Heart failure with preserved right ventricular ejection fraction in postoperative adults with congenital heart disease: A subtype of severe right ventricular pathophysiology

Endothelial Progenitor Cells as Biomarkers of Cardiovascular Pathologies: A Narrative Review

Endothelial progenitor cells (EPC) may influence the integrity and stability of the vascular endothelium. The association of an altered total EPC number and function with cardiovascular diseases (CVD) and risk factors (CVF) was discussed; however, their role and applicability as biomarkers for clinical purposes have not yet been defined. Endothelial dysfunction is one of the key mechanisms in CVD. The assessment of endothelial dysfunction in vivo remains a major challenge, especially for a clinical evaluation of the need for therapeutic interventions or for primary prevention of CVD. One of the main challenges is the heterogeneity of this particular cell population. Endothelial cells (EC) can become senescent, and the majority of circulating endothelial cells (CEC) show evidence of apoptosis or necrosis. There are a few viable CECs that have properties similar to those of an endothelial progenitor cell. To use EPC levels as a biomarker for vascular function and cumulative cardiovascular risk, a correct definition of their phenotype, as well as an update on the clinical application and practicability of current isolation methods, are an urgent priority.

Comparison of Clinical Profiles in Patients with Protein-Losing Enteropathy With and Without Fontan Circulation

Protein-losing enteropathy (PLE) is a life-threatening complication in patients following the Fontan operation. However, PLE also develops in some patients with congenital heart disease (CHD) after biventricular repair (BVR). This study compared clinical profiles of PLE patients following the Fontan operation with those after BVR. We retrospectively reviewed clinical charts of postoperative CHD patients with PLE. The study population comprised 42 PLE patients (14BVR, 28Fontan). Postoperative follow-up period until onset was significantly shorter in the Fontan group than in the BVR group (14 ± 2 vs. 8 ± 1 years, p = 0.02), while there was no difference in PLE onset age between groups. Furthermore, there were no differences in prevalence of clinically relevant arrhythmias, cardiac output, or central venous pressure between the two groups at PLE onset. Percentage of structural lesions (valve regurgitation and/or stenotic lesions) responsible for development of PLE and ventricular end-diastolic pressure were higher in the BVR group than in the Fontan group (93 vs. 50%, p < 0.01), (13.4 ± 6.3 vs. 7.5 ± 4.1, p < 0.0001). Catheter intervention was applied in 2Fontan and 6BVR patients, while surgical intervention was required in 8BVR and 7Fontan patients. Of these, catheter intervention was effective in 2 (25%, 1Fontan, 1BVR) and surgical intervention was effective in 4 (26.7%, 1Fontan, 3BVR). Only one patient (5.3%) improved without intervention. Complete PLE remission rate was higher in the BVR group than in the Fontan group (38 vs. 7%, p = 0.02). During follow-up, death of 2 BVR and 8 Fontan patients occurred. There were no group differences in 5- to 10-year survival rates after PLE onset (81 vs. 81%, BVR, 81 vs. 66%, Fontan). Although BVR patients may have greater chance of PLE remission when compared with those exhibiting Fontan pathophysiology, mortality in PLE-CHD patients was significantly high regardless of postoperative hemodynamics.

Diastolic dysfunction in tetralogy of Fallot: Comparison of echocardiography with catheterization

BACKGROUND

Right ventricular (RV) systolic dysfunction has been associated with adverse outcomes in tetralogy of Fallot (TOF). However, the role and etiology of diastolic dysfunction remain incompletely defined. We assessed the association between traditional echocardiographic measures of diastolic function with catheter-based RV end-diastolic pressure (RVEDP) and identified clinical characteristics independently associated with diastolic dysfunction.

METHODS

Single-center, retrospective cohort study of surgically repaired TOF patients undergoing cardiac catheterization with echocardiograms within 3 months prior to the catheterization. Tricuspid inflow and tissue Doppler measurements (E/A, E/e', and deceleration time) defined diastolic dysfunction, graded as impaired relaxation, pseudonormal, or restrictive physiology. Regression analyses tested associations between echocardiographic parameters, RVEDP, and clinical characteristics.

RESULTS

Ninety-four subjects were included. Catheterization age was 8.9 years (interquartile range 4.4, 15.9). RVEDP was 9.5 ± 2.5 mm Hg. Sixty-one (65%) subjects had echocardiographic evidence of diastolic dysfunction. RVEDP was not associated with echocardiographic parameters of diastolic function (grade of dysfunction, E/e', or E/A). Higher RVEDP was associated with larger right atrial and RV end-diastolic area, independently of weight and degree of pulmonary or tricuspid regurgitation, though was not associated with indexed right atrial or RV end-diastolic area. Greater number of interim procedures was associated with higher RVEDP, E/e', and the presence of diastolic dysfunction by echocardiography.

