Implantation of a left ventricular assist device as a destination therapy in Duchenne muscular dystrophy patients with end stage cardiac failure: management and lessons learned

Initial multicenter experience with ventricular assist devices in children and young adults with muscular dystrophy: An ACTION registry analysis

PURPOSE

Cardiac disease results in significant morbidity and mortality in patients with muscular dystrophy (MD). Single centers have reported their ventricular assist device (VAD) experience in specific MDs and in limited numbers. This study sought to describe the outcomes associated with VAD therapy in an unselected population across multiple centers.

METHODS

We examined outcomes of patients with MD and dilated cardiomyopathy implanted with a VAD at Advanced Cardiac Therapies Improving Outcomes Network (ACTION) centers from 9/2012 to 9/2020.

RESULTS

A total of 19 VADs were implanted in 18 patients across 12 sites. The majority of patients had dystrophinopathy (66%) and the median age at implant was 17.2 years (range 11.7-29.5). Eleven patients were non-ambulatory (61%) and 6 (33%) were on respiratory support pre-VAD. Five (28%) patients were implanted as a bridge to transplant, 4 of whom survived to transplant. Of 13 patients implanted as bridge to decision or destination therapy, 77% were alive at 1 year and 69% at 2 years. The overall frequencies of positive outcome (transplanted or alive on device) at 1 year and 2 years were 84% and 78%, respectively. Two patients suffered a stroke, 2 developed sepsis, 1 required tracheostomy, and 1 experienced severe right heart failure requiring right-sided VAD.

CONCLUSIONS

This study demonstrates the potential utility of VAD therapies in patients with muscular dystrophy. Further research is needed to further improve outcomes and better determine which patients may benefit most from VAD therapy in terms of survival and quality of life.

Right Ventricular Function and T1-Mapping in Boys With Duchenne Muscular Dystrophy

BACKGROUND

Clinical management of boys with Duchenne muscular dystrophy (DMD) relies on in-depth understanding of cardiac involvement, but right ventricular (RV) structural and functional remodeling remains understudied.

PURPOSE

To evaluate several analysis methods and identify the most reliable one to measure RV pre- and postcontrast T1 (RV-T1) and to characterize myocardial remodeling in the RV of boys with DMD.

STUDY TYPE

Prospective.

POPULATION

Boys with DMD (N = 27) and age-/sex-matched healthy controls (N = 17) from two sites.

FIELD STRENGTH/SEQUENCE

3.0 T using balanced steady state free precession, motion-corrected phase sensitive inversion recovery and modified Look-Locker inversion recovery sequences.

ASSESSMENT

Biventricular mass (Mi), end-diastolic volume (EDVi) and ejection fraction (EF) assessment, tricuspid annular excursion (TAE), late gadolinium enhancement (LGE), pre- and postcontrast myocardial T1 maps. The RV-T1 reliability was assessed by three observers in four different RV regions of interest (ROI) using intraclass correlation (ICC).

STATISTICAL TESTS

The Wilcoxon rank sum test was used to compare RV-T1 differences between DMD boys with negative LGE(-) or positive LGE(+) and healthy controls. Additionally, correlation of precontrast RV-T1 with functional measures was performed. A P-value <0.05 was considered statistically significant.

RESULTS

A 1-pixel thick RV circumferential ROI proved most reliable (ICC > 0.91) for assessing RV-T1. Precontrast RV-T1 was significantly higher in boys with DMD compared to controls. Both LGE(-) and LGE(+) boys had significantly elevated precontrast RV-T1 compared to controls (1543 [1489-1597] msec and 1550 [1402-1699] msec vs. 1436 [1399-1473] msec, respectively). Compared to healthy controls, boys with DMD had preserved RVEF (51.8 [9.9]% vs. 54.2 [7.2]%, P = 0.31) and significantly reduced RVMi (29.8 [9.7] g vs. 48.0 [15.7] g), RVEDVi (69.8 [29.7] mL/m² vs. 89.1 [21.9] mL/m² ), and TAE (22.0 [3.2] cm vs. 26.0 [4.7] cm). Significant correlations were found between precontrast RV-T1 and RVEF (β = -0.48%/msec) and between LV-T1 and LVEF (β = -0.51%/msec).

