Left ventricular mass in childhood dilated cardiomyopathy: a possible predictor for selection of patients for cardiac transplantation

Anaemia is a predictor of early death or cardiac transplantation in children with idiopathic dilated cardiomyopathy

INTRODUCTION

The aim of our study was to establish the prevalence and the prognostic value of haematological abnormalities in children with cardiac failure.

PATIENTS AND METHODS

A series of 218 consecutive children with a first diagnosis of idiopathic dilated cardiomyopathy were retrospectively examined. Haematological evaluation was performed at first diagnosis. Death or cardiac transplantation was the main outcome measure.

RESULTS

The median age was 0.6 years, ranging from 1 day to 15.8 years and median follow-up was 2.65 years, ranging from 0 to 17.2 years. After a median interval of 0.2 years, ranging from 0 to 8.7 years, 56 patients died and 25 were transplanted. Event-free survival at 1 and 5 years was 68% (95% confidence interval, 63-75%) and 62% (95% confidence interval, 56-69%). Blood levels of haemoglobin less than 10 grams per decilitre, urea over 8 millimoles per litre, and C-reactive protein over 10 milligrams per litre were found in 24%, 20%, and 24% of patients, respectively. The log-rank test showed that haemoglobin (p = 0.000) and C-reactive protein (p = 0.021) were predictors of death or transplantation. In the multivariate Cox model, haemoglobin (hazard ratio = 0.735; confidence interval = 0.636-0.849; p = 0.000) and urea (hazard ratio = 1.083; confidence interval = 1:002-1:171; p = 0.045) were predictive of poor outcome. Cubic spline functions showed that the positive role of haemoglobin on survival was linear for values less than 12 grams per decilitre and null for values more than 12 grams per decilitre. Adaptive index models for risk stratification and Classification and Regression Tree analysis allowed to identify the cut-off values for haemoglobin (less than 10.2 grams per decilitre) and urea (more than 8.8 millimoles per litre), as well as to derive a predictor model.

CONCLUSIONS

In children with idiopathic dilated cardiomyopathy, anaemia is the strongest independent prognostic factor of early death or transplantation.

Is myocardial performance index an independent echocardiographic marker of death in children with idiopathic dilated cardiomyopathy?

BACKGROUND

Myocardial performance index (MPI) was reported as a parameter of ventricular systolic and diastolic function, as well as a useful tool to predict the outcome in patients with ventricular dysfunction.

HYPOTHESIS

To compare MPI with classical echocardiographic parameters as an independent marker of death in children with idiopathic dilated cardiomyopathy (IDCM).

METHODS

Fifty-five children (13 deaths) underwent 104 echocardiograms from January 1996 to May 2005. Right ventricle (RV) MPI and left ventricle (LV) MPI, and 9 classical echocardiographic parameters (left atrium [LA]/body surface area [BSA], distance between mitral E point and ventricular septum, LV mass/body surface area, RV shortening fraction, LV end-systolic and end-diastolic dimensions/body surface area, LV ejection fraction, fiber circumferential shortening velocity, and mitral deceleration time) were compared. Statistical analysis was performed by chi-square, Pearson's correlation and Student t-test, Kaplan-Meier method, Cox's method, and receiver operating curve (ROC). Statistical significance was considered with alpha<0.05 and p=0.80].

RESULTS

Univariate analysis showed that all studied parameters were markers of death. There was a high correlation between RVMPI and LVMPI (r=0.847]-p=0.0001]); therefore, to avoid bias, RVMPI was discharged from multivariate analysis. In the deceased group, moderate/severe mitral regurgitation was frequent (76.9%; confidence interval [CI[ 95%=46.2%- 94.9%) and it was considered in multivariate analysis. In Cox's multivariate analysis, LVMPI was the only independent marker of death (p=0.0213]). The ideal cut-off was 0.63 with 92.3% sensitivity, 66.7% specificity, and fitted ROC area=0.918].

CONCLUSIONS

In children with IDCM, LVMPI is an independent marker of death.

