Colonization with Multidrug-resistant Organisms in Patients with Ventricular Assist Devices

Infection is a leading cause of morbidity and mortality in patients with ventricular assist devices (VAD). The impact of colonization with multidrug-resistant organisms (MDRO) on outcomes in this cohort is unknown. Patients on VAD support from July 2008 to September 2018 at a single site were evaluated for MDRO colonization after implantation. MDROs included methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus species, and extended-spectrum beta-lactamase producing gram-negative bacteria. 378 patients with 433 VADs were included. 42.6% (n = 161) of patients were colonized with an MDRO throughout the duration of VAD support. Eighty-two VAD infections occurred, 74.4% (n = 61) of whom were MDRO colonized before infection. MDRO colonization was associated with an increased risk of a subsequent VAD infection (hazard ratio 3.704, p < 0.001). MDRO colonization is common after VAD implantation and is associated with future VAD infections. Further study is needed to determine best management strategies for VAD recipients with MDRO colonization given this increased risk.

The outcome of patients with peripartum cardiomyopathy and consecutive implantation of a left ventricular assist device

OBJECTIVES

Peripartum cardiomyopathy (PPCM) is a form of systolic heart failure occurring toward the end of pregnancy or in the period after delivery. Lack of myocardial recovery or therapy-refractory cardiogenic shock are rare complications and left ventricular assist device (LVAD) systems might be used as a life-saving option. The aim of this study was to investigate outcomes of PPCM patients supported with LVAD, registered in the European Registry for Patients with Mechanical Circulatory Support (EUROMACS).

METHODS

All patients registered in EUROMACS with a primary diagnosis of PPCM were included in this study. Demographic, preoperative, intraoperative, postoperative, and follow-up data were collected and patients analysed concerning their outcome after initiation of LVAD therapy.

RESULTS

Between May 2011 and September 2018, 16 patients with PPCM and consecutive LVAD implantation were enrolled into EUROMACS. The median age of the patient population was 31 (26;41) years with a mean left ventricular ejection fraction (LV-EF) of 15% ± 6%. In-hospital mortality after LVAD implantation was 6% (n = 1). One-year mortality accounted for 13% (n = 2). Six patients (40%) were transplanted with a median support time of 769 (193;1529) days. Weaning of LVAD support due to ventricular recovery was feasible in 3 (20%) patients.

CONCLUSION

In patients with severe PPCM, LVAD therapy is associated with considerably low in-hospital mortality, potentially allowing bridging to heart transplantation, or left ventricular recovery. Therefore, durable mechanical support should be considered as a treatment option in this, by nature, young and often otherwise healthy patient population.

Risk of left ventricular assist device driveline infection: A systematic literature review

BACKGROUND

Left ventricular assist devices (LVADs) improve quality of life in end-stage heart failure but can cause serious complications such as infections with driveline infection causing significant morbidity and mortality.

OBJECTIVES

The purpose of this systematic literature review is to synthesize the literature to determine variables associated with driveline infection and seek opportunities to improve nursing management of LVAD drivelines.

METHODS

A systematic literature review was performed. The evidence was synthesized using the Johns Hopkins Nursing Evidence-Based Practice tools and the Chain of Infection epidemiological framework.

RESULTS

Thirty-four studies focused on vulnerable host, portal of entry, and causative organism aspects of the Chain of Infection. Increased BMI, younger age, exposed driveline velour showed increased risk of infection and driveline dressing protocol change showed lower risk of infection.

CONCLUSIONS

Although some risk factors for infection were identified, evidence is still limited. Nurses are uniquely positioned to improve driveline management, disrupting the chain of infection.

The impact of infection among left ventricular assist device recipients on post-transplantation outcomes: A retrospective review

INTRODUCTION

Left ventricular assist device (LVAD) infections are common, and the consequences of LVAD infections on orthotopic heart transplantation (OHT) outcomes are not well described.

AIMS

The aim of this study was to describe clinical characteristics and evaluate risk factors for developing LVAD infections, and examine outcomes of LVAD-specific infections (VSI) after OHT.

METHODS

We retrospectively investigated the records of 74 consecutive patients at two institutions who had undergone LVAD placement and subsequent OHT between January 2007 and December 2012.