DATA CONCLUSION

Precontrast RV-T1 is elevated in boys with DMD compared to healthy controls and is negatively correlated with RVEF.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 2.

Is there a future for the use of left ventricular assist devices in Duchenne muscular dystrophy?

Duchenne muscular dystrophy (DMD) is the most common form of childhood muscular dystrophy resulting in progressive muscle wasting and weakness. With advancements in respiratory care and the use of glucocorticoids, cardiomyopathy has surpassed respiratory compromise as the leading cause of morbidity and mortality in this patient population. As muscular dystrophy remains a relative contraindication to heart transplantation, end-stage heart failure management represents a major therapeutic challenge. Long-term left ventricular assist device (LVAD) therapy has emerged as a promising management strategy to improve the survival and quality of life in DMD cardiomyopathy. Preoperative planning, optimal patient selection, aggressive postoperative rehabilitation, and continued discussion of goals of care are critical considerations for the appropriate use of LVAD in DMD patients with cardiomyopathy.

Duchenne Muscular Dystrophy: the Heart of the Matter

PURPOSE OF REVIEW

Duchenne muscular dystrophy is one of many neuromuscular disorders, but it frequently causes severe disability early in life and early death. Cardiac involvement is an important cause of morbidity and mortality.

RECENT FINDINGS

Heart disease in Duchenne muscular dystrophy can include a cardiomyopathy leading to end-stage heart failure along with associated supraventricular and ventricular arrhythmias. This article reviews the diagnosis and treatment of heart disease in Duchenne muscular dystrophy as well as emerging therapies.

Muscle and cardiac therapeutic strategies for Duchenne muscular dystrophy: past, present, and future

BACKGROUND

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration and results in functional decline, loss of ambulation and early death of young men due to cardiac or respiratory failure. Although the major cause of the disease has been known for many years-namely mutation in the DMD gene encoding dystrophin, one of the largest human genes-DMD is still incurable, and its treatment is challenging.

METHODS

A comprehensive and systematic review of literature on the gene, cell, and pharmacological experimental therapies aimed at restoring functional dystrophin or to counteract the associated processes contributing to disease progression like inflammation, fibrosis, calcium signaling or angiogenesis was carried out.

RESULTS

Although some therapies lead to satisfying effects in skeletal muscle, they are highly ineffective in the heart; therefore, targeting defective cardiac and respiratory systems is vital in DMD patients. Unfortunately, most of the pharmacological compounds treat only the symptoms of the disease. Some drugs addressing the underlying cause, like eteplirsen, golodirsen, and ataluren, have recently been conditionally approved; however, they can correct only specific mutations in the DMD gene and are therefore suitable for small sub-populations of affected individuals.

CONCLUSION

In this review, we summarize the possible therapeutic options and describe the current status of various, still imperfect, strategies used for attenuating the disease progression.

Duchenne Dilated Cardiomyopathy: Cardiac Management from Prevention to Advanced Cardiovascular Therapies

Duchenne muscular dystrophy (DMD) cardiomyopathy (DCM) is characterized by a hypokinetic, dilated phenotype progressively increasing with age. Regular cardiac care is crucial in DMD care. Early recognition and prophylactic use of angiotensin converting enzyme inhibitors (ACEi) are the main stay therapeutic strategy to delay incidence of DMD-DCM. Pharmacological treatment to improve symptoms and left ventricle (LV) systolic function, have been widely implemented in the past years. Because of lack of DMD specific drugs, actual indications for established DCM include current treatment for heart failure (HF). This review focuses on current HF strategies to identify, characterize, and treat DMD-DCM.

