Prospective, multicenter study of ventricular assist device infections

Prospective evaluation of the Moleculight i:X™ in the early detection of driveline infections

OBJECTIVES

Driveline infection (DLI) is a common complication in patients with left ventricular assist devices. This complication can seriously undermine quality of life while on left ventricular assist devices. Current diagnosis of a DLI in the outpatient setting is based on clinical examination and later bacteria isolation. The Moleculight i:XTM is a handheld fluorescence imaging device capable to visualize bacterial colonization in real-time. We here evaluated the performance of the Moleculight i:XTM for diagnosis of DLIs as this device may have the potential advantage to rapidly identify infection and therefore promptly influence therapy.

METHODS

A total of 107 examinations in patients with suspected DLIs were prospectively included in this study. All examinations took place in the outpatient setting. In addition to the standard treatment, Moleculight fluorescence images were captured and swabs were taken at the area of maximal luminosity. Wounds and pictures were reviewed and classified as positive or negative by a wound specialist and two heart surgeons independently from microbiological results.

RESULTS

The Moleculight i:XTM showed positive results (red fluorescence) in 19 cases (17.76%), whereas microbiological examination was positive for microorganisms in 74 cases (69.16%). The most common bacteria was Staphylococcus aureus. The findings resulted in a sensitivity of 13.51% and a specificity of 72.73%. The positive predictive value was 52.63% and the negative predictive value was 27.27%. Sub-analyses of different wound dressings or previous antibiotic treatment did not show any relevant difference.

CONCLUSIONS

The results of the Moleculight i:X show a low sensitivity and specificity when being used to detect DLIs in the outpatient setting. Clinical examination and swabs should remain the gold standard despite the delay for bacteria isolation and consequent antibiotic treatment. Sensitivity and specificity of the Moleculight i:X in open wounds after surgical revision of the driveline remain to be clarified.

Vitamin D Deficiency and Driveline Infections in Patients With Left Ventricular Assist Devices

BACKGROUND

Despite major advancements in the field of durable left ventricular assist devices (LVADs), driveline infection is a major source of morbidity and mortality. Risk factors have been proposed, but few are modifiable. We evaluated vitamin D deficiency as a potential modifiable risk factor for driveline infection.

METHODS AND RESULTS

This single-center, retrospective study included 134 LVAD recipients between 2010 and 2022. Patients were divided into two groups based on their pre-implant vitamin D levels: the vitamin D sufficient group (≥ 30 ng/mL) and the vitamin D deficient group (< 30 ng/mL). The Kaplan-Meier method estimated 18-month freedom from driveline infection. The Cox proportional hazards model estimated the effect of vitamin D deficiency on driveline infections. Kaplan-Meier estimates for infection-free survival were significantly higher in the sufficient group (90.5% vs. 69.6%, p = 0.014). Vitamin D deficiency (HR: 3.644, 95% CI: 1.271-10.448, p = 0.016) and obesity (HR: 3.190, 95% CI: 1.464-7.400, p = 0.004) were found to be independent risk factors for driveline infection.

CONCLUSION

Our findings support vitamin D deficiency as a potential modifiable risk factor for driveline infection. Obesity was also noted as a significant risk factor for infection. Further research is warranted to establish causality and assess the impact of vitamin D repletion on infection rates.

Psychiatric Disorders and Associated Factors in Left Ventricular Assist Device Implantation and Heart Transplant Candidates

INTRODUCTION

End-stage heart failure (ESHF) remains a significant challenge despite optimal treatment, with heart transplantation (HTx) being the gold standard of care. Mechanical circulatory support (MCS) devices such as left ventricular assist devices (LVADs) are increasingly used for temporary or permanent treatment. Psychiatric comorbidities are common in patients with ESHF and may affect treatment outcomes, but the relationship between sociodemographic, clinical, and psychiatric characteristics remains unclear.

METHODS

A medical record based, descriptive cross-sectional study was conducted on 94 ESHF patients scheduled for HTx or LVAD therapy. Sociodemographic, clinical, and psychiatric data, including psychiatric diagnoses and systemic inflammatory markers, were collected from medical records. Univariate analyses compared patients with (PD) and without psychiatric disorders (No-PD).

RESULTS

Of the participants, 37% had active psychopathology, with major depressive disorder (MDD) and generalized anxiety disorder (GAD) being prevalent. Approximately half of those diagnosed received their first psychiatric diagnosis at the time of assessment. Sociodemographic factors did not differ significantly between the PD and No-PD groups. While no significant difference was observed in ejection fraction (%) and inflammatory markers such as C-reactive protein (CRP), lymphocyte count was higher in the PD group.

CONCLUSIONS

Preoperative psychiatric assessment is crucial to identify psychiatric comorbidities in ESHF patients undergoing HTx or LVAD therapy. Despite limitations, this study sheds light on previously unexplored aspects, such as the relationship between ejection fraction and psychiatric comorbidities and the relationship between depressive symptoms and inflammatory markers obtained from complete blood count. Furthermore, the fact that almost half of the patients with psychiatric comorbidity were first diagnosed during the pre-treatment psychiatric assessment underlines the importance of pre-LVAD and pre-HTX psychiatric evaluation.

Infections in Patients with Mechanical Circulatory Support

Patients on mechanical circulatory support are at heightened risk for infection given the invasive nature of the devices with internal and external components, the surgical implantation of the devices, and the presence of foreign material susceptible to biofilm formation. This review discusses the new International Society for Heart and Lung Transplantation mechanical circulatory support device infection definitions, inclusive of durable and acute mechanical circulatory support infections, and describes their epidemiology, diagnosis, and management. A multidisciplinary approach is essential for optimal management. Timing of transplantation in the context of active infection is addressed, and areas of future research are highlighted.

Complications of Left Ventricular Assist Devices: A Case Study of Recurrent Bacteremia and Implications for Infection Management

Heart failure (HF) is a complex clinical condition with symptoms that result from ineffective ejection of blood due to functional or structural impairment of the heart. The most common causes of HF include ischemic heart disease, myocardial infarction (MI), hypertension, and valvular heart disease (VHD). As HF progresses to advanced stages, interventions, like left ventricular assist devices (LVADs), become essential, especially for patients ineligible for heart transplantation. However, LVADs carry substantial infection risks, particularly for bacteremia, which complicates management, patient morbidity, and patient outcomes in some cases.  Our case involves a 61-year-old male with a medical history of American College of Cardiology (ACC)/American Heart Association (AHA) stage D heart failure secondary to non-ischemic cardiomyopathy, a history of biventricular implantable cardioverter defibrillator (ICD) implantation, and an LVAD as destination therapy who experienced recurrent episodes of LVAD-associated infection. Post-implantation, he developed repeated driveline infections with Methicillin-resistant Staphylococcus aureus (MRSA) and Corynebacterium, necessitating prolonged antibiotic courses, incision and drainage, and wound care, but no device functionality issues. The patient's non-adherence to infection control measures further complicated his clinical course, with multiple hospital admissions due to recurrent infections and associated symptoms. Psychosocial factors, including anxiety and depression, significantly impacted his adherence to driveline care, highlighting the critical role of comprehensive patient support in managing LVAD complications. This case underscores the importance of candidate selection, patient education, and stringent infection control protocols in LVAD management. Early identification of patients at high infection risk, combined with ongoing psychosocial support, can improve outcomes and reduce complications. Given the potential for recurrent infections, enhanced screening for psychosocial issues and preventive strategies are essential for patients undergoing LVAD implantation.

Association between psychosocial factors and left ventricular assist device implant outcomes: A systematic review

BACKGROUND

Psychosocial assessment is a core component of the multidisciplinary evaluation for left ventricular assist device (LVAD) implantation. The degree to which psychosocial conditions are considered a contraindication to LVAD implantation continues to be debated. This systematic review examines modifiable psychosocial factors as predictors of outcomes in patients undergoing LVAD implantation.

METHODS

We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The search resulted in 2509 articles. After deduplication, abstract and full-text review, 20 relevant articles were identified.

