Cardiomyopathy and heart transplantation in children

A Review of Pediatric Cardiomyopathy

Though pediatric cardiomyopathy is rare in children, there is significant associated morbidity and mortality. Etiology varies from inborn errors of metabolism to familial genetic mutations and myocyte injury. Major classes include dilated, hypertrophic, restrictive, and non-compaction. Diagnosis generally involves a combination of clinical history and echocardiography. The use of cross-sectional imaging is gaining popularity. Management varies between subtype and may involve a combination of medical and surgical interventions depending on clinical status.

Association between ACR1 gene product expression and cardiomyopathy in children

Cardiomyopathy is a heterogeneous heart disease. Although morbidity of pediatric cardiomyopathy has been on the increase, effective treatments have not been identified. The aim of the study was to examine the expression of ACR1 gene products in association with cardiomyopathy in children. In total, 73 patients and 76 healthy subjects were enrolled in the study, from April, 2013 to April, 2015. The relative expression of ACR1 mRNA and protein were quantified in all cases, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), ELISA and western blot analysis. Immunohistochemistry was used to stain cardiac tissue samples to reveal differences between the patients and the control group. The results showed that the level of ACR1 mRNA by RT-qPCR was not different between the two study groups. However, ELISA and western blot analysis showed a significant difference, with patients expressing lower levels of ACR1. Additionally, immunohistochemistry revealed the levels of ACR1 were reduced in patients as the time course of disease increased. Thus, there is an association between the inhibition of ACR1 expression and the development of the disease. These findings are useful in the elucidation of the pathogenesis of pediatric cardiomyopathy, a severe disease with few effective treatment options available.

Follow-up of the patients after stem cell transplantation for pediatric dilated cardiomyopathy

Dilated cardiomyopathy is a serious problem in pediatric cardiology. Despite the relatively low incidence, the mortality is high. The conservative therapy does not improve the prognosis, and possibilities of heart transplantation are limited. There are multiple trials of use of stem cells for ischemic heart disease in the adult population. This allows us to believe that the method has perspectives in pediatric cardiology. We performed the cell therapy for seven patients, six of them had complete one yr follow-up after procedure. Five to 30 milliliters of bone marrow was aspirated from the iliac crest and 17 to 122 million BMCs were isolated. The average basal EF was 33.5%. We observed increasing of EF up to 54% (=9.54, p=0.00154) in a 6-month period and up to 54.5% (=10.82, p= 0.00315) after one yr. The changes of LVEDV also were observed. The LVEDV decreased in average per 13.05%. There were no observed side effects or heart rhythm disorders. Intramyocardial administration of bone marrow-derived progenitor cells proved to be a technically feasible and safe method. Up until now, the results obtained have been promising and we suppose that bone marrow-derived progenitor cell intramyocardial transplantation can be used.

Early predictors of survival to and after heart transplantation in children with dilated cardiomyopathy

BACKGROUND

The importance of clinical presentation and pretransplantation course on outcome in children with dilated cardiomyopathy listed for heart transplantation is not well defined.

METHODS AND RESULTS

The impact of age, duration of illness, sex, race, ventricular geometry, and diagnosis of myocarditis on outcome in 261 children with dilated cardiomyopathy enrolled in the Pediatric Cardiomyopathy Registry and Pediatric Heart Transplant Study was studied. End points included listing as United Network for Organ Sharing status 1, death while waiting, and death after transplantation. The median age at the time of diagnosis was 3.4 years, and the mean time from diagnosis to listing was 0.62±1.3 years. Risk factors associated with death while waiting were ventilator use and older age at listing in patients not mechanically ventilated (P=0.0006 and P=0.03, respectively). Shorter duration of illness (P=0.04) was associated with listing as United Network for Organ Sharing status 1. Death after transplantation was associated with myocarditis at presentation (P=0.009), nonwhite race (P<0.0001), and a lower left ventricular end-diastolic dimension z score at presentation (P=0.04). In the myocarditis group, 17% (4 of 23) died of acute rejection after transplantation.

