Prevention and early treatment of driveline infections in ventricular assist device patients – The DESTINE staging proposal and the first standard of care protocol

Feasibility Testing of the Bionet Sonar Ultrasound Transcutaneous Energy Transmission (UTET) System for Wireless Power and Communication of a LVAD

PURPOSE

To address the clinical need for totally implantable mechanical circulatory support devices, Bionet Sonar is developing a novel Ultrasonic Transcutaneous Energy Transmission (UTET) system that is designed to eliminate external power and/or data communication drivelines.

METHODS

UTET systems were designed, fabricated, and pre-clinically tested using a non-clinical HeartWare HVAD in static and dynamic mock flow loop and acute animal models over a range of pump speeds (1800, 2400, 3000 RPM) and tissue analogue thicknesses (5, 10, 15 mm).

RESULTS

The prototypes demonstrated feasibility as evidenced by meeting/exceeding function, operation, and performance metrics with no system failures, including achieving receiver (harvested) power exceeding HVAD power requirements and data communication rates of 10kB/s and pump speed control (> 95% sensitivity and specificity) for all experimental test conditions, and within healthy tissue temperature range with no acute tissue damage.

CONCLUSION

During early-stage development and testing, engineering challenges for UTET size reduction and stable and safe operation were identified, with solutions and plans to address the limitations in future design iterations also presented.

Mechanical Characterization of Anchoring Devices for the Prevention of Driveline Infection in Left Ventricular Assist Device Patients

Driveline infection (DLI) is associated with increased mortality and morbidity in left ventricular assist device (LVAD) patients. Because trauma to the driveline exit-site (DLES) is a risk factor for DLI, adhesive anchoring devices are used to immobilize the DL. In this study, commonly used products (identified through literature review and contact with nine international VAD implantation centers) were mechanically characterized to evaluate their effectiveness in preventing DLES trauma. Eight devices were tested in an in vitro abdominal model of the DLES, where a tensile force (10 N) was applied to a HeartMate 3 DL, whereas the resulting force ( FTotal ) on the DLES was recorded using a three-axis load cell. Four devices (CathGrip: FTotal = 2.1 ± 0.4 N, Secutape: FTotal = 2.6 ± 0.3 N, Hollister: FTotal = 2.7 ± 0.5 N, Tubimed: FTotal = 2.9 ± 0.2 N) were significantly ( p < 0.05) better at preventing tensile forces at the DLES compared to the other four devices (Main-Lock: FTotal = 3.7 [0.7] N, Secutape sensitive: FTotal = 3.9 ± 0.4 N, Foley Anchor: FTotal = 4.3 ± 0.5 N, Grip-Lok: FTotal = 5.4 ± 0.8 N). Immobilization of the DL with each anchoring device resulted in lower tensile force on the DLES than without an anchor ( FTotal = 8.2 ± 0.3 N). In conclusion, the appropriate selection of anchoring devices plays a critical role in reducing the risk of DLI, whereas the CathGrip, Secutape, Hollister, or Tubimed were superior in preventing trauma to the DLES in this study.

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.

Driveline infection according to driveline positioning in left ventricular assist device implant recipients

We conducted a prospective, open-labeled, clinical trial, with a two-by-two factorial design, of argon cold plasma application and two different types of driveline positioning for the prevention of driveline infection (DLI) in 80 patients with a left ventricular assist device (LVAD) implant. Here, we present the results of intracorporeal loop positioning (n = 40) versus no intracorporeal loop positioning (n = 40). Patients were followed up for 1 year. According to the Driveline Expert STagINg and carE grading (DESTINE) system, a DLI was considered in case of a stage 2 or higher graded infection. During follow-up, 29 (36%) patients experienced a DLI, 16 in the group with intracorporeal loop positioning and 13 in the group with no intracorporeal loop positioning. Kaplan-Meier estimates of freedom from DLI showed no statistically significant difference between study groups during follow-up (p = 0.33). In detail, 30-day freedom from DLI was for the groups with and without intracorporeal loop positioning 92 and 92%, respectively, and 1-year freedom from DLI was 51 and 62%, respectively. In conclusion, this controlled clinical trial was unable to show a statistically significant difference in freedom from DLI during one year of follow-up in groups with or without intracorporeal loop positioning. However, larger trials have to confirm these results.

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.

Driveline dressings used in heartmate patients and local complications: A retrospective cohort

BACKGROUND

Patients with long-term ventricular assist devices (VAD) are predisposed to infection, bleeding, and pressure injuries at the insertion of the driveline. There is no consensus on a driveline dressing protocol. Chlorhexidine is often used to clean the driveline exit site and has been associated with lower rates of infection. For driveline coverage, bacteriostatic agents and transparent film have shown good results, but are costly. The same issue was associated with anchorage devices.