RESULTS

Included studies evaluated socioeconomic status (n = 6), caregiver characteristics (n = 6), non-adherence (n = 6), substance use (n = 13), and psychiatric disorder (n = 8). The most commonly measured outcomes were all-cause death, readmission rate, and adverse events. Studies varied widely in definition of each psychosocial factor and selected outcomes. No psychosocial factor was consistently associated with a specific outcome in all studies. Socioeconomic status was generally not associated with outcomes. Non-adherence, psychiatric disorder, and substance use were associated with higher risks of mortality, adverse events, and/or readmission. Findings on caregiver characteristics were mixed.

CONCLUSION

Of the psychosocial factors studied, non-adherence, psychiatric disorder, and substance use were the most consistently associated with an increased risk of mortality, readmission, and/or adverse events. Heterogeneity in research methodology and study quality across studies precludes firm conclusions regarding the impact of psychosocial factors on long-term patient outcomes. The results of this review reveal a need for adequately powered studies that use uniform definitions of psychosocial factors to clarify relationships between these factors and outcomes after LVAD implantation.

Left ventricular assist device temporary explantation as a strategy for infection control in a pediatric patient

We report a case of temporary Berlin Heart EXCOR® explantation in a pediatric patient with idiopathic dilated cardiomyopathy who suffered an uncontrollable inflow cannulation site infection while on bridge-to-transplantation. Despite failure to thrive and catheter-related infections, once free of the device, the patient was cured of infection using systemic antibiotics and surgical debridement. The patient underwent EXCOR® reimplantation after four months, and is awaiting heart transplantation in stable condition. A life-threatening ventricular assist device-related infection may require device explantation under conditions that may not fulfill conventional explantation criteria despite risks. Temporary explantation can be an effective strategy if isolated systolic dysfunction is managed carefully.

Outcomes of treatment for deep left ventricular assist device infection

OBJECTIVE

Among left ventricular assist device patients, the most commonly infected component is the drive line, which can be managed with antibiotics and local debridement. Infection of intrathoracic device components is less common but more difficult to manage. Herein we describe the incidence of deep device infection (DDI) at our center as well as management and outcomes.

METHODS

We retrospectively reviewed 658 patients who underwent implantable left ventricular assist device insertion with HeartMate 2 (Abbott) or HeartMate 3 (Abbott) devices between January 2004 and June 2021. DDI was defined according to radiographic and clinical criteria. Cumulative incidence was calculated using a Fine-Gray subdistribution model; survival analysis was performed using the method of Kaplan and Meier.

RESULTS

There were 32 (4.8%) DDIs during this study period. Drive line infection and re-exploration for bleeding were associated with development of DDI. Cumulative incidence of DDI increased over time, affecting 11% (7%-18%) at 5 years. The dominant microbes involved in DDI were Pseudomonas aeruginosa (19%) and methicillin-resistant Staphylococcus aureus (13%). Nineteen patients (59%) with device infection underwent device exchange, 6 (19%) underwent initial transplant, and 7 (22%) were treated solely with debridement and antibiotics. Of those who underwent device exchange, 12 (63%) developed reinfection of their new device and 6 underwent subsequent heart transplant. Patients who underwent transplantation for management of device infection had improved 5-year survival (80% vs 11%; P = .01) but 3 patients (25%) developed deep sternal wound infection after transplant.

CONCLUSIONS

DDI is a rare but challenging complication in this destination era. Heart transplantation is the preferred management strategy for eligible patients but infectious complication is common.

The association between cataract surgery and mental health in older adults: a review

BACKGROUND

Although cataract surgery has been proposed as a potentially modifiable protective factor for enhancing emotional well-being in cataract patients, studies examining the relationship between anxiety or depression and cataract surgery have yielded inconsistent findings. This review summarizes existing evidence to establish whether cataract surgery is associated with depression and anxiety in older adults.

METHODS

A literature search was conducted across PubMed, Medline, Web of Science, and Embase databases. An initial screening by abstracts and titles was performed, followed by a review and assessment of the methodological quality of the relevant full papers, and final inclusion of 44 studies were deemed eligible for inclusion in this review.

RESULTS

Among 44 included studies, 36 studies (81.8%) were observational studies concerning the association of cataract surgery or cataracts with anxiety or depression, four studies (9.1%) were interventional studies, and four studies (9.1%) were reviews. Cataract surgery notably enhances the mental health of individuals with impaired vision. However, the multifaceted nature of psychological well-being, influenced by various factors, suggests that cataract surgery may not address all aspects comprehensively. Additionally, preoperative anxiety and depression significantly impact cataract surgery outcomes.

CONCLUSION

Vision impairment in older adults is closely associated with increased symptoms of depression and anxiety. While surgical intervention for cataracts improves these symptoms, it might be less effective for mental disorders with multifactorial causes. Notably, anxiety or depression poses challenges to successful preoperative and intraoperative cataract surgeries.

In-vitro external fixation pin-site model proof of concept: A novel approach to studying wound healing in transcutaneous implants

External fixation is an essential surgical technique for treating trauma, limb lengthening and deformity correction, however infection is common, with infection rates ranging from 4.5 to 100% of cases. Throughout the literature researchers and clinicians have highlighted a relationship between excessive movement of the pin and skin and an increase in the patient's risk of infection, however, currently no studies have addressed this role of pin-movement on pin-site wounds. This preliminary study describes a novel in vitro pin-site model, developed using a full-thickness human skin equivalent (HSE) model in conjunction with a bespoke mechanical system which simulates pin-movement. The effect of pin-movement on the wound healing response of the skin equivalents was assessed by measuring the expression of pro-inflammatory cytokines. Six human skin equivalent models were divided into three test groups: no pin as the control, static pin-site wound and dynamic pin-site wound (n = 3). On day 3 concentrations of IL-1α and IL-8 showed a significant increase compared to the control when a static fixation pin was implanted into the skin equivalent (p < 0.05) and (p < 0.005) respectively. Levels of IL-1α and IL-8 increased further in the dynamic sample compared to the static sample (p < 0.05) and (p < 0.0005). This study demonstrates for the first time the application of HSE model to study external-fixation pin-movement in vitro. The results of this study demonstrated pin-movement has a negative effect on soft-tissue wound-healing, supporting the anecdotal evidence reported in the literature, however further analysis of wound heading would be required to verify this hypothesis.

Left ventricular assist device-associated driveline infections as a specific form of complicated skin and soft tissue infection/acute bacterial skin and skin structure infection - issues and therapeutic options

PURPOSE OF REVIEW

This review comments on the current guidelines for the treatment of wound infections under definition of acute bacterial skin and skin structure infections (ABSSSI). However, wound infections around a catheter, such as driveline infections of a left ventricular assist device (LVAD) are not specifically listed under this definition in any of the existing guidelines.

RECENT FINDINGS

Definitions and classification of LVAD infections may vary across countries, and the existing guidelines and recommendations may not be equally interpreted among physicians, making it unclear if these infections can be considered as ABSSSI. Consequently, the use of certain antibiotics that are approved for ABSSSI may be considered as 'off-label' for LVAD infections, leading to rejection of reimbursement applications in some countries, affecting treatment strategies, and hence, patients' outcomes. However, we believe driveline exit site infections related to LVAD can be included within the ABSSSI definition.

SUMMARY

We argue that driveline infections meet the criteria for ABSSSI which would enlarge the 'on-label' antibiotic armamentarium for treating these severe infections, thereby improving the patients' quality of life.

