Heart Transplantation in Muscular Dystrophy Patients: Is it a Viable Option?

Is Cardiac Transplantation Still a Contraindication in Patients with Muscular Dystrophy-Related End-Stage Dilated Cardiomyopathy? A Systematic Review

Inherited muscular diseases (MDs) are genetic degenerative disorders typically caused by mutations in a single gene that affect striated muscle and result in progressive weakness and wasting in affected individuals. Cardiac muscle can also be involved with some variability that depends on the genetic basis of the MD (Muscular Dystrophy) phenotype. Heart involvement can manifest with two main clinical pictures: left ventricular systolic dysfunction with evolution towards dilated cardiomyopathy and refractory heart failure, or the presence of conduction system defects and serious life-threatening ventricular arrhythmias. The two pictures can coexist. In these cases, heart transplantation (HTx) is considered the most appropriate option in patients who are not responders to the optimized standard therapeutic protocols. However, cardiac transplant is still considered a relative contraindication in patients with inherited muscle disorders and end-stage cardiomyopathies. High operative risk related to muscle impairment and potential graft involvement secondary to the underlying myopathy have been the two main reasons implicated in the generalized reluctance to consider cardiac transplant as a viable option. We report an overview of cardiac involvement in MDs and its possible association with the underlying molecular defect, as well as a systematic review of HTx outcomes in patients with MD-related end-stage dilated cardiomyopathy, published so far in the literature.

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.

Heart transplantation in muscular dystrophy: Single-center analysis

INTRODUCTION

Cardiac involvement may occur in many forms of muscular dystrophy (MD). While cardiac disease may progress to warrant heart transplantation (HTx), there may be contraindications related to extra-cardiac disease including pulmonary and skeletal muscle involvement that limit overall survival and impairs post-transplant rehabilitation efforts. This study describes the MD HTx experience at a single high-volume center.

METHODS

We examined the clinical characteristics and outcomes of patients with MD with heart failure (HF) (n = 28), patients with MD status post HTx (n = 20) and non-MD HTx control group (n = 40) matched 2:1 for age at transplant, sex, listing status, and antibody sensitization.

RESULTS

Patients with MD who underwent HTx had increased ventilator days (2 vs 1 days, p = 0.013), increased hospital length of stay (20 vs 12 days, p = 0.022), and increased discharge to inpatient rehab (60% vs 8%, p<0.001). By one year post HTx, patients with MD more often required assistive devices for walking (55% vs 10%, p = 0.01). Nonetheless, post-HTx survival was similar at 1 year (100% vs 97.5%, p = 0.48) and 5 years (95.0% vs 87.5%, p = 0.36). Of the HTx recipients with MD, 95% were followed by a neurologist, 60% by a neuromuscular specialist as part of the Muscular Dystrophy Association Clinic at our center.

CONCLUSION

Transplantation is a feasible option for patients with MD and advanced heart failure. MD patients who undergo transplantation may benefit from multidisciplinary specialized care to optimize MD-related morbidity. This article is protected by copyright. All rights reserved.

Mid-Term Outcomes of Heart Transplantation in Children with Genetic Disorders

BACKGROUND

Many congenital heart diseases (CHD) are associated with genetic defects. Children with complex CHD often develop heart failure, requiring heart transplant. Given the broad spectrum of genetic pathologies and dearth of transplants performed in these children, little is known regarding their outcomes.

METHODS

We conducted a retrospective review of heart transplants performed at a high-volume center from 2007-2021. Patients were separated into pathogenic molecular and copy number variants, aneuploidies, and variants of uncertain significance, and compared to those without known genetic diagnoses. Variables included genetic diagnoses, bridge-to-transplant approach, preoperative comorbidities, operative characteristics, and postoperative complications. Outcomes included ICU-free days to 28 days, hospital mortality, survival, rejection, re-transplantation, and educational status at latest follow-up.

RESULTS

223 patients were transplanted over the study period: 9.9% (22/223) had pathogenic molecular variants, 4.5% (10/223) had copy number variants, 1.8% (4/223) had aneuploidies, and 9.0% (20/223) had variants of uncertain significance. The most common anomalies were Turner syndrome (n=3) and 22q11.2 deletion syndrome (n=2). Children with aneuploidies had higher rates of hepatic dysfunction and hypothyroidism, while those with pathogenic copy number variants had higher rates of preoperative gastrostomy and stroke. Children with aneuploidies were intubated longer post-transplant, with greater need for re-intubation, and had the fewest ICU-free days. Mortality and mean survival did not differ. At median follow-up of 4.4 (1.9-8.8) years, 89.7% (26/29) of survivors with pathogenic anomalies were attending or had graduated school.

CONCLUSIONS

Despite more preoperative comorbidities, mid-term outcomes following heart transplant in children with genetic syndromes and disorders are promising.

