Effects of Pulmonary Regurgitation on Distensibility and Flow of the Branch Pulmonary Arteries in Tetralogy of Fallot

Significant pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) may affect flow in the pulmonary artery (PA) side branches. We sought to assess flow changes and distensibility of the PA side branches in vivo and test correlation with the degree of PR and right-ventricular (RV) dilatation. Thirty patients after TOF repair and 16 controls underwent cardiovascular magnetic resonance for quantification of RV volumes and measurement of flow in the PA side branches. RV volumes and function, blood flow volumes, and cross-sectional area of the main, left (LPA), and right (RPA) PA were measured and regurgitant volumes and distensibility calculated. Results were compared between the LPA and the RPA and between patients and controls. Median regurgitation fraction of PR was 41% (range 22-60%). Regurgitant fraction was greater in the LPA (40%) than in the RPA (29%), resulting in lower net flow into the LPA (p<0.001). LPA area was significantly greater than that of the RPA (303.9 vs. 232.7mm2/m2) (p<0.0001). The LPA showed lower distensibility than the RPA (39 vs. 44%). PA side branch distensibility correlated with MPA regurgitant volume (p=0.001), MPA regurgitant fraction (p=0.001), and RV end-diastolic volume (p=0.03). PA side branches have greater distensibility in patients with PR than in normal subjects. Significant PR leads to changes in flow profile and distensibility of the PA side branches. The LPA shows greater regurgitant volume and greater area but lower distensibility than the RP

Geometry and dimensions of the pulmonary artery bifurcation in children and adolescents: assessment in vivo by contrast-enhanced MR-angiography

We sought to establish normal values for the diameters of the main (MPA), right (RPA), and left (LPA) pulmonary arteries and for the angles describing the geometry of the pulmonary artery bifurcation in children by using contrast-enhanced magnetic resonance angiography (CE-MRA). CE-MRA was performed in 69 children without cardiovascular disease. The median age was 10±4.9years (range 2-20), weight 37.4±18.5kg (10-82), body surface area (BSA) 1.18±0.4m2 (0.48-2.07). The pulmonary artery diameters and angles were measured at standardized sites and projections. Regression analysis of diameters and angles in relation to BSA demonstrated linear relationship between the cross-sectional diameters of the pulmonary arteries and the square root of BSA (BSA0.5). Normalized mean diameters were for the MPA 17.6±5.1mm/m2, origin of RPA 13.1±2.9mm/m2, origin of LPA 14.2±2.9mm/m2. The MPA showed a mean antero-posterior inclination of 33°±8° and a lateral leftward angulation of 18°±5°. The mean angle of the bifurcation was 99.5°±10.3°. Both side branches showed a supero-inferior course of the proximal segments, steeper for the RPA (7.7°±6.5°) than for the LPA (2.1°±7.8°). Normative curves in relation to BSA are presented for all measurements. This study provides normative values by CE-MRA for the main pulmonary artery and its side branches in children during somatic growth. These data can be used for identifying pulmonary arteries anomalies in children, and evaluate the need and the modality for treatmen

Flow evaluation software for four-dimensional flow MRI: a reliability and validation study

PURPOSE Four-dimensional time-resolved phase-contrast cardiovascular magnetic resonance imaging (4D flow MRI) enables blood flow quantification in multiple vessels, which is crucial for patients with congenital heart disease (CHD). We investigated net flow volumes in the ascending aorta and pulmonary arteries by four different postprocessing software packages for 4D flow MRI in comparison with 2D cine phase-contrast measurements (2D PC). MATERIAL AND METHODS 4D flow and 2D PC datasets of 47 patients with biventricular CHD (median age 16, range 0.6-52 years) were acquired at 1.5 T. Net flow volumes in the ascending aorta, the main, right, and left pulmonary arteries were measured using four different postprocessing software applications and compared to offset-corrected 2D PC data. Reliability of 4D flow postprocessing software was assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC). Linear regression of internal flow controls was calculated. Interobserver reproducibility was evaluated in 25 patients. RESULTS Correlation and agreement of flow volumes were very good for all software compared to 2D PC (ICC ≥ 0.94; bias ≤ 5%). Internal controls were excellent for 2D PC (r ≥ 0.95, p < 0.001) and 4D flow (r ≥ 0.94, p < 0.001) without significant difference of correlation coefficients between methods. Interobserver reliability was good for all vendors (ICC ≥ 0.94, agreement bias < 8%). CONCLUSION Haemodynamic information from 4D flow in the large thoracic arteries assessed by four commercially available postprocessing applications matches routinely performed 2D PC values. Therefore, we consider 4D flow MRI-derived data ready for clinical use in patients with CHD

