Left ventricular assist device-related infections: a multicentric study

Advanced Heart Failure: Therapeutic Options and Challenges in the Evolving Field of Left Ventricular Assist Devices

Heart Failure is a chronic and progressively deteriorating syndrome that has reached epidemic proportions worldwide. Improved outcomes have been achieved with novel drugs and devices. However, the number of patients refractory to conventional medical therapy is growing. These advanced heart failure patients suffer from severe symptoms and frequent hospitalizations and have a dismal prognosis, with a significant socioeconomic burden in health care systems. Patients in this group may be eligible for advanced heart failure therapies, including heart transplantation and chronic mechanical circulatory support with left ventricular assist devices (LVADs). Heart transplantation remains the treatment of choice for eligible candidates, but the number of transplants worldwide has reached a plateau and is limited by the shortage of donor organs and prolonged wait times. Therefore, LVADs have emerged as an effective and durable form of therapy, and they are currently being used as a bridge to heart transplant, destination lifetime therapy, and cardiac recovery in selected patients. Although this field is evolving rapidly, LVADs are not free of complications, making appropriate patient selection and management by experienced centers imperative for successful therapy. Here, we review current LVAD technology, indications for durable MCS therapy, and strategies for timely referral to advanced heart failure centers before irreversible end-organ abnormalities.

Dynamics of bacterial pathogens at the driveline exit site in patients with ventricular assist devices: A prospective, observational, single-center cohort study

BACKGROUND

Driveline infections (DLIs) at the exit site are frequent in patients with left ventricular assist devices (LVADs). The dynamics from colonization to infection are yet to be investigated. We combined systematic swabbing at the driveline exit site and genomic analyses to study the dynamics of bacterial pathogens and get insights into DLIs pathogenesis.

METHODS

A prospective, observational, single-center cohort study at the University Hospital of Bern, Switzerland was performed. Patients with LVAD were systematically swabbed at the driveline exit site between June 2019 and December 2021, irrespective of signs and symptoms of DLI. Bacterial isolates were identified and a subset was whole-genome sequenced.

RESULTS

Fifty-three patients were screened, of which 45 (84.9%) were included in the final population. Bacterial colonization at the driveline exit site without manifestation of DLI was frequent and observed in 17 patients (37.8%). Twenty-two patients (48.9%) developed at least one DLI episode over the study period. Incidence of DLIs reached 2.3 cases per 1000 LVAD days. The majority of the organisms cultivated from exit sites were Staphylococcus species. Genome analysis revealed that bacteria persisted at the driveline exit site over time. In four patients, transition from colonization to clinical DLI was observed.

CONCLUSIONS

Our study is the first to address bacterial colonization in the LVAD-DLI setting. We observed that bacterial colonization at the driveline exit site was a frequent phenomenon, and in a few cases, it preceded clinically relevant infections. We also provided acquisition of hospital-acquired multidrug-resistant bacteria and the transmission of pathogens between patients.

Infections in Patients With Left Ventricular Assist Devices: Current State and Future Perspectives

Mechanical circulatory support is increasingly being used as bridge-to-transplant and destination therapy in patients with advanced heart failure. Technologic improvements have led to increased patient survival and quality of life, but infection remains one of the leading adverse events following ventricular assist device (VAD) implantation. Infections can be classified as VAD-specific, VAD-related, and non-VAD infections. Risk of VAD-specific infections, such as driveline, pump pocket, and pump infections, remains for the duration of implantation. While adverse events are typically most common early (within 90 days of implantation), device-specific infection (primarily driveline) is a notable exception. No diminishment over time is seen, with event rates of 0.16 events per patient-year in both the early and late periods postimplantation. Management of VAD-specific infections requires aggressive treatment and chronic suppressive antimicrobial therapy is indicated when there is concern for seeding of the device. While surgical intervention/hardware removal is often necessary in prosthesis-related infections, this is not so easily accomplished with VADs. This review outlines the current state of infections in patients supported with VAD therapy and discusses future directions, including possibilities with fully implantable devices and novel approaches to treatment.

