidermidis remains the predominant pathogen in prosthetic-device infections. Ventricular assist devices, a recently developed form of therapy for end-stage congestive heart failure, have had considerable success. However, infections, most often caused by Staphylococcus epidermidis, have limited their long-term use. The transcutaneous driveline entry site acts as a potential portal of entry for bacteria, allowing development of either localized or systemic infections. A novel in vitro binding assay using explanted drivelines obtained from patients undergoing transplantation and a heterologous lactococcal system of surface protein expression were used to identify S. epidermidis surface components involved in the pathogenesis of driveline infections. Of the four components tested, SdrF, SdrG, PIA, and GehD, SdrF was identified as the primary ligand. SdrF adherence was mediated via its B domain attaching to host collagen deposited on the surface of the driveline. Antibodies directed against SdrF reduced adherence of S. epidermidis to the drivelines. SdrF was also found to adhere with high affinity to Dacron, the hydrophobic polymeric outer surface of drivelines. Solid phase binding assays showed that SdrF was also able to adhere to other hydrophobic artificial materials such as polystyrene. A murine model of infection was developed and used to test the role of SdrF during in vivo driveline infection. SdrF alone was able to mediate bacterial adherence to implanted drivelines. Anti-SdrF antibodies reduced S. epidermidis colonization of implanted drivelines. SdrF appears to play a key role in the initiation of ventricular assist device driveline infections caused by S. epidermidis. This pluripotential adherence capacity provides a potential pathway to infection with SdrF-positive commensal staphylococci first adhering to the external Dacron-coated driveline at the transcutaneous entry site, then spreading along the collagen-coated internal portion of the driveline to establish a localized infection. This capacity may also have relevance for other prosthetic device–related infections.

This study investigates the manner in which heart pumps become infected. Infections involving the driveline, the cord that connects the pump to its external power source, are a major complication of implantation of these devices. In this study, we examined why Staphylococcus epidermidis, a bacteria that is commonly found on the skin, is responsible for the majority of these infections. The ability of different surface molecules of S. epidermidis to attach to drivelines removed from patients undergoing transplantation was tested. SdrF, one of the S. epidermidis surface proteins studied, showed the highest adherence to the drivelines. This binding appeared to involve attachment of the B subunit of SdrF to collagen, a molecule that coats the driveline following implantation. SdrF also mediated attachment to the non-implanted Dacron material that is used to coat the drivelines. A mouse driveline infection model also demonstrated that SdrF was sufficient to initiate a driveline infection. Driveline infection can therefore be hypothesized to occur via: 1) skin colonization by S. epidermidis; 2) adherence of SdrF-positive S. epidermidis to the Dacron surface at the skin entry site; 3) migration of bacteria along the driveline; 4) adherence to the internal driveline via the collagen coating its surface; and 5) initiation of infection.

Infections associated with ventricular assist devices: epidemiology and effect on prognosis after transplantation

BACKGROUND

Ventricular assist devices (VADs) can be used as a bridge to orthotopic heart transplantation (OHT) in people with severe congestive heart failure. Although they can be inserted for an indefinite time period (unlike balloon pumps), they do carry a substantial risk of infection. We studied the epidemiology, microbiology, and consequences of infection in patients with VADs who ultimately had cardiac transplantation.

METHODS

Records of VAD-supported patients at our institution between January 1995 and January 2005 were identified by ICD-9 code. Infection was classified as driveline infection, pocket infection, mediastinitis, or VAD endocarditis in increasing severity of illness.

RESULTS

Of 73 patients identified by ICD-9 code, 60 had charts available for review. Of these 60, 72% had a VAD infection: 13 had VAD endocarditis; 3, mediastinitis; 25, pocket infection; and 29, driveline infection. The only association of infection (43 patients, 72%) and demography or underlying disease was that of endocarditis with older age (median age 59 vs. 53 years; P=0.02) and diabetes mellitus (13 patients, 30%; risk ratio 3.4; P=0.01). The duration of VAD support was longer in infected patients (median 125 days) vs. uninfected ones (25 days). Median survival measured from the time of VAD placement (although also true from the time of transplantation) was shorter in patients with VAD endocarditis (120 days) and pocket infection (350 days) vs. no infection (>2400 days) with a significant P=0.017 for endocarditis. Four patients had infections after transplantation that were caused by the same organism as their VAD infection. The predominant pathogens in VAD infection were Staphylococcus and Enterococcus spp.

