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.

Management of aortic valve insufficiency in patients with continuous-flow left ventricular assist device: a republication of the review published in Japanese Journal of Artificial Organs

Since 2011, implantable ventricular assist devices have been a standard treatment for severe heart failure alongside heart transplantation in Japan. However, the limited availability of donors has led to a prolonged wait for transplants, now averaging 1719 days, intensifying the issue of aortic insufficiency in patients with continuous flow ventricular assist devices. These devices limit the opening of the aortic valve, leading to sustained closure and increased shear stress, which accelerates valve degradation. Risk factors for aortic insufficiency include having a smaller body surface area, being of advanced age, and the presence of mild aortic insufficiency prior to device implantation. In patients presenting with mild or moderate aortic regurgitation at the time of ventricular assist device implantation, interventions such as aortic valve repair or bioprosthetic valve replacement are performed with the aim of halting its progression. The choice of surgical procedure should be tailored to each patient's individual condition. The management of de novo aortic insufficiency in patients with continuous flow ventricular assist devices remains challenging, with no clear consensus on when to intervene. Interventions for significant aortic insufficiency typically consider the patient's symptoms and aortic insufficiency severity. De novo aortic insufficiency progression in continuous flow ventricular assist devices patients necessitates careful monitoring and intervention based on individual patient assessments and valve condition. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 77-80), with some modifications.

Current issues of destination therapy in Japan: to achieve 5-year or even longer survival

In April 2021, destination therapy (DT) was finally approved in Japan. Since DT does not aim at heart transplantation (HT), our goal is to have a patient safely remain on an implantable ventricular assist device (VAD) for the rest of his/her life. To achieve this goal, similarly to bridge-to-transplant (BTT) patients, the authors believe the following six aspects are even more crucial in DT patients: (1) to appropriately assess risks before implantation, (2) to carefully determine the ability to manage the device by multidisciplinary discussions, (3) to prevent complications by improving the quality of care, (4) to expand the number of facilities that can take care of DT patients by improving collaboration among the facilities, (5) to reduce the burden of caregivers by utilizing social resources, and (6) to establish a home palliative care system based on advance care planning. In addition, for elderly DT patients to live happy and long lives, it is essential to help them to find a purpose of life and to keep activities of daily living, such as employment, schooling, and participation in social activities, just like the general elderly population. Our goals are not only to do our best for the patients just in front of us, but also to establish a system to follow up our DT cohort, same as BTT one, by all-Japan manner. In the present review, we discuss the current state of DT in Japan and what we need to focus on to maintain or improve its long-term performance.

Caregivers of patients with long-term implantable ventricular assist device: a republication of the article published in the Japanese Journal of Artificial Organs

Implantable ventricular assist device (VAD) has enabled patients with severe heart failure to be discharged from the hospital and to continue their care at home. The presence of caregivers is essential to maintain home care of patients with VAD. The caregivers are mainly the family members who live with the patient with VAD. The caregivers need to be trained (1) VAD device management, (2) disinfection of driveline skin punctures, (3) medication management, and (4) responding to sudden changes. The caregivers' lifestyle is also forced to change. In this article, we discuss the role of caregivers in the VAD era, where long-term support beyond 5 years is now possible. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 81-84), with some modifications.

Vascular function in patients with advanced heart failure and continuous-flow or pulsatile ventricular assist devices

BACKGROUND

A significant proportion of patients with heart failure (HF) progress to an advanced stage, which is associated with a substantial increase in morbidity and mortality. These patients may be eligible for advanced treatment strategies such as mechanical circulatory support with ventricular assist devices (VAD). Vascular dysfunction is a hallmark of heart failure pathophysiology and prognosis. However, whether and to what degree the hemodynamic benefits of VADs influence vascular function remain unknown.

