Ventricular assist device use in congenital heart disease with a comparison to heart transplant

In the era of outpatient ventricular assist devices, is it time to reconsider the practice of bridging older children to transplant on outpatient inotropes?

OBJECTIVE

Ventricular assist devices (VADs) and inotropes are feasible modalities to bridge children to heart transplant (HT) in outpatient settings. However, it is unclear which modality yields superior clinical status at HT and posttransplant survival.

METHODS

The United Network for Organ Sharing was used to identify patients aged 18 years or younger, weighing >25 kg, from 2012 to 2022 who were outpatients at HT (n = 835). Patients were grouped by bridging modality at HT: VAD (n = 235 [28%]), inotropes (n = 176 [21%]), or neither (no support) (n = 424 [50%]).

RESULTS

VAD patients were of similar age (P = .260) but heavier (P = .007) and more likely to have dilated cardiomyopathy (P < .001) than their inotrope counterparts. VAD patients had similar clinical status at HT but superior functional status (performance scale >70%) (59% vs 31%) (P < .001). Overall posttransplant survival in VAD patients (1-year and 5-year survival, 97% and 88%, respectively) was comparable to patients with no support (93% and 87%, respectively) (P = .090) and those on inotropes (98% and 83%, respectively) (P = .089). One-year conditional survival was superior for VAD vs inotrope (2-year and 6-year survival, 96% and 91%, respectively vs 97% and 79%, respectively) (P = .030) and 5-year conditional survival for VAD patients was superior to inotrope (7-year and 10-year survival, 100% and 100%, respectively vs 100% and 88%, respectively) (P = .022) and no support (100% and 83%, respectively) (P = .011).

CONCLUSIONS

Consistent with prior studies, short-term outcomes for pediatric patients bridged to HT in the outpatient setting with VAD or inotropes is excellent. However, compared with outpatients bridged to HT on inotropes, outpatient VAD support allowed for better functional status at HT and superior late posttransplant survival.

Heart transplantation surgery in children and young adults with congenital heart disease

BACKGROUND

Pediatric cardiac transplantation remains a surgical challenge as a variety of cardiac and vessel malformation are present in patients with congenital heart disease (CHD). Despite limited availability and acceptability of donor hearts, the number of heart transplantations remains on a stable level with improved survival and quality of life.

OBSERVATION

As treatment options for CHD continue to improve and the chances of survival increase, more adult CHD patients are listed for transplantation. This review focuses on the clinical challenges and modified techniques of pediatric heart transplantations.

CONCLUSION

Not only knowledge of the exact anatomy, but above all careful planning, interdisciplinary cooperation and surgical experience are prerequisites for surgical success.

Surgical strategies for the management of end-stage heart failure in infants and children: A 15-year experience with a patient-tailored approach

End‐stage heart failure (ESHF) in pediatric age is an ongoing challenge. Heart transplantation is the final option, but its long‐term outcomes are still suboptimal in children. An alternative patient‐tailored surgical protocol to manage ESHF in children is described. Retrospective, single‐center analysis of pediatric patients admitted to our institution between April 2004 and February 2021 for ESHF. Our current protocol is as follows: (a) Patients <1 year with isolated left ventricular dysfunction due to dilated cardiomyopathy underwent pulmonary artery banding (PAB). (b) Patients <10 years and <20 kg, who did not meet previous criteria were managed with Berlin Heart EXCOR. (c) Patients >10 years or >20 kg, underwent placement of intracorporeal Heartware. Primary outcomes were survival, transplant incidence, and postoperative adverse events. A total of 24 patients (mean age 5.3 ± 5.9 years) underwent 26 procedures: PAB in 6 patients, Berlin Heart in 11, and Heartware in 7. Two patients shifted from PAB to Berlin Heart. Overall survival at 1‐year follow‐up and 5‐year follow‐up was 78.7% (95%CI = 62%‐95.4%) and 74.1% (95%CI = 56.1%‐92.1%), respectively. Berlin Heart was adopted in higher‐risk settings showing inferior outcomes, whereas a PAB enabled 67% of patients to avoid transplantation, with no mortality. An integrated, patient‐tailored surgical strategy, comprehensive of PAB and different types of ventricular assist devices, can provide satisfactory medium‐term results for bridging to transplant or recovery. The early postoperative period is critical and requires strict clinical vigilance. Selected infants can benefit from PAB that has demonstrated to be a safe bridge to recovery.