CONCLUSION

VAD use as a bridge to cardiac transplantation is associated with a large number of device-related infections. Patients with infected VADs, on average, wait longer for transplantation than patients with uninfected VADs, and patients with VAD endocarditis have a shorter survival than patients with no VAD infection or simple driveline infection.

Ventricular assist device-related infections

Heart failure is a leading cause of death in developed nations despite medical management. Cardiac transplantation is a potentially lifesaving intervention for approximately 4000 advanced heart failure patients per year; however, the demand for donor hearts far exceeds the supply. Ventricular assist devices provide temporary support for patients with severe heart failure until myocardial recovery occurs or a donor heart becomes available. For those ineligible for transplantation, ventricular assist devices may be used permanently and have demonstrated reduced mortality and an improved quality of life compared with continued medical therapy. Nonetheless, these devices are under-used, in part due to the frequency of complications. Device-related infections are one of the most frequent sequelae of ventricular assist device placement and occur in 18-59% of cases. Infections can involve any part of the device and confer substantial morbidity and mortality. Here, we provide an introduction to ventricular assist devices, explore the nature and pathogenesis of ventricular assist device-related infections, discuss problems with diagnosis, and present treatment and prevention strategies.

Abdominal Complications of Ventricular Assist Device Placement

BACKGROUND

Ventricular assist devices (VADs) provide a bridge to transplantation for patients awaiting heart transplant. Because of its intra-abdominal placement, the potential exists for major abdominal complications. The purpose of this study is to identify VAD-associated abdominal complications and their incidence, and to describe preventive measures.

METHODS

Records of patients having had VAD placement were identified from our registry from April 12, 1995, when the first VAD placement occurred, to July 15, 2003. Each patient was evaluated for the occurrence of an abdominal complication, defined as mechanical small bowel obstruction, infection with an abdominal source, hernia, or other abdominal pathology occurring after VAD placement.

RESULTS

One hundred twenty-four VADs were implanted in 100 patients. Of these patients, 82 received one VAD, 13 received two devices, four received three devices, and one patient received four devices. Twelve abdominal complications occurred in 11 patients (11%). There was a 36% (4/11) pre-transplant mortality rate in patients with an abdominal complication, compared to 17% (15/89) pre-transplant mortality in patients without an abdominal complication (p = 0.21). Three of five patients with abdominal infection died.

CONCLUSIONS

Abdominal complications after VAD placement are common. Intra-abdominal VAD infection is the most common and serious complication, leading to a mortality rate of 60% in our population. Additionally, small bowel obstructions, incisional and inguinal hernias, acalculous cholecystitis, and pancreatitis also occurred. Appropriate preventive measures may decrease the risk of developing many of these complications.

Multicenter experience: prevention and management of left ventricular assist device infections

Implantable left ventricular assist devices (LVADs) have demonstrated clinical success in both the bridge-to-transplantation and destination-therapy patient populations; however, infection remains one of the most common causes of mortality during mechanical circulatory support. Thus, serious LVAD infections may negate the benefits of LVAD implantation, resulting in decreased quality of life, increased morbidity and mortality, and increased costs associated with implantation. Prevention of device-related infection is crucial to the cost-effective use of mechanical circulatory support devices. Therefore, adherence to evidence-based infection control and prevention guidelines, meticulous surgical technique and optimal postoperative surgical site care form the foundation for LVAD associated infection prevention.