METHODS AND RESULTS

In this study, we evaluated endothelial vascular function with flow-mediated vasodilatation (FMD) and with flicker-light induced retinal vasodilatation (FID). 34 patients with a VAD (age 58 ± 10 years, 85% male, 74% ischemic heart disease, 26 continuous-flow (CF)-LVAD, and 8 pulsatile biventricular (bi)-VAD) were compared to 34 propensity-matched patients (mean age 62 ± 9 years, 68% male, 59% ischemic heart disease) with advanced HF (AdvHF). Endothelial function of larger arteries (FMD) was significantly better in patients after VAD implantation compared to matched AdvHF patients (7.2 ± 4.6% vs. 5.0 ± 3.2%, p = 0.03), whereas microvascular arteriolar function (FIDart) did not differ (0.99 ± 1.43% vs. 1.1 ± 1.7%, p = 0.78). The arterio-venous ratio (AVR) was higher in the VAD group (0.90 ± 0.06 vs 0.85 ± 0.09, p = 0.01), reflecting wider retinal arteriolar and narrower venular diameters. There was no difference in vascular function between patients with CF-LVAD and pulsatile Bi-VAD.

CONCLUSION

In patients with advanced heart failure, VAD implantation was associated with better endothelial function at the level of large arteries, but not in the microcirculation.

[Healthcare quality and safety in left ventricular assist device therapy from the patient perspective: A qualitative study on relevant aspects of care]

INTRODUCTION

Implantation of a left ventricular assist device (LVAD) requires extensive aftercare. It is largely unclear how aftercare should be designed from the patients' perspective. Implications can be developed based on an examination of the healthcare context. Its main components are mapped on five tiers in the Human Factors of Home Health Care Model by Henriksen, Joseph, and Zayas-Caban (2009). Using this model, the present study explores the patient perspective on the context of healthcare after an LVAD implantation.

METHODS

We employed a qualitative cross-sectional study, in which LVAD patients participated in semi-structured interviews. The transcribed interviews were analyzed using content analysis. First, relevant meaning units were identified and deductively categorized into the model. Then, categories of care-related aspects were developed inductively within each of the model tiers.

RESULTS

We interviewed 18 patients aged 33 to 78 years who had been living with the LVAD between a few weeks and more than 10 years. Twenty-eight categories related to care aspects were developed within the model tiers: 3 categories on patient characteristics (e.g., self-management skills), 3 on caregiver characteristics (e.g., professionalism), 11 healthcare-related tasks and requirements (e.g., wound management), 8 on factors of the physical environment (e.g., controllability), medical devices and technologies (e.g., carrying systems for external components), and cultural, social and community environment (e.g., interaction with peers), as well as 3 on external environmental factors (e.g., healthcare infrastructure).

DISCUSSION

The present study represents the first investigation focusing on aspects of the healthcare context influencing healthcare quality and safety from the perspective of LVAD patients in Germany. LVAD aftercare covers a broad and complex range of tasks. For this, patients, caregivers and healthcare professionals need specific knowledge, which is lacking in various respects. In the first place, this is compensated by the patients' own initiative and the personal care provided by the VAD outpatient clinics.

CONCLUSION

Three key recommendations to optimize aftercare from the patient perspective are derived: Patients would benefit from a more flexible and decentralized aftercare concept, to which telemedicine could contribute. LVAD-specific expertise among general healthcare providers is perceived as insufficient by patients and could be strengthened through training and counseling services. The broad scope of tasks and the high level of responsibilities in LVAD aftercare pose challenges for patients and their families, which could be addressed through continuous information and training programs.

Ventricular assist device support in paediatric patients with restrictive cardiomyopathy-clinical outcomes and haemodynamics

OBJECTIVES

Restrictive cardiomyopathy is rare and is generally associated with worse clinical outcomes compared to other cardiomyopathies. Ventricular assist device (VAD) support for these children is seldom applied and often hampered by the surgical difficulties.

METHODS

All paediatric (<19 years) patients with a restricted cardiomyopathy supported by a VAD from the EUROMACS database were included and compared to patients with a dilated cardiomyopathy (retrospective database analyses). Participating centres were retrospectively contacted to provide additional detailed echo and Swan Ganz measurements to analyse the effect of VAD support on pulmonary artery pressure and right ventricular function.