Palliative Care Engagement for Pediatric Ventricular Assist Device Patients: A Single-Center Experience

Outcomes in pediatric patients with ventricular assist devices (VADs) for advanced heart failure (HF) are improving, but the risk of associated morbidity and mortality remains substantial. Few data exist on the involvement of pediatric palliative care (PPC) in this high-risk patient population. We aimed to characterize the extent of palliative care involvement in the care of patients requiring VAD placement at our institution. Single-center retrospective chart review analyzing all VAD patients at a large pediatric center over a 4 year period. Timing and extent of palliative care subspecialty involvement were analyzed. Between January 2014 and December 2017, 55 HF patients underwent VAD implantation at our institution. Pediatric palliative care utilization steadily increased over consecutive years (2014: <10% of patients, 2015: 20% of patients, 2016: 50% of patients, and 2017: 65% of patients) and occurred in 42% (n = 23) of all patients. Of these, 57% (n = 13) occurred before VAD placement while 43% (n = 10) occurred after implantation. Patients who died during their VAD implant hospitalization (24%, n = 13) were nearly twice as likely to have PPC involvement (62%) as those who reached transplant (38%). Of those who died, patients who had PPC involved in their care were more likely to limit resuscitation efforts before their death. Four patients had advanced directives in place before VAD implant, of which three had PPC consultation before device placement. Three families (5%) refused PPC involvement when offered. Pediatric palliative care utilization is increasing in VAD patients at our institution. Early PPC involvement occurred in the majority of patients and appears to lead to more frequent discussion of goals-of-care and advanced directives.

Advances in Stem Cell Modeling of Dystrophin-Associated Disease: Implications for the Wider World of Dilated Cardiomyopathy

Familial dilated cardiomyopathy (DCM) is mostly caused by mutations in genes encoding cytoskeletal and sarcomeric proteins. In the pediatric population, DCM is the predominant type of primitive myocardial disease. A severe form of DCM is associated with mutations in the DMD gene encoding dystrophin, which are the cause of Duchenne Muscular Dystrophy (DMD). DMD-associated cardiomyopathy is still poorly understood and orphan of a specific therapy. In the last 5 years, a rise of interest in disease models using human induced pluripotent stem cells (hiPSCs) has led to more than 50 original studies on DCM models. In this review paper, we provide a comprehensive overview on the advances in DMD cardiomyopathy disease modeling and highlight the most remarkable findings obtained from cardiomyocytes differentiated from hiPSCs of DMD patients. We will also describe how hiPSCs based studies have contributed to the identification of specific myocardial disease mechanisms that may be relevant in the pathogenesis of DCM, representing novel potential therapeutic targets.

Destination-Therapy Ventricular Assist Device in Children: "The Future Is Now"

Durable ventricular assist devices (VADs) have significantly improved survival to transplantation among children with advanced stages of heart failure. The fundamental goals of VAD therapy include decreasing mortality, minimizing adverse events, and improving quality of life. As the pediatric VAD experience has evolved with reduced device related complications and improved survival, VAD therapy is being considered not only as a bridge to transplantation (BTT) but also as a bridge to decision (BTD) and as destination therapy (DT). Data regarding pediatric DT VAD are limited to anecdotal or case reports of children being supported for long periods with VADs and by default being classified as DT VAD. This article reviews current trends in the use of DT VAD and adverse events in children vs adults on VAD, and provides a framework for patient selection with the use of a multidisciplinary approach including palliative care. The general approach to determining DT VAD candidacy should include: 1) a reasonable success that the patient will survive the peri- and postoperative state; and 2) a high likelihood that the patient will be able to be discharged out of hospital and have adequate caregiver support. Patients with muscular dystrophy and failing Fontan physiology are examples of pediatric populations for whom DT VAD may be considered and which require unique considerations.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

Pediatric Ventricular Assist Device

There have been great advances in ventricular assist device (VAD) treatment for pediatric patients with advanced heart failure. VAD support provides more time for the patient in the heart transplant waiting list. Augmented cardiac output improves heart failure symptoms, end-organ function, and general condition, and consequently provides beneficial effects on post-transplant outcomes. Miniaturized continuous flow devices are more widely adopted for pediatric patient with promising results. For infants and small children, still paracorporeal pulsatile device is the only option for long-term support. Younger age, congenital heart disease, biventricular support, patient's status and end-organ dysfunction at the time of implantation are risks for poor outcomes. Patient selection, timing of implantation, and selection of device for each patient are critical for optimal clinical outcomes.