CONCLUSIONS

Mechanical ventilator use and older age at listing predicted death while waiting, whereas nonwhite race, smaller left ventricular dimension, and myocarditis were associated with death after transplantation. Although 97% of children with clinically or biopsy-diagnosed myocarditis at presentation survived to transplantation, they had significantly higher posttransplantation mortality compared with children without myocarditis, raising the possibility that preexisting viral infection or inflammation adversely affects graft survival.

Heart failure secondary to dilated cardiomyopathy: a role for emergency physician bedside ultrasonography

Heart failure as a result of cardiomyopathy is an uncommon presentation in the pediatric emergency department (PED). The initial presenting symptoms in these cases are often nonspecific and may be confused with more common pediatric illnesses. We report a case of a 3-year-old girl initially discharged from a PED after routine evaluation of vomiting and diarrhea with a diagnosis of acute gastroenteritis only to return 1 week later in heart failure from a dilated cardiomyopathy. A bedside ultrasound performed by the emergency physician in the PED allowed for the initiation of appropriate, rapid, goal-directed therapy and expedited timely transport to a facility with pediatric cardiothoracic surgery. We will review dilated cardiomyopathy and the role of emergency physician echocardiography.

Fibrofatty changes in failed pediatric cardiac allografts

The pathogenesis of right ventricular fibrofatty changes can be broadly divided into genetic or acquired. The genetic cause is termed arrhythmogenic right ventricular dysplasia, an inherited cardiomyopathy characterized by fibrofatty replacement of the right ventricular myocardium, and represents an underdiagnosed cardiac entity leading to syncope, recurrent ventricular tachycardias, heart failure, and sudden death. Our study demonstrates that fibrofatty changes can also be seen in pediatric cardiac allografts. Conversely, fat replacement without fibrosis may be seen secondary to infectious myocarditis, chronic inflammation, and ischemia and as part of the aging process. We examined 29 failed cardiac allografts to identify the etiology of graft failure. In this study, 4 patients (13%) had severe right ventricular fibrofatty changes, and when compared with control patients, those with fibrofatty changes had a shorter interval from transplant to graft failure, 2.75 years vs 5.45 years (P  =  0.029). Neither body mass index nor other physiologic parameters found on electrocardiography, echocardiography, or cardiac catherization were different between groups. Furthermore, arrhythmias indicative of arrhythmogenic right ventricular dysplasia were not observed in the study group. This study suggests the fibrofatty infiltration in cardiac allografts is a clinically different entity from arrhythmogenic right ventricular dysplasia and has an unknown etiology. Our study findings suggest that identifying fibrofatty infiltrates in cardiac transplant patients during routine right ventricular biopsy can be a predictive factor for shortened life of the pediatric cardiac allograft.

[Usefulness of intracoronary therapy with progenitor cells in patients with dilated cardiomyopathy: Bridge or alternative to heart transplantation?]

INTRODUCTION AND OBJECTIVES

Some paediatric publications have recently raised the value of intracoronary therapy with autologous bone marrow-derived progenitor cells (APCs) in children with dilated cardiomyopathy (DCM) and heart failure. We describe the usefulness of this treatment in two infants with severe DCM and heart failure, who had been transferred to our hospital for cardiac transplant evaluation.

PATIENTS AND METHODS

The first patient was a 3 months old male weighing 4 kg. The second was a 4 months old male weighing 5 kg. At the time of admission, both were in poor clinical condition (NYHA IV), with severe dilation and systolic dysfunction (ejection fraction [EF]<30%) of the left ventricle and marked elevation of NT-proBNP, requiring treatment with mechanical ventilation and inotropic iv infusion. After mobilization with G-CSF for 4 days, APCs were obtained from peripheral blood by leukocytapheresis, administering them by a slow intracoronary bolus injection using a stop-flow technique (6.15x106 CD34-positive cells/Kg in the first patient, and 10.55x106 CD34-positive cells/Kg in the second).

RESULTS

Since the first week after the procedure, clinical status of patients improved and echocardiography showed a decrease in left ventricular dilation. A month later, there was a significant improvement in EF (> 40%) and NT-proBNP levels, subsequently maintained throughout the follow-up. However, four months later in the first patient, the left ventricle dilated again and its function slightly worsened, but without any significant impact in his clinical status.