RESULTS

Forty-four paediatric VAD-supported patients diagnosed with restricted cardiomyopathy were included, with a median age at implantation of 5.0 years. Twenty-six of the 44 patient with a restricted cardiomyopathy survived to transplantation (59.1%), 16 died (36.4%) and 2 are still on ongoing VAD support (4.5%) after a median duration of support of 95.5 days (interquartile range 33.3-217.8). Transplantation probability after 1 and 2 years of VAD support in patients with a restricted cardiomyopathy were comparable to patients with a dilated cardiomyopathy (52.3% vs 51.4% and 59.5% vs 60.1%, P = 0.868). However, mortality probability was higher in the restricted cardiomyopathy cohort (35.8% vs 17.0% and 35.8% vs 19.0%, P = 0.005). Adverse event rates were high (cerebrovascular accident in 31.8%, pump thrombosis in 29.5%, major bleeding 25.0%, eventual biventricular support in 59.1%). In the atrially cannulated group, cerebrovascular accident and pump thrombosis occurred in twice as much patients (21.1% vs 40.0%, P = 0.595 and 15.8% vs 40.0%, P = 0.464; probably non-significant due to the small numbers). Pulmonary arterial pressures improved after implantation of a VAD, and 6 patients who were initially labelled as ineligible due to pulmonary hypertension could eventually be transplanted.

CONCLUSIONS

VAD support in children with a restricted cardiomyopathy is rarely performed. Mortality and adverse event rates are high. On the other hand, survival to cardiac transplantation was 59.1% with all patients surviving the 1st 30 days after cardiac transplantation. Pulmonary arterial pressures improved while on support, potentially making cardiac transplantation a viable option for previously ineligible children.

The European Registry for Patients with Mechanical Circulatory Support (EUROMACS): fourth Paediatric EUROMACS (Paedi-EUROMACS) report

OBJECTIVES

The use of ventricular assist devices (VADs) in children is increasing. However, absolute numbers in individual centres and countries remain small. Collaborative efforts such as the Paedi-European Registry for Patients with Mechanical Circulatory Support (EUROMACS) are therefore essential for combining international experience with paediatric VADs. Our goal was to present the results from the fourth Paedi-EUROMACS report.

METHODS

All paediatric (<19 years) patients from the EUROMACS database supported by a VAD were included. Patients were stratified into a congenital heart disease (CHD) group and a group with a non-congenital aetiology. End points included mortality, a transplant and recovery. Cox proportional hazard models were used to explore associated factors for mortality, cerebrovascular accident and pump thrombosis.

RESULTS

A total of 590 primary implants were included. The congenital group was significantly younger (2.5 vs 8.0 years, respectively, P < 0.001) and was more commonly supported by a pulsatile flow device (73.5% vs 59.9%, P < 0.001). Mortality was significantly higher in the congenital group (30.8% vs 20.4%, P = 0.009) than in the non-congenital group. However, in multivariable analyses, CHD was not significantly associated with mortality [hazard ratio (HR) 1.285; confidence interval (CI) 0.8111-2.036, P = 0.740]. Pump thrombosis was the most frequently reported adverse event (377 events in 132 patients; 0.925 events per patient-year) and was significantly associated with body surface area (HR 0.524, CI 0.333-0.823, P = 0.005), CHD (HR 1.641, CI 1.054-2.555, P = 0.028) and pulsatile flow support (HR 2.345, CI 1.406-3.910, P = 0.001) in multivariable analyses.

CONCLUSIONS

This fourth Paedi-EUROMACS report highlights the increasing use of paediatric VADs. The patient populations with congenital and non-congenital aetiologies exhibit distinct characteristics and clinical outcomes.