Daptomycin Pharmacokinetics in Blood and Wound Fluid in Critical Ill Patients with Left Ventricle Assist Devices

Daptomycin is a cyclic lipopeptide antibiotic with bactericidal effects against multidrug-resistant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). For critically ill patients, especially in the presence of implants, daptomycin is an important therapeutic option. Left ventricle assist devices (LVADs) can be utilized for intensive care patients with end-stage heart failure as a bridge to transplant. We conducted a single-center prospective trial with critically ill adults with LVAD who received prophylactic anti-infective therapy with daptomycin. Our study aimed to evaluate the pharmacokinetics of daptomycin in the blood serum and wound fluids after LVAD implantation. Daptomycin concentration were assessed over three days using high-performance liquid chromatography (HPLC). We detected a high correlation between blood serum and wound fluid daptomycin concentration at 12 h (IC95%: 0.64 to 0.95; r = 0.86; p < 0.001) and 24 h (IC95%: -0.38 to 0.92; r = 0.76; p < 0.001) after antibiotic administration. Our pilot clinical study provides new insights into the pharmacokinetics of daptomycin from the blood into wound fluids of critically ill patients with LVADs.

Radionuclide Imaging of Infective Endocarditis

Infective endocarditis (IE) is associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management. Due to difficulties in the diagnosis, a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data is used. Imaging, including echocardiography, molecular imaging techniques, and coronary CT angiography (CTA) is central to detect infections involving heart valves and implanted cardiovascular devices, also allowing for early detection of septic emboli and metastatic. This article describes the main clinical application of white blood cell SPECT/CT and [¹⁸F]FDG-PET/CT and CTA in IE and infections associated with cardiovascular implantable electronic devices.

Molecular Imaging of Valvular Diseases and Cardiac Device Infection

The use of positron emission tomography imaging with 18F-fluorodeoxyglucose in the diagnostic workup of patients with suspected prosthetic valve endocarditis and cardiac device infection (implantable electronic device and left ventricular assist device) is gaining momentum in clinical practice. However, in the absence of prospective randomized trials, guideline recommendations about 18F-fluorodeoxyglucose positron emission tomography in this setting are currently largely based on expert opinion. Measurement of aortic valve microcalcification occurring as a healing response to valvular inflammation using 18F-sodium fluoride positron emission tomography represents another promising clinical approach, which is associated with both the risk of native valve stenosis progression and bioprosthetic valve degeneration in research trials. In this review, we consider the role of molecular imaging in cardiac valvular diseases, including aortic stenosis and valvular endocarditis, as well as cardiac device infections.

Dalbavancin as chronic antibiotic suppression therapy for left ventricular assist device driveline infection due to methicillin-resistant Staphylococcus aureus: a case report

Left Ventricular Assist Devices (LVADs) represent an important therapeutic option in the management of advanced heart failure. We report a case of 74 years-old male with a Jarvik 2000® (Jarvik Heart, New York, USA) LVAD who presented with an infection of the LVAD driveline due to methicillin-resistant Staphylococcus aureus (MRSA) that was treated with dalbavancin as chronic antimicrobial suppression therapy without adverse events and maintaining a good quality of life for more than 37 weeks. Dalbavancin could represent a valid option for the treatment of LVAD infections because of its efficacy, pharmacokinetic/pharmacodynamic proprieties, safety and tolerability.

Nontuberculous Mycobacterial Infections Associated With Left Ventricular Assist Devices in 3 Patients

Durable left ventricular assist devices (LVADs) provide circulatory support in patients with end-stage heart failure; however, complications include infection of the driveline exit site. Nontuberculous mycobacterial infections are rare in patients with LVADs, but they should be considered in those who have undergone device exchanges and have bacterial infections with driveline exit-site discharge but no fever or leukocytosis. We reviewed the charts of patients who had an LVAD implanted at our institution from January 2009 through December 2019, to identify those with a device-related nontuberculous mycobacterial infection. Collected data included patient demographics, premorbid conditions, infection type, previous device complications, treatment, and outcomes. We identified infections in 3 patients (mean age, 41 yr): Mycobacterium abscessus in 2 and M. chimaera in 1. All had a HeartMate II device and had undergone device exchanges for pump thrombosis or for driveline fault or infections. All presented with driveline exit-site discharge without fever or leukocytosis. The mean time between initial device implantation and diagnosis of a nontuberculous mycobacterial infection was 55 months. All 3 patients were treated with antibiotics and underwent localized surgical débridement; one underwent an additional device exchange. The M. abscessus infections disseminated, and both patients died; the patient with M. chimaera infection continued to take suppressive antibiotics. Nontuberculous mycobacterial infections are associated with high morbidity and mortality rates, warranting prompt diagnosis and treatment.

