Successful heart transplantation in patients with inherited myopathies associated with end-stage cardiomyopathy

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.

Genetic disease and intellectual disability as contraindications to transplant listing in the United States: A survey of heart, kidney, liver, and lung transplant programs

Discrimination based on disability is prohibited in organ transplantation, yet studies suggest it continues in listing practices for intellectual disability and genetic diseases. It is not known if this differs between adult and pediatric programs, or by organ type. We performed an online, forced-choice survey of psychosocial listing criteria for adult and pediatric heart, kidney, liver, and lung transplant programs in the United States. Of 650 programs contacted, 343 (52.8%) submitted complete. A minority of programs had formal listing guidelines for any condition considered (Down Syndrome, Duchenne Muscular Dystrophy, Becker Muscular Dystrophy, DiGeorge Syndrome, and Wolf Hirschhorn Syndrome; and mild [IQ < 70] and severe [IQ < 35] intellectual disability), although a majority had encountered most. Pediatric programs were significantly (P < .02) more lenient in the level of contraindication to listing for all genetic conditions considered except Duchenne Muscular Dystrophy, and for mild and severe intellectual disability. Level of contraindication differed significantly by organ type (heart, lung, liver, and kidney) for Duchenne Muscular dystrophy (P = <.001), Becker Muscular Dystrophy (P < .001), DiGeorge Syndrome (P < .001), Wolf-Hirschhorn syndrome (P = .0012), and severe intellectual disability (P < .001). There is significant variation among transplant programs in availability of guidelines for as well as listing practices regarding genetic diseases and intellectual disability, differing by both adult vs pediatric program, and organ type. Programs with absolute contraindications to listing for specific genetic diseases or intellectual disability should reframe their approach, ensuring individualized assessments and avoiding elimination of patients based on membership in a particular group.

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.

Dystrophin-Deficient Cardiomyopathy

Dystrophinopathies are a group of distinct neuromuscular diseases that result from mutations in the structural cytoskeletal Dystrophin gene. Dystrophinopathies include Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), X-linked dilated cardiomyopathy, as well as DMD and BMD female carriers. The primary presenting symptom in most dystrophinopathies is skeletal muscle weakness. However, cardiac muscle is also a subtype of striated muscle and is similarly affected in many of the muscular dystrophies. Cardiomyopathies associated with dystrophinopathies are an increasingly recognized manifestation of these neuromuscular disorders and contribute significantly to their morbidity and mortality. Recent studies suggest that these patient populations would benefit from cardiovascular therapies, annual cardiovascular imaging studies, and close follow-up with cardiovascular specialists. Moreover, patients with DMD and BMD who develop end-stage heart failure may benefit from the use of advanced therapies. This review focuses on the pathophysiology, cardiac involvement, and treatment of cardiomyopathy in the dystrophic patient.

Heart transplantation in patients with dystrophinopathic cardiomyopathy: Review of the literature and personal series

Cardiomyopathy associated with dystrophinopathies [Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), X-linked dilated cardiomyopathy (XL-dCM) and cardiomyopathy of Duchenne/Becker (DMD/BMD) carriers] is an increasing recognized manifestation of these neuromuscular disorders and notably contributes to their morbidity and mortality. Dystrophinopathic cardiomyopathy (DCM) is the result of the dystrophin protein deficiency at the myocardium level, parallel to the deficiency occurring at the skeletal muscle level. It begins as a "presymptomatic" stage in the first decade of life and evolves in a stepwise manner toward pictures of overt cardiomyopathy (hypertrophic stage, arrhythmogenic stage and dilated cardiomyopathy). The final stage caused by the extensive loss of cardiomyocytes results in an irreversible cardiac failure, characterized by frequent episodes of acute congestive heart failure (CHF), despite a correct pharmacological treatment. The picture of a severe dilated cardiomyopathy with intractable heart failure is typical of BMD, XL-dCM and cardiomyopathy of DMD/BMD carriers, while it is less frequently observed in patients with DMD. Heart transplantation (HT) is the only curative therapy for patients with dystrophinopathic end-stage heart failure who remain symptomatic despite an optimal medical therapy. However, no definitive figures exist in literature concerning the number of patients with DCM transplanted, and their outcome. This overview is to summarize the clinical outcomes so far published on the topic, to report the personal series of dystrophinopathic patients receiving heart transplantation and finally to provide evidence that heart transplantation is a safe and effective treatment for selected patients with end-stage DCM.