Interventions for preventing and treating cardiac complications in Duchenne and Becker muscular dystrophy and X-linked dilated cardiomyopathy

BACKGROUND

The dystrophinopathies include Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and X-linked dilated cardiomyopathy (XLDCM). In recent years, co-ordinated multidisciplinary management for these diseases has improved the quality of care, with early corticosteroid use prolonging independent ambulation, and the routine use of non-invasive ventilation signficantly increasing survival. The next target to improve outcomes is optimising treatments to delay the onset or slow the progression of cardiac involvement and so prolong survival further.

OBJECTIVES

To assess the effects of interventions for preventing or treating cardiac involvement in DMD, BMD, and XLDCM, using measures of change in cardiac function over six months.

SEARCH METHODS

On 16 October 2017 we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE and Embase, and on 12 December 2017, we searched two clinical trials registries. We also searched conference proceedings and bibliographies.

SELECTION CRITERIA

We considered only randomised controlled trials (RCTs), quasi-RCTs and randomised cross-over trials for inclusion. In the Discussion, we reviewed open studies, longitudinal observational studies and individual case reports but only discussed studies that adequately described the diagnosis, intervention, pretreatment, and post-treatment states and in which follow-up lasted for at least six months.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed the titles and abstracts identified from the search and performed data extraction. All three authors assessed risk of bias independently, compared results, and decided which trials met the inclusion criteria. They assessed the certainty of evidence using GRADE criteria.

MAIN RESULTS

We included five studies (N = 205) in the review; four studies included participants with DMD only, and one study included participants with DMD or BMD. All studied different interventions, and meta-analysis was not possible. We found no studies for XLDCM. None of the trials reported cardiac function as improved or stable cardiac versus deteriorated.The randomised first part of a two-part study of perindopril (N = 28) versus placebo (N = 27) in boys with DMD with normal heart function at baseline showed no difference in the number of participants with a left ventricular ejection fraction (LVEF%) of less than 45% after three years of therapy (n = 1 in each group; risk ratio (RR) 1.04, 95% confidence interval (CI) 0.07 to 15.77). This result is uncertain because of study limitations, indirectness and imprecision. In a non-randomised follow-up study, after 10 years, more participants who had received placebo from the beginning had reduced LVEF% (less than 45%). Adverse event rates were similar between the placebo and treatment groups (low-certainty evidence).A study comparing treatment with lisinopril versus losartan in 23 boys newly diagnosed with Duchenne cardiomyopathy showed that after 12 months, both were equally effective in preserving or improving LVEF% (lisinopril 54.6% (standard deviation (SD) 5.19), losartan 55.2% (SD 7.19); mean difference (MD) -0.60% CI -6.67 to 5.47: N = 16). The certainty of evidence was very low because of very serious imprecision and study limitations (risk of bias). Two participants in the losartan group were withdrawn due to adverse events: one participant developed an allergic reaction, and a second exceeded the safety standard with a fall in ejection fraction greater than 10%. Authors reported no other adverse events related to the medication (N = 22; very low-certainty evidence).A study comparing idebenone versus placebo in 21 boys with DMD showed little or no difference in mean change in cardiac function between the two groups from baseline to 12 months; for fractional shortening the mean change was 1.4% (SD 4.1) in the idebenone group and 1.6% (SD 2.6) in the placebo group (MD -0.20%, 95% CI -3.07 to 2.67, N = 21), and for ejection fraction the mean change was -1.9% (SD 9.8) in the idebenone group and 0.4% (SD 5.5) in the placebo group (MD -2.30%, 95% CI -9.18 to 4.58, N = 21). The certainty of evidence was very low because of study limitations and very serious imprecision. Reported adverse events were similar between the treatment and placebo groups (low-certainty evidence).A multicentre controlled study added eplerenone or placebo to 42 patients with DMD with early cardiomyopathy but preserved left ventricular function already established on ACEI or ARB therapy. Results showed that eplerenone slowed the rate of decline of magnetic resonance (MR)-assessed left ventricular circumferential strain at 12 months (eplerenone group median 1.0%, interquartile range (IQR) 0.3 to -2.2; placebo group median 2.2%, IQR 1.3 to -3.1%; P = 0.020). The median decline in LVEF over the same period was also less in the eplerenone group (-1.8%, IQR -2.9 to 6.0) than in the placebo group (-3.7%, IQR -10.8 to 1.0; P = 0.032). We downgraded the certainty of evidence to very low for study limitations and serious imprecision. Serious adverse events were reported in two patients given placebo but none in the treatment group (very low-certainty evidence).A randomised placebo-controlled study of subcutaneous growth hormone in 16 participants with DMD or BMD showed an increase in left ventricular mass after three months' treatment but no significant improvement in cardiac function. The evidence was of very low certainty due to imprecision, indirectness, and study limitations. There were no clinically significant adverse events (very low-certainty evidence).Some studies were at risk of bias, and all were small. Therefore, although there is some evidence from non-randomised data to support the prophylactic use of perindopril for cardioprotection ahead of detectable cardiomyopathy, and for lisinopril or losartan plus eplerenone once cardiomyopathy is detectable, this must be considered of very low certainty. Findings from non-randomised studies, some of which have been long term, have led to the use of these drugs in daily clinical practice.