Single-Center Experience With Protocolized Treatment of Left Ventricular Assist Device Infections

Purpose

Because of the current lack of evidence-based antimicrobial treatment guidelines, Left Ventricular Assist Device (LVAD) infections are often treated according to local insights. Here, we propose a flowchart for protocolized treatment, in order to improve outcome.

Methods

The flowchart was composed based on literature, consensus and expert opinion statements. It includes choice, dosage and duration of antibiotics, and indications for suppressive therapy, with particular focus on Staphylococcus aureus (SA) (Figure 1). The preliminary treatment results of 28 patients (2 from start cephalexin suppressive therapy) after implementation in July 2018 are described.

Results

Cumulative incidence for first episode of infection in a 3-year time period was 27% (26 of 96 patients with an LVAD). Twenty-one of 23 (91%) first episodes of driveline infection (10 superficial and 13 deep; nine of 13 caused by SA) were successfully treated with antibiotics according to flowchart with complete resolution of clinical signs and symptoms. For two patients with deep driveline infections, surgery was needed in addition. There were no relapses of deep driveline infections, and only 2 SA deep driveline re-infections after 6 months. Nine patients received cephalexin of whom four patients (44%) developed a breakthrough infection with cephalexin-resistant gram-negative bacteria.

Conclusions

The first results of this protocolized treatment approach of LVAD infections are promising. Yet, initiation of cephalexin suppressive therapy should be carefully considered given the occurrence of infections with resistant micro-organisms. The long-term outcome of this approach needs to be established in a larger number of patients, preferably in a multi-center setting.

Trends and Outcomes of Left Ventricular Assist Device Therapy: JACC Focus Seminar

As the prevalence of advanced heart failure continues to rise, treatment strategies for select patients include heart transplantation or durable left ventricular assist device (LVAD) support, both of which improve quality of life and extend survival. Recently, the HeartMate 3 has been incorporated into clinical practice, the United Network for Organ Sharing donor heart allocation system was revised, and the management of LVAD-related complications has evolved. Contemporary LVAD recipients have greater preoperative illness severity, but survival is higher and adverse event rates are lower compared with prior eras. This is driven by advances in device design, patient selection, surgical techniques, and long-term management. However, bleeding, infection, neurologic events, and right ventricular failure continue to limit broader implementation of LVAD support. Ongoing efforts to optimize management of patients implanted with current devices and parallel development of next-generation devices are likely to further improve outcomes for patients with advanced heart failure.

Clinical considerations for the evaluation of patients with left ventricular assist devices

ABSTRACT

A left ventricular assist device (LVAD) provides mechanical circulatory support for patients with end-stage heart failure. As these devices become more prevalent, clinicians must be familiar with the device's function, common complications, and management strategies when evaluating this patient population.

Infective endocarditis: Role of molecular techniques in early diagnosis

Infective endocarditis (IE), a heart valve infection primarily caused by bacteria such as streptococci or staphylococci, causes significant morbidity and mortality. Despite the long-term use of broad-spectrum antimicrobials, the infection is often difficult to manage. The latest diagnostic modalities for IE are discussed in this study. Blood culture use in pathogen identification can lead to loss of precious time as well as generation of false negative reports. The first steps in diagnosis are blood cultures and echocardiography, but molecular techniques can be extremely useful and may be used for an accurate and early diagnosis.

Identifying Causative Microorganisms in Left Ventricular Assist Device Infections as a Guide for Developing Bacteriophage Therapy

BACKGROUND

As more left ventricular-assist devices (LVADs) are implanted, multidrug-resistant LVAD infections are becoming increasingly common, partly due to bacterial biofilm production. To aid in developing bacteriophage therapy for LVAD infections, we have identified the most common bacterial pathogens that cause LVAD driveline infections (DLIs) in our heart transplant referral center.