Contemporary Outcomes of Heart Transplantation in Children with Heterotaxy Syndrome: Sub-Optimal Pre-Transplant Optimization Translates into Early Post-Transplant Mortality

Patients with heterotaxy syndrome and congenital heart disease (CHD) experience inferior cardiac surgical outcomes. Heart transplantation outcomes are understudied, however, particularly compared to non-CHD patients. Data from UNOS and PHIS were used to identify 4803 children (< 18 years) undergoing first-time heart transplant between 2003 and 2022 with diagnoses of heterotaxy (n = 278), other-CHD (n = 2236), and non-CHD cardiomyopathy (n = 2289). Heterotaxy patients were older (median 5 yr) and heavier (median 17 kg) at transplant than other-CHD (median 2 yr and 12 kg), and younger and lighter than cardiomyopathy (median 7 yr and 24 kg) (all p < 0.001). UNOS status 1A/1 at listing was not different between groups (65-67%; p = 0.683). At transplant, heterotaxy and other-CHD patients had similar rates of renal dysfunction (12 and 17%), inotropes (10% and 11%), and ventilator-dependence (19 and 18%). Compared to cardiomyopathy, heterotaxy patients had comparable renal dysfunction (9%, p = 0.058) and inotropes (46%, p = 0.097) but more hepatic dysfunction (17%, p < 0.001) and ventilator-dependence (12%, p = 0.003). Rates of ventricular assist device (VAD) were: heterotaxy-10%, other-CHD-11% (p = 0.839 vs. heterotaxy), cardiomyopathy-37% (p < 0.001 vs. heterotaxy). The 1-year incidence of acute rejection post-transplant was comparable between heterotaxy and others (p > 0.05). While overall post-transplant survival was significantly worse for heterotaxy than others (p < 0.05 vs. both), conditional 1-year survival was comparable (p > 0.3 vs. both). Children with heterotaxy syndrome experience inferior post-heart transplant survival, although early mortality appears to influence this trend, with 1-year survivors having equivalent outcomes. Given similar pre-transplant clinical status to others, heterotaxy patients are potentially under risk-stratified. Increased VAD utilization and pre-transplant end-organ function optimization may portend improved outcomes.

Improving Mechanical Circulatory Support Outcomes in Failing Bidirectional Glenn Physiology

There remains high morbidity and mortality with mechanical circulatory support (MCS) in failing bidirectional Glenn (BDG) physiology. We performed a retrospective analysis of children with BDG physiology supported with MCS before and after 2018. Fourteen patients met inclusion criteria (median age 1.5 years, weight 9 kg). Prior to 2018 (n = 7), with variable anticoagulation and strategies including pulsatile VAD, continuous flow VAD, and extracorporeal membrane oxygenation (ECMO), 3 (43%) of patients were transplanted with a total of 536 patient-days of support (median 59 days). Major hemocompatability-related adverse event (MHRAE) rate was 63 per 100 patient-months. After 2018 (n = 7), using a staged support strategy (ECMO to pulsatile VAD) and bivalirudin anticoagulation, 5 (71%) patients were transplanted with a total of 1260 patient-days of support (median 188 days) and MHRAE rate of 24 per 100 patient-months. Despite challenging physiology, we have observed improved survival and reduced MHRAE despite longer support duration.

Case series: successful salvage from refractory cardiogenic shock caused by COVID-19-associated myocardial injury with temporary ventricular assist devices

Background

Coronavirus disease 2019 (COVID-19) is predominantly known to cause respiratory injury; however, the present case series highlights four instances in which the infection resulted in significant cardiac complications. Among such cases, some represent severe cardiogenic shock, which necessitates the immediate introduction of mechanical circulatory support (MCS) for salvage.

Case summary

This case series involved patients with COVID-19-associated myocardial injury leading to fulminant cardiogenic shock. These patients required immediate implementation of peripheral MCS, followed by an instant upgrade to a central MCS system due to anatomical limitations and severe biventricular dysfunction. Central MCS provided effective ventricular unloading, resulting in a significant and prompt improvement in ventricular function. The treatment timeline showed rapid deterioration followed by remarkable recovery within 2 weeks of MCS initiation, demonstrating the effectiveness of aggressive and tailored MCS strategies in managing severe COVID-19-related cardiac complications.