Epidemiology and Risk Factors for Nosocomial Infections in Left Ventricular Assist Device Recipients

Left ventricular assist devices (LVADs) have been increasingly used as a valid option to improve the prognosis and reduce the symptoms of end-stage heart failure. However, long-term complications, mostly infections and coagulation disorders, are frequent. We described the epidemiology and risk factors for nosocomial infections (NIs) in a cohort of adult patients who underwent continuous-flow LVAD implant between January 2010 and December 2017 in Turin, Italy. Secondary outcomes were the prevalence of multidrug-resistant (MDR) bacteria and mortality. Results: Overall, 64 LVADs were implanted. A total of 32 (50%) patients experienced at least one episode of NI, with a total of 46 infectious events. VAD-related infections occurred in 22 patients (68.8%). Non VAD-related NIs occurred in 12 patients (37.5%), mainly low respiratory tract infections. Length of intensive care unit admission was a risk factor for NI (OR 1.224, 95%CI; 1.049, 1.429). Gram-negative bacilli were responsible for 58.8% of VAD-related infections and 79.5% of non-VAD related infections. In sixteen patients (50%), at least one episode of infection was related to an MDR strain. INTERMACS class and length of MV were independent risk factors for NIs by MDR strains (respectively, OR 2.12, 95%CI: 1.08, 6.80; p = 0.02 and OR 1.46, 95%CI: 1.07, 5.52, p = 0.047). In-hospital mortality was 6.3%. No differences in mortality were observed between infected and non-infected patients (p = 0.61) even when caused by MDR strains (p = 0.143). Conclusion: the rate of nosocomial infections in LVAD patients is associated with the length of ICU admission, and the etiology of nosocomial infection after LVAD implant is mainly due to GNB, including a high rate of MDR strains, especially KPC-KP and MDR PA.

Postoperative care of 14 patients with left ventricular assist devices: a case series

A left ventricular assist device is a mechanical device that is surgically implanted in the heart to partially or completely replace the function of the heart. Left ventricular assist devices are of vital importance in the treatment of patients with heart failure. There are different recommendations for the postoperative care of patients undergoing left ventricular assist device implantation in different countries, and no uniform standard has been developed. The first implantation of a left ventricular assist device in Eastern China was performed in February 2021; since that date, 14 patients underwent implantation until February 2023. This report describes the postoperative care of these 14 patients with end-stage heart failure who underwent left ventricular assist device placement, all of whom were discharged with a good prognosis.

Driveline infections in left ventricular assist devices-Incidence, epidemiology, and staging proposal

BACKGROUND

Driveline infections (DLI) are a serious complication in patients with left ventricular assist devices (LVAD). Apart from the differentiation between superficial and deep DLI, there is no consensus on the classification of the severity of DLI. Little is known about risk factors and typical bacteria causing DLI in centrifugal-flow LVADs.

METHODS

In this single-center study with 245 patients, DLI were classified by their local appearance using a modification of a score suggested by the Sharp Memorial group. The driveline exit site was inspected routinely every 6 months.

RESULTS

Severe DLI were detected in 34 patients (15%) after 6 months and in 24 patients (22%) after 24 months. The proportion of patients with DLI increased significantly during the follow-up (p = 0.0096). The most common bacteria in local smears were Corynebacterium, coagulase-negative Staphylococcus, and Staphylococcus aureus. Fifty-nine patients were hospitalized more than once for DLI. In these patients, S. aureus was the most common bacterium. It was also the most common bacterium in blood cultures. Higher BMI, no partnership, and a HeartMate 3 device were identified as risk factors for DLI in a multivariable cause-specific Cox regression.

CONCLUSION

This study is a standardized analysis of DLI in a large cohort with centrifugal-flow LVADs.

Clinical and economic impact of ventricular assist device infections: a real-world claims analysis

BACKGROUND

VAD therapy has revolutionized the treatment of end-stage heart failure, but infections remain an important complication. The objective of this study was to characterize the clinical and economic impacts of VAD-specific infections.

METHODS

A retrospective analysis of a United States claims database identified members ≥ 18 years with a claim for a VAD implant procedure, at least 6 months of pre-implant baseline data, and 12 months of follow-up between 1 June 2016 and 31 December 2019. Cumulative incidence of infection was calculated. Infection and non-infection cohorts were compared regarding mortality, healthcare utilization, and total cost. Regression models were used to identify risk factors associated with infections and mortality.

RESULTS

A total of 2,259 patients with a VAD implant were included, with 369 experiencing infection (12-month cumulative incidence 16.1%). Patients with infection were 2.1 times more likely to die (p < 0.001, 95% CI [1.5-2.9]). The mean 12-month total cost per US patient was $354,339 for the non-infection cohort and $397,546 for the infection cohort, a difference of $43,207 (p < 0.0001).

CONCLUSIONS

VAD infections were associated with higher mortality, more healthcare utilization, and higher total cost. Strategies to minimize VAD-specific infections could lead to improved clinical and economic outcomes.

Relevance of cardiac imaging in the evolving landscape of infective endocarditis management

Infective endocarditis (IE) is an increasingly recognized condition with high morbidity. Patients with atypical symptoms, culture-negative infections, and prosthetic cardiac devices and implants represent challenging populations to evaluate and manage. Recent major society guidelines have recommended the appropriate incorporation of multimodality imaging in the evaluation of these more complex IE cases. This article draws on the available literature regarding the different cardiac imaging modalities and discusses the role of multimodality imaging in IE.

Neutrophil Structural and Functional Alterations After High Mechanical Shear Stress Exposure

Patients on mechanical circulatory support are prone to infections, increasing morbidity and mortality. These circulatory support devices generate high mechanical shear stress (HMSS) that can causes trauma to blood. When leukocytes become damaged, their immune response function may be impaired or weakened, leading to increased infection vulnerability. This study examined neutrophil structural and functional alterations after exposure to 75, 125, and 175 Pa HMSS for 1 second. Human blood was exposed to three levels of HMSS using a blood shearing device. Neutrophil morphological alteration was characterized by examining blood smears. Flow cytometry assays were used to analyze expression levels of CD62L and CD162 receptors, activation level (CD11b), and aggregation (platelet-neutrophil aggregates). Neutrophil phagocytosis and rolling were examined via functional assays. The results show neutrophil structure (morphology and surface receptors) and function (activation, aggregation, phagocytosis, rolling) were significantly altered after HMSS exposure. These alterations include cell membrane damage, loss of surface receptors (CD62L and CD162), initiation of activation and aggregation, upregulation of phagocytic ability and increased rolling speed. The alterations were the most severe after 175 Pa exposure. HMSS caused damage and activation of neutrophils, potentially impairing normal neutrophil function, leading to weakened immune defense and increasing a patient's vulnerability to infections.

Risk factors for new antidepressant use after surgery in Sweden: a nationwide, observational cohort study

Background

Whilst somatic complications after major surgery are being increasingly investigated, the research field has scarce data on psychiatric outcomes such as postoperative depression. This study evaluates the impact of patient and surgical factors on the risk of depression after surgery using the proxy measure of prescribed and collected antidepressants.

Methods

An observational, registry-based, national multicentre cohort study of individuals ≥18 yr of age who underwent noncardiac surgery between 2007 and 2014. Exclusion criteria included history of antidepressant use defined by collection of a prescription within 5 yr before surgery. Participants were identified using a surgical database from 23 Swedish hospitals and data were linked to National Board of Health and Welfare registers for collection of prescribed antidepressants. Descriptive statistics were used for baseline data and logistic regression for predictive factors.

Results

Of 223 617 patients, 4.9% had a new prescription of antidepressants collected 31-365 days after surgery. Antidepressant prescription was associated with increasing age, female sex, and more comorbidities. The incidence of antidepressant prescription was highest after neurosurgery, vascular, and thoracic surgery. Affective and anxiety disorders were risk factors. In the whole cohort and within the aforementioned surgical subtypes, acute and cancer surgery increased the risk of antidepressant prescription.

Conclusions

This study brings novel insights to the epidemiology of postoperative antidepressant treatment in antidepressant-naive patients. One in 20 postoperative patients are prescribed antidepressants but with knowledge of risk factors, interventional strategies can be tested.

Mortality following durable left ventricular assist device implantation by timing and type of first infection

OBJECTIVE

Although infections are common after left ventricular assist device implantation, the relationship between timing and type of first infection with regard to mortality is less well understood.

METHODS

The Society of Thoracic Surgeons Interagency Registry for Mechanically Assisted Circulatory Support patients receiving a primary left ventricular assist device from April 2012 to May 2017 were included. The primary exposure was defined 3 ways: any infection, timing of first infection (early: ≤90 days; intermediate: 91-180 days; late: >180 days), and type (ventricular assist device specific, ventricular assist device related, non-ventricular assist device). The association between first infection and all-cause mortality was estimated using Cox regression.