OBJECTIVES

The purpose of this study was to evaluate the types of dressings used in the driveline of patients using HeartMate (HM) and to describe the incidence density of local complications (infection, bleeding, and pressure injury) within 30 days postoperatively.

METHODS

A retrospective cohort study was conducted and included 22 patients admitted to the Intensive Care Unit after implantation of HM II and III in a Brazilian private hospital.

RESULTS

Several types of dressings were used in the drivelines. There were 22 different types of dressings. Dressing type 6 (Chlorhexidine, Excilon, Gauze and IV3000) were the most used (45.4%). Subjects using the Flexi-Trak anchoring device had a higher rate of local bleeding (50.0%) and those who used the Hollister device had more infection (61.1%) and pressure injury associated with a medical device (11.1%), compared to others. Infection was the primary complication (45.4%), followed by local bleeding (27.7%).

CONCLUSION

Despite the high variability of products used in the driveline of patients using HeartMate, the dressing made with chlorhexidine, silver-impregnated absorbent foam and transparent film, and the use of anchoring devices was the most frequently used. Infection was the most common complication.

Insights into the daily life of ventricular assist device coordinators: Outcome of an international questionnaire

BACKGROUND

As the incidence of heart failure in developed countries is on the rise, mechanical circulatory support (MCS) often remains the only treatment option for patients with end-stage heart failure and is well established worldwide. Even though VAD coordinators play a key role in VAD programs, their responsibilities and daily duties are not clearly defined and characterized. Recently published data from the first 5-year multicenter clinical trial assessing experience with the HeartMate 3 left ventricular system (Abbott, Abbott Park, IL) show an overall survival of 61% at 5 years. When it comes to possible improvements to these systems, it is necessary for developers not only to know the status quo but also to determine and consider the visions and wishes of those individuals who take care of patients, provide education and deal with possible complications. This would be helpful a meaningful effort towards implementing a standard of care.

METHODS

To fill this knowledge gap, we conducted an online survey using the SurveyMonkey tool, addressing representatives of programs implanting VADs worldwide. Representatives answered a standardized block of 14 questions and were asked to provide responses within 3 months.

RESULTS

A total of 91 VAD coordinators from centers of various regions of the world completed the survey. The majority came from European countries. The numbers of patients followed up by the centers ranged from <20 to 390 patients. The majority of VAD coordinators had a nursing background (68%). Seventy-seven percent of the centers operate a 24-h hotline and 3-monthly visits to the outpatient department are most common. Fifty-nine percent of the centers do not use an infection scoring system for driveline wound care. The majority of the centers indicated that an optimized follow-up concept including wound care, medication, and social care is crucial and the key issue for an improved outcome. Smaller components and intensified psychosocial support ranked highest in questions about how to improve quality of life. Surprisingly, the future prospects of telemetric monitoring were not rated high in significance.

CONCLUSIONS

There is a wide variability in the composition and tasks of VAD programs worldwide. Implementing a standard of care and improving psychosocial care as well as equipment is regarded most important to improve outcomes and quality of life. From the point of view of those responsible, the significance of telemetric monitoring seemed overrated.

Transdermal wires for improved integration in vivo

Alternative engineering approaches have led the design of implants with controlled physical features to minimize adverse effects in biological tissues. Similar efforts have focused on optimizing the design features of percutaneous VAD drivelines with the aim to prevent infection, omitting however a thorough look on the implant-skin interactions that govern local tissue reactions. Here, we utilized an integrated approach for the biophysical modification of transdermal implants and their evaluation by chronic sheep implantation in comparison to the standard of care VAD drivelines. We developed a novel method for the transfer of breath topographical features on thin wires with modular size. We examined the impact of implant's diameter, surface topography, and chemistry on macroscopic, histological, and physical markers of inflammation, fibrosis, and mechanical adhesion. All implants demonstrated infection-free performance. The fibrotic response was enhanced by the increasing diameter of implants but not influenced by their surface properties. The implants of small diameter promoted mild inflammatory responses with improved mechanical adhesion and restricted epidermal downgrowth, in both silicone and polyurethane coated transdermal wires. On the contrary, the VAD drivelines with larger diameter triggered severe inflammatory reactions with frequent epidermal downgrowth. We validated these effects by quantifying the infiltration of macrophages and the level of vascularization in the fibrotic zone, highlighting the critical role of size reduction for the benign integration of transdermal implants with skin. This insight on how the biophysical properties of implants impact local tissue reactions could enable new solutions on the transdermal transmission of power, signal, and mass in a broad range of medical devices.