AUTHORS' CONCLUSIONS

Based on the available evidence from RCTs, early treatment with ACE inhibitors or ARBs may be comparably beneficial for people with a dystrophinopathy; however, the certainty of evidence is very low. Very low-certainty evidence indicates that adding eplerenone might give additional benefit when early cardiomyopathy is detected. No clinically meaningful effect was seen for growth hormone or idebenone, although the certainty of the evidence is also very low.

Cardiac Management of the Patient With Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) results in a progressive cardiomyopathy that produces significant morbidity and mortality. To improve the quality of life in patients with DMD, cardiac care is focused on surveillance and management, with the goal of slowing the onset and progression of heart failure complications. The current article is intended to be an expanded review on the cardiac management data used to inform the 2018 DMD Care Considerations recommendations as well as be a discussion on clinical controversies and future management directions. The new cardiac guidance includes changes regarding noninvasive imaging surveillance of cardiac function and pharmacologic therapy. Many emerging therapies lack sufficient evidence-based data to be recommended in the 2018 DMD Care Considerations. These are discussed in the present article as clinical controversies and future directions. Important emerging therapies include new heart failure medications, mechanical circulatory support with ventricular assist devices, heart transplantation, and internal cardiac defibrillators. Future research studies should be focused on the risks and benefits of these advanced therapies in patients with DMD. We conclude this review with a brief discussion on the relationship between the heart and the recently developed medications that are used to directly target the absence of dystrophin in DMD.

Dystrophin Cardiomyopathies: Clinical Management, Molecular Pathogenesis and Evolution towards Precision Medicine

Duchenne’s muscular dystrophy is an X-linked neuromuscular disease that manifests as muscle atrophy and cardiomyopathy in young boys. However, a considerable percentage of carrier females are often diagnosed with cardiomyopathy at an advanced stage. Existing therapy is not disease-specific and has limited effect, thus many patients and symptomatic carrier females prematurely die due to heart failure. Early detection is one of the major challenges that muscular dystrophy patients, carrier females, family members and, research and medical teams face in the complex course of dystrophic cardiomyopathy management. Despite the widespread adoption of advanced imaging modalities such as cardiac magnetic resonance, there is much scope for refining the diagnosis and treatment of dystrophic cardiomyopathy. This comprehensive review will focus on the pertinent clinical aspects of cardiac disease in muscular dystrophy while also providing a detailed consideration of the known and developing concepts in the pathophysiology of muscular dystrophy and forthcoming therapeutic options.