RESULTS

Forty-six of 74 (62%) LVAD recipients who underwent OHT had pre-transplant infections, and 18 (24%) had LVAD-specific infection (VSI), of which 71% were caused by gram-negative organisms. Of pre-transplant non-LVAD infections, Clostridium difficile infection (CDI) was the most common (26%) followed by urinary tract infection (UTI, 16%) and pneumonia (PNA 15%). Univariate analysis comparing subjects with VSI to those without VSI showed a significant association with time spent outside the hospital prior to transplantation (median 231.8 days vs 142.2 days, P < 0.03) and total time between VAD placement and OHT (244.0 days and 150.5 days, P < 0.002). Logistic regression was performed and significant predictors for VAD-related infection were age and the presence of diabetes, with type of device as an effect modifier. Six months post-OHT survival was not significantly affected by the presence of VSI prior to transplant. There was a trend toward an association between the presence of any infection and post-transplant rejection (P < 0.09). There were 10 post-transplant deaths by 6 months. Of these deaths, 4/10 (40%) were cardiopulmonary and 6/10 (60%) were related to infections.

CONCLUSIONS

Advanced age and presence of diabetes were predictors of VSI, as well as type of VAD device, although device choice is likely affected by many clinical factors including age and comorbidities, as well as institution-specific preferences. VSI was not associated with a decrease in 6-month post-OHT survival. However, infections remain the major causes of death by 6 months post-transplant. Certain infections are associated with an increased risk of rejection, which merits further investigation.

Elevated Body Mass Index Is Not a Risk Factor for Adverse Outcomes Following Ventricular Assist Device Implantation

BACKGROUND

Despite ventricular assist devices (VADs) becoming more common in heart failure (HF) treatment, it is still uncertain which patients are more prone to complications. One potential risk factor is increased body mass index (BMI), which is known to increase both all-cause mortality and mortality from ischemic heart disease; however, the role of the BMI in predicting morbidity and mortality following device implantation is unclear.

METHODS

The study population for this single-institution retrospective chart review consisted of 136 patients with HF, who underwent VAD implantation between 2004 and 2015. Patients were divided into 2 groups based on their BMI: a nonobese group (18.5 < BMI < 30.0; n = 82) or an obese group (BMI >30.0; n = 54). These groups were compared at baseline and after implantation for survival, hospital readmission, and adverse events.

RESULTS

No significant difference was found in initial hospital length of stay, number or length of readmissions, or readmission diagnosis. At 1 year, rates of ongoing device support, orthotopic heart transplant (OHT), and death were not significantly different between groups ( P = .89, P = .90, and P = .70, respectively). Multivariate analysis did not identify obesity as an independent predictor of mortality ( P = .90); only biventricular assist device implantation was associated with decreased survival (hazard ratio [HR] = 5.90, P = .002).

CONCLUSION

Obesity in itself should not preclude the use of VAD support in patients with HF, as carefully selected obese patients were shown to have similar rates of hospital readmission, 1-year outcomes, and survival following device implantation compared to nonobese patients.

Readmission due to driveline infection can be predicted by new score by using serum albumin and body mass index during long-term left ventricular assist device support

Survival in patients with continuous flow left ventricular assist device (CF LVAD) had been increased owing to improved perioperative management procedures. The second target for successful long-term LVAD treatment was to reduce readmission especially due to device-specific infection, which was one of the major unsolved complications. Among 57 enrolled patients who had received CF LVAD and been followed for 530 days on median at our institute between 2008 and 2014, 21 patients experienced readmission due to driveline infection (DLI) at 190 days after the surgery on median. Considering the result of Uni/Multivariate Cox regression analyses demonstrating lower serum albumin concentration (S-ALB) (hazard ratio 0.144) and body mass index (BMI) (hazard ratio 0.843) both obtained at discharge were independent predictors of readmission due to DLI, we constructed a New Score "7 × [S-ALB (g/dL)] + [BMI]", which significantly stratified readmission-free rate into 3 groups [low (>50 Pt), intermediate (44-50 Pt), and high risk group (<44 Pt)] during 2-year study period (p = 0.008). Survival remained unchanged irrespective of DLI, whereas those with DLI needed longer in-hospital treatment (p < 0.05). In conclusion, readmission due to DLI could be predicted by using two simple nutrition parameters at discharge. Early nutrition assessment and intervention may reduce readmission and improve patients' quality of life during long-term LVAD support.