Argon Cold Plasma Use and Driveline Infection in Left Ventricular Assist Device Implant Recipients

We conducted a prospective open-labeled, clinical trial, with a two-by-two factorial design, of argon cold plasma (ACP) application and two different types of driveline positioning for the prevention of driveline infection (DLI) in patients with a left ventricular assist device (LVAD) implant. Here, we present the results of ACP application versus no ACP application. Eighty patients were allocated to the control group (no preventive ACP use; n = 40) or ACP group (preventive ACP use for 30 days post-LVAD implantation; n = 40). Patients were followed up for 1 year. The secondary endpoint was survival on device. Preventive ACP use improved 30 day freedom from DLI significantly (100% vs. 85%; p = 0.012); results remained significant at 6 months (92% vs. 69%, p = 0.007) and were 55% and 60%, respectively ( p = 0.65) at 1 year follow-up. With respect to survival on device, results in the control and ACP groups did not differ significantly at 30 days (97.5% vs. 100%, respectively; p = 0.32), but tended to be lower in the control group than in the ACP group at 1 year follow-up (74% vs. 90%, respectively; p = 0.09). In conclusion, preventive ACP use was able to significantly reduce DLI both during the application period and up to 6 months after LVAD implantation.

Long-term assist device patients admitted to ICU: Tips and pitfalls

Left ventricular assist device (LVAD) therapy is well-established in the treatment of end-stage cardiac failure. Indications are bridge to transplant (BTT), bridge to candidacy (BTC), bridge to recovery (BTR), and destination therapy (DT). The durability and adverse event (AE) rate of LVADs have improved over the years. However, due to donor shortage, the duration of support in the BTT population has increased tremendously; similarly, DT patients are on the device for a long time. Consequently, the number of readmissions of long-term LVAD patients has increased. In cases of severe AEs, intensive care unit (ICU) treatment can be necessary. Infectious complications are the most common AE. Furthermore, embolic or hemorrhagic strokes can occur due to foreign surfaces, acquired von Willebrand syndrome, and anticoagulation treatment. Another consequence of the coagulative status, in combination with the continuous flow, are gastrointestinal bleeding events. Moreover, in most patients, an isolated LVAD is implanted, and this involves the risk of late right heart failure. Adjustment of pump speed and optimization of the volume status can help solve this issue. Malignant arrhythmias, pre-existing or de novo after LVAD implantation, can be a life-threatening AE. Antiarrhythmic medical therapy or ablation are potential treatment options. As for specific LVADs, the Medtronic HeartWare™ ventricular assist device (HVAD) is not manufactured and distributed currently; however, 4000 patients are still on the device. Pump thrombosis can occur, wherein thrombolytic therapy is the first-line treatment option. Additionally, the HVAD can fail to restart after controller exchange due to technical issues, and precautions must be taken. The Momentum 3 trial showed superior survival without pump exchange or disabling stroke in patients treated with the HeartMate 3^Ⓡ (HM3; Abbott, Abbott Park, IL, USA) device in comparison to the HeartMate II (HMII). However, in a few cases, a twisted graft or bio debris formation between the outflow graft and bend relief could be observed, causing outflow graft obstruction. Patients on LVADs are still heart failure patients, in many cases with comorbidities. Therefore, many situations can occur requiring ICU treatment. Ethical aspects should always be the focus when taking care of these patients.

Vitamin D deficiency and driveline infection in patients with a left ventricular assist device implant

Driveline infection is a frequent complication in recipients of durable left ventricular assist devices (LVAD), but its cause is largely unclear. Since vitamin D supplementation can reduce the risk of infections, we aimed at investigating the association of vitamin D deficiency with driveline infection. In 154 patients with continuous flow LVAD implants, we assessed 2-year risk of driveline infection according to vitamin D status (circulating 25-hydroxyvitamin D < 25 nmol/L or ⩾25 nmol/L). Of the study cohort, 34% (n = 53) had 25-hydroxyvitamin D concentrations <25 nmol/L. Kaplan-Meir estimates of 2-year freedom from driveline infection were in the vitamin D deficient and vitamin D non-deficient groups 49.7% and 74.2%, respectively (p = 0.017). Covariate-adjusted hazard ratio of driveline infection for the vitamin D deficient versus non-deficient group was 2.51 [95% CI: 1.11-5.69; p = 0.028). Circulating concentrations of endocrine regulators of calcium and phosphorus metabolism such as parathyroid hormone, 1,25-dihydroxyvitamin D, and fibroblast growth factor-23 were not significantly associated with the risk of driveline infection (p-values > 0.15). In total, our data indicate that in LVAD recipients deficient vitamin D status is a predictor of driveline infection, but future studies are needed to investigate whether these associations are causal.