Discussion

This study provides significant insights into the cardiovascular implications of COVID-19, particularly in the context of severe myocardial injury that leads to cardiogenic shock. The report underscores the importance of early recognition and intervention in such cases, focusing on the use of MCS as a life-saving modality. The findings also revealed unique pathological features of COVID-19-associated myocardial injury, including macrophage-predominant infiltration and microthrombosis, which are distinct from the features of conventional myocarditis. These findings highlight the need for further research on the pathophysiology of COVID-19-related cardiac injuries and the development of targeted therapeutic strategies.

Current status and future directions in pediatric ventricular assist device

A ventricular assist device (VAD) is a form of mechanical circulatory support that uses a mechanical pump to partially or fully take over the function of a failed heart. In recent decades, the VAD has become a crucial option in the treatment of end-stage heart failure in adult patients. However, due to the lack of suitable devices and more complicated patient profiles, this therapeutic approach is still not widely used for pediatric populations. This article reviews the clinically available devices, adverse events, and future directions of design and implementation in pediatric VADs.

Predictors of long-term success after successful explantation of continuous flow left ventricular assist device support

OBJECTIVES

Predictors and evaluations of continuous flow left ventricular assist device (cf-LVAD) explantation in recovered patients remain under discussion due to lack of evidence on long-term safety and efficacy. This study summarized our experiences regarding cf-LVAD explantation in non-ischaemic dilated cardiomyopathy patients and estimated a predictor for sufficient myocardial recovery allowing left ventricular assist device explant.

METHODS

We retrospectively identified 135 adult patients with cf-LVAD therapy as bridge to heart transplant due to non-ischaemic dilated cardiomyopathy. Of those, 13 patients underwent device explantation (recovery group) after myocardial recovery. Twelve (92%) of the explanted patients were evaluated using our weaning protocol and underwent surgical explantation. Meanwhile, the remaining 122 continued with cf-LVAD therapy (non-recovery group).

RESULTS

Multivariate logistic regression analysis revealed time interval between the first heart failure event and cf-LVAD implantation as an independent predictor for successful explantation. The optimal time interval cutoff value to predict cf-LVAD explantation was 7 months, with a sensitivity of 91.0% and specificity of 84.6%. Echocardiography in patients with successful cf-LVAD explantation showed significant improvement of left ventricular function and dimensions at 6 months postoperatively. The 13 explanted patients are currently alive at a median of 30 (interquartile range; 18-58) months after explantation. The survival rate free from rehospitalization due to heart failure following explantation was 100%. Left ventricular function and remodelling after explantation were also preserved.

CONCLUSIONS

In non-ischaemic dilated cardiomyopathy patients with a short interval between the first heart failure event and cf-LVAD therapy, left ventricular myocardium may recover in an early phase after device implantation.

Moving forwards to patient-centred care for patients with ventricular assist devices: A mixed methods study of nurses' perspectives

OBJECTIVES

To identify nurses' caring behaviours toward patients with left ventricular assist devices and deepen their understanding of experiences in nursing care. Patients with left ventricular assist devices require care in many aspects, but there is limited in-depth research about caring behaviours and experiences from the perspective of nurses providing care.

RESEARCH METHODOLOGY/DESIGN

Mixed methods study with a sequential explanatory design. Data were collected from clinical nurses with experience caring for patients using left ventricular assist devices in South Korea between May-August 2022.

MAIN OUTCOME MEASURES

Quantitative data (n = 79) were collected through an online survey of the Caring Behaviours Inventory - 24 and analysed using descriptive statistics. For qualitative data (n = 15), nurses' caring experiences were collected through individual interviews and analysed using Colaizzi's phenomenological method.

RESULTS

The overall average of caring behaviours was 4.80 ± 0.85, specifically, 'knowledge and skill' (5.04 ± 0.78), 'assurance' (5.01 ± 0.79), 'respect' (4.85 ± 0.90), and 'connectedness' (4.04 ± 0.99), respectively. The experience of caring was trapped in the uncomfortable reality of left ventricular assist device nursing, causing device-focused care, and approaching the essence of nursing through care focused on the patient's wholeness.

CONCLUSIONS

Caring for patients with a left ventricular assist devices was challenging for nurses. However, through the care process, they realised the meaning of patient-centred care, reflected in the essence of nursing, and sublimated it into an opportunity to grow.