MATERIALS AND METHODS

We studied a retrospective cohort of patients who received LVADs from November 2003 to August 2017 to identify the common causative organisms of LVAD infection. We also studied a prospective cohort of patients diagnosed with DLIs from October 2018 to May 2019 to collect bacterial strains from DLIs for developing bacteriophages to lyse causative pathogens. LVAD infections were classified as DLI, bacteremia, and pump/device infections in the retrospective cohort.

RESULTS

In the retrospective cohort of 582 patients, 186 (32.0%) developed an LVAD infection, with 372 microbial isolates identified. In the prospective cohort, 96 bacterial strains were isolated from 54 DLIs. The microorganisms causing DLIs were similar in the two cohorts; the most common isolate was Staphylococcus aureus. We identified 6 prospective S. aureus strains capable of biofilm formation. We developed 3 bacteriophages that were able to lyse 5 of 6 of the biofilm-forming S. aureus strains.

CONCLUSIONS

Similar pathogens caused LVAD DLIs in our retrospective and prospective cohorts, indicating our bacterial strain bank will be representative of future DLIs. Our banked bacterial strains will be useful in developing phage cocktails that can lyse ≥80% of the bacteria causing LVAD infections at our institution.

No Association between Clinical Periodontal Conditions and Microbiological Findings on Driveline of Patients with Left-Ventricular Assist Devices (LVAD)

The aim of this retrospective study was to investigate whether there would be an association between periodontal disease parameters and positive bacterial findings at the driveline of patients with a left ventricular assist device (LVAD). Patients with an LVAD, who underwent a full oral and microbiological examination between 2016 and 2018, were included. During oral examination, periodontitis severity (stage and grade) and the periodontal inflamed surface area (PISA) were evaluated. A microbiological analysis was performed from swabs of the driveline, whereby different bacterial species were cultivated and analyzed. A total of 73 patients were included in the current study. The majority of participants (80.8%) had at least one positive bacterial finding during the study period. Most patients had a periodontitis stage of III-IV (80.9%). The determined PISA of the total group was 284.78 ± 352.29 mm². No associations were found between the periodontal disease parameters and the bacterial findings in general, the bacterial findings on the day of oral examination or the bacterial findings 12 months prior to/after the oral examination (p > 0.05). Periodontitis is not associated with cultivated microbiological findings at the driveline of patients with an LVAD and thus appears not to be a risk indicator for driveline colonization. Nevertheless, the high periodontal burden in LVAD patients underlines the need for their improved periodontal care.

The Predictive Value of Changes in Body Mass Index for the Incidence of Device-Specific Infections in Patients With Implantable Left Ventricular Assist Devices

BACKGROUND

Implantable left ventricular assist devices (LVAD) have improved quality of life and survival in patients with advanced heart failure. However, LVAD-specific infections and predicting which patients will develop infections remain challenging. This study investigated whether changes in body mass index (BMI) during hospitalization following LVAD implantation are associated with LVAD-specific infections within 1 year of implantation.Methods and Results:Patients (n=135) undergoing LVAD implantation were retrospectively divided into 2 groups based on changes in BMI from LVAD implantation to discharge: those with and without decreases in BMI. Each group was further subdivided according to baseline albumin concentrations (high [>3.7 g/dL] and low [≤3.7 g/dL]). Twenty patients developed LVAD-specific infections within 1 year. Receiver operating characteristic curve analysis resulted in a ∆BMI cut-off of less than -0.128 kg/m². In multivariate analysis, younger patients and those with decreases in BMI had significantly higher rates of LVAD-specific infection (P=0.010 and P=0.035, respectively). LVAD-specific infection rates were significantly higher for patients with low albumin and decreases in BMI than for patients with low albumin but no decrease in BMI.

CONCLUSIONS

Decreases in BMI during hospitalization after LVAD implantation and younger age were independently associated with LVAD-specific infection within 1 year. Strict patient management may be needed to avoid decreases in BMI during hospitalization after LVAD implantation, particularly in patients with low baseline albumin concentrations.

Epidemiology of Left Ventricular Assist Device Infections: Findings From a Large Nonregistry Cohort

BACKGROUND

Infection is a major complication during circulatory support with a left ventricular assist device (VAD). Changes in device characteristics and treatment practices in the last decade can affect the epidemiology of infection. The International Society for Heart and Lung Transplantation (ISHLT) has published recommendations on the prevention and management of VAD infections, but data to support these recommendations remain sparse.