Bioactive compounds: a goldmine for defining new strategies against pathogenic bacterial biofilms?

Most human infectious diseases are caused by microorganisms growing as biofilms. These three-dimensional self-organized communities are embedded in a dense matrix allowing microorganisms to persistently inhabit abiotic and biotic surfaces due to increased resistance to both antibiotics and effectors of the immune system. Consequently, there is an urgent need for novel strategies to control biofilm-associated infections. Natural products offer a vast array of chemical structures and possess a wide variety of biological properties; therefore, they have been and continue to be exploited in the search for potential biofilm inhibitors with a specific or multi-locus mechanism of action. This review provides an updated discussion of the major bioactive compounds isolated from several natural sources - such as plants, lichens, algae, microorganisms, animals, and humans - with the potential to inhibit biofilm formation and/or to disperse established biofilms by bacterial pathogens. Despite the very large number of bioactive products, their exact mechanism of action often remains to be clarified and, in some cases, the identity of the active molecule is still unknown. This knowledge gap should be filled thus allowing development of these products not only as novel drugs to combat bacterial biofilms, but also as antibiotic adjuvants to restore the therapeutic efficacy of current antibiotics.

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.

Driveline Infection in Left Ventricular Assist Device Patients: Effect of Standardized Protocols, Pathogen Type, and Treatment Strategy

Driveline infection (DLI) is common after left ventricular assist device (LVAD). Limited data exist on DLI prevention and management. We investigated the impact of standardized driveline care initiatives, specific pathogens, and chronic antibiotic suppression (CAS) on DLI outcomes. 591 LVAD patients were retrospectively categorized based on driveline care initiatives implemented at our institution (2009-2019). Era (E)1: nonstandardized care; E2: standardized driveline care protocol; E3: addition of marking driveline exit site; E4: addition of "no shower" policy. 87(15%) patients developed DLI at a median (IQR) of 403(520) days. S. aureus and P. aeruginosa were the most common pathogens. 31 (36%) of DLI patients required incision and drainage (I&D) and 5 (5.7%) device exchange. P. aeruginosa significantly increased risk for initial I&D (HR 2.7, 95% CI, 1.1-6.3) and recurrent I&D or death (HR 4.2, 95% CI, 1.4-12.5). Initial I&D was associated with a significant increased risk of death (HR 2.92 (1.33-6.44); P = 0.008) when compared to patients who did not develop DLI. Implementation of standardized driveline care protocol (E2) was associated with increased 2-year freedom from DLI compared to nonstandardized care (HR 0.36, 95% CI, 0.2-0.6, P < 0.01). Additional preventive strategies (E3&E4) showed no further reduction in DLI rates. 57(65%) DLI patients received CAS, 44% of them required escalation to intravenous antibiotics and/or I&D. Presence of P. aeruginosa DLI markedly increased risk for I&D or death. Conditional survival of patients progressing to I&D is diminished. Standardized driveline care protocol was associated with a significant reduction in DLI, while additional preventive strategies require further testing.

Association Between Care Fragmentation and Total Spending After Durable Left Ventricular Device Implant: A Mediation Analysis of Health Care-Associated Infections Within a National Medicare-Society of Thoracic Surgeons Intermacs Linked Dataset

BACKGROUND

Care fragmentation is associated with higher rates of infection after durable left ventricular assist device (LVAD) implant. Less is known about the relationship between care fragmentation and total spending, and whether this relationship is mediated by infections.

METHODS

Total payments were captured from admission to 180 days post-discharge. Drawing on network theory, a measure of care fragmentation was developed based on the number of shared patients among providers (ie, anesthesiologists, cardiac surgeons, cardiologists, critical care specialists, nurse practitioners, physician assistants) caring for 4,987 Medicare beneficiaries undergoing LVAD implantation between July 2009 - April 2017. Care fragmentation was measured using average path length, which describes how efficiently information flows among network members; longer path length indicates greater fragmentation. Terciles based on the level of care fragmentation and multivariable regression were used to analyze the relationship between care fragmentation and LVAD payments and mediation analysis was used to evaluate the role of post-implant infections.

