Rates and types of infections in left ventricular assist device recipients: A scoping review

Pump exchange for major device related infection in patients receiving a durable left ventricular assist device

BACKGROUND

Device-related infection (DRI) remains a cause of morbidity and mortality following durable left ventricular assist device (dLVAD) implantation. We evaluated outcomes following pump exchange (PE) for DRI following dLVAD implantation.

METHODS

Forty-nine patients underwent PE between 1/2007 and 12/2022 for major DRI. Outcomes included survival, incidence of subsequent DRI, and proportion of patients achieving success (freedom from DRI at 1-year following PE).

RESULTS

Median age was 49 years. Median time from primary implant to DRI diagnosis and from diagnosis to PE was 26 and 4.1 months, respectively. Median time to DRI recurrence was 5.8 months with 76% of patients achieving success. Success was obtained in 23/24 (96%) of patients whose time to PE from DRI diagnosis was ≤4 months and 14/25 (56%) if time >4 months.

CONCLUSION

Most patients achieve success following PE for DRI. The risk of subsequent DRI and mortality remains high. Early (≤4 months) PE following DRI diagnosis increases the likelihood of success, while reducing the rate of subsequent DRI.

Impact of Diabetes Mellitus on Outcomes in Patients with Left Ventricular Assist Devices

Heart failure (HF) represents a significant health burden in the United States, resulting in substantial mortality and healthcare costs. Through the array of treatment options available, including lifestyle modifications, medications, and implantable devices, HF management has evolved. Left ventricular assist devices (LVADs) have emerged as a crucial intervention, particularly in patients with advanced HF. However, the prevalence of comorbidities such as diabetes mellitus (DM) complicates treatment outcomes. By elucidating the impact of DM on LVAD outcomes, this review aims to inform clinical practice and enhance patient care strategies for individuals undergoing LVAD therapy. Patients with DM have higher rates of hypertension, dyslipidemia, peripheral vascular disease, and renal dysfunction, posing challenges to LVAD management. The macro/microvascular changes that occur in DM can lead to cardiomyopathy and HF. Glycemic control post LVAD implantation is a critical factor affecting patient outcomes. The recent literature has shown significant decreases in hemoglobin A1c following LVAD implantation, representing a possible bidirectional relationship between DM and LVADs; however, the clinical significance of this decrease is unclear. Furthermore, while some studies show increased short- and long-term mortality in patients with DM after LVAD implantation, there still is no literature consensus regarding either mortality or major adverse outcomes in DM patients.

Body mass index-dependent immunological profile changes after left ventricular assist device implantation

Purpose

Infection is a common complication following left ventricular assist device (LVAD) implantation. Patients with obesity are particularly at risk due to their high percentage of adipose tissue and the resulting chronic inflammatory state and resulting immunological changes. This study investigated changes of immunological parameters in relation to body mass index (BMI) during the first year after LVAD implantation.

Methods

Blood samples were obtained prior to LVAD implantation and at 3 (1st FU), 6 (2nd FU) and 12 mo (3rd FU) after LVAD implantation. Patients were divided into three groups (normal weight: BMI of 18.5-24.9 kg/m2; n=12; pre-obesity: 25.0-29.9 kg/m2; n=15; obesity: ≥ 30.0 kg/m2; n=17) based on their BMI at the time of LVAD implantation. Flow cytometric analyses for CD4+ and CD8+ T cells, regulatory T cells (Tregs), B cells as well as dendritic cells (DCs) were performed.

Results

After LVAD implantation, obese patients (0.51 ± 0.20%) showed a higher proportion of overall DCs than normal-weight (0.28 ± 0.10%) and pre-obese patients (0.32 ± 0.11%, p<0.01) at 3rd FU. The proportion of BDCA3+ myeloid DCs was lower in obese patients (64.3 ± 26.5%) compared to normal-weight patients (82.7 ± 10.0%, pnormal-weight vs. obesity=0.05) at 2nd FU after LVAD implantation. The analysis of BDCA4+ plasmacytoid DCs revealed a reduced proportion in pre-obese (21.1 ± 9.8%, pnormal-weight vs. pre-obesity=0.01) and obese patients (23.7 ± 10.6%, pnormal-weight vs. obesity=0.05) compared to normal-weight patients (33.1 ± 8.2%) in the 1st FU. T cell analysis showed that CD4+ T cells of obese patients (62.4 ± 9.0%) significantly increased in comparison to pre-obese patients (52.7 ± 10.0%, ppre-obesity vs. obesity=0.05) and CD8+ T cells were lower in obese patients (31.8 ± 8.5%) than in normal-weight patients (42.4 ± 14.2%; pnormal-weight vs. obesity=0.04) at the 3rd FU. Furthermore, we observed significantly reduced proportions of Tregs in pre-obese patients compared to normal-weight and obese patients at 2nd FU (p=0.02) and 3rd FU (p=0.01) after LVAD implantation.

Conclusion

This study reported changes of the innate and adaptive immune system of pre-obese and obese compared to normal-weight patients one year after LVAD implantation. DCs and their subsets, CD8+ T cells and Tregs were affected immune cell populations that indicate immunological changes which might increase the incidence of postoperative infection.

Bacteriophage-Enriched Galenic for Intrapericardial Ventricular Assist Device Infection

We report a case of severe outflow graft infection following left ventricular assist device (LVAD) implantation. A 51-year old male LVAD patient was readmitted to our hospital presenting signs of systemic infection. One year previously, LVAD implantation (HeartMate3, Abbott, Chicago, IL, USA) with concomitant patent foramen ovale closure had been performed in the context of end-stage heart failure due to dilative cardiomyopathy (INTERMACS III). The indication for LVAD-therapy was bridge-to-candidacy, since the patient did not instantly fulfill all criteria for cardiac transplantation. At admission, a PET-CT scan unveiled fluid accumulation, encircling the outflow-graft prosthesis (SUVmax 10.5) with contrast-enhancement involving the intrathoracic driveline (SUVmax 11.2). Since cardiac transplantation was not feasible, the patient underwent surgical revision. In the first step, redo sternotomy was performed with local debridement, including jet lavage. Intraoperative swabs confirmed bacterial infection with staphylococcus aureus. Following this, the patient underwent negative pressure wound therapy (NPWT) with instillation using the V.A.C. VERAFLO system (KCI-3M, San Antonio, TX, USA) for a total of 19 days. Due to the severity of infection, local bacteriophage application was performed within the wound closure. In order to concentrate phage therapy at the infection site, phages were applied using a novel semi-fluid galenic. After wound closure, the patient was discharged with an uneventful course. A control PET-CT scan 3 months after discharge showed a significant decrease in infection (outflow graft: SUVmax 7.2, intrathoracic driveline: SUVmax 3.0) correlated with contrast enhancement. Bacterial infection of intrathoracic VAD components represents a severe and potentially life-threatening complication. If cardiac transplantation is not feasible, complex wound management strategies are required. Local bacteriophage therapy might be a promising addition to already established therapeutical options. In order to improve bacteriophage retention at the wound site, application of a viscous galenic might be beneficial.