Outcome Predictors for Pediatric Dilated Cardiomyopathy: A Systematic Review

Dilated cardiomyopathy comprises the largest group of pediatric cardiomyopathy functional types and is the most common indication for heart transplant in children over 5 years old. Prognostic factors for this condition have long been sought by many researchers. In a systematic review of these factors, we found 32 relevant articles published since 1976. Four studies report finding no predictive factors. In the remaining 28 studies, several factors indicating better prognosis stand out across multiple articles: younger age at diagnosis, higher left-ventricular fractional shortening and ejection fraction, and the presence of myocarditis. Results for other factors conflict across studies: severe mitral regurgitation, arrhythmias, and a family history of cardiomyopathy. Elevated left-ventricular end diastolic pressure was statistically significant in two studies, but it may be of limited utility as a result of its invasiveness. Although most children have congestive heart failure at presentation, only two studies found it to be a significant predictor of mortality. The largest study of this factor qualified the increased risk to 1 year after presentation. Other significant predictors that have not been analyzed or reported by more than one study group, are right ventricular failure and impaired cardiac adrenergic innervation, as detected by radiolabeled meta-iodobenzylguanidine imaging. Although 1- and 5-year survival rates have steadily improved, as more children with DCM receive cardiac transplants, event-free survival rates (the absence of "heart death" resulting in death or transplant) are similar to those from decades ago. A unified risk algorithm may assist in clinical decision-making but requires more studies. Other studies are needed to assess the post-transplant survival experience.

Outcome factors of idiopathic dilated cardiomyopathy in children - a long-term follow-up review

BACKGROUND

Idiopathic dilated cardiomyopathy in children has a high rate of mortality. Cardiac transplantation is the treatment of choice in those who fail to respond to therapeutics. Several studies have been carried out to determine unfavourable prognoses, and to provide an early indication for cardiac transplantation. Nevertheless, no consensus has been reached on the matter.

OBJECTIVE

To propose predictors of death in children with idiopathic dilated cardiomyopathy.

METHODS

We reviewed data extending over 22 years from 142 consecutive children with idiopathic dilated cardiomyopathy, of whom 36 died. The criteria for inclusion were the presence of congestive heart failure or cardiomegaly in a routine chest X-ray, confirmed by enlargement and hypo kinesis of the left ventricle in the echocardiogram. We included asymptomatic children in functional class I. Based on Cox's analysis of clinical and laboratory data, we sought any predictors of death.

RESULTS

In univariate analysis, the predictors were functional class IV at presentation (p equal to 0.0001), dyspnoea (p equal to 0.0096), and reduced pedal pulses (p equal to 0.0413). In chest X-ray, they were maximal cardiothoracic ratio (p equal to 0.0001) and pulmonary congestion (p equal to 0.0072). In the electrocardiogram, right atrium overload (p equal to 0.0118), ventricular arrhythmias (p equal to 0.0148) and heart rate (p equal to 0.027). In the echocardiogram, mitral regurgitation of grade 3 to 4 (p equal to 0.002), the left atrial to aortic ratio (p equal to 0.0001), and left ventricle ejection fraction (p equal to 0.0266). In multivariate analysis, the independent predictors were maximum cardiothoracic ratio (p equal to 0.0001), left ventricle ejection fraction (p equal to 0.0013), mitral regurgitation of grade 3 or 4 (p equal to 0.0017), functional class IV at presentation (p equal to 0.0028), and ventricular arrhythmias (p equal to 0.0253).

CONCLUSION

Children, who have these predictors of death should be considered for early heart transplantation when no improvement is observed in clinical treatment.

Indications for Heart Transplantation in Pediatric Heart Disease

Background— Since the initial utilization of heart transplantation as therapy for end-stage pediatric heart disease, improvements have occurred in outcomes with heart transplantation and surgical therapies for congenital heart disease along with the application of medical therapies to pediatric heart failure that have improved outcomes in adults. These events justify a reevaluation of the indications for heart transplantation in congenital heart disease and other causes of pediatric heart failure.

Methods and Results— A working group was commissioned to review accumulated experience with pediatric heart transplantation and its use in patients with unrepaired and/or previously repaired or palliated congenital heart disease (children and adults), in patients with pediatric cardiomyopathies, and in pediatric patients with prior heart transplantation. Evidence-based guidelines for the indications for heart transplantation or retransplantation for these conditions were developed.

Conclusions— This evaluation has led to the development and refinement of indications for heart transplantation for patients with congenital heart disease and pediatric cardiomyopathies in addition to indications for pediatric heart retransplantation.