Gender differences in risk of bloodstream and surgical site infections

BACKGROUND

Identifying patients most at risk for hospital- and community-associated infections is one essential strategy for preventing infections.

OBJECTIVE

To investigate whether rates of community- and healthcare-associated bloodstream and surgical site infections varied by patient gender in a large cohort after controlling for a wide variety of possible confounders.

DESIGN

Retrospective cohort study.

PARTICIPANTS

All patients discharged from January 1, 2006 through December 31, 2008 (133,756 adult discharges and 66,592 pediatric discharges) from a 650-bed tertiary care hospital, a 220-bed community hospital, and a 280-bed pediatric acute care hospital within a large, academic medical center in New York, NY.

MAIN MEASURES

Data were collected retrospectively from various electronic sources shared by the hospitals and linked using patients' unique medical record numbers. Infections were identified using previously validated computerized algorithms.

KEY RESULTS

Odds of community-associated bloodstream infections, healthcare-associated bloodstream infections, and surgical site infections were significantly lower for women than for men after controlling for present-on-admission patient characteristics and events during the hospital stay [odds ratios (95 % confidence intervals) were 0.85 (0.77-0.93), 0.82 (0.74-0.91), and 0.78 (0.68-0.91), respectively]. Gender differences were greatest for older adolescents (12-17 years) and adults 18-49 years and least for young children (<12 years) and older adults (≥ 70 years).

CONCLUSIONS

In this cohort, men were at higher risk for bloodstream and surgical site infections, possibly due to differences in propensity for skin colonization or other anatomical differences.

Infectious Complications of Mechanical Circulatory Support (MCS) Devices

Left-ventricular assist devices and other forms of mechanical circulatory support are increasingly important in the routine therapy of patients with end-stage congestive heart failure. Technology may help to decrease the rate of infections associated with these devices, but with larger numbers of implants being utilized across the globe, infections overall are becoming more commonplace. Becoming familiar with appropriate techniques for prevention and with the ideal approach to diagnostic and therapeutic strategies is key to managing mechanical circulatory support infections in this unique, but growing, patient population.

Variability in infection control measures for the percutaneous lead among programs implanting long-term ventricular assist devices in the United States

Ventricular assist devices (VADs) are a surgical treatment for heart failure. These devices may be implanted as a bridge to transplant or as destination therapy. After surgical recovery and education regarding device care, patients are discharged home. Meticulous care of the driveline must be taken to prevent infection and trauma of the site throughout the perioperative event and for the duration of support. Currently a standardized protocol for care of the driveline and exit site does not exist. VAD coordinators from across the country discussed the variability in care at different centers in the United States through a series of conference calls. A survey consisting of 16 questions was developed. The survey included questions on preoperative antibiotic recommendations, driveline placement and exit site suturing, frequency of dressing changes, and showering practices. VAD coordinators shared center-specific dressing protocols and any driveline success stories. This survey was sent to 73 centers; 38 centers (52%) responded. The purpose of the survey was to define current practice in order to move toward a standard of practice or protocol based on expert opinion for VAD driveline care and to assess the need for future studies.

Current status of mechanical circulatory support: a systematic review

Heart failure is a major public health problem and its management requires a significant amount of health care resources. Even with administration of the best available medical treatment, the mortality associated with the disease remains high. As therapeutical strategies for heart failure have been refined, the number of patients suffering from the disease has expanded dramatically. Although heart transplantation still represents the gold standard therapeutical approach, the implantation of mechanical circulatory support devices (MCSDs) evolved to a well-established management for this disease. The limited applicability of heart transplantation caused by a shortage of donor organs and the concurrent expand of the patient population with end-stage heart failure led to a considerable utilization of MCSDs. This paper outlines the current status of mechanical circulatory support.