Current Practices in Treating Cardiomyopathy and Heart Failure in Duchenne Muscular Dystrophy (DMD): Understanding Care Practices in Order to Optimize DMD Heart Failure Through ACTION

Cardiac disease has emerged as a leading cause of mortality in Duchenne muscular dystrophy in the current era. This survey sought to identify the diagnostic and therapeutic approach to DMD among pediatric cardiologists in Advanced Cardiac Therapies Improving Outcomes Network. Pediatric cardiology providers within ACTION (a multi-center pediatric heart failure learning network) were surveyed regarding their approaches to cardiac care in DMD. Thirty-one providers from 23 centers responded. Cardiac MRI and Holter monitoring are routinely obtained, but the frequency of use and indications for ordering these tests varied widely. Angiotensin converting enzyme inhibitor and aldosterone antagonist are generally initiated prior to onset of systolic dysfunction, while the indications for initiating beta-blocker therapy vary more widely. Seventeen (55%) providers report their center has placed an implantable cardioverter defibrillator in at least 1 DMD patient, while 11 providers (35%) would not place an ICD for primary prevention in a DMD patient. Twenty-three providers (74%) would consider placement of a ventricular assist device (VAD) as destination therapy (n = 23, 74%) and three providers (10%) would consider a VAD only as bridge to transplant. Five providers (16%) would not consider VAD at their institution. Cardiac diagnostic and therapeutic approaches vary among ACTION centers, with notable variation present regarding the use of advanced therapies (ICD and VAD). The network is currently working to harmonize medical practices and optimize clinical care in an era of rapidly evolving outcomes and cardiac/skeletal muscle therapies.

Acute heart failure and bradyarrhythmia in a young male—what hides beneath the surface?: a case report

Background

Muscular dystrophies (MDs) are characterized by early-onset muscular atrophy and weakness, with frequent cardiac involvement. Myocardial dysfunction and conduction system involvement are often rapidly progressive despite medical and device therapy, and may even precede muscular symptoms, posing a challenge to diagnosis.

Case summary

We report a case of a young male admitted to a cardiac intensive care unit due to ‘de novo’ acute heart failure (HF) and atrial flutter with a slow ventricular response. Careful evaluation of past medical history revealed the presence of neuromuscular symptoms since childhood, disregarded throughout adult age. Diagnostic workup allowed to establish a diagnosis of non-dilated hypokinetic cardiomyopathy secondary to Emery-Dreifuss MD, due to lamin A/C (LMNA) gene mutation. Our patient was treated with neurohormonal modulation therapy and a cardiac resynchronization therapy defibrillator (CRT-D) was implanted, but due to worsening advanced HF, cardiac transplantation was needed.

Discussion

Association of skeletal muscle and cardiac symptoms should always raise the suspicion for an underlying MD, since the consequences of a missed diagnosis are often dramatic. A timely diagnosis is crucial to prevent sudden death due to arrhythmias in these patients and to delay the progressive course of cardiomyopathy.

Is heart transplantation a real option in patients with Duchenne syndrome? Inferences from a case report

Duchenne muscular dystrophy (DMD) is the most frequent and severe form of MD. It firstly affects the skeletal muscles, causing severe disability, and subsequently the myocardium. The only two options to treat end‐stage heart failure in these patients are either a left ventricular assist device (LVAD) implantation as destination therapy or a heart transplant. These hypotheses are still controversial, and data are very limited. We describe the case of an 18‐year‐old male patient, affected by DMD and in a wheelchair from the age of 11. He progressively developed dilated cardiomyopathy, and in 2016, at the age of 14 years, he underwent HeartWare LVAD implantation, as destination therapy, without post‐operative complications. He has been followed up for 47 consecutive months; and 30 months after LVAD implantation, he developed an infection of the exit site, treated by antibiotics and surgical toilette. Following this event, on the basis of patient's good general conditions and willingness, we started to consider heart transplant as an option. Before the patient was listed, he underwent accurate workup, and we found higher values of forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow, compared with the predicted values of same‐age DMD patients. The patient have neither scoliosis nor need for non‐invasive mechanical ventilation, and finally, he was always treated with steroids with stable thoraco‐abdominal function over the years. According to these considerations, the patient was listed for heart transplant. In 12 February 2020, at the age of 18 years, the patient underwent heart transplant with no post‐operative complications. Cardiac transplantation is not considered a valid option for DMD patients, because of the shortage of donor availability and the systemic nature of DMD disease. Considering that this patient had already experienced an LVAD‐related complication and he had better general condition than his DMD peers, we listed him for a heart transplant. We described the case of a DMD patient who underwent successful heart transplantation after 47 months of HeartWare LVAD assistance. Three months' follow‐up is uneventful.