Skeletal and smooth muscle alpha-actin mRNA in endomyocardial biopsy samples of dilated cardiomyopathy patients

Skeletal or smooth muscle alpha-actin isoform is reexpressed in hypertrophied or failing heart in experimental animals, however, it has been unknown whether there is a switching of these genes in the human heart. In this study, we assessed alpha-actin isoform mRNA in biopsied specimens from the left ventricle of patients with dilated cardiomyopathy (DCM). The biopsy was performed in 21 patients (DCM; 16, normal; 5). Skeletal and smooth muscle alpha-actin mRNA levels were assessed by quantitative reverse transcriptase-polymerase chain reaction using a synthetic RNA as internal control. The level of both alpha-actin mRNAs correlated well with the mean cardiomyocyte diameter as an index of cardiac hypertrophy. Further, there was a clear correlation between the expression of skeletal alpha-actin mRNA or smooth muscle alpha-actin mRNA and the ejection fraction. These results suggested that mRNAs for skeletal and smooth muscle alpha-actin isoforms are increased in the hypertrophic and/or failing heart. These mRNAs may be an useful marker for the pathological state of cardiomyopathy.

Association of a G994-->T missense mutation in the plasma platelet-activating factor acetylhydrolase gene with genetic susceptibility to nonfamilial dilated cardiomyopathy in Japanese

BACKGROUND

Although several genes or genetic loci that are responsible for or confer susceptibility to familial dilated cardiomyopathy (DCM) have been identified, genetic defects that underlie nonfamilial DCM remain to be characterized. Mice lacking manganese superoxide dismutase exhibit DCM, suggesting that impairment of the defense mechanisms against oxidative stress is an important susceptibility factor for DCM. Plasma platelet-activating factor (PAF) acetylhydrolase also acts as a key defense against oxidative stress by hydrolyzing PAF and oxidized phospholipids. Thus, abnormalities in the activity of this enzyme may result in predisposition to myocardial damage.

METHODS AND RESULTS

The possible association of a G994 (M allele)-->T (m allele) missense mutation in the plasma PAF acetylhydrolase gene with genetic susceptibility to nonfamilial DCM has now been investigated in 122 Japanese individuals with this condition and 226 healthy control subjects. PAF acetylhydrolase activity in plasma was significantly associated with plasma PAF acetylhydrolase genotype in both DCM patients and healthy control subjects. The frequency of the mutant m allele was significantly higher in DCM patients than in control subjects. Left ventricular mass (LVM) and the LVM index in DCM patients with Mm or mm genotypes were significantly greater than those in patients with the MM genotype.

CONCLUSIONS

The G994-->T mutation in the plasma PAF acetylhydrolase gene is associated with nonfamilial DCM in Japanese subjects. Although the mutation is unlikely to be a causative factor, it may contribute to genetic susceptibility to or progression of nonfamilial DCM.

Prognostic value of echocardiography in children with idiopathic dilated cardiomyopathy

Mortality of pediatric patients with idiopathic dilated cardiomyopathy (IDC) is highest during the first 1 to 2 years the child is first seen. The echocardiograms of 72 infants and children with IDC were reviewed to determine whether left ventricular shortening fraction (LVSF), end-diastolic dimension, and wall mass were helpful in predicting outcome. Patients who were alive at last follow-up (group 1) were compared to those who died or required heart transplant (group 2). None of the indexes obtained at first examination were predictive of survival. Shortening fraction had improved significantly at follow-up 1 to 6 months after first examination in group 1 (15.1 +/- 0.9 to 24.4 +/- 1.8, p < 0.001) but remained unchanged in group 2 (14.1 +/- 1.5 to 15.3 +/- 3.2). No significant trends were noted in left ventricular end-diastolic dimension or wall mass. The 1- and 5-year actuarial survival for all patients was 75% and 60%, respectively. Persistent depression of LVSF < 15% was associated with a significantly lower survival rate (1-year 46%; 5-year 29%) compared to patients in whom follow-up LVSF was > 15% (1-year 97%; 5-year 90%; p < 0.05). It is concluded that the follow-up LVSF obtained at least 1 month after first examination is helpful in identifying pediatric patients who would benefit from early cardiac transplantation.