Cardiac Involvement Classification and Therapeutic Management in Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an inherited myogenic disorder due to mutations in the dystrophin gene on chromosome Xp21.1. The clinical picture included peripheral muscle weakness, cardiomyopathy and chronic respiratory insufficiency. In this paper, the authors review cardiac involvement in patients with DMD, propose a cardiac impairment classification and discuss therapeutic management options.

Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management

A coordinated, multidisciplinary approach to care is essential for optimum management of the primary manifestations and secondary complications of Duchenne muscular dystrophy (DMD). Contemporary care has been shaped by the availability of more sensitive diagnostic techniques and the earlier use of therapeutic interventions, which have the potential to improve patients' duration and quality of life. In part 2 of this update of the DMD care considerations, we present the latest recommendations for respiratory, cardiac, bone health and osteoporosis, and orthopaedic and surgical management for boys and men with DMD. Additionally, we provide guidance on cardiac management for female carriers of a disease-causing mutation. The new care considerations acknowledge the effects of long-term glucocorticoid use on the natural history of DMD, and the need for care guidance across the lifespan as patients live longer. The management of DMD looks set to change substantially as new genetic and molecular therapies become available.

Evolution of Biventricular Loading Condition in Pediatric LVAD Patient: A Prospective and Observational Study

The aim of this study was to describe the echocardiographic trend of left ventricular (LV) and right ventricular (RV) function after implantation of a pulsatile flow left ventricular assist device (LVAD) in children. From 2013 to 2016, we prospectively evaluated 13 consecutive pediatric Berlin Heart EXCOR LVAD patients. Clinical and echocardiographic data were collected at baseline, within 24 h after implantation and monthly until LVAD explant. Median age and weight at the implantation was 8 (4-23) months and 5 (4.6-8.3) kg at the time of implantation, respectively. All were affected by dilated cardiomyopathy. Average LVAD support time was 226.2 ± 121.2 days. Nine (70%) were transplanted, 4 (30%) died. LV end-systolic and end-diastolic volumes were reduced until the follow up of two months (P = 0.019 and P = 0.001). A progressive increase in RV dimensions was observed. After 4 months of follow up, RV fractional area change worsening was statistically related with the deterioration of LV unloading (P = 0.0036). Four patients needed prolonged inotropic support for RV failure. Pulsatile LVAD in pediatrics is followed by an early and mid-term LV unloading, as expressed by a decrease in LV volumes and diameters at echocardiogram. The effects of unloading do not remain stable at long term follow up. RV function improved in the acute phase, but a progressive dilatation of RV was noted over time. In some patients, RV failure might lead to the need of an increase of inotropic support at long term follow up.

Talking with caregivers of children living in the community with ventricular assist devices

A VAD is a mechanical pump used to support the functioning of a failing heart. As a pediatric therapy, a VAD is used as a temporary solution for poor heart function, a bridge to transplantation or recovery, or a destination therapy. The goal of this qualitative study was to explore the perspectives of family and professional caregivers of children who are supported by VADs in outpatient settings. Semi-structured interviews were conducted with 22 caregivers of school-aged children discharged home on VAD support. Interviews were transcribed, and data were analyzed using qualitative content analysis. Caregivers identified issues facing children on VAD support in the contexts of home, school, and other childhood places including being physically connected to a device; experiencing changes; living a medical life; negotiating restrictions; cost of care; family, kinship, and community; and, present and future living. While a child with a VAD may have much in common with other medically complex children, the technological complications and risks of living with a VAD are uniquely identified by caregivers as an issue, especially when considering the way that children with a VAD are connected to their device-implanted yet exterior, mobile yet restricted, and autonomous yet dependent.