RESULTS

The patient cohort was 81% male, 73% white, 11% Intermacs Profile 1 with mean (SD) age of 63.1 years (11.1). The mean (SD) level of care fragmentation in provider networks was 1.7 (0.2) and mean (SD) payment from admission to 180 days post-discharge was $246,905 ($109,872). Mean (SD) total payments at the lower, middle, and upper terciles of care fragmentation were $250,135 ($111,924), $243,288 ($109,376), and $247,290 ($108,241), respectively. In mediation analysis, the indirect effect of care fragmentation on total payments, through infections, was positive and statistically significant (β=16032.5, p=0.008).

CONCLUSIONS

Greater care fragmentation in the delivery of care surrounding durable LVAD implantation is associated with a higher incidence of infections, and consequently, higher payments for Medicare beneficiaries. Interventions to reduce care fragmentation may reduce the incidence of infections and in turn enhance the value of care for patients undergoing durable LVAD implantation.

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.

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.

2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: Developed by the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). With the special contribution of the Heart Failure Association (HFA) of the ESC

Document Reviewers: Rudolf A. de Boer (CPG Review Coordinator) (Netherlands), P. Christian Schulze (CPG Review Coordinator) (Germany), Magdy Abdelhamid (Egypt), Victor Aboyans (France), Stamatis Adamopoulos (Greece), Stefan D. Anker (Germany), Elena Arbelo (Spain), Riccardo Asteggiano (Italy), Johann Bauersachs (Germany), Antoni Bayes-Genis (Spain), Michael A. Borger (Germany), Werner Budts (Belgium), Maja Cikes (Croatia), Kevin Damman (Netherlands), Victoria Delgado (Netherlands), Paul Dendale (Belgium), Polychronis Dilaveris (Greece), Heinz Drexel (Austria), Justin Ezekowitz (Canada), Volkmar Falk (Germany), Laurent Fauchier (France), Gerasimos Filippatos (Greece), Alan Fraser (United Kingdom), Norbert Frey (Germany), Chris P. Gale (United Kingdom), Finn Gustafsson (Denmark), Julie Harris (United Kingdom), Bernard Iung (France), Stefan Janssens (Belgium), Mariell Jessup (United States of America), Aleksandra Konradi (Russia), Dipak Kotecha (United Kingdom), Ekaterini Lambrinou (Cyprus), Patrizio Lancellotti (Belgium), Ulf Landmesser (Germany), Christophe Leclercq (France), Basil S. Lewis (Israel), Francisco Leyva (United Kingdom), AleVs Linhart (Czech Republic), Maja-Lisa Løchen (Norway), Lars H. Lund (Sweden), Donna Mancini (United States of America), Josep Masip (Spain), Davor Milicic (Croatia), Christian Mueller (Switzerland), Holger Nef (Germany), Jens-Cosedis Nielsen (Denmark), Lis Neubeck (United Kingdom), Michel Noutsias (Germany), Steffen E. Petersen (United Kingdom), Anna Sonia Petronio (Italy), Piotr Ponikowski (Poland), Eva Prescott (Denmark), Amina Rakisheva (Kazakhstan), Dimitrios J. Richter (Greece), Evgeny Schlyakhto (Russia), Petar Seferovic (Serbia), Michele Senni (Italy), Marta Sitges (Spain), Miguel Sousa-Uva (Portugal), Carlo G. Tocchetti (Italy), Rhian M. Touyz (United Kingdom), Carsten Tschoepe (Germany), Johannes Waltenberger (Germany/Switzerland) All experts involved in the development of these guidelines have submitted declarations of interest. These have been compiled in a report and published in a supplementary document simultaneously to the guidelines. The report is also available on the ESC website www.escardio.org/guidelines For the Supplementary Data which include background information and detailed discussion of the data that have provided the basis for the guidelines see European Heart Journal online.

Preventing Driveline Infection during Left Ventricular Assist Device Support by the HeartMate 3: A Survey-Based Study

PURPOSE

Driveline infection (DLI) is a significant source of morbidity and mortality during left ventricular assist device (LVAD) support yet limited studies are available to describe center-level prevalence, preventive practices and their potential effectiveness.

METHODS

We surveyed LVAD centers in the United States to determine program burden and preventive practices for DLI during HeartMate (HM) 3 support. An online, anonymous, question-based survey was sent to expert providers at implanting centers. Only a single respondent completed the survey for each center. As an exploratory analysis, we compared specific DLI preventive practices between centers with low (≤10%) and high (>10%) reported prevalence of DLI.