METHODS

We performed a retrospective review of 455 patients who underwent VAD placement from 2009 to 2015. Infection episodes were defined using ISHLT criteria and were also grouped as endovascular or local. Analysis included descriptive statistics.

RESULTS

There were 174 patients (38.6%) with a VAD infection. Infection incidence was 36.9 cases per 100 person-years of VAD support. The driveline was the most common infection site (67.2%). Systemic inflammatory response syndrome (SIRS) criteria were not satisfied in 29.2% of patients with endovascular infections, and computed tomography (CT) examinations were normal in 37.7% of cases. Gram-positive bacteria caused 65.6% of infections in patients with an available culture. Antimicrobial suppression was used in 72.3% of patients who survived treatment. Median survival after infection was 35 months for patients with VAD-related infections versus 14 months for patients with VAD-specific infections.

CONCLUSIONS

VAD infections continue to be a major complication after implantation. Clinical criteria alone were not predictive of serious infections, and many patients with confirmed infection had normal CTs. Patients with VAD-specific infections had lower median survival than patients with VAD-related infections.

Diagnosis and Image-guided Therapy of Cardiac Left Ventricular Assist Device Infections

Due to limited availability of donor hearts, more and more end stage heart failure patients are dependent on left ventricular assist device (LVAD) as their destination therapy rather than the original intended use as a bridge for heart transplantation. While LVADs improve life expectancy in these patients, infection emerges as one of the major adverse events. Early and accurate localization of LVAD infection is critical, as it can significantly influence clinical management decisions and ultimately impact patient outcome. Although the International Society of Heart and Lung Transplantation has defined 3 categories for LVAD infection: (1) LVAD-specific infection, (2) LVAD-related infection, and (3) non-LVAD infection, there is still lack of standardized criteria for diagnosing these 3 types of LVAD infections. Morphologically based imaging tools such as transesophageal echocardiogram and cardiac computed tomography (CT) or CT angiogram have limited roles in diagnosing LVAD infections due to their nonspecific findings, often affected by significant streaking and beam hardening artifacts from the metal device. In contrast, ¹⁸F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/CT has repeatedly shown a high sensitivity and specificity for LVAD infection diagnosis, albeit in small number of subjects. Beyond its accuracy for detecting infection, FDG PET/CT can predict clinical outcome based on the location of LVAD infection. As a functional imaging tool, FDG PET/CT can demonstrate the extent and severity of LVAD infection, as well as infectious embolism and potential extra-cardiac source of infection, which are all critical for providing optimal patient care, justifying its judicious and precise use in the workup of LVAD infection.

Gallium-67 Single-Photon Emission Computed Tomography Affects Management of Infections of Left Ventricular Assist Devices

Our institution employs gallium-67 single-photon emission computed tomography low-dose CT (Ga-SPECT-CT) to determine the presence and extent of left ventricular assist device (LVAD) infections. We present a retrospective single-center study of 41 LVAD recipients who underwent Ga-SPECT-CT from January 2011 to June 2018 to determine whether Ga-SPECT-CT led to changes in antimicrobial therapy, LVAD revision or exchange, or application for 1A exception. The average age was 56.6 years, predominantly male (80.5%) and diabetic (68.3%), divided between ischemic (48.8%) and nonischemic (51.2%) cardiomyopathy. The majority had HeartMate II devices (82.9%). Device-related infections were classified as possible (12.2%), probable (36.6%), proven (36.6%), or rejected (14.6%). Sensitivity was 68.6% and specificity was 100%. Most VAD-specific infections were percutaneous deep driveline infections (DRIs) (34.1%), and VAD-related infections were primarily bloodstream infections (31.7%). Staphylococcus aureus was the major pathogen isolated. Gallium-67 single-photon emission computed tomography low-dose CT resulted in changes in management in more than half (53.7%) of patients: starting (24.4%) or stopping (17.1%) antimicrobial therapy, LVAD revision (22.0%) or exchange (12.2%), and the application for 1A exception for transplant listing (17.1%). We conclude that Ga-SPECT-CT is an effective modality for determining the presence and extent of LVAD DRIs, and contributed to a change in management in more than half of cases.