Left ventricular assist device-related infection: treatment and outcome

BACKGROUND

Left ventricular assist device (LVAD) implantation has become an effective treatment option for patients with severe heart failure awaiting transplantation. Significant infection rates have been reported among LVAD recipients. However, few reports have focused specifically on device infection, its treatment, and the impact of LVAD-related infection on clinical outcome.

METHODS

Forty-six LVAD-related infections were diagnosed in 38 (50%) of 76 patients who underwent LVAD implantation as a bridge to transplantation. Twenty-nine episodes of LVAD-related bloodstream infection (BSI) (including 5 that were cases of LVAD endocarditis) and 17 episodes of local LVAD infection were identified.

RESULTS

Diabetes mellitus appeared to increase the risk of BSI among patients with LVAD infection. LVAD-related infection delayed transplantation, as reflected by longer device-support times (a mean duration +/- SEM of 182.8+/-31.1 days, compared with 66.3+/-8.8 days; P<or=.001). Continuous antimicrobial treatment before, during, and after transplantation was associated with fewer relapses than was a limited course of antibiotics (P<.001). A trend for longer hospital stays after receipt of a transplant and increased early mortality was observed in the cohort with LVAD-related infection, although long-term survival was similar to that associated with patients without LVAD-related infection. Posttransplantation invasive vancomycin-resistant Enterococcus faecium (VREF) infection was diagnosed in 6 patients with LVAD-related infection; 4 of these patients died. No VREF infections were identified in patients without LVAD-related infection.

CONCLUSIONS

Our observations suggest that LVAD-related infection is common and may require antimicrobial therapy before, during, and after transplantation, but that it does not prevent successful transplantation. However, patients with LVAD-related infection appear to be at increased risk for invasive VREF infection, which may contribute to early mortality after transplantation.

Risk factor analysis of Swedish Left Ventricular Assist Device (LVAD) patients

BACKGROUND

The use of left ventricular assist devices (LVADs) is established as a bridge to heart transplantation.

METHODS

All Swedish patients on the waiting list for heart transplantation, treated with LVAD since 1993 were retrospectively collected into a database and analyzed in regards to risk factors for mortality and morbidity.

RESULTS

Fifty-nine patients (46 men) with a median age of 49 years (range, 14 to 69 years), Higgins score median of 9 (range, 3 to 15), EuroScore median of 10 (range, 5 to 17) were investigated. Dominating diagnoses were dilated cardiomyopathy in 61% (n = 36) and ischemic cardiomyopathy in 18.6% (n = 11). The patients were supported with LVAD for a median time of 99.5 days (range, 1 to 873 days). Forty-five (76%) patients received transplants, and 3 (5.1%) patients were weaned from the device. Eleven patients (18.6%) died during LVAD treatment. Risk factor analysis for mortality before heart transplantation showed significance for a high total amount of autologous blood transfusions (p < 0.001), days on mechanical ventilation postoperatively (p < 0.001), prolonged postoperative intensive care unit stay (p = 0.007), and high central venous pressure 24 hours postoperatively and at the final measurement (p = 0.03 and 0.01, respectively). Mortality with LVAD treatment was 18.6% (n = 11). High C-reactive protein (p = 0.001), low mean arterial pressure (p = 0.03), and high cardiac index (p = 0.03) preoperatively were risk factors for development of right ventricular failure during LVAD treatment.

CONCLUSIONS

The Swedish experience with LVAD as a bridge to heart transplantation was retrospectively collected into a database. This included data from transplant and nontransplant centers. Figures of mortality and morbidity in the database were comparable to international experience. Specific risk factors were difficult to define retrospectively as a result of different protocols for follow-up among participating centers.

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.

Infection in ventricular assist devices: prevention and treatment

Infection is one of the most important challenges to the use of implanted mechanical circulatory support systems (MCSS), particularly as we enter the era of permanent device use in patients who are not candidates for cardiac transplantation. This paper describes the pathogenesis of MCSS infection, with particular attention to the role of biofilm-forming bacteria. Suggestions are presented for the prevention and treatment of infections in implanted MCSS.