IMPLICATIONS FOR CLINICAL PRACTICE

Nurses must focus on patient-centred care for left ventricular assist devices. To achieve this, it is essential to create a clinical environment and educational system for nurses to provide effective nursing care and enhance patient participation.

Intersection of social determinants of health with ventricular assist device therapy: An integrative review

BACKGROUND

Social determinants of health (SDOH) may influence the clinical management of patients with heart failure. Further research is warranted on the relationship between SDOH and Ventricular Assist Device (VAD) therapy for heart failure.

OBJECTIVES

The purpose of this integrative review was to synthesize the state of knowledge on the intersection of SDOH with VAD therapy.

METHODS

Guided by Whittemore and Knafl's methodology, this literature search captured three concepts of interest including VAD therapy, SDOH, and their domains of intersection with patient selection, decision-making, treatment outcome, and resource allocation. CINAHL, Embase, PsycINFO, PubMed, and Web of Science were searched in March 2023. Articles were included if they were peer-reviewed publications in English, published between 2006 and 2023, conducted in the United States, and examined VAD therapy in the context of adult patients (age ≥ 18 years).

RESULTS

22 quantitative studies meeting the inclusion criteria informed the conceptualization of SDOH using the Healthy People 2030 framework. Four themes captured how the identified SDOH intersected with different processes relating to VAD therapy: patient decision-making, healthcare access and resource allocation, patient selection, and treatment outcomes. Most studies addressed the intersection of SDOH with healthcare access and treatment outcomes.

CONCLUSION

This review highlights substantial gaps in understanding how SDOH intersect with patient and patient selection for VAD. More research using mixed methods designs is warranted. On an institutional level, addressing bias and discrimination may have mitigated health disparities with treatment outcomes, but further research is needed for implementing system-wide change. Standardized assessment of SDOH is recommended throughout clinical practice from patient selection to outpatient VAD care.

Design and Rationale for the Direct Oral Anticoagulant Apixaban in Left Ventricular Assist Devices (DOAC LVAD) Study

Implantable left ventricular assist device (LVAD) therapy is used to improve quality of life, alleviate symptoms and extend survival rates in patients with advanced heart failure. Patients with LVADs require chronic anticoagulation to reduce the risk of thromboembolic complications, and they commonly experience bleeding events. Apixaban is a direct oral anticoagulant that has become first-line therapy for patients with nonvalvular atrial fibrillation and venous thromboembolism; however, its safety in patients with LVADs has not been well characterized. The evaluation of the hemocompatibility in the DOAC LVAD (Direct Oral Anti-Coagulant apixaban in Left Ventricular Assist Devices) trial is a phase 2, open-label trial of patients with LVADs who were randomized to either apixaban or warfarin therapy. Patients randomized to apixaban will be started on a dosage of 5 mg twice daily, whereas those randomized to warfarin will be managed at an International Normalized Ratio goal of 2.0-2.5. All patients will be treated with aspirin at 81 mg daily. We plan to randomize and follow as many as 40 patients for 24 weeks to evaluate the primary outcomes of freedom from death or hemocompatibility-related adverse events (stroke, device thrombosis, bleeding, aortic root thrombus, and arterial non-CNS thromboembolism). The DOAC LVAD trial will establish the feasibility of apixaban anticoagulant therapy in patients with LVADs. Clinicaltrials.gov: NCT04865978.

Successful Bridge to Heart Transplantation through Ventricular Assist Device Implantation and Concomitant Fontan Completion in a Patient with Glenn Physiology: A Case Report

A 3-year-old boy with Glenn physiology exhibited refractory heart failure with reduced ejection fraction. To improve the patient's oxygen saturation, he underwent ventricular assist device (VAD) implantation with concomitant Fontan completion. The extracardiac conduit Fontan operation was performed with a 4-mm fenestration. For VAD implantation, Berlin Heart cannulas were positioned at the left ventricular apex and the neo-aorta. Following weaning from cardiopulmonary bypass, a temporary continuous-flow VAD, equipped with an oxygenator, was utilized for support. After a stabilization period of 1 week, the continuous-flow VAD was replaced with a durable pulsatile-flow device. Following 3 months of support, the patient underwent transplantation without complications. The completion of the Fontan procedure at the time of VAD implantation, along with the use of a temporary continuous-flow device with an oxygenator, may aid in stabilizing postoperative hemodynamics. This approach could contribute to a safe transition to a durable pulsatile VAD in patients with Glenn physiology.