Remodelling of the right ventricle after early pulmonary valve replacement in children with repaired tetralogy of Fallot: assessment by cardiovascular magnetic resonance

Aims Correct timing of pulmonary valve replacement (PVR) is crucial for preventing complications of pulmonary regurgitation and right ventricular (RV) dilatation after repair of tetralogy of Fallot. We sought to assess the remodelling of the RV after early PVR in children, using cardiovascular magnetic resonance (CMR). Methods and results Twenty children with severe pulmonary regurgitation and RV dilatation and mean age 13.9±3 years underwent CMR evaluation 5.6±1.8 months before and 5.9±0.6 months after PVR. PVR was performed when the RV end-diastolic volume exceeded 150 mL/m2, as measured by CMR. The time interval between primary repair and PVR was 12±3 years. Post-operative CMR demonstrated a significant reduction of the RV end-diastolic volume from 189.8±33.4 to 108.7±25.8 mL/m2 (P<0.0001), of the RV end-systolic volume from 102.4±27.3 to 58.2±16.3 mL/m2 (P<0.0001), and of the RV mass from 48.7±12.3 to 35.8±7.7 g/m2 (P<0.0001). The RV ejection fraction did not change significantly. Conclusion Prompt RV remodelling, with reduction of RV volume and mass, is observed after performing PVR if the RV end-diastolic volume exceeds 150 mL/m2. Early PVR may prevent the detrimental complications of severe pulmonary regurgitatio

GABRB1 Single Nucleotide Polymorphism Associated with Altered Brain Responses (but not Performance) during Measures of Impulsivity and Reward Sensitivity in Human Adolescents

Variations in genes encoding several GABAA receptors have been associated with human drug and alcohol abuse. Among these, a number of human studies have suggested an association between GABRB1, the gene encoding GABAA receptor β1 subunits, with Alcohol dependence (AD), both on its own and comorbid with other substance dependence and psychiatric illnesses. In the present study, we hypothesized that the GABRB1 genetically-associated increased risk for developing alcoholism may be associated with impaired behavioral control and altered sensitivity to reward, as a consequence of altered brain function. Exploiting the IMAGEN database (Schumann et al., 2010), we explored in a human adolescent population whether possession of the minor (T) variant of the single nucleotide polymorphism (SNP) rs2044081 is associated with performance of tasks measuring aspects of impulsivity, and reward sensitivity that are implicated in drug and alcohol abuse. Allelic variation did not associate with altered performance in either a stop-signal task (SST), measuring one aspect of impulsivity, or a monetary incentive delay (MID) task assessing reward anticipation. However, increased functional magnetic resonance imaging (fMRI) blood-oxygen-level dependent (BOLD) response in the right hemisphere inferior frontal gyrus (IFG), left hemisphere caudate/insula and left hemisphere inferior temporal gyrus (ITG) during MID performance was higher in the minor (T) allelic group. In contrast, during SST performance, the BOLD response found in the right hemisphere supramarginal gyrus, right hemisphere lingual and left hemisphere inferior parietal gyrus indicated reduced responses in the minor genotype. We suggest that β1-containing GABAA receptors may play a role in excitability of brain regions important in controlling reward-related behavior, which may contribute to susceptibility to addictive behavior

Feasibility of non-gated dynamic fetal cardiac MRI for identification of fetal cardiovascular anatomy