Infections in children with left ventricular assist device

BACKGROUND

There are limited data about pediatric left ventricular assist device (VAD) infections in developing countries. This study aimed to investigate device postimplantation infectious complications and their pathogenic profile.

METHODS

Data were analyzed from patient charts involving 27 patients with dilated cardiomyopathy who underwent left VAD implantation at a leading tertiary care center in Turkey.

RESULTS

The study included 17 boys and ten girls with a median age of 12.22 years (range 17 months to 18 years). Nineteen patients were diagnosed with idiopathic, and three were diagnosed with familial dilated cardiomyopathy. Twenty-two out of 27 subjects (%81.48) developed 80 infection episodes in total. The most common type of left VAD-specific infection was the exit site of the driveline. Infected patients with left VAD had a significantly prolonged hospitalization compared with the patients without infection (P = .014). Infection-induced pediatric intensive care unit (ICU) admission was higher in patients with fungal infection(P = .023). Gram-positive staphylococci were the most commonly isolated bacterial pathogens, followed by Gram-negative bacteria. Five patients developed fungal infections. None of the fungal infection patients underwent transplantation(P = .035). Seven deaths occurred in our study group. All deaths were in the infected group. Mortality was associated with the presence of multidrug-resistant Gram-negative bacterial infections (P = .015), an increased number of infection episodes (P = .003), and hospitalization due to infection (P = .003).

CONCLUSION

Ventricular assist device-related infections were frequent among our study patients. The predominantly isolated agents were Gram-positive bacterial pathogens. However, the emergence of relatively high rate of Gram-negative bacterial and fungal infections was associated with mortality before the transplantation. Establishing local programs for surveillance data, controlling for infection rates, and antibiotic stewardship are essential to reduce mortality of VAD patients in developing countries.

In Full Flow: Left Ventricular Assist Device Infections in the Modern Era

With the rising prevalence of heart disease in the United States, there is increasing reliance on durable mechanical circulatory support (MCS) to treat patients with end-stage heart failure. Left ventricular assist devices (LVADs), the most common form of durable MCS, are implanted mechanical pumps that connect to an external power source through a transcutaneous driveline. First-generation LVADs were bulky, pulsatile pumps that were frequently complicated by infection. Second-generation LVADs have an improved design, though infection remains a common and serious complication due to the inherent nature of implanted MCS. Infections can affect any component of the LVAD, with driveline infections being the most common. LVAD infections carry significant morbidity and mortality for LVAD patients. Therefore, it is paramount for the multidisciplinary team of clinicians caring for these patients to be familiar with this complication. We review the epidemiology, prevention, diagnosis, treatment, and outcomes of LVAD infections.

Nasal colonization with Staphylococcus aureus is a risk factor for ventricular assist device infection in the first year after implantation: A prospective, single-centre, cohort study

OBJECTIVES

To assess, whether S. aureus nasal colonization is a risk factor for infections in patients with durable ventricular assist device (VAD).

METHODS

Prospective, single-centre, cohort study (i) ascertaining S. aureus nasal colonization status of patients admitted for VAD-implantation and detecting time to first episode of VAD-specific or -related infection according to International Society for Heart and Lung Transplantation criteria during follow-up and (ii) comparing whole genomes of S. aureus from baseline colonization and later infection.

RESULTS

Among 49 patients (17 colonized, 32 non-colonized), S. aureus VAD-infections occurred with long latency after implantation (inter quartile range 76-217 days), but occurred earlier (log-rank test P = 0.006) and were more common (9/17, 52.9% vs. 4/32, 12.5%, P = 0.005; incidence rates 2.81 vs. 0.61/1000 patient days; incidence rate ratio 4.65, 95% confidence interval 1.30-20.65, P = 0.009) among those nasally colonized with S. aureus before implantation. We found a similar but less pronounced effect of colonization status when analysing its effect on all types of VAD-infections (10/17, 58.8% vs. 7/32, 21.9%, P = 0.01). These findings remained robust when adjusting for potential confounders and restricting the analysis to 'proven infections'. 75% (6/8) of paired S. aureus samples from colonization and VAD-infection showed concordant whole genomes.

CONCLUSIONS

In patients with durable VAD, S. aureus nasal colonization is a source of endogenous infection, often occurring months after device-implantation and affecting mostly the driveline. Hygiene measures interrupting the endogenous route of transmission in VAD-patients colonized with S. aureus long-term may about half the burden of infections and require clinical scrutiny.

