The Impact of Left Ventricular Assist Device Infections on Postcardiac Transplant Outcomes: A Systematic Review and Meta-Analysis

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.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Left Ventricular Assist Device: Review of Antimicrobial Prophylaxis Strategies and Incidence of Infections at a Tertiary Care Center 12-Year Experience

Background

Left ventricular assist devices (LVAD) have an associated infection rate of 13%-80% postimplant. An optimal strategy for surgical infection prophylaxis (SIP) at the time of implantation has not been well defined. We aimed to evaluate the different LVAD implantation antibiotic prophylaxis regimens as well as the incidence of LVAD infection at our institution.

Methods

We performed a single-center, retrospective study of patients who underwent LVAD implantation between February 2007 and June 2019. The primary outcome was the incidence of LVAD infection (LVADI), within 3 months and 1 year of placement, between patients who received expanded or narrow-spectrum regimens for SIP. We assessed outcomes using Kaplan-Meier, time-to-first event. We used a noninferiority analysis, which was established if the narrow-spectrum event rate was no more than 5% greater than the expanded-spectrum event rate.

Results

We included 399 patients, 305 (76.4%) patients received narrow-spectrum SIP, whereas the remaining 94 (23.6%) patients received the expanded-spectrum regimen. Statistical noninferiority of the narrow spectrum to the multiple drug regimen was demonstrated at both time points, and statistical superiority of the narrow-spectrum group across 12-month follow up was further evident (P = .037).

Conclusions

We report evidence supporting noninferiority, or even superiority, of the narrow-spectrum over expanded-spectrum antimicrobial prophylaxis strategy with respect to LVADI. These findings support data-driven antimicrobial prophylaxis strategies.

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.

Full-scale numerical simulation of hemodynamics based on left ventricular assist device

Ventricular assist devices have been widely used and accepted to treat patients with end-stage heart failure. The role of VAD is to improve circulatory dysfunction or temporarily maintain the circulatory status of patients. In order to be closer to the medical practice, a multi-Domain model of the left ventricular coupled axial flow artificial heart was considered to study the effect of its hemodynamics on the aorta. Because whether LVAD itself was connected between the left ventricular apex and the ascending aorta by catheter in the loop was not very important for the analysis of simulation results, on the premise of ensuring the multi-Domain simulation, the simulation data of the import and export ends of LVAD were imported to simplify the model. In this paper, the hemodynamic parameters in the ascending aorta, such as blood flow velocity vector, wall shear stress distribution, vorticity current intensity, vorticity flow generation, etc., have been calculated. The numerical conclusion of this study showed the vorticity intensity under LVAD was significantly higher than that under patients' conditions and the overall condition is similar to that of a healthy ventricular spin, which can improve heart failure patients' condition while minimizing other pitfalls. In addition, high velocity blood flow during left ventricular assist surgery is mainly concentrated near the lining of the ascending aorta lumen. What's more, the paper proposes to use Q criterion to determine the generation of vorticity flow. The Q criterion of LVAD is much higher than that of patients with heart failure, and the closer the LVAD is to the wall of the ascending aorta, the greater the Q criterion is. All these are beneficial to the effectiveness of LVAD in the treatment of heart failure patients and provide clinical suggestions for the LVAD implantation in clinical practice.

Impact of pretransplant bloodstream infection on clinical outcomes after heart transplantation

BACKGROUND

Active bloodstream infection (BSI) is a contraindication for heart transplantation (HT). However, some critical patients with BSI may undergo HT as a life-saving procedure. We aimed to investigate the impact of pretransplant BSI on the clinical outcomes after HT.

METHODS

We enrolled 511 consecutive patients who underwent HT between 1999 and 2019. Patients were divided into two groups based on the presence of BSI within 30 days preoperatively. Forty-three patients (8.4%) with BSI who were clinically stable and had no metastatic infection were considered for HT on an individual basis. In-hospital mortality, incidence of early postoperative BSI, length of postoperative hospital stays, and long-term survival were compared between the groups. Logistic and Cox regression analyses were performed to identify risk factors for in-hospital and 1-year mortality.

RESULTS

Patients with pretransplant BSI had a high incidence of previous cardiopulmonary resuscitation, pretransplant ventilator use, mechanical circulatory support use, renal replacement therapy, United Network for Organ Sharing status 1A, and a prolonged preoperative hospital waiting period. The in-hospital mortality rate was higher in patients with pretransplant BSI (21% versus 12%, p = 0.081), and the mortality rate was very high (33.3%) for those with BSI 0-15 days before HT. In addition, patients with pretransplant BSI had a significantly longer postoperative hospital stay than patients in the control group. However, long-term survival was similar in both groups.

CONCLUSIONS

Although pretransplant BSI was associated with higher in-hospital mortality and prolonged postoperative hospital stay, patients who survived the early period had a similar long-term prognosis. This article is protected by copyright. All rights reserved.