Dilated cardiomyopathy with severe arrhythmias in Emery-Dreifuss muscular dystrophy: from ablation to heart transplantation

We present 38-years male patient. He has suffered from muscle weakness since 5 years. Arrhythmias appeared at the age of 32. In 37 years he had sick sinus syndrome, transient AV block II degree, paroxysmal atrial fibrillation, atrial flutter, ventricular arrhythmias. At this time, dilated cardiomyopathy was also detected. The evaluation revealed knees and elbows contractures, increased level of creatine kinase. The genetic testing revealed a frame shift deletion c.del619C in the emerin (EMD) gene and c.IVS4-13T> A in the lamin (LMNA) gene, and c.del619C deletion in the heterozygous state in a patient`s mother. Radiofrequency ablation of cavotricuspid isthmus, implantable cardioverter-defibrillator (ICD) implantation were performed. Heart transplantation was performed nine months later, due to severe heart failure and electrical storm. A morphological evaluation revealed sclerosis, atrophy and hypertrophy of cardiomyocytes. He underwent an induction therapy with (basiliximab) methylprednisolone, tacrolimus, mycophenolate after heart transplantation. During 40 months after transplantation, patient`s condition is satisfactory.

CONCLUSION

heart failure in Emery-Dreifuss muscular dystrophy can progress quickly unless the previously stable condition. The use of correct regimens of immunosuppression therapy provides good long-term results of the heart transplantation.

Cardiomyopathy in becker muscular dystrophy: Overview

Becker muscular dystrophy (BMD) is an X-linked recessive disorder involving mutations of the dystrophin gene. Cardiac involvement in BMD has been described and cardiomyopathy represents the number one cause of death in these patients. In this paper, the pathophysiology, clinical evaluations and management of cardiomyopathy in patients with BMD will be discussed.

Clinical outcomes after cardiac transplantation in muscular dystrophy patients

BACKGROUND

Patients with muscular dystrophy are at risk of developing a dilated cardiomyopathy and can progress to advanced heart failure. At present, it is not known whether such patients can safely undergo cardiac transplantation.

METHODS

This was a retrospective review of the Cardiac Transplant Research Database, a multi-institutional registry of 29 transplant centers in the United States, from the years 1990 to 2005. The post-cardiac transplant outcomes of 29 patients with muscular dystrophy were compared with 275 non-muscular dystrophy patients with non-ischemic cardiomyopathy, matched for age, body mass index, gender, and race.

RESULTS

Becker's muscular dystrophy was present in 52% of the patients. Survival in the muscular dystrophy patients was similar to the controls at 1 year (89% vs 91%; p = 0.5) and at 5 years (83% vs 78%; p = 0.5). The differences in rates of cumulative infection, rejection, or allograft vasculopathy between the 2 groups were not significant (p > 0.5 for all comparisons).

CONCLUSIONS

Recognizing the limitations of the present investigation (ie, selection bias and data lacking in the functional capacity of the muscular dystrophy patients), the current study suggests that the clinical outcomes after cardiac transplantation in selected patients with muscular dystrophy are similar to those seen in age-matched patients with non-ischemic cardiomyopathy.

Cardiac involvement in Becker muscular dystrophy

The present review gives an overview of the clinical and subclinical manifestations of cardiac involvement (CI) in Becker muscular dystrophy (BMD), its pathophysiological background, diagnostic possibilities and therapeutic options for CI in BMD patients and carriers. CI may be subclinical or symptomatic. Up to 100% of patients develop subclinical CI. The onset of symptomatic CI is usually in the third decade of life, rarely in the first decade. One-third of patients develop dilative cardiomyopathy with concomitant heart failure. In BMD patients, CI manifests as electrocardiographic abnormalities, hypertrophic cardiomyopathy, dilation of the cardiac cavities with preserved systolic function, dilative cardiomyopathy or cardiac arrest. There is no correlation between CI and the severity of myopathy. CI is more prominent in patients than carriers. As soon as the diagnosis of BMD is established, a comprehensive cardiac examination should be performed. Because CI in BMD is progressive and adequate therapy is available, cardiac investigations need to be regularly repeated. If CI in BMD is recognized early, appropriate therapy may be applied early, resulting in a more favourable outcome.