RESULTS

The cohort included 12,957 patients at 166 centers (destination therapy: 47.4%, bridge-to-transplant: 41.2%). First infections were most often non-ventricular assist device (54.2%). Rates of first infection were highest in the early interval (10.7/100 person-months). Patients with any infection had a significantly higher adjusted hazard of death (hazard ratio, 2.63; 2.46-2.86). First infection in the intermediate interval was associated with the largest increase in adjusted hazard of death (hazard ratio, 3.26; 2.82-3.78), followed by late (hazard ratio, 3.13; 2.77-3.53) and early intervals (hazard ratio, 2.37; 2.16-2.60). Ventricular assist device-related infections were associated with the largest increase in hazard of death (hazard ratio, 3.02; 2.69-3.40), followed by ventricular assist device specific (hazard ratio, 2.92; 2.57-3.32) and non-ventricular assist device (hazard ratio, 2.42; 2.20-2.65).

CONCLUSIONS

Relative to those without infection, patients with any postimplantation infection had an increased risk of death. Ventricular assist device-related infections and infections occurring in the intermediate interval were associated with the largest increase in risk of death. After left ventricular assist device implantation, infection prevention strategies should target non-ventricular assist device infections in the first 90 days, then shift to surveillance/prevention of driveline infections after 90 days.

Depression among Patients with an Implanted Left Ventricular Assist Device: Uncovering Pathophysiological Mechanisms and Implications for Patient Care

Depression is a common and devastating mental illness associated with increased morbidity and mortality, partially due to elevated rates of suicidal attempts and death. Select patients with end-stage heart failure on a waiting-list for a donor heart undergo left ventricular assist device (LVAD) implantation. The LVAD provides a circulatory flow of oxygenated blood to the body, mimicking heart functionality by operating on a mechanical technique. LVAD improves functional capacity and survivability among patients with end-stage heart failure. However, accumulating data suggests that LVAD recipients suffer from an increased incidence of depression and suicide attempts. There is scarce knowledge regarding the pathological mechanism and appropriate treatment approach for depressed LVAD patients. This article summarizes the current evidence on the association between LVAD implantation and occurrence of depression, suggesting possible pathological mechanisms underlying the device-associated depression and reviewing the current treatment strategies. The summarized data underscores the need for a rigorous pre-(LVAD)-implantation psychiatric evaluation, continued post-implantation mental health assessment, and administration of antidepressant treatment as necessary.

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.

Prophylactic negative pressure wound therapy is not effective for preventing driveline infection following left ventricular assist device implantation

BACKGROUND

Driveline infection (DLI) following left ventricular assist device (LVAD) implantation remains an unresolved problem. Negative pressure wound therapy (NPWT) promotes wound healing by applying negative pressure on the surface of the wound. Recently, the prophylactic application of NPWT to closed surgical incisions has decreased surgical site infections in various postsurgical settings. Therefore, we evaluated the efficacy and safety of prophylactic NPWT for preventing DLI in patients with LVAD implantation.

METHODS

Prophylactic NPWT was provided to 50 patients who received continuous-flow LVADs as bridge-to-transplant therapy at our institution between May 2018 and October 2020 (NPWT group). The negative pressure dressing was applied immediately after surgery and retained on the driveline exit site for 7 days with a continuous application of -125 mm Hg negative pressure. The primary outcome was DLI within 1 year of LVAD implantation. We compared the rate of DLI incidence in the NPWT group with that in the historical control cohort (50 patients) treated with the standard dressing (SD) who received LVAD implantation between July 2015 and April 2018 (SD group).

RESULTS

No severe complications were associated with the NPWT. During the follow-up period, DLI was diagnosed in 16 participants (32%) in the NPWT group and 21 participants (42%) in the SD group. The rates of DLI incidence and freedom from DLI did not differ between groups (p = 0.30 and p = 0.63).

CONCLUSIONS

Prophylactic NPWT at the driveline exit site was safe following LVAD implantation. However, it did not significantly reduce the risk of DLI.

Driveline erosion of the colon as a late complication of LVAD implantation

A 69-year-old man with ischemic cardiomyopathy underwent left ventricular assist device (LVAD) implantation as destination therapy. One month after LVAD placement, the patient reported abdominal pain with driveline site purulence. Serial wound and blood cultures were positive for various Gram-positive and Gram-negative organisms. Abdominal imaging revealed a possible intracolonic course of the driveline at the splenic flexure, but there were no imaging findings suggestive of bowel perforation. A colonoscopy did not identify a perforation. The patient was treated with antibiotics but continued to experience driveline infections over the next 9 months until frank stool started draining from the driveline exit site. Our case illustrates driveline erosion of the colon causing the insidious formation of an enterocutaneous fistula and highlights a rare late complication of LVAD therapy.

Learning objective

Colonic erosion by the driveline can cause enterocutaneous fistula formation over a period of months. A change from typical infectious organisms for driveline infection should prompt investigation of a gastrointestinal source. In cases where computed tomography of the abdomen does not show perforation and there is concern for an intracolonic course of the driveline, colonoscopy or laparoscopy may be diagnostic.

Flap Coverage of Infected Ventricular Assist Devices Influences Patient Outcomes

BACKGROUND

The use of left ventricular assist devices (LVADs) for patients with end-stage cardiac failure awaiting heart transplantation has become increasingly common. However, ventricular assist device-related infections remain a major problem complicating their long-term use. Poor data exist to determine how to manage these infections after operative debridement.

METHODS

Patients who underwent insertion of a ventricular assist device and had a subsequent readmission for LVAD infection at the University of Rochester Medical Center from 2012 to 2022 were identified through accessing the medical records archives of the hospital. Patients were followed retrospectively for an average of 3.2 years. Patient demographics, preoperative diagnosis/disease state, type of ventricular assist device inserted, postoperative day of ventricular assist device infection onset, infectious organism identified at initial washout, infectious organism identified at time of definitive device coverage, timing of coverage procedure after the initial washout for infection, type of flap used for coverage, 90-day complications after definitive coverage, and lifetime return to operating room for infection were reviewed. Comparison analysis with a χ2 test was used to analyze outcomes.

RESULTS

Of 568 patients admitted with an LVAD-related infection 117 underwent operative debridement. Of these, 34 underwent primary closure, 31 underwent closure with secondary intention (negative pressure wound therapy with split thickness skin grafting), and 52 were closed with a flap (pectoralis, omental, latissimus, or vertical rectus abdominus musculocutaneous flap). There was a statistically significant higher incidence of return to the operating room (RTOR) for infection over a lifetime with primary closure compared with secondary intention and flap reconstruction (P = 0.01, 0.02), but no difference in 90-day complications (P = 0.76, P = 0.58). Eighty-three patients had a positive culture upon definitive coverage with 24 having a postsurgical complication, 15 of which required lifetime RTOR for infection. Thirty four were closed with negative cultures with 9 having a complication and 4 requiring RTOR for infection. This was not statistically significant for complications or RTOR (P = 0.79, 0.40). Culture data were further substratified into bacterial cultures (n = 73) versus fungal cultures (n = 10), and there was no statistically significant difference between these compared with complications or RTOR (P = 0.40, 0.39).

CONCLUSIONS

Coverage of infected LVADs with locoregional flaps or allowing to granulate using wound vac therapy has a decreased lifetime RTOR for future infections for these patients without increase in 90-day complications. Timing of RTOR should not be impacted by positive cultures provided there is healthy granulation tissue in the wound.