Relation of Left Ventricular Assist Device Infections With Cardiac Transplant Outcomes

Left ventricular assist device (LVAD)-specific infections (LSIs) are common in patients on LVAD support awaiting heart transplant (HT), yet their impact on post-HT outcomes is not completely understood. We hypothesized that LSIs would result in vasoplegia and negatively affect post-HT 30-day and 1-year outcomes. LSI was defined as driveline, pump, or pocket infection. The short-term outcome was a composite of acute renal failure, allograft rejection, and mortality at 30 days after HT. The long-term outcome was a composite of allograft rejection and death within 1 year after HT. We performed a retrospective analysis of 111 HT recipients bridged with durable LVAD support at our institution from May 2012 to August 2019. Of these, 63 patients had LSIs, with 94% of the infections being driveline infections. Vasoplegia was more prevalent in the LSI group but not significantly (7 vs 2 persons, p = 0.3). There was no difference in the composite end point of acute renal failure, rejection, or death at 30 days (30% vs 25%, p = 0.55) or 1-year end point of rejection and death (38% vs 40%, p = 0.87) in patients with LSI versus those without LSI. In conclusion, LSIs were common in patients on LVAD who underwent HT in our single-center contemporary cohort. However, LSI was not associated with adverse outcomes at 30 days or at 1 year after HT.

Cefazolin plus ertapenem and heart transplantation as salvage therapy for refractory LVAD infection due to methicillin-susceptible Staphylococcus aureus: A case series

The use of left ventricular assist devices (LVADs) is increasingly more common as the availability of donor organs in relation to failing hearts is outstandingly limited. Infections are the most common complications in LVAD recipients, particularly those caused by Staphylococcus spp. Refractory LVAD-related infections are not uncommon as achieving adequate source control is often not feasible before heart transplantation. Evidence suggest that cefazolin plus ertapenem is effective in refractory methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, but this approach has not been described in LVAD recipients. In this article, we report two cases of refractory MSSA bacteremia in LVAD recipients that were successfully treated with salvage therapy with cefazolin plus ertapenem and subsequent heart transplantation. This treatment strategy should be considered in patients with refractory LVAD-associated infection due to MSSA that are not responding to standard treatment.

Continuous-flow left ventricular assist device systems infections: current outcomes and management strategies

Left ventricular assisted devices (LVADs) are increasingly used for management of patients with advanced heart failure. However, infection remains one of the most commonly reported complications. Diagnosis, as well as treatment of LVAD infections is challenging. There are multiple diagnostic modalities that have been used to assist with accurate diagnosis of LVAD infections. Treatment of the infection can be especially challenging in these patients, given the presence of the implantable device that cannot be easily replaced or removed. There are no clinical trials assessing the best approach to diagnosis, treatment or long-term management of LVAD infections. In this article we review the most recent diagnostic modalities and treatment approaches, as well as offer our guidance on diagnosis and treatment of LVAD infections.

Successful Treatment of Driveline Infection with Vacuum-Assisted Closure Therapy and Instillation Therapy

Background  Driveline infection is a serious complication in left ventricular assist device (LVAD) patients. We report the case of a patient who was successfully treated by combining instillation and vacuum-assisted closure (VAC) therapy.

Case Description  A 65-year-old LVAD patient presented with recurrent driveline infection. Local therapy with VAC therapy in combination with instillation of polyhexanide was performed for 2 weeks. The patient remains free from infection for twelve months by now.

Conclusion  This case is the first to present the combination of polyhexanide instillation with VAC as treatment for driveline infection. This therapy may thus be an option for patients who lack any other surgical option.

Outcomes of patients with infection related to a ventricular assist device after heart transplantation

BACKGROUND

Despite significant advances in durable mechanical support survival, infectious complications remain the most common adverse event after ventricular assist device (VAD) implantation and the leading cause of early death after transplantation. In this study, we aim to describe our local infectious epidemiology and review short-term survival and infectious incidence rates in the post-transplantation period and assess risk factors for infectious episodes after transplantation.

METHODS

Retrospective single-center study of all consecutive adult heart transplant patients from 2008 to 2017. Survival data were estimated and summarized using the Kaplan-Meier method. We quantified and evaluated the difference in the incidence rate between patients with and without infection using a Fine-Gray model. The outcome of interest is the time to first infection diagnosis with post-transplant death as the competing event.

RESULTS

Among 278 heart transplant patients, 74 (26.5%) underwent LVAD implantation. Twenty-one patients (28.3%) developed an infection while supported by an LVAD. When compared to patients supported by an LVAD without a preceding infection, BMI was significantly greater (31.2 vs 27.8 kg/m² , P = .03). Median follow-up post-transplantation was 3.01 years. Significant risk factors for the competing risk regression for infection after heart transplantation include LVAD infection (HR 1.94, [95% CI] 1.11-3.39, P = .020) and recipient COPD (HR 2.14, [95% CI] 1.39-3.32, P = .001) when adjusted for recipient age, gender, hypertension, diabetes mellitus, and body mass index.

CONCLUSIONS

Patients with LVAD-related infection had a significantly increased risk of infectious complications after heart transplantation. Further research on the avoidance of induction agents and reduced maintenance immunosuppression in this patient population is warranted.