Minimum inhibitory concentration changes in relapsed left ventricular assist device driveline infections

Driveline infection is the most common infectious complication in patients with left ventricular assist devices. Minimum inhibitory concentration changes are not well described in relapsed driveline infections. This retrospective descriptive epidemiology study of patients with left ventricular assist device implantation between January 1, 2013, and August 1, 2017, who developed driveline infection with positive cultures aimed to describe minimum inhibitory concentration changes. Of the 330 patients underwent left ventricular assist device implantation, 30 (9%) met criteria for driveline infection. Median duration of follow-up was 26 months (interquartile range 16, 39) and time to first driveline infection was 171 days (interquartile range 83, 403). There were 74 driveline infections: 40 new and 34 relapsed. Staphylococcus aureus was most common in new and relapsed driveline infection. Thirteen patients comprised the 34 relapsed infections, 9 of which experienced a minimum inhibitory concentration change. Median time to first minimum inhibitory concentration change was 56 days (interquartile range 36-88), and type of minimum inhibitory concentration change was an increase in five cases, decrease in two cases, and both increase and decrease in two cases. Minimum inhibitory concentration changes did not result in resistance in S. aureus but did in Pseudomonas aeruginosa and Mycobacterium fortuitum relapsed driveline infection. Time to first relapse from initial infection was longer in those who received suppressive therapy, 60 days versus 83 days, p = 0.047. Relapsed driveline infections were most common with S. aureus. Minimum inhibitory concentration changes were quite variable and may not be the major contributor to relapsed infection in gram-positive driveline infection.

Mycobacterium chelonae, an 'atypical' cause of an LVAD driveline infection

We describe the first patient with a left ventricular assist device (LVAD) driveline infection caused by Mycobacterium chelonae presenting with persistent infection despite conventional antibiotics. Treatment was successful with surgical debridement, driveline exit relocation, and a 4-month period of antibiotics. In the case of a culture-negative LVAD driveline infection, non-tuberculous mycobacteria should be considered. This case illustrates that multidisciplinary collaboration is essential in providing optimal care for LVAD patients.

Risk factors and prognostic impact of left ventricular assist device-associated infections

BACKGROUND

Left ventricular assist device (LVAD)-associated infections may be life-threatening and impact patients' outcome. We aimed to identify the characteristics, risk factors, and prognosis of LVAD-associated infections.

METHODS

Patients included in the ASSIST-ICD study (19 centers) were enrolled. The main outcome was the occurrence of LVAD-associated infection (driveline infection, pocket infection, or pump/cannula infection) during follow-up.

RESULTS

Of the 652 patients enrolled, 201 (30.1%) presented a total of 248 LVAD infections diagnosed 6.5 months after implantation, including 171 (26.2%), 51 (7.8%), and 26 (4.0%) percutaneous driveline infection, pocket infection, or pump/cannula infection, respectively. Patients with infections were aged 58.7 years, and most received HeartMate II (82.1%) or HeartWare (13.4%). Most patients (62%) had implantable cardioverter-defibrillators (ICDs) before LVAD, and 104 (16.0%) had ICD implantation, extraction, or replacement after the LVAD surgery. Main pathogens found among the 248 infections were Staphylococcus aureus (n = 113' 45.4%), Enterobacteriaceae (n = 61; 24.6%), Pseudomonas aeruginosa (n = 34; 13.7%), coagulase-negative staphylococci (n = 13; 5.2%), and Candida species (n = 13; 5.2%). In multivariable analysis, HeartMate II (subhazard ratio, 1.56; 95% CI, 1.03 to 2.36; P = .031) and ICD-related procedures post-LVAD (subhazard ratio, 1.43; 95% CI, 1.03-1.98; P = .031) were significantly associated with LVAD infections. Infections had no detrimental impact on survival.

CONCLUSIONS

Left ventricular assist device-associated infections affect one-third of LVAD recipients, mostly related to skin pathogens and gram-negative bacilli, with increased risk with HeartMate II as compared with HeartWare, and in patients who required ICD-related procedures post-LVAD. This is a plea to better select patients needing ICD implantation/replacement after LVAD implantation.