Durable ventricular assist device in adult patients with single ventricle: a systematic literature review

The worldwide experience with mechanical circulatory support in adult patients with single ventricle and Fontan palliation is limited. We aimed to see the outcomes in such patients on durable left ventricular assist device. We systematically reviewed the English language literature found on PubMed and Google Scholar, searching the terms "Fontan," "single ventricle," "ventricular assist device," "LVAD," and "mechanical circulatory support," and selected all individual cases with reported outcomes. We identified 4 patients on pulsatile left ventricular assist device, all of whom were successfully bridged to transplant, and 15 patients on continuous flow LVAD, age 25.9 ± 5.8, predominantly males. Mean time on LVAD support was 718.6 ± 616.5 days, and only 2 patients (13.3%) died. Durable left ventricular assist device support in adult patients with Fontan provides excellent results and should be used more frequently.

Impact of inflammation and steroids on anti-coagulation in children supported on a ventricular assist device

Critically ill pediatric patients supported on ventricular assist devices (VADs) are increasingly being anticoagulated on bivalirudin, but with difficulty monitoring anticoagulation. Activated partial thromboplastin time (aPTT) has recently been shown to poorly correlate with bivalirudin plasma concentrations, while dTT had excellent correlation. However, aPTT is the more common monitoring test and dTT testing is rarely used. In addition, effects of frequent clinical VAD scenarios (such as inflammation) on the accuracy of aPTT and dTT testing remains uncertain. We reviewed the effects of clinical scenarios (infection/inflammation, chylothorax, and steroids administration) on anticoagulation monitoring in 10 pediatric VAD patients less than 3 years at Cincinnati Children's Hospital Medical Center from 10/27/2020 to 5/6/2022 using bivalirudin for anticoagulation. There were 16 inflammation/infection, 3 chylothorax, and 6 steroids events. Correlation between dTT and aPTT was significantly lower after infection/inflammation, with dTT increasing prior to inflammation/infection while aPTT remained unchanged. In addition, steroids are administered to VAD patients to reduce inflammation and thus additionally stabilize anticoagulation. However, this anticoagulation stabilization effect was reflected more accurately by dTT compared to aPTT. In children requiring VAD support utilizing bivalirudin anticoagulation, inflammation/infection is a common occurrence resulting in anticoagulation changes that may be more accurately reflected by dTT as opposed to aPTT.

Long-term kidney outcomes in pediatric continuous-flow ventricular assist device patients

BACKGROUND

Continuous-flow ventricular assist devices (CF-VADs) are used increasingly in pediatric end-stage heart failure (ESHF) patients. Alongside common risk factors like oxidant injury from hemolysis, non-pulsatile flow constitutes a unique circulatory stress on kidneys. Post-implantation recovery after acute kidney injury (AKI) is commonly reported, but long-term kidney outcomes or factors implicated in the evolution of chronic kidney disease (CKD) with prolonged CF-VAD support are unknown.

METHODS

We studied ESHF patients supported > 90 days on CF-VAD from 2008 to 2018. The primary outcome was CKD (per Kidney Disease Improving Global Outcomes (KDIGO) criteria). Secondary outcomes included AKI incidence post-implantation and CKD evolution in the 6-12 months of CF-VAD support.