CONCLUSIONS

Intracoronary therapy with APCs can be an alternative in children, especially infants, with DCM and heart failure. It can reduce the waiting list mortality, improve clinical status and provide more time on the waiting list to receive a suitable organ, or even to make transplantation unnecessary.

Surgical Management of Unusual Cardiac Tumors in Infants and Children

While most primary tumors of the heart are histologically benign, they are significant space-occupying lesions with serious functional implications for the heart and lungs. Herein, we highlight our experience with the surgical management of selected cardiac tumors in the pediatric population between 2008 and 2010. (1) Intrapericardial teratomas in the fetus can produce fatal tamponade from compression by the attendant pericardial effusion, and a critical life-saving maneuver preoperatively is to drain the effusion prenatally, followed by an expeditious resection after birth. (2) Rhabdomyomas, the most common of the pediatric cardiac tumors, can be intracavitary, large, and associated with the mitral subvalvular apparatus. (3) Cardiac fibromas should be aggressively resected or at least debulked, especially given their propensity for dysrrhythmias. The key to success is as complete a resection as possible, but not at the expense of other normal structures. (4) Complex nonobstructive hypertrophic myopathy can be thought of as a type of neoplastic overgrowth, and aggressive resection of even midcavitary obstructive lesions should be considered as a viable alternative to primary transplantation.

Myofibrillar remodeling in cardiac hypertrophy, heart failure and cardiomyopathies

BACKGROUND

A wide variety of pathological conditions have been shown to result in cardiac remodelling and myocardial dysfunction. However, the mechanisms of transition from adaptive to maladaptive alterations, as well as those for changes in cardiac performance leading to heart failure, are poorly understood.

OBSERVATIONS

Extensive studies have revealed a broad spectrum of progressive changes in subcellular structures and function, as well as in signal transduction and metabolism in the heart, among different cardiovascular disorders. The present review is focused on identifying the alterations in molecular and biochemical structure of myofibrils (myofibrillar remodelling) in hypertrophied and failing myocardium in different types of heart diseases. Numerous changes at the level of gene expression for both contractile and regulatory proteins have already been reported in failing hearts and heart diseases; these changes are potential precursors for heart failure such as cardiac hypertrophy and cardiomyopathies. Myofibrillar remodelling, as a consequence of proteolysis, oxidation, and phosphorylation of some functional groups in both contractile and regulatory proteins in hearts failing due to different etiologies, has also been described.

CONCLUSIONS

Although myofibrillar remodelling appears to be associated with cardiac dysfunction, alterations in both contractile and regulatory proteins are dependent on the type and stage of heart disease.

Idiopathic restrictive cardiomyopathy in children

OBJECTIVE

To define the natural history of idiopathic restrictive cardiomyopathy in a paediatric population and to identify any factors predictive of outcome.

DESIGN

Retrospective analysis of patients born between 1970 and 2002 were identified from the Children's Hospital of Pittsburgh cardiology database. Demographic data, mode of presentation, echocardiographic and haemodynamic findings at diagnosis, survival time, and manner of death were evaluated.

SETTING

Tertiary referral and transplant centre for paediatric patients with cardiac disease.

PATIENTS

All local and referred patients with idiopathic restrictive cardiomyopathy born after 1970 and under 21 years of age at time of diagnosis.

RESULTS

21 patients were identified. Probability of survival at 1, 5, and 10 years was 80.5% (95% confidence interval (CI) 58 to 100), 39% (95% CI 17 to 61), and 20% (95% CI 0 to 42), respectively. Median age of presentation was 3.8 years (mean (SD) 5.7 (6.1) years). Median survival without transplantation was 2.2 years (mean (SD) 4.6 (5.4) years). Age at presentation, sex, and presence or absence of heart failure symptoms at presentation were not associated with clinical course. Right (p = 0.05) and left ventricular end diastolic pressures (p = 0.04) and ratio of left atrial to aortic root dimensions (LA:Ao) (p = 0.03) at presentation had a significantly negative correlation with survival time after diagnosis.

CONCLUSIONS

Without transplantation, most children with restrictive cardiomyopathy have a very poor prognosis. Longer survival from diagnosis was correlated with lower LA:Ao and cardiac filling pressures at diagnosis. Survival time was not influenced by the symptoms present at diagnosis.