CONCLUSIONS

Diastolic dysfunction, as determined by echocardiography-derived and catheter-based (RVEDP) measures, is prevalent in this TOF population. These measures are not associated with each other; therefore, echocardiographic parameters of diastolic function are not reflective of RVEDP. The development of noninvasive parameters that correlate with filling pressures is required.

Impact of Cardiac Progenitor Cells on Heart Failure and Survival in Single Ventricle Congenital Heart Disease

RATIONALE

Intracoronary administration of cardiosphere-derived cells (CDCs) in patients with single ventricles resulted in a short-term improvement in cardiac function.

OBJECTIVE

To test the hypothesis that CDC infusion is associated with improved cardiac function and reduced mortality in patients with heart failure.

METHODS AND RESULTS

We evaluated the effectiveness of CDCs using an integrated cohort study in 101 patients with single ventricles, including 41 patients who received CDC infusion and 60 controls treated with staged palliation alone. Heart failure with preserved ejection fraction (EF) or reduced EF was stratified by the cardiac function after surgical reconstruction. The main outcome measure was to evaluate the magnitude of improvement in cardiac function and all-cause mortality at 2 years. Animal studies were conducted to clarify the underlying mechanisms of heart failure with preserved EF and heart failure with reduced EF phenotypes. At 2 years, CDC infusion increased ventricular function (stage 2: +8.4±10.0% versus +1.6±6.4%, P=0.03; stage 3: +7.9±7.5% versus -1.1±5.5%, P<0.001) compared with controls. In all available follow-up data, survival did not differ between the 2 groups (log-rank P=0.225), whereas overall patients treated by CDCs had lower incidences of late failure (P=0.022), adverse events (P=0.013), and catheter intervention (P=0.005) compared with controls. CDC infusion was associated with a lower risk of adverse events (hazard ratio, 0.411; 95% CI, 0.179-0.942; P=0.036). Notably, CDC infusion reduced mortality (P=0.038) and late complications (P<0.05) in patients with heart failure with reduced EF but not with heart failure with preserved EF. CDC-treated rats significantly reversed myocardial fibrosis with differential collagen deposition and inflammatory responses between the heart failure phenotypes.

CONCLUSIONS

CDC administration in patients with single ventricles showed favorable effects on ventricular function and was associated with reduced late complications except for all-cause mortality after staged procedures. Patients with heart failure with reduced EF but not heart failure with preserved EF treated by CDCs resulted in significant improvement in clinical outcome.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifiers: NCT01273857 and NCT01829750.

MEF2C loss-of-function mutation contributes to congenital heart defects

Congenital heart disease (CHD) is the most common type of developmental abnormality in humans, and is a leading cause for substantially increased morbidity and mortality in affected individuals. Increasing studies demonstrates a pivotal role of genetic defects in the pathogenesis of CHD, and presently mutations in more than 60 genes have been associated with CHD. Nevertheless, CHD is of pronounced genetic heterogeneity, and the genetic basis underpinning CHD in a large proportion of patients remains unclear. In the present study, the whole coding exons and splicing donors/acceptors of the MEF2C gene, which codes for a transcription factor essential for normal cardiovascular development, were sequenced in 200 unrelated patients affected with CHD, and a novel heterozygous missense mutation, p.L38P, was identified in an index patient with patent ductus arteriosus (PDA) and ventricular septal defect (VSD). Genetic scan of the mutation carrier's family members available showed that the mutation was present in all affected family members but absent in unaffected family members. Analysis of the proband's pedigree revealed that the mutation co-segregated with PDA, which was transmitted as an autosomal dominant trait with complete penetrance. The mutation changed the amino acid that was completely conserved evolutionarily, and did not exist in 300 unrelated, ethnically-matched healthy individuals used as controls. Functional deciphers by using a dual-luciferase reporter assay system unveiled that the mutant MEF2C protein had a significantly reduced transcriptional activity. Furthermore, the mutation significantly diminished the synergistic activation between MEF2C and GATA4, another cardiac core transcription factor that has been causally linked to CHD. In conclusion, this is the first report on the association of a MEF2C loss-of-function mutation with an increased vulnerability to CHD in humans, which provides novel insight into the molecular mechanisms underlying CHD, implying potential implications for early diagnosis and timely prophylaxis of CHD.