RESULTS

We enrolled 134 patients; 84/134 (63%) were male, median age was 13 [IQR 9.9, 15.9] years, 72/134 (54%) had preexisting CKD at implantation, and 85/134 (63%) had AKI. At 3 months, of the 91/134 (68%) still on a CF-VAD, 34/91 (37%) never had CKD, 13/91 (14%) developed de novo CKD, while CKD persisted or worsened in 49% (44/91). Etiology of heart failure, extracorporeal membrane oxygenation use, duration of CF-VAD, AKI history, and kidney replacement therapy were not associated with different CKD outcomes. Mortality was higher in those with AKI or preexisting CKD.

CONCLUSIONS

In the first multicenter study to focus on kidney outcomes for pediatric long-term CF-VAD patients, preimplantation CKD and peri-implantation AKI were common. Both de novo CKD and worsening CKD can happen on prolonged CF-VAD support. Proactive kidney function monitoring and targeted follow-up are important to optimize outcomes.

Special Considerations for Mechanical Circulatory Support or Device Therapy in Adult Congenital Heart Disease Heart Failure

Heart failure has become the leading cause of mortality in adult congenital heart disease (ACHD) patients after the fifth decade of life. There is scanty evidence supporting the use of guideline-directed medical therapy in ACHD, especially in systemic right ventricle or single ventricle physiology. In complex patients, diagnosing heart failure and timely referral for advanced therapies are challenging. Mechanical circulatory support has been significantly developed over the past decade and has recently emerged as a feasible therapeutic option for these patients. This review summarizes current evidence of mechanical circulatory support in this population, its potential uses, and challenges.

Experimentally-guided in silico design of engineered heart tissues to improve cardiac electrical function after myocardial infarction

Engineered heart tissues (EHTs) built from human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) showed promising results for cardiac function restoration following myocardial infarction. Nevertheless, human iPSC-CMs have longer action potential and lower cell-to-cell coupling than adult-like CMs. These immature electrophysiological properties favor arrhythmias due to the generation of electrophysiological gradients when hiPSC-CMs are injected in the cardiac tissue. Culturing hiPSC-CMs on three-dimensional (3D) scaffolds can promote their maturation and influence their alignment. However, it is still uncertain how on-scaffold culturing influences the overall electrophysiology of the in vitro and implanted EHTs, as it requires expensive and time consuming experimentation. Here, we computationally investigated the impact of the scaffold design on the EHT electrical depolarization and repolarization before and after engraftment on infarcted tissue. We first acquired and processed electrical recordings from in vitro EHTs, which we used to calibrate the modeling and simulation of in silico EHTs to replicate experimental outcomes. Next, we built in silico EHT models for a range of scaffold pore sizes, shapes (square, rectangular, auxetic, hexagonal) and thicknesses. In this setup, we found that scaffolds made of small (0.2 mm2), elongated (30° half-angle) hexagons led to faster EHT activation and better mimicked the cardiac anisotropy. The scaffold thickness had a marginal role on the not engrafted EHT electrophysiology. Moreover, EHT engraftment on infarcted tissue showed that the EHT conductivity should be at least 5% of that in healthy tissue for bidirectional EHT-myocardium electrical propagation. For conductivities above such threshold, the scaffold made of small elongated hexagons led to the lowest activation time (AT) in the coupled EHT-myocardium. If the EHT conductivity was further increased and the hiPSC-CMs were uniformly oriented parallel to the epicardial cells, the total AT and the repolarization time gradient decreased substantially, thus minimizing the likelihood for arrhythmias after EHT transplantation.

Does concomitant tricuspid valve intervention at the time of left ventricular assist device placement for patients with significant tricuspid regurgitation lead to improved outcomes compared to isolated left ventricular assist device placement?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'In patients with advanced heart failure (HF) and moderate to severe functional tricuspid regurgitation (TR) undergoing left ventricular assist device (LVAD) placement is concomitant tricuspid valve intervention (TVI) superior for the clinical outcomes of survival, right ventricular failure, rehospitalizations for HF, functional status, and quality of life?' Altogether, 56 papers were found using the reported search, of which 12 papers represented the best evidence to answer the clinical question. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Our search found no significant clinical benefit for concomitant TVI at the time of LVAD placement. We conclude that patient with moderate-to-severe TR should not routinely undergo concomitant TVI with LVAD placement.