Challenges and opportunities in dystrophin-deficient cardiomyopathy gene therapy

The last decade has evidenced unprecedented progress in gene therapy of Duchenne and Becker muscular dystrophy (DMD and BMD) skeletal muscle disease. Cardiomyopathy is a leading cause of morbidity and mortality in both patients and carriers of DMD, BMD and X-linked dilated cardiomyopathy. However, there is little advance in heart gene therapy. The gene, the vector, vector delivery, the target tissue and animal models are five fundamental components in developing an effective gene therapy. Intensive effort has been made in optimizing gene transfer vectors and methods. Systemic and/or local delivery of recombinant adeno-associated viral vector have resulted in widespread transduction in the rodent heart. The current challenge is to define other parameters that are essential for a successful gene therapy such as the best candidate gene(s), the optimal expression level and the target tissue. This review focuses on these long-ignored aspects and points out future research directions. In particular, we need to address whether all or only some of the recently developed mini- and microgenes are protective in the heart, whether partial correction can lead to whole heart function improvement, whether over-expression is hazardous and whether correcting skeletal muscle disease can slow down or stop the progression of cardiomyopathy. Discussion is also made on whether the current mouse models can meet these research needs.

Beta-blocker therapy for cardiac dysfunction in patients with muscular dystrophy

BACKGROUND

In muscular dystrophy, cardiac function deteriorates with time and heart failure is one of the major causes of death. Although the combination of angiotensin-converting enzyme inhibitors (ACEI) and beta-blockers improves cardiac function in adults, little is known about the efficacy of those drugs in patients with muscular dystrophy.

METHODS AND RESULTS

The effect of the beta-blocker, carvedilol, and/or ACEI on ventricular function in patients with muscular dystrophy was studied. Carvedilol and an ACEI were given to 13 patients (ACEI group; mean age 18 years, range 7-27 years), and an ACEI only to 15 patients (carvedilol group; mean age 15 years, range 8-29 years). Diagnoses included Duchenne muscular dystrophy (n=25), Fukuyama muscular dystrophy (n=2), and Emery-Dreifuss muscular dystrophy (n=1). Echocardiographic parameters of the left ventricle were measured during the 2-3 years of follow-up. In the carvedilol group, combination therapy of carvedilol and an ACEI for 2 years resulted in a significant increase in left ventricular fractional shortening (LVFS). In the ACEI group, there was no significant change in LVFS. Left ventricular end-diastolic dimension increased in the ACEI group, but not in the carvedilol group.

CONCLUSION

Carvedilol plus an ACEI improves left ventricular systolic function in patients with muscular dystrophy.

Cardiac rehabilitation after heart transplantation in a patient with Becker's muscular dystrophy: a case report

Becker's muscular dystrophy (BMD) is associated with abnormal cardiac findings in 75% of cases; up to one third will develop ventricular dilatation leading to congestive heart failure, at times necessitating cardiac transplant. Candidates are selected from a base of heart failure patients who are usually New York Heart Association (NYHA) class III or IV. Treatment in a phase II cardiac rehabilitation program after transplantation is associated with functional improvement in patients without BMD, but there are no reports of patients with this disorder. We present the case of a 38-year-old man diagnosed with BMD with associated dilated cardiomyopathy. The patient was a NYHA class IIIa and underwent orthotopic cardiac transplantation for intractable heart failure followed by treatment in a phase II cardiac rehabilitation program. At the end of cardiac rehabilitation, his 12-minute walking distance had improved from 716.28 to 929.64 m (30% improvement), he had increased his conditioning metabolic equivalent level from 3.5 to 5.5 (55% improvement), he had a weight loss from 81.65 to 78.93 kg, and his body mass index changed from 23 to 22 kg/m2. The patient now has returned to work, is using a stationary bicycle once a day for 30 minutes, and is walking 1 hour a day. This suggests that treatment in a cardiac rehabilitation program is effective in patients with BMD after cardiac transplant.