New Wound Management of Driveline Infections with Cold Atmospheric Plasma

The use of ventricular assist devices as a bridge to transplant or as destination therapy has increased. Wound complications increase morbidity in this cohort. Cold atmospheric plasma is a source of reactive oxygen and nitrogen species and can reduce the microbial load in skin wounds without negative effects on the surrounding tissue. We evaluated our cold atmospheric plasma treatment for LVAD driveline infections in a retrospective single-center study for peri- and postintervention outcome analysis. Between April 2019 and September 2019, 15 male patients were included (5 HVAD, 10 HeartMate III). The wounds were treated for a mean of 368.5 s with a reduction of bacterial load in treated wounds in 60% of patients, regardless of the pathogen. The most common pathogen was staphylococcus aureus (n = 8 patients). There was a significant reduction of the wound scale (scale 2.80 vs. 1.18; p < 0.001) plus a significant reduction in size (16.08 vs. 1.90 cm3; p = 0.047). Seven patients (46.6%) were free from any signs of local or systemic infection during 1-year follow-up. Five patients (33%) received a heart transplantation. Cold atmospheric plasma treatment is a potent, safe, and painless adjuvant technique for treating driveline infection without the need for repeating surgical interventions.

Infection following CF-LVAD exchange for non-infectious indications: A systematic review and meta-analysis

Introduction:

Patients on continuous flow left ventricular assist devices (CF-LVADs) often require CF-LVAD exchange. The purpose of this study was to investigate the incidence of infection following CF-LVAD exchange performed for non-infectious indications.

Methods:

An electronic literature search was performed to identify all studies of patients undergoing CF-LVAD exchange for pump thrombosis or device malfunction. Of 2,698 articles identified, 6 studies with 81 total patients met the inclusion criteria. Cohort-level data were pooled for meta-analysis.

Results:

Mean patient age was 60 years (95% CI: 41–78), and 74% were male (95% CI: 61–84). Pump thrombosis was the most common indication for exchange in 70% of patients (95% CI: 47–86). Other indications were driveline fracture and electrical malfunction in 21% (95% CI: 5–56) and 12% (95% CI: 4–33) of patients, respectively. Prior to exchange, 95% of patients were on HeartMate II (HM2) LVADs (95% CI: 86–98) and average duration of support for these patients was 27.1 months (95% CI: 9.3–44.8). The majority were placed on a HM2 following exchange (88% (95% CI: 45–98)) versus HM3 (12% (95% CI: 2–55)). Follow-up was an average of 16.4 months (95% CI: 6.8–26.0). Following exchange, 16 of 81 patients developed infection, with pooled mean incidence of 24% (95% CI: 14–38). 30-day mortality was 14% (95% CI: 7–26). Survival at follow-up was 65% (95% CI: 52–76).

Conclusions:

Infection following CF-LVAD exchange can occur at rates higher than those observed with primary implantation; therefore, effective strategies need to implemented early and consistently to help lower infections rates and help improve outcomes following exchange.

Threatened Ventricular Assist Devices: Meta-analysis of Negative Pressure Therapy and Flap Reconstruction Outcomes

Infected Ventricular Assist Device (VAD)-associated wounds are common and associated with significant morbidity and mortality. The efficacy of hardware salvage utilizing flaps and negative pressure wound therapy (NPWT) remains understudied. We hypothesized that patients treated with flaps and/or NPWT would have higher hardware salvage rates compared with other surgical management strategies.

METHODS

A meta-analysis study evaluating VAD-associated wounds was performed following PRISMA guidelines. Primary predictor variables were flap-reconstruction (FR), NPWT, no FR, and infection location (mediastinum versus driveline). Primary outcomes were hardware retention (salvage) versus explantation, infection recurrence, or death. Twenty-nine studies were included. Standard statistical methods included logistic regression analysis.

RESULTS

Seventy-four subjects with nonsignificant demographic differences between cohorts were identified. Overall salvage was 59.5% in both driveline and mediastinum cohorts. Overall, NPWT significantly improved salvage compared with no NPWT [77.4% versus 46.5% respectively (P = 0.009)], and FR significantly improved salvage compared with no FR [68.6% versus 39.1% respectively (P = 0.022)]. Logistic regression analysis predicting odds of salvage by FR (area under curve = 0.631) was significantly three times higher (95% CI: 1.2-9.5) and predicting the odds for salvage by NPWT (area under curve = 0.656) was significantly four times higher (95% CI: 1.4-11.1) compared with other treatment.

CONCLUSIONS

NPWT or flap reconstruction for treatment of threatened VAD hardware was associated with a significantly improved device salvage compared with other surgical strategies. Further study should focus on subgroup analysis of flaps utilized and synergistic treatment benefits.

Pre-operative risk factors for driveline infection in left ventricular-assist device patients

AIMS

Implantation of left ventricular-assist devices (LVAD) to treat end-stage heart failure is of increasing relevance due to donor shortage. Infections of the driveline are common adverse events. LVAD infections can lead to high urgency listings for transplantation. However, transplantation in patients with infection leads to worse post-transplantation outcomes. This study aims to evaluate specific risk factors for driveline infections at the time of implantation.

METHODS AND RESULTS

Four hundred forty-one patients receiving either Heartmate II or Heartware system from August 2009 to October 2013 were assessed. An expert committee sorted patients into four different groups concerning the likeliness of infection. Twenty-eight (6%) of discussed infection cases were judged as secured, 33 (7%) as likely, 18 (4%) as possible, and 20 (4%) as unlikely. The remaining 342 (78%) subjects showed either no signs of infection at all times (329 [75%]) or developed signs of infection in a second observation period within 1 year after ending of the first observation period (13 [3%]). For a better discriminatory power, cases of secured and likely infections were tested against the group with no infection at all times in a Cox proportional hazard model. Among all variables tested by univariate analysis (significance level P < 0.15), only age (P = 0.07), LVAD-type (P = 0.12), need for another thoracic operation (P = 0.02), and serum creatinine value (P = 0.02) reached statistical significance. These were subsequently subjected to multivariate analysis to calculate the cumulative risk of developing a drive infection. The multivariate analysis showed that of all the potential risk factors tested, only the necessity of re-thoracotomy or secondary thoracic closure had a significant, protective effect (hazard ratio [95% CI] = 0.45 [0.21-0.95]; P = 0.04).

CONCLUSION

This single-centre cohort study shows that driveline infections are common adverse events. The duration of support represents the major risk factor for LVAD driveline infections.

Preoperative Depression Influences Outcomes Following Total Ankle Arthroplasty

INTRODUCTION

Total ankle arthroplasty (TAA) is increasing in incidence. While preoperative depression is known to affect outcomes following other procedures, its effect on outcomes following TAA are unknown. Therefore, the purpose of this study was to investigate this relationship.

METHODS

This is a retrospective cohort study using the Nationwide Readmission Database (NRD). All patients undergoing TAA were included. Two cohorts (those with and without preoperative depression) were created. Logistic regression was then performed to assess the contribution of a preoperative diagnosis of depression on rates of 90-day complications, while controlling for patient demographic and comorbid data.

RESULTS

Overall, 8047 patients were included, of whom, 11.4% (918) were depressed. Compared to patients without depression, patients with depression had increased odds of the following: nonhome discharge (OR 1.61, 95% CI 1.31-1.98), extended length of stay (>2 days; OR 1.34, 95% CI 1.15-1.57), prosthetic complication (OR 1.39, 95% CI 1.10-1.74), wound complication (OR 1.59, 95% CI 1.11-2.29), prosthetic joint infection (OR 1.82, 95% CI 1.06-3.15), superficial surgical site infection (OR 1.62, 95% CI 1.02-2.58), and medical complication (OR 1.32, 95% CI 1.03-1.68).

DISCUSSION

Depression in patients undergoing TAA is common and is associated with increased health care utilization and complications following surgery. The modifiability of depression should be investigated with future studies.

LEVELS OF EVIDENCE

Prognostic, Level III: Comparative study.

Decreasing driveline infections in patients supported on ventricular assist devices: a care pathway approach

Background

Driveline infections (DLIs) are a common adverse event in patients on ventricular assist devices (VADs) with incidence ranging from 14% to 59%. DLIs have an impact on patients and the healthcare system with efforts to prevent DLIs being essential. Prior to our intervention, our program had no standard driveline management presurgery and postsurgery. The purpose of this Quality Improvement (QI) initiative was to reduce DLIs and related admissions among patients with VAD within the first year post implant.