The evolution of long-term pediatric ventricular assistance devices: a critical review

Introduction: The gap between the number of heart failure patients and the number of potential heart donors has never been larger than today, especially among the pediatric population. The use of mechanical circulatory support is seen as a potential alternative for clinicians to treat more patients. This treatment has proven its efficiency on short-term use. However, in order to replace heart transplant, the techniques should be used over longer periods of time.Areas covered: This review aims at furnishing an engineering vision of the evolution of ventricular assistance devices used in pediatrics. A critical analysis of the clinical complications related to devices generation is made to give an overview of the design improvements made since their inception.Expert opinion: The long-term use of a foreign device in the body is not without consequences, especially among fragile pediatric patients. Moreover, the size of their body parts increases the technical difficulties of such procedure. The balance between the living cells of the body is disturbed by the devices, mostly by the shear stress generated. To provide a safe mechanical circulatory support for long-term use, the devices should be more hemocompatible, preserving blood cells, adapted to the patient's systemic grid and miniaturized for pediatric use.

Autologous skeletal myoblast patch implantation prevents the deterioration of myocardial ischemia and right heart dysfunction in a pressure-overloaded right heart porcine model

Right ventricular dysfunction is a predictor for worse outcomes in patients with congenital heart disease. Myocardial ischemia is primarily associated with right ventricular dysfunction in patients with congenital heart disease and may be a therapeutic target for right ventricular dysfunction. Previously, autologous skeletal myoblast patch therapy showed an angiogenic effect for left ventricular dysfunction through cytokine paracrine effects; however, its efficacy in right ventricular dysfunction has not been evaluated. Thus, this study aimed to evaluate the angiogenic effect of autologous skeletal myoblast patch therapy and amelioration of metabolic and functional dysfunction, in a pressure-overloaded right heart porcine model. Pulmonary artery stenosis was induced by a vascular occluder in minipigs; after two months, autologous skeletal myoblast patch implantation on the right ventricular free wall was performed (n = 6). The control minipigs underwent a sham operation (n = 6). The autologous skeletal myoblast patch therapy alleviated right ventricular dilatation and ameliorated right ventricular systolic and diastolic dysfunction. 11C-acetate kinetic analysis using positron emission tomography showed improvement in myocardial oxidative metabolism and myocardial flow reserve after cell patch implantation. On histopathology, a higher capillary density and vascular maturity with reduction of myocardial ischemia were observed after patch implantation. Furthermore, analysis of mRNA expression revealed that the angiogenic markers were upregulated, and ischemic markers were downregulated after patch implantation. Thus, autologous skeletal myoblast patch therapy ameliorated metabolic and functional dysfunction in a pressure-overloaded right heart porcine model, by alleviating myocardial ischemia through angiogenesis.

Heart failure in the young: Insights into myocardial recovery with ventricular assist device support

Background

Data on ventricular unloading-promoted myocardial recovery and post-weaning outcome in children is scarce. We analyzed the weaning outcome in children with heart failure (HF) supported with ventricular assist device (VAD).

Methods

A multi-institutional data on VAD implanted in 193 children and adolescents with HF between April 1990 and November 2015 was reviewed. Among them, 25 children (mean age 3.4±3.0, range, 0.058-16.3 years, 15 females) were weaned from VAD. Etiology of HF were myocarditis (n=11), dilated cardiomyopathy (DCMP) (n=7), ischemic HF (n=3), arrhythmogenic CMP (n=1), post-correction of congenital heart disease (CHD) (n=1) and acute graft failure (n=1). Mean duration of HF before VAD implantation was 59.4±3 days.

Results

Age, duration of HF, DCMP, cardiac arrest and duration of VAD are essential clinical characteristics to delineate who may have the potential to myocardial recovery. Echocardiographic parameters pre-implantation, during the final off-pump trial and during the post-explantation follow-ups revealed that LVEF, LVEDD and relative wall thickness (RWT) showed significant differences (P<0.001) among patients stratified by outcome to assess recovery. Presently, 21 (84.0%) of the weaned patients are alive with their native hearts 1.3-19.1 years after VAD explantation. An additional weaned patient had HF recurrence 3 months post-weaning and was transplanted.

Conclusions

Post-weaning myocardial recovery and cardiac stability of children with HF from several etiologies supported with a VAD appears sustainable and durable. Young patients with short HF duration are more likely to recover. Absence of cardiac arrest, cardiac size, geometry and function may prospectively identify patients who may be likely to have myocardial recovery.

The role of ventricular assist device in children

The first and successful implantation of a ventricular assist device in 1990 has allowed an 8-year-old child with an end-stage heart failure to undergo a heart transplantation. This milestone paved the way to consider support with ventricular assist in the armamentarium of heart failure management in infants, children and adolescents. Several systems have evolved and faded owing to unacceptable complications. Indications and contraindications to implantation have been established. Anticoagulation management is still on its way to impeccability. Despite the challenges, issues and concerns revolving around ventricular assist devices, the system definitely supports pediatric patients with end-stage heart failure until heart transplantation and could allow recovery of the myocardium.