RESULTS

Seventy-eight centers responded to the survey (response rate: 50%). Respondent were comprised of 37 (47%) heart failure cardiologists, 27 (35%) LVAD coordinators and 14 (18%) cardiothoracic surgeons. The prevalence of DLI during HM3 was reported as ≤10% by 27 (35%), 11-25% by 36 (46%) and >25% by 16 (19%) of centers. Thirteen (17%) centers had a body mass index threshold for device placement, 29 (37%) utilized a counter incision, 66 (81%) placed an anchor stitch and 69 (88%) used an external device to stabilize the DL. Proportionally more centers with a low DLI prevalence used a wound vacuum 6(22%) vs. 3(6%, p=0.03) than those with high DLI.

CONCLUSION

Variation exists in reported prevalence and practices of preventing and managing driveline infections across centers during HM3 support. Further studies are warranted to develop and assess the effectiveness of standardized preventive strategies.

Driveline Features as Risk Factor for Infection in Left Ventricular Assist Devices: Meta-Analysis and Experimental Tests

Background: Risk factors for driveline infection (DLI) in patients with left ventricular assist devices are multifactorial. The aim of this study was to analyze the correlation between mechanical driveline features and DLI occurrence. Methods: A meta-analysis was conducted that included studies reporting DLI rates at 6 months after implantation of any of three contemporary devices (HVAD with Pellethane or Carbothane driveline, HeartMate II, and HeartMate 3). Further, outer driveline diameter measurements and ex-vivo experimental three-point bending and torsion tests were performed to compare the stiffness of the four different driveline types. Results: 21 studies with 5,393 patients were included in the meta-analysis. The mean weighted DLI rates ranged from 7.2% (HeartMate II) to 11.9% (HeartMate 3). The HeartMate II driveline had a significantly lower maximal bending force (Loadmax) (4.52 ± 0.19 N) compared to the Carbothane HVAD (8.50 ± 0.08 N), the HeartMate 3 (11.08 ± 0.3 N), and the Pellethane HVAD driveline (15.55 ± 0.14 N) (p < 0.001). The maximal torque (Torquemax) of the HeartMate II [41.44 (12.61) mNm] and the Carbothane HVAD driveline [46.06 (3.78) mNm] were significantly lower than Torquemax of the Pellethane HVAD [46.06 (3.78) mNm] and the HeartMate 3 [95.63 (26.60) mNm] driveline (p < 0.001). The driveline of the HeartMate 3 had the largest outer diameter [6.60 (0.58) mm]. A relationship between the mean weighted DLI rate and mechanical driveline features (Torquemax) was found, as the the HeartMate II driveline had the lowest Torquemax and lowest DLI rate, whereas the HeartMate 3 driveline had the highest Torquemax and highest DLI rate. Conclusions: Device-specific mechanical driveline features are an additional modifiable risk factor for DLI and may influence clinical outcomes of LVAD patients.

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.

Systems of conductive skin for power transfer in clinical applications

The primary aim of this article is to review the clinical challenges related to the supply of power in implanted left ventricular assist devices (LVADs) by means of transcutaneous drivelines. In effect of that, we present the preventive measures and post-operative protocols that are regularly employed to address the leading problem of driveline infections. Due to the lack of reliable wireless solutions for power transfer in LVADs, the development of new driveline configurations remains at the forefront of different strategies that aim to power LVADs in a less destructive manner. To this end, skin damage and breach formation around transcutaneous LVAD drivelines represent key challenges before improving the current standard of care. For this reason, we assess recent strategies on the surface functionalization of LVAD drivelines, which aim to limit the incidence of driveline infection by directing the responses of the skin tissue. Moreover, we propose a class of power transfer systems that could leverage the ability of skin tissue to effectively heal short diameter wounds. In this direction, we employed a novel method to generate thin conductive wires of controllable surface topography with the potential to minimize skin disruption and eliminate the problem of driveline infections. Our initial results suggest the viability of the small diameter wires for the investigation of new power transfer systems for LVADs. Overall, this review uniquely compiles a diverse number of topics with the aim to instigate new research ventures on the design of power transfer systems for IMDs, and specifically LVADs.

Immobilization-induced symptomatic hypercalcemia treated with zoledronate in a child with a left ventricular assist device

Differential diagnosis of hypercalcemia in children includes confirmation of hyperthyroidism, infection, inflammatory processes, and malignant tumors. Immobilization-induced hypercalcemia is rare in healthy individuals, although it can occur in adolescent males, especially after fracture. Immobility can cause increased skeletal calcium release and hypercalcemia, and this condition is also known as resorptive hypercalcemia. We present a case of a 10-year-old adolescent girl with advanced heart failure who underwent implantation with a HeartMate 3 left ventricular assist device. She had symptoms of abdominal pain, vomiting, and constipation on the fifth month of hospitalization. She subsequently developed immobilization-induced symptomatic hypercalcemia (serum calcium, 12.1 mg/dL; corrected calcium 12.8 mg/dL; parathormone, 1.9 pg/mL; calcium/creatinine ratio in spot urine, 1.21). However, hypercalcemia is uncommon in children with advanced heart failure. Bisphosphonate therapy was initiated because our patient did not respond to hydration and furosemide treatment, and she had persistent abdominal pain, vomiting, and constipation. The patient&apos;s complaints were resolved on the second day after administrating bisphosphonate, and hypercalcemia did not recur.