Methicillin-resistant Staphylococcus aureus in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice review the epidemiology, diagnosis, prevention, and management of methicillin-resistant Staphylococcus aureus (MRSA) infections in solid organ transplantation. Despite an increasing armamentarium of antimicrobials active against MRSA, improved diagnostic tools, and overall declining rates of infection, MRSA infections remain a substantial cause of morbidity and mortality in solid organ transplant recipients. Pre- and post-transplant MRSA colonization is a significant risk factor for post-transplant MRSA infection. The preferred initial treatment of MRSA bacteremia remains vancomycin. Hand hygiene, chlorhexidine bathing in the ICU, central-line bundles that focus on reducing unnecessary catheter use, disinfection of patient equipment, and the environment along with antimicrobial stewardship are all aspects of an infection prevention approach to prevent MRSA transmission and decrease healthcare-associated infections.

Right ventricular failure following left ventricular assist device implantation is associated with a preoperative pro-inflammatory response

Background

Systemic inflammation during implant of a durable left ventricular assist device (LVAD) may contribute to adverse outcomes. We investigated the association of the preoperative inflammatory markers with subsequent right ventricular failure (RVF).

Materials and methods

Prospective data was collected on 489 patients from 2003 through 2017 who underwent implantation of a durable LVAD. Uni- and multivariable correlation with leukocytosis was determined using linear and binary logistic regression. The population was also separated into low (< 10.5 K/ul, n = 362) and high (> 10.5 K/ul, n = 127) white blood cell count (WBC) groups. Mantel-Cox statistics was used to analyze survival data.

Results

Postop RVF was associated with a higher preop WBC (11.3 + 5.7 vs 8.7 + 3.1) and C-reactive protein (CRP, 5.6 + 4.4 vs 3.3 + 4.7) levels. Multivariable analysis identified an independent association between increased WBC preoperatively with increased lactate dehydrogenase (LDH, P < 0.001), heart rate (P < 0.001), CRP (P = 0.006), creatinine (P = 0.048), and INR (P = 0.049). The high WBC group was more likely to be on preoperative temporary circulatory support (17.3% vs 6.4%, P < 0.001) with a trend towards greater use of an intra-aortic balloon pump (55.9% vs 47.2%, P = 0.093). The high WBC group had poorer mid-term survival (P = 0.042).

Conclusions

Postop RVF is associated with a preoperative pro-inflammatory environment. This may be secondary to the increased systemic stress of decompensated heart failure. Systemic inflammation in the decompensated heart failure may contribute to RVF after LVAD implant.

High-Quality Draft Genome Sequence of Pseudomonas aeruginosa 268 Isolated from a Patient with a Left Ventricular Assist Device

Pseudomonas aeruginosa is known to cause persistent bloodstream infections associated with left ventricular assist devices (LVAD). Here, we present the high-quality draft genome assembly for a clinical isolate, P. aeruginosa 268.

Pseudomonas aeruginosa is known to cause persistent bloodstream infections associated with left ventricular assist devices (LVAD). Here, we present the high-quality draft genome assembly for a clinical isolate, P. aeruginosa 268. The genome sequence is available in GenBank under accession number CP032761.

The "3M" Approach to Cardiovascular Infections: Multimodality, Multitracers, and Multidisciplinary

Cardiovascular infections are associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management, as early treatment improves the prognosis. The diagnosis cannot be made on the basis of a single symptom, sign, or diagnostic test. Rather, the diagnosis requires a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data. The application of multimodality imaging, including molecular imaging techniques, has improved the sensitivity to detect infections involving heart valves and vessels and implanted cardiovascular devices while also allowing for early detection of septic emboli and metastatic infections before these become clinically apparent. In this review, we describe data supporting the use of a Multimodality, Multitracer, and Multidisciplinary approach (the 3M approach) to cardiovascular infections. In particular, the role of white blood cell SPECT/CT and [¹⁸F]FDG PET/CT in most prevalent and clinically relevant cardiovascular infections will be discussed. In addition, the needs of advanced hybrid equipment, dedicated imaging acquisition protocols, specific expertise for image reading, and interpretation in this field are discussed, emphasizing the need for a specific reference framework within a Cardiovascular Multidisciplinary Team Approach to select the best test or combination of tests for each specific clinical situation.