Continuous-flow devices and percutaneous site infections: clinical outcomes

BACKGROUND

Although continuous-flow left ventricular assist device (LVAD) support has become standard therapy, the complexities of device and patient management remain a challenge. In particular, percutaneous site infections (PSI) are a serious complication during the post-implant course. We sought to study the incidence, risk factors, and clinical effect of PSI.

METHODS

Data were obtained from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Registry. All adult patients who received a primary intracorporeal continuous flow LVAD between June 2006 and September 2010 were included. Descriptive statistics, Kaplan-Meier depictions, and multivariable analysis in the parametric hazard domain were used for statistical analysis.

RESULTS

A total of 239 PSIs were documented in 197 of 2,006 recipients (9.8%) of a continuous-flow LVAD. Mean follow-up was 8.1 months. Mean time to development of a PSI was 6.6 months. At 1 year after implant, nearly 19% of continuous-flow LVAD recipients developed a PSI. Multivariate analysis showed younger age (hazard ratio, 1.20; p < 0.0001) was the only factor predicting a PSI. Continuous-flow LVAD recipients who did not develop a PSI had improved survival (p = 0.004). Twenty-three patients died after development of a PSI. Sepsis was the most common cause of death (26.1%).

CONCLUSIONS

PSIs occur in approximately 19% of continuous-flow LVAD recipients by 12 months after implant. Young age is the only predictor of PSI. Importantly, development of a PSI adversely affects survival. Efforts to enhance driveline integration and to develop future totally implantable systems are warranted.

Left ventricular assist device-related infections: past, present and future

Over the last decade, left ventricular assist device (LVAD) implantation has emerged as an alternative treatment strategy in patients with advanced heart failure irrespective of their transplant eligibility. However, success and applicability of this therapy is largely limited by high complication rates associated with these devices. Although superior outcomes have been achieved with the second-generation continuous-flow LVADs, device-related infections continue to be a prevalent complication in this patient population and contribute significantly to the financial burden of this therapy due to an increased need for hospitalizations and surgical interventions. Patient selection, device design and LVAD-induced immune system dysfunction appear to be major risk factors for the development of device-related infections. Improvements in device design and better patient selection strategies, particularly with respect to identifying individuals with genetic susceptibility to device-related infections, may further reduce this prevalent complication and improve outcomes in patients with advanced heart failure.

Toward total implantability using free-range resonant electrical energy delivery system: achieving untethered ventricular assist device operation over large distances

Heart failure is a terminal disease with a very poor prognosis. Although the gold standard of treatment remains heart transplant, only a minority of patients can benefit from transplants. Another promising alternative is mechanical circulatory assistance using ventricular assist devices. The authors envision a completely implantable cardiac assist system affording tether-free mobility in an unrestricted space powered wirelessly by the innovative Free-Range Resonant Electrical Energy Device (FREE-D) system. Patients will have no power drivelines traversing the skin, and this system will allow power to be delivered over room distances and will eliminate trouble-prone wirings, bulky consoles, and replaceable batteries.

Driveline infections in patients supported with a HeartMate II: incidence, aetiology and outcome

OBJECTIVES

To investigate the incidence and outcome of driveline infections in patients supported with a continuous flow left ventricular assist device (HeartMate II (HMII)) and to study the microbiological aetiology.

DESIGN

Retrospective analysis of 31 patients who received an implantation of a HMII. Follow-up was from implantation to either device explantation, death or closure of the study. Clinical signs of infections were divided into superficial, deep or systemic and compared to culture and gram stain, the clinical course and infectious parameters.

RESULTS

The incidence of driveline infections was 1.65 episodes per patient per year. Staphylococcus aureus and Escherichia coli were the most common bacterial aetiology. More than two weeks of treatment was required in 81% of the patients. In terms of detecting superficial driveline infections, leucocyte count demonstrated a sensitivity of 27% and C-reactive protein (CRP) a sensitivity of 28%. In 22 cases of driveline infections plasma pro-calcitonin was found to be normal.

CONCLUSION

Driveline infections are common in HMII recipients but primarily remain superficial and are reasonably easy to manage. Infectious agents mostly originate from the skin and gastrointestinal tract. Blood biomarkers did not appear to be helpful in detecting driveline infections.