Methods

In anticipation of the QI project, we undertook a review of the programs’ current driveline management procedures and completed a survey with patients with VAD to identify current barriers to proper driveline management. Retrospective data were collected for a pre-QI intervention baseline comparison group, which included adult patients implanted with a durable VAD between 1 January 2017 and 31 July 2018. A three-pronged care pathway (CP) was initiated among patients implanted during August 2018 to July 2019. The CP included standardised intraoperative, postoperative and predischarge teaching initiatives and tracking. Using statistical process control methods, DLIs and readmissions in the first year post implant were compared between patients in the CP group and non-CP patients. P-charts were used to detect special cause variation.

Results

A higher proportion of CP group patients developed a DLI in the first year after implant (52% vs 32%). None developed a DLI during the index admission, which differed from the non-CP group and met criteria for special cause variation. There was a downward trend in cumulative DLI-related readmissions among CP group patients (55% vs 67%). There was no association between CP compliance and development of DLIs within 1 year post implant.

Conclusion

The CP did not lead to a reduction in the incidence of DLIs but there was a decrease in the proportion of patients with DLIs during their index admission and those readmitted for DLIs within 1 year post implant. This suggests that the CP played a role in decreasing the impact of DLIs in this patient population. However, given the short time period of follow-up longer follow-up will be required to look for sustained effects.

Does infection predispose to thrombosis during long term ventricular assist device support?

BACKGROUND

Infections and thrombotic events remain life-threatening complications in patients with ventricular assist devices (VAD).

METHODS

We describe the relationship between both events in our cohort of patients (n=220) supported with the HeartWare VAD (HVAD). This is a retrospective analysis of patients undergoing HVAD implantation between July 2009 and March 2019 at the Freeman Hospital, Newcastle upon Tyne, United Kingdom.

RESULTS

Infection was the most common adverse event in HVAD patients, with 125 patients (56.8%) experiencing ≥ one infection (n=168, 0.33 event-per-person-year-EPPY), followed by pump thrombosis (PT) in 61 patients (27.7%, 0.16 EPPY). VAD-specific infections were the largest group of infections. Of the 125 patients who had an infection, 66 (53%) had a thrombotic event. Both thrombotic events and infections were related to the duration of support, though there was only limited evidence that infections predispose to thrombosis. Those with higher than median levels of CRP during the infection were more likely to have an ischaemic stroke (IS) (34.5% vs 16.7%, p=0.03), though not PT or a combined thrombotic event (CTE: first PT or IS). However, in multivariate analysis there was no significant effect of infection predisposing to CTE.

CONCLUSIONS

Infection and thrombotic events are significant adverse events related to the duration of support in patients receiving HVADs. Infections do not clearly predispose to thrombotic events.

Infección temprana de la malla quirúrgica en herniorrafia incisional. Incidencia, factores de riesgo y desenlaces en más de 60.000 pacientes

Introducción. La infección de la malla en cirugía de reparación de hernias de pared abdominal es un desenlace pobre, asociado a un incremento en el riesgo de complicaciones. El objetivo del presente estudio fue analizar la incidencia, los factores asociados y desenlaces en pacientes llevados a herniorrafia incisional con malla con posterior diagnóstico de infección temprana. Métodos. Estudio de cohorte retrospectiva. Se utilizaron los datos de egresos hospitalarios de la National Inpatient Sample (NIS) de los Estados Unidos de América para identificar a todos los pacientes adultos llevados a herniorrafia incisional durante los años 2010 a 2015. Se utilizaron modelos de regresión logística bivariada y multivariada para evaluar los factores de riesgo en infección temprana de la malla, y finalmente, modelos de regresión logística y lineal, según el tipo de variable dependiente, de tipo stepwise forward para evaluar la asociación entre el diagnóstico de infección de malla y los desenlaces adversos. Resultados. En total se incluyeron 63.925 pacientes. La incidencia de infección temprana de la malla fue de 0,59 %, encontrando como factores asociados: comorbilidades (obesidad, desnutrición proteico calórica, anemia carencial y depresión), factores clínico-quirúrgicos (adherencias peritoneales, resección intestinal, cirugía laparoscópica y complicaciones no infecciosas de la herida) y administrativos o asistenciales. Conclusiones. La infección temprana, aunque infrecuente, se asocia con un aumento significativo en el riesgo de complicaciones. La optimización prequirúrgica con base en los factores de riesgo para este desenlace nefasto es un elemento clave para la reducción de la incidencia y mitigación del impacto de la infección en los pacientes con herniorrafía incisional con malla.

Bacteriophages for the Treatment of Graft Infections in Cardiovascular Medicine

Bacterial infections of vascular grafts represent a major burden in cardiovascular medicine, which is related to an increase in morbidity and mortality. Different factors that are associated with this medical field such as patient frailty, biofilm formation, or immunosuppression negatively influence antibiotic treatment, inhibiting therapy success. Thus, further treatment strategies are required. Bacteriophage antibacterial properties were discovered 100 years ago, but the focus on antibiotics in Western medicine since the mid-20th century slowed the further development of bacteriophage therapy. Therefore, the experience and knowledge gained until then in bacteriophage mechanisms of action, handling, clinical uses, and limitations were largely lost. However, the parallel emergence of antimicrobial resistance and individualized medicine has provoked a radical reassessment of this approach and cardiovascular surgery is one area in which phages may play an important role to cope with this new scenario. In this context, bacteriophages might be applicable for both prophylactic and therapeutic use, serving as a stand-alone therapy or in combination with antibiotics. From another perspective, standardization of phage application is also required. The ideal surgical bacteriophage application method should be less invasive, enabling highly localized concentrations, and limiting bacteriophage distribution to the infection site during a prolonged time lapse. This review describes the latest reports of phage therapy in cardiovascular surgery and discusses options for their use in implant and vascular graft infections.

Ventricular Assist Device Driveline Infection and Development of Intracranial Hemorrhage: A Case Series

Durable left ventricular assist devices (LVAD) are frequently complicated by driveline infection. The objective of this case series was to examine whether an association exists between driveline infection and intracranial hemorrhage. This retrospective case series included patients at a single tertiary care hospital on durable LVAD support who developed intracranial hemorrhage. Physical examination data, vital signs, and laboratory markers of sepsis including blood cultures and imaging of driveline sites were reviewed. A total of nine patients were included in the case series. At the time of hemorrhagic event, five patients had active driveline infection, and five patients were found to be bacteremic. All bacteremic patients were found to have supratherapeutic INR at the time of presentation. Although five patients experienced subarachnoid hemorrhage, only one patient was found to have a cerebral aneurysm. This case series highlights a possible association between LVAD driveline infection and intracranial hemorrhage, and the need for further research to better understand the pathophysiology driving this association.

Treatment of HeartMate III-LVAD driveline infection by negative pressure wound therapy: Result of our case series

Driveline infection is one of the most frequent complications following left ventricular assist device (LVAD) treatment and there is no consensus for its management. The standard approach to treat foreign-body infection is complete device ablation, which is not always feasible and therefore not an elected method for LVAD driveline infections. Here we share the results from a series of cases successfully treated for driveline infection by negative pressure wound therapy (NPWT) therapy. Between 2016 and 2020, five male patients were hospitalized in our unit with a driveline infection of HeartMate III-LVAD^®. Ultrasonography and/or thoraco-abdominal CT confirmed the diagnosis, infection localization, and abscess formation. Following an antibiotic treatment, an urgent surgical abscess drainage and debridement of the infected tissues were performed. At the end of the procedure, NPWT was applied. NPWT re-dressing and debridement of wound was performed every 3-4 days. The wound was closed surgically after obtaining negative culture results and good healing. The patients were discharged in good condition, without signs of infection. Two patients underwent successful heart transplantation after 1 and 13 months. Other patients did not show any residual or recurrent infection during the follow-up within 25 months. Driveline infection following LVAD implantation is a significant complication and a challenging in terms of management for both; the surgical team and the patient. These results from our case series report a successful and less invasive approach by using NPWT for the treatment of LVAD driveline infections.