Prevalence and management of driveline infections in mechanical circulatory support - a single center analysis

Background

Driveline infections in continuous-flow left ventricular assist devices (cf-LVAD) remain the most common adverse event. This single-center retrospective study investigated the risk factors, prevalence and management of driveline infections.

Methods

Patients treated after cf-LVAD implantation from December 2014 to January 2020 were enrolled. Baseline data were collected and potential risk factors were elaborated. The multi-modal treatment was based on antibiotic therapy, daily wound care, surgical driveline reposition, and heart transplantation. Time of infection development, freedom of reinfection, freedom of heart transplantation, and death in the follow-up time were investigated.

Results

Of 75 observed patients, 26 (34.7%) developed a driveline infection. The mean time from implantation to infection diagnosis was 463 (±399; range, 35–1400) days. The most common pathogen was Staphylococcus aureus (n = 15, 60%). First-line therapy was based on antibiotics, with a primary success rate of 27%. The majority of patients (n = 19; 73.1%) were treated with surgical reposition after initial antibiotic therapy. During the follow-up time of 569 (±506; range 32–2093) days, the reinfection freedom after surgical transposition was 57.9%. Heart transplantation was performed in eight patients due to resistant infection. The overall mortality for driveline infection was 11.5%.

Conclusions

Driveline infections are frequent in patients with implanted cf-LVAD, and treatment does not efficiently avoid reinfection, leading to moderate mortality rates. Only about a quarter of the infected patients were cured with antibiotics alone. Surgical driveline reposition is a reasonable treatment option and does not preclude subsequent heart transplantation due to limited reinfection freedom.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01589-6.

Five-year outcomes of patients supported with HeartMate 3: a single-centre experience

OBJECTIVES

The HeartMate 3 left ventricular assist device was first implanted in 2014 and received the Conformité Européenne mark in 2015. Since then, several trials demonstrated its high haemocompatibility associated with good survival and low adverse events rates. Herein, we report our institutional experience with patients supported with HeartMate 3 for 5 years.

METHODS

This prospective cohort study included patients receiving a HeartMate 3 implantation in 2014 as part of the HeartMate 3 Conformité Européenne Mark clinical trial. Patients had follow-up visits every 3 months while on left ventricular assist device support, and all patients completed the 5-year follow-up. The primary end point was survival at 5 years. Secondary end points included adverse events, health status and quality of life.

RESULTS

Eight patients (men: 75%) aged 59 years (min-max: 52-66 years) were enrolled. At 5 years, survival was 100%. Patients remained on support for a median time of 1825 days (min-max: 101-1825 days); 2 patients successfully received cardiac transplants. No right heart failure, haemolysis, pump thrombosis, pump malfunction or neurological events occurred in any patients. A driveline infection was observed in 6 patients (0.25 events/patient-year). Compared to baseline, a significant improvement in quality of life and in New York Heart Association functional class was noted after the implant and for the whole follow-up time. A slight decline in kidney function and in the 6-min walk test results occurred after 3 years.

CONCLUSIONS

This study reports the longest single-centre follow-up of the HeartMate 3, showing excellent haemocompatibility over time with high survival and low complication rates at 5 years.

Driveline exit-site care protocols in patients with left ventricular assist devices: a systematic review

 

OBJECTIVES

Driveline infections continue to be a significant complication following left ventricular assist device (LVAD) implantation. Driveline exit-site care is crucial for the prevention of infections; however, there are no uniform guidelines. The goal of this study was to provide an overview of the currently published driveline exit-site care protocols in patients with LVAD.

METHODS

A systematic literature review was performed. Studies before 15 December 2020 were included if the number of driveline infections was a primary outcome and the driveline exit-site care protocol was explained.

RESULTS

Eleven articles were included in the systematic review, including 1602 patients with LVADs. The median of the frequency of driveline infections in the articles was 13.8% with a range of 0–52.6%. There was a marked variability in the methods of care of driveline exit sites, without a standardized driveline dressing technique in patients with LVADs. The frequency of driveline infections was 6–7.5% in studies using a dressing kit that included chlorhexidine, a silver-based dressing and an anchoring device. Furthermore, there was variability in the anchoring devices and the frequency of dressing changes, which varied from daily to weekly. No specific anchoring device or change frequency was found to be superior.