Pediatric ventricular assist device therapy for advanced heart failure-Hong Kong experience

Ventricular assist devices (VADs) are life-saving options for children with heart failure unresponsive to medical therapy as a bridge to transplantation or cardiac recovery. We present a retrospective review of 13 consecutive children who underwent implantation of VAD between 2001 and 2018 in our center. The median age was 12 years (1-17 years), weight was 45 kg (10-82 kg). Etiologies of heart failure were dilated cardiomyopathy (CMP) (n = 8), myocarditis (n = 2), ischemic CMP (n = 1), restrictive CMP (n = 1) and congenital heart disease (n = 1). Pre-implantation ECMO was used in 5, mechanical ventilation in 4, renal replacement therapy in 2 and IABP in 1. Devices used were: Berlin Heart EXCOR left VAD (LVAD), biventricular VAD (BIVAD) (n = 5, 2), CentriMag LVAD, BIVAD (n = 1, 2), HeartWare (n = 2), HeartMate II (n = 1). Median duration of support was 45 days (3-823 days). Overall survival was 85%. Four patients were successfully bridged to transplantation, 2 died while on a device, 4 remain on support and 3 were weaned from VAD. Late death occurred in 2 transplanted patients. Complications included bleeding requiring reoperation in 1, neurologic events in 3, driveline infections and pericardial effusion in 2 each. In one patient, CentriMag BIVAD provided support for 235 days, which is longest reported duration on such a VAD in the Asia Pacific region. Survival for pediatric patients of all ages is excellent using VADs. Given the severity of illness in these children morbidity and mortality is acceptable. VADs could potentially be used as a long-term bridge to transplantation in view of the donor shortage in the pediatric population.

HeartWare Ventricular Assist Device Implantation for Pediatric Heart Failure-A Single Center Approach

While pediatric HeartWare HVAD application has increased, determining candidacy and timing for initiation of pediatric VAD support has remained a challenge. We present our experience with a systematic approach to HVAD implantation as a bridge to pediatric heart transplantation. We performed a retrospective, single center review of pediatric patients (n = 11) who underwent HVAD implantation between September 2014 and January 2018. Primary endpoints evaluated were survival to heart transplantation, need for right ventricular assist device (RVAD) at any point, ongoing HVAD support, or death. Median patient age was 11 years (range: 3-16). Median BSA was 1.25 m² (range: 0.56-2.1). Heart failure etiologies requiring support were dilated cardiomyopathy (n = 8), myocarditis (n = 1), congenital mitral valve disease (n = 1), and single ventricle heart failure (n = 1). Median time from cardiac ICU admission for heart failure to HVAD placement was 15 days (range 3-55), based on standardized VAD implantation criteria involving imaging assessment and noncardiac organ evaluation. The majority of patients (91%) were INTERMACS Level 2 at time of implant. Three patients (27%) had CentriMag RVAD placement at time of HVAD implantation. Two of these three patients had successful RVAD explanation within 2 weeks. Median length of HVAD support was 60 days (range 6-405 days). Among the 11 patients, survival during HVAD therapy to date is 91% (10/11) with 9 (82%) bridged to heart transplantation and one (9%) continuing to receive support. Posttransplant survival has been 100%, with median follow-up of 573 days (range 152-1126). A systematic approach to HVAD implantation can provide excellent results in pediatric heart failure management for a variety of etiologies and broad BSA range.

Outcomes and Trends of Ventricular Assist Device Selection in Children with End-Stage Heart Failure

We aimed to examine trends in ventricular assist device (VAD) selection, continuous flow devices (CFD) versus pulsatile flow devices (PFD), and their associated outcomes in children eligible for both device types. To accomplish this, the United Network for Organ Sharing database was reviewed for pediatric patients listed for heart transplant (HT) from January 2007 to June 2014. Patients were included if a durable VAD was present at wait listing or when removed from the waiting list and who met size eligibility for a CFD (BSA > 1.0 m). In total, 253 patients met inclusion criteria, 144 (57%) CFD and 109 (43%) PFD. Device type varied significantly based on year with CFD increasing from 11% in 2007 to 88% in 2014 (p < 0.01). PFD patients were younger, had a lower BSA, and an increased rate of extracorporeal membrane oxygenation and biventricular assist device support at listing. Survival to transplant or recovery was similar for CFDs and PFDs (96 vs. 94%; p = 0.57), as was the post-HT survival, 95% for both device types. Despite PFD patients having more risk factors for a poor outcome, survival was similar between device types. Even so, there is a dramatic trend toward CFD utilization in patients who are large enough to support one.