On the function of biosynthesized cellulose as barrier against bacterial colonization of VAD drivelines

Bacterial colonization of drivelines represents a major adverse event in the implantation of left ventricular assist devices (L-VADs) for the treatment of congestive heart failure. From the external driveline interface and through the skin breach, pathogens can ascend to the pump pocket, endangering the device function and the patient’s life. Surface Micro-Engineered Biosynthesized cellulose (BC) is an implantable biomaterial, which minimizes fibrotic tissue deposition and promotes healthy tissue regeneration. The topographic arrangement of cellulose fibers and the typical material porosity support its potential protective function against bacterial permeation; however, this application has not been tested in clinically relevant animal models. Here, a goat model was adopted to evaluate the barrier function of BC membranes. The external silicone mantle of commercial L-VAD drivelines was implanted percutaneously with an intervening layer of BC to separate them from the surrounding soft tissue. End-point evaluation at 6 and 12 weeks of two separate animal groups revealed the local bacterial colonization at the different interfaces in comparison with unprotected driveline mantle controls. The results demonstrate that the BC membranes established an effective barrier against the bacterial colonization of the outer driveline interface. The containment of pathogen infiltration, in combination with the known anti-fibrotic effect of BC, may promote a more efficient immune clearance upon driveline implantation and support the efficacy of local antibiotic treatments, therefore mitigating the risk connected to their percutaneous deployment.

Ventricular Assist Device Driveline Infections: A Systematic Review

Infection is the most common complication in patients undergoing ventricular assist device (VAD) implantation. Driveline exit site (DLES) infection is the most frequent VAD infection and is a significant cause of adverse events in VAD patients, contributing to morbidity, even mortality, and repetitive hospital readmissions. There are many risk factors for driveline infection (DLI) including younger age, smaller constitution of patients, obesity, exposed velour at the DLES, longer duration of device support, lower cardiac index, higher heart failure score, DLES trauma, and comorbidities such as diabetes mellitus, chronic kidney disease, and depression. The incidence of DLI depends also on the device type. Numerous measures to prevent DLI currently exist. Some of them are proven, whereas the others remain controversial. Current recommendations on DLES care and DLI management are predominantly based on expert consensus and clinical experience of the certain centers. However, careful and uniform DLES care including obligatory driveline immobilization, previously prepared sterile dressing change kits, and continuous patient education are probably crucial for prevention of DLI. Diagnosis and treatment of DLI are often challenging because of certain immunological alterations in VAD patients and microbial biofilm formation on the driveline surface areas. Although there are many conservative and surgical methods described in the DLI treatment, the only possible permanent solution for DLI resolution in VAD patients is heart transplantation. This systematic review brings a comprehensive synthesis of recent data on the prevention, diagnostic workup, and conservative and surgical management of DLI in VAD patients.

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.

The role of chronic suppressive antibiotics therapy in superficial drive line infection relapse of left ventricular assist devices: A retrospective cohort from a tertiary care center

INTRODUCTION

Drive line infections (DLIs) are common complications of left ventricular assist devices (LVADs). Data on use of suppression antibiotic therapy are limited.

METHODS

We performed a retrospective review of 451 patients who underwent LVAD placement from January 2009 to May 2015. First superficial DLIs were included for analysis. We examined factors associated with the use of chronic suppressive antibiotics (CSAs) therapy. Cox proportional hazards models were performed to identify factors associated with DLI relapse with the same organism as the initial DLI.

RESULTS

A total of 69 patients developed a superficial DLI within a median of 195 (interquartile range [IQR] 98-348) days of LVAD insertion. The median age was 57 years, 87% were males, and 74% were White. Gram positive bacteria caused 61% of infections, with Staphylococcus aureus being the most common (35%). Forty-three (62%) patients received suppressive antibiotic therapy. Relapse DLI occurred in 29 (42%) patients. Independent risk factors for relapse infection in multivariable analysis were sepsis (aHR 5.94 [CI 1.42-24.92]), and MRSA DLI (aHR 4.19 [CI 1.37-12.79]). There was no difference in the proportion of patients with relapse among those who were treated with antibiotic suppression therapy versus not (44% vs. 38%, p = 0.64), although relapse occurred at a later time in those who received suppression (185 vs. 69 days, p < 0.01).

CONCLUSION

CSA therapy was associated with delayed time to DLI relapse but no significant difference in the proportion of patients with relapse. A prospective study is needed to examine the effect of suppression on relapse rates.

A prospective comparative study of the MNA-SF and GNRI nutritional screening tools in predicting infectious complications among elderly patients over 70 years undergoing posterior lumbar arthrodesis

Malnutrition is a risk factor for postoperative infectious complications of elderly patients undergoing posterior lumbar arthrodesis. At present, there is no gold standard for nutrition screening tools. We analyzed the value of predicting infectious complications among elderly patients over 70 years undergoing posterior lumbar arthrodesis by comparing the MNA-SF and GNRI. Demographic data, anthropometric measurements, serum albumin, surgical data and the occurrence of infectious complications and LOS were collected. Mini Nutritional Assessment short form (MNA-SF), Geriatric Nutritional Risk Index (GNRI) were performed within 24 h before surgery. Multivariable logistic regression analyses were used to identify predictors of infectious complications. The discriminatory performances of GNRI and MNA-SF scores for the occurrence of infectious complications were determined by receiver operating characteristic curves (ROC) analyses and the area under the curve (AUC). The study included 252 patients with a median age of 76.82 ± 6.41 years (range 70-84 years), and 142 patients (56.3%) were female. There were no significant differences in infectious complications (p = 0.236) and LOS (p = 0.580) among different GNRI categories. 27.3% malnourished patients evaluated by the MNA-SF suffered from infectious complications and 10.1% patients at risk of malnourished had infectious complications. Those patients had statistically significant higher prevalence of infectious complications (p = 0.002) and longer LOS (p = 0.023) than well-nourished patients. Multivariable analysis revealed that preoperative malnutrition and at risk of malnourished by the MNA-SF was significantly associated with infections. The area under the curve (AUC) of MNA-SF was 0.754, which was significantly high than AUC of GNRI (0.623) (Delong's test, p = 0.033). This study demonstrated that MNA-SF is a simple and effective tool for predicting the risk of infectious complications in elderly patients undergoing posterior lumbar arthrodesis.

Impact of antimicrobial selection for prophylaxis of left ventricular assist device surgical infections

BACKGROUND

Surgical site infections (SSIs) after left ventricular assist device (LVAD) implantation are associated with high mortality, while surgical prophylaxis is variable.

METHODS

This retrospective study included adult patients who underwent LVAD implantation at a single center. We compared outcomes in patients who received narrow antimicrobial prophylaxis (cefazolin, vancomycin, or both) to those who received broad antimicrobial prophylaxis (any antimicrobial combination targeting gram-positive and gram-negative organisms not included in the narrow group) at 30-day and 1-year postimplantation. Cox-proportional hazards models and log-rank tests were used for survival analysis.

RESULTS

Among the 39 and 65 patients comprising narrow and broad groups respectively, there was no difference in rate of SSI at 30 days (6.2% vs. 12.8%, p = .290) and 1 year (16.9% vs. 25.6%, p = .435). Comparing narrow to broad prophylaxis, the risk of mortality (hazard ratio [HR] = 0.44, 95% confidence interval [CI] = 0.15-1.35, logrank p = .14), and composite of mortality and infection was reduced (HR = 0.92, 95% CI = 0.45-1.88, logrank p = .83), but did not reach statistical significance. Most culture positive infections were due to gram-positive bacteria (70%) and the most common organisms were the Staphylococcus spp (47%). There were no significant differences in the rate of SSI at 1-year (p = 1.00) and mortality (p = .33) by device type.

CONCLUSIONS

The rates of infection and all-cause mortality were not different between patients who received narrow or broad prophylaxis. This highlights an opportunity for institutions to narrow their surgical infection prophylaxis protocols to primarily cover gram-positive organisms.