A current approach to heart failure in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a genetic, progressive neuromuscular condition that is marked by the long-term muscle deterioration with significant implications of pulmonary and cardiac dysfunction. As such, end-stage heart failure (HF) in DMD is increasingly becoming the main cause of death in this population. The early detection of cardiomyopathy is often challenging, due to a long subclinical phase of ventricular dysfunction and difficulties in assessment of cardiovascular symptomatology in these patients who usually loose ambulation during the early adolescence. However, an early diagnosis of cardiovascular disease in patients with DMD is decisive since it allows a timely initiation of cardioprotective therapies that can mitigate HF symptoms and delay detrimental heart muscle remodelling. Echocardiography and ECG are standardly used for screening and detection of cardiovascular abnormalities in these patients, although these tools are not always adequate to detect an early, clinically asymptomatic phases of disease progression. In this regard, cardiovascular magnetic resonance (CMR) with late gadolinium enhancement is emerging as a promising method for the detection of early cardiac involvement in patients with DMD. The early detection of cardiac dysfunction allows the therapeutic institution of various classes of drugs such as corticosteroids, beta-blockers, ACE inhibitors, antimineralocorticoid diuretics and novel pharmacological and surgical solutions in the multimodal and multidisciplinary care for this group of patients. This review will focus on these challenges and available options for HF in patients with DMD.

The Ventricular Assist Device in the Life of the Child: A Phenomenological Pediatric Study

What is it like for a child to live with an artificial heart? The use of some medical therapies in children requires developmental considerations, is associated with psychosocial consequences, and calls for ethical sensitivities. A critical case is the ventricular assist device (VAD), a mechanical pump used to support the functioning of a failing heart. As a pediatric therapy, the device can be used as a temporary solution for poor heart function, a bridge to transplantation or recovery, or as a destination therapy. While the mechanical-technical operation of the VAD is well understood, the clinical-technical aspects of young people living with this device are largely unexplored. Drawing on interviews of school-aged children, the aim of this phenomenological study is to explore how a VAD may structure or condition a child's meaningful experience of their world outside the hospital. The driveline of an implanted VAD is the peripheral attachment, extruding through the skin to connect the controller-power supply. The materiality of the device may be interruptive, restrictive, and disturbing to the psycho-physical being and sense of self-identity of the child as a child. And while a child equipped with a VAD is not necessarily conspicuous among other children, the child may experience the device as an exposing presence, while living with the worry of a caregiver who takes on the role not simply of parent but of watchful health professional. A phenomenological understanding of the VAD should assist parents and caregiving health professionals knowing how to deal with specific issues arising in the life of the VAD child.

Obesity and Premature Loss of Mobility in Two Adolescents with Becker Muscular Dystrophy After HeartMate II Implantation

Weight gain is common after implantation of continuous-flow ventricular assist devices. Obesity can have a significant negative impact on mobility. For adolescents with Becker muscular dystrophy (BMD), for whom the ability to ambulate often persists into the mid-3rd decade, preservation of functional ability is critical. We report two cases of Thoratec HeartMate II left ventricular assist device (LVAD) implantation in adolescents with BMD for whom postoperative weight gain contributed significantly to an accelerated loss of ambulation and, in one case, driveline fracture in the context of repeated falls. As LVADs become an increasingly common therapy for endstage heart failure in adolescents with BMD, care must be focused not only on maintenance of device functionality, but also on management of aggressive weight, and preservation of ambulation, and skeletal muscle strength.

X-Linked Dilated Cardiomyopathy: A Cardiospecific Phenotype of Dystrophinopathy

X-linked dilated cardiomyopathy (XLDCM) is a distinct phenotype of dystrophinopathy characterized by preferential cardiac involvement without any overt skeletal myopathy. XLDCM is caused by mutations of the Duchenne muscular dystrophy (DMD) gene and results in lethal heart failure in individuals between 10 and 20 years. Patients with Becker muscular dystrophy, an allelic disorder, have a milder phenotype of skeletal muscle involvement compared to Duchenne muscular dystrophy (DMD) and sometimes present with dilated cardiomyopathy. The precise relationship between mutations in the DMD gene and cardiomyopathy remain unclear. However, some hypothetical mechanisms are being considered to be associated with the presence of some several dystrophin isoforms, certain reported mutations, and an unknown dystrophin-related pathophysiological mechanism. Recent therapy for Duchenne muscular dystrophy, the severe dystrophinopathy phenotype, appears promising, but the presence of XLDCM highlights the importance of focusing on cardiomyopathy while elucidating the pathomechanism and developing treatment.