Role of paediatric assist device in bridge to transplant

Background

While heart transplantation has gained recognition as the gold standard therapy for advanced heart failure, the scarcity of donor organs has become an important concern. The evolution of surgical alternatives such as ventricular assist devices (VADs), allow for recovery of the myocardium and ensure patient survival until heart transplantation becomes possible. This report elaborates the role of VADs as a bridge to heart transplantation in infants and children (≤18 years old) with end-stage heart failure.

Methods

A retrospective review of the medical records of 201 heart transplant recipients between May 1986 and September 2014 identified 78 children [38.8%; mean age 7.2 (7.8±6.0) years old; IQR: 2.6-11.8 years] with advanced heart failure who were supported with a VAD [left VAD (LVAD) =21; biventricular VAD (BVAD) =57] as a bridge to heart transplantation. Fourteen (17.9%) patients were less than 1 year old; 15 (19.2%) children had a cardiac arrest and underwent cardiopulmonary resuscitation, with 7 of these patients also requiring extracorporeal membrane oxygenation (ECMO) support prior to implantation of a VAD. The aetiology of heart failure was primarily cardiomyopathy (dilative, restrictive from endocardial fibrosis, idiopathic or toxic-induced), reported in 56 (71.8%) patients. The VADs employed were primarily Berlin Heart EXCOR^® (n=63), HeartWare (n=13), Berlin Heart INCOR^® (n=1), and Toyobo (n=1).

Results

Mean duration of VAD support was 59 (133.37±191.57) days (range, 1-945 days; IQR: 23-133 days) before a donor heart became available. The primary complication encountered while patients were being bridged to transplant was mediastinal bleeding (7.8%). The main indication for pump exchanges was thrombus formation in the valves. There was no incidence of technical failure of the blood pump or driving system components. Skin infections around the cannulae occurred in 2.5%. Adverse neurological symptoms (thromboembolism 11.1%, cerebral haemorrhage 3.6%) that occurred did not have any permanent neurological sequelae that could be detected on clinical examination in this study. Mean duration of follow-up was 9.4 (10.3±7.6) years (IQR: 3.74-15.14 years). Cumulative survival rates of patients bridged to transplantation with VAD were 93.6%±2.8%, 84.6%±4.1%, 79.1%±4.7%, 63.8%±6.2%, 61.6%±7.1%, and 52.1%±9.3% at 30 days, 1, 5, 10, 15 and 20 years, respectively. There was no statistically significant difference (P=0.79) in survival rates of patients bridged to heart transplantation with VAD compared to those who underwent primary heart transplantation. Post-transplant survival rates stratified according to the type of VAD implanted and number of ventricles supported were not statistically different (P=0.93 and 0.73, respectively). In addition, post-transplant survival rates were not significantly different when age, gender and diagnosis were adjusted for. Furthermore, no statistically significant difference was found when post-transplant survival rates of children who had episodes of rejection were compared to those who did not have episodes of rejection.

Conclusions

The results in this series demonstrate that VADs satisfactorily support paediatric patients with advanced heart failure from a variety of aetiologies until heart transplantation. The data further suggests that patients bridged with VADs have comparable long-term post-transplant survival as those undergoing primary heart transplantation.

Functional status of United States children supported with a left ventricular assist device at heart transplantation

BACKGROUND

As survival with pediatric left ventricular assist devices (LVADs) has improved, decisions regarding the optimal support strategy may depend more on quality of life and functional status (FS) rather than mortality alone. Limited data are available regarding the FS of children supported with LVADs. We sought to compare the FS of children supported with LVADs vs vasoactive infusions to inform decision making around support strategies.

METHODS

Organ Procurement and Transplant Network data were used to identify all United States children aged between 1 and 21 years at heart transplant (HT) between 2006 and 2015 for dilated cardiomyopathy and supported with an LVAD or vasoactive infusions alone at HT. FS was measured using the 10-point Karnofsky and Lansky scale.

RESULTS

Of 701 children who met the inclusion criteria, 430 (61%) were supported with vasoactive infusions, and 271 (39%) were supported with an LVAD at HT. Children in the LVAD group had higher median FS scores at HT than children in the vasoactive infusion group (6 vs 5, p < 0.001) but lower FS scores at listing (4 vs 6, p < 0.001). The effect persisted regardless of patient location at HT (home, hospital, intensive care) or device type. Discharge by HT occurred in 46% of children in the LVAD group compared with 26% of children in the vasoactive infusion cohort (p = 0.001). Stroke was reported at HT in 3% of children in the LVAD cohort and in 1% in the vasoactive infusion cohort (p = 0.04).

CONCLUSIONS

Among children with dilated cardiomyopathy undergoing HT, children supported with LVADs at HT have higher FS than children supported with vasoactive infusions at HT, regardless of device type or hospitalization status. Children supported with LVADs at HT were more likely to be discharged from the hospital but had a higher prevalence of stroke at HT.