CONCLUSIONS

Based on this systematic review, driveline exit care protocols that included chlorhexidine, a silver-based dressing, the use of an anchoring device and dressing kits might be best in reducing driveline infection rates. However, prospective studies with larger cohorts are needed to establish the optimal protocol for driveline exit-site care.

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.

Ventricular Assist Device-Specific Infections

Ventricular assist device (VAD)-specific infections, in particular, driveline infections, are a concerning complication of VAD implantation that often results in significant morbidity and even mortality. The presence of a percutaneous driveline at the skin exit-site and in the subcutaneous tunnel allows biofilm formation and migration by many bacterial and fungal pathogens. Biofilm formation is an important microbial strategy, providing a shield against antimicrobial treatment and human immune responses; biofilm migration facilitates the extension of infection to deeper tissues such as the pump pocket and the bloodstream. Despite the introduction of multiple preventative strategies, driveline infections still occur with a high prevalence of ~10-20% per year and their treatment outcomes are frequently unsatisfactory. Clinical diagnosis, prevention and management of driveline infections are being targeted to specific microbial pathogens grown as biofilms at the driveline exit-site or in the driveline tunnel. The purpose of this review is to improve the understanding of VAD-specific infections, from basic "bench" knowledge to clinical "bedside" experience, with a specific focus on the role of biofilms in driveline infections.

Left ventricular assist device driveline infections in three contemporary devices

Driveline infections (DLI) are common adverse events in left ventricular assist devices (LVADs), leading to severe complications and readmissions. The study aims to characterize risk factors for DLI readmission 2 years postimplant. This single‐center study included 183 LVAD patients (43 HeartMate II [HMII], 29 HeartMate 3 [HM3], 111 HVAD) following hospital discharge between 2013 and 2017. Demographics, clinical parameters, and outcomes were retrospectively analyzed and 12.6% of patients were readmitted for DLI, 14.8% experienced DLI but were treated in the outpatient setting, and 72.7% had no DLI. Mean C‐reactive protein (CRP), leukocytes and fibrinogen were higher in patients with DLI readmission (P < .02) than in outpatient DLI and patients without DLI, as early as 60 days before readmission. Freedom from DLI readmission was comparable for HMII and HVAD (98% vs. 87%; HR, 4.52; 95% CI, 0.58‐35.02; P = .15) but significantly lower for HM3 (72%; HR, 10.82; 95% CI, 1.26‐92.68; P = .03). DLI (HR, 1.001; 95% CI, 0.999‐1.002; P = .16) or device type had no effect on mortality. DLI readmission remains a serious problem following LVAD implantation, where CRP, leukocytes, and fibrinogen might serve as risk factors already 60 days before. HM3 patients had a higher risk for DLI readmissions compared to HVAD or HMII, possibly because of device‐specific driveline differences.

Blood stream infection and outcomes in recipients of a left ventricular assist device

OBJECTIVES

METHODS

We retrospectively analysed all adult recipients of a continuous-flow LVAD between 2006 and 2016 at the Division of Cardiac Surgery, Medical University of Vienna (n = 257; devices: Medtronic HeartWare® HVAD®, Abbott HeartMate II®, Abbott HeartMate 3™). The primary outcome was all-cause mortality during follow-up. Secondary outcomes included the risk of stroke and pump thrombus during follow-up as well as the probability of heart transplantation (HTx). Risk factors for the development of ≥1 positive BC were evaluated additionally.

RESULTS

The incidence of ≥1 positive BC during the first year of LVAD support was 32.1% [95% confidence interval (CI) 26.4–37.9]. Multivariable Cox proportional cause-specific hazards regression analysis showed that a positive BC was associated with significantly increased all-cause mortality [hazard ratio (HR) 5.51, 95% CI 3.57–8.51; P &lt; 0.001]. Moreover, a positive BC was associated with a significantly increased risk of stroke (HR 2.41, 95% CI 1.24–4.68; P = 0.010). There was no association with the risk of pump thrombus or the probability of HTx. Independent risk factors for a positive BC included preoperative albumin and extracorporeal membrane oxygenation/intra-aortic balloon pump support.

CONCLUSIONS

Blood stream infection is common and associated with a significantly increased risk of all-cause mortality and stroke at any given time during LVAD support. Effective strategies of prevention and treatment are necessary.