Association of preoperative infections, nasal Staphylococcus aureus colonization and gut microbiota with left ventricular assist device outcomes

AIMS

Infections are common following left ventricular assist device (LVAD) implantation and predict adverse events. Infections are frequent prior to LVAD implantation although their impact on postoperative outcomes remains unknown. Gut and nasal microbial imbalance may predispose to mucosal colonization with pathogens. Herein, we investigated the predictive role of pre-LVAD infections, and explored the association of nasal Staphylococcus aureus (SA) colonization and gut microbiota, on postoperative outcomes.

METHODS AND RESULTS

Overall, 254 LVAD patients were retrospectively categorized based on pre-LVAD infection status: Group 1, bacterial/fungal bloodstream infection (BSI); Group 2, other bacterial/fungal; Group 3, viral; and Group 4, no infection. In a subset of patients, nasal SA colonization (n = 140) and pre-LVAD stool (n = 25) were analysed using 16S rRNA sequencing. A total of 75 (29%) patients had a pre-LVAD infection [Group 1: 22 (29%); Group 2: 41 (55%); Group 3: 12 (16%)]. Pre-LVAD BSIs were independent predictors of 1-year postoperative mortality and infections [Group 1 vs. 4: hazard ratio (HR) 2.70, P = 0.036 vs. HR 1.8, P = 0.046]. In an unadjusted analysis, pre-LVAD infections other than BSIs, INTERMACS profile ≤2, higher serum creatinine, lower serum albumin and nasal SA colonization were also significantly associated with postoperative infections. Patients with early post-LVAD infections exhibited decreased microbial diversity (P < 0.05).

CONCLUSIONS

Pre-LVAD infections are common. BSIs independently predict postoperative mortality and infections. Additional studies are needed to confirm our findings that pre-LVAD SA nasal colonization and gut microbial composition can help stratify patients' risk for infectious complications after LVAD implantation.

Contemporary Management Strategies in VAD Infection

PURPOSE OF REVIEW

The use of durable ventricular assist devices (VAD) to manage end-stage heart failure is increasing, but infection remains a leading cause of morbidity and mortality among patients with VAD. In this review, we synthesize recent data pertaining to the epidemiology, diagnosis, management, and prevention of VAD infections, discuss transplant considerations in patients with VAD infections, and highlight remaining knowledge gaps. We also present a conceptual framework for treating clinicians to approach these infections that draws on the same principles that guide the treatment of analogous infections that occur in patients without VAD.

RECENT FINDINGS

Despite advances in device design, surgical techniques, and preventative interventions, more than a third of VAD recipients still experience infection as an adverse outcome. Positron emission tomography has emerged as a promising modality for identifying and characterizing VAD infections. High-quality data to support many of the routine therapeutic strategies currently used for VAD infections-including suppressive antibiotic therapy, surgical debridement/device exchange, and novel antimicrobials for emerging multidrug-resistant organisms-remain limited. Although pre-transplant VAD infection may impact some early transplant outcomes, transplantation remains a viable option for patients with most types of VAD infection. Standardized definitions of VAD infection applied to large registry datasets have yielded key insights into the epidemiology of infectious complications among VAD recipients, but more prospective studies are needed to evaluate the effectiveness of existing and novel diagnostic and therapeutic strategies.

Risk Factors for Repeat Infection and Mortality After Extraction of Infected Cardiovascular Implantable Electronic Devices

OBJECTIVES

This study sought to investigate the factors associated with repeat infection following lead extraction procedures.

BACKGROUND

Although lead extraction is an essential therapy for patients with cardiovascular implantable electronic device (CIED) infection, repeat infection still occurs in some patients.

METHODS

The authors reviewed data for consecutive patients who underwent extraction of infected CIEDs from August 2003 to May 2019. Repeat infection was defined as infective endocarditis, sepsis with no alternative focus, or pocket infection after extraction of infected CIEDs.

RESULTS

Extraction of infected CIEDs was performed in 496 patients. The most commonly implicated pathogen was Staphylococcus aureus (188 patients). In 449 patients (90.5%), all leads were completely extracted using only transvenous techniques. Thirty-three patients (6.7%) underwent surgical lead extraction, and 14 (2.8%) had retained leads or lead components. After a median follow-up of 352 [40 to 1,255] days after CIED extraction, 144 patients (29.0%) died. Repeat infection occurred in 47 patients (9.5%) with the median time from the extraction to repeat infection of 103 [45 to 214] days. In multivariable analysis, presence of a left ventricular assist device, younger age at extraction, and S. aureus infection were independent predictors of repeat infection. Additionally, chronic kidney disease, congestive heart failure, presence of septic emboli, S. aureus infection, and occurrence of major complications were independent predictors of increased mortality.

CONCLUSIONS

Patients with S. aureus infection have a high risk of repeat infection and poor prognosis after CIED extraction. Repeat infection is also predicted by younger age and the presence of a left ventricular assist device, whereas mortality was predicted by congestive heart failure, chronic kidney disease, and septic emboli.

The Preimplantation Psychosocial Evaluation and Prediction of Clinical Outcomes During Mechanical Circulatory Support: What Information Is Most Prognostic?

BACKGROUND

Psychosocial evaluations are required for long-term mechanical circulatory support (MCS) candidates, no matter whether MCS will be destination therapy (DT) or a bridge to heart transplantation. Although guidelines specify psychosocial contraindications to MCS, there is no comprehensive examination of which psychosocial evaluation domains are most prognostic for clinical outcomes. We evaluated whether overall psychosocial risk, determined across all psychosocial domains, predicted outcomes, and which specific domains appeared responsible for any effects.

METHODS

A single-site retrospective analysis was performed for adults receiving MCS between April 2004 and December 2017. Using an established rating system, we coded psychosocial evaluations to identify patients at low, moderate, or high overall risk. We similarly determined risk within each of 10 individual psychosocial domains. Multivariable analyses evaluated whether psychosocial risk predicted clinical decisions about MCS use (DT versus bridge), and postimplantation mortality, transplantation, rehospitalization, MCS pump exchange, and standardly defined adverse medical events (AEs).

RESULTS

In 241 MCS recipients, greater overall psychosocial risk increased the likelihood of a DT decision (odds ratio, 1.76; P = 0.017); and postimplantation pump exchange and occurrence of AEs (hazard ratios [HRs] ≥ 1.25; P ≤ 0.042). The individual AEs most strongly predicted were cardiac arrhythmias and device malfunctions (HRs ≥ 1.39; P ≤ 0.032). The specific psychosocial domains predicting at least 1 study outcome were mental health problem severity, poorer medical adherence, and substance use (odds ratios and HRs ≥ 1.32; P ≤ 0.010).

CONCLUSIONS

The psychosocial evaluation predicts not only clinical decisions about MCS use (DT versus bridge) but important postimplantation outcomes. Strategies to address psychosocial risk factors before or soon after implantation may help to reduce postimplantation clinical risks.

Heart Sound Analysis in Individuals Supported With Left Ventricular Assist Devices

OBJECTIVE

LVADs are surgically implanted mechanical pumps that improve survival rates of individuals with advanced heart failure. LVAD therapy is associated with high morbidity, which can be partially attributed to challenges with detecting LVAD complications before adverse events occur. Current methods used to monitor for complications with LVAD support require frequent clinical assessments at specialized LVAD centers. Analysis of recorded precordial sounds may enable real-time, remote monitoring of device and cardiac function for early detection of LVAD complications. The dominance of LVAD sounds in the precordium limits the utility of routine cardiac auscultation of LVAD recipients. In this work, we develop a signal processing pipeline to mitigate sounds generated by the LVAD.

METHODS

We collected in vivo precordial sounds from 17 LVAD recipients, and contemporaneous echocardiograms from 12 of these individuals, to validate heart valve closure timings.

RESULTS

We characterized various acoustic signatures of heart sounds extracted from in vivo recordings, and report preliminary findings linking fundamental heart sound characteristics and level of LVAD support.

CONCLUSION

Mitigation of LVAD sounds from precordial sound recordings of LVAD recipients enables analysis of intrinsic heart sounds.

SIGNIFICANCE

These findings provide proof-of-concept evidence of the clinical utility of heart sound analysis for bedside and remote monitoring of LVAD recipients.

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.