INTRODUCTION To evaluate the feasibility of identifying the fetal cardiac and thoracic vascular structures with non-gated dynamic balanced steady-state free precession (SSFP) MRI sequences. METHODS We retrospectively assessed the visibility of cardiovascular anatomy in 60 fetuses without suspicion of congenital heart defect. Non-gated dynamic balanced SSFP sequences were acquired in three anatomic planes of the fetal thorax. The images were analyzed following a segmental approach in consensus reading by an experienced pediatric cardiologist and radiologist. An imaging score was defined by giving one point to each visualized structure, yielding a maximum score of 21 points. Image quality was rated from 0 (poor) to 2 (excellent). The influence of gestational age (GA), field strength, placenta position, and maternal panniculus on image quality and imaging score were tested. RESULTS 30 scans were performed at 1.5T, 30 at 3T. Heart position, atria and ventricles could be seen in all 60 fetuses. Basic diagnosis (>12 points) was achieved in 54 cases. The mean imaging score was 16.8+/-3.8. Maternal panniculus (r=-0.3; p=0.015) and gestational age (r=0.6; p<0.001) correlated with imaging score. Field strength influenced image quality, with 1.5T being better than 3T images (p=0.012). Imaging score or quality were independent of placenta position. DISCUSSION/CONCLUSION Fetal cardiac MRI with non-gated SSFP sequences enables recognition of basic cardiovascular anatomy

Management and outcome of Ebstein's anomaly in children

Abstract Objectives To assess clinical presentation, treatment, and outcome of children with Ebstein's anomaly. Background Data on long-term outcome of children with Ebstein's anomaly are scarce. Methods Retrospective analysis of all children with Ebstein's anomaly treated between February, 1979 and January, 2009 in a single tertiary institution. Primary outcomes included patient survival and need for intervention, either cardiac surgery or catheter intervention. Results A total of 42 patients were diagnosed with Ebstein's anomaly at a median age of 5 days ranging from 1 day to 11.7 years. Symptoms included cyanosis, heart murmur, and/or dyspnoea. Associated cardiac anomalies occurred in 90% of the patients. Average follow-up was 9.5 plus or minus 7.0 years. The overall mortality rate was 14%. Of the six patients, three died postnatally before treatment. Cardiac surgery and/or catheter-guided interventions were required in 33 patients (79%). Cardiac surgery was performed in 21 (50%) patients at a median age of 9.1 years (range 0.1-16.5 years), including biventricular repair in 13 (62%), one-and-a-half chamber repair in seven (33%), and a staged single-ventricle repair in one. Peri-operative mortality was 4%. Catheter-guided interventions consisted of device closure of an atrial septal defect in three cases and radiofrequency ablation of accessory pathways in nine patients. The estimated 10-year survival was 85.3 plus or minus 5.6%. Conclusion In children, Ebstein's anomaly is usually diagnosed in the first year of age. Even though children with Ebstein's anomaly often require an intervention, their peri-operative mortality is low and long-term survival is good. Symptomatic newborns requiring an intervention may have a worse outcom

Evolutionary associations between host traits and parasite load: insights from Lake Tanganyika cichlids

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Parasite diversity and abundance (parasite load) vary greatly among host species. However, the influence of host traits on variation in parasitism remains poorly understood. Comparative studies of parasite load have largely examined measures of parasite species richness, and are predominantly based on records obtained from published data. Consequently, little is known about the relationships between host traits and other aspects of parasite load, such as parasite abundance, prevalence, and aggregation. Meanwhile, understanding of parasite species richness may be clouded by limitations associated with data collation from multiple independent sources. We conducted a field study of Lake Tanganyika cichlid fishes and their helminth parasites. Using a Bayesian phylogenetic comparative framework, we tested evolutionary associations between five key host traits (body size, gut length, diet breadth, habitat complexity, number of sympatric hosts) predicted to influence parasitism, together with multiple measures of parasite load. We find that the number of host species that a particular host may encounter due to its habitat preferences emerges as a factor of general importance for parasite diversity, abundance, and prevalence, but not parasite aggregation. In contrast, body size and gut size are positively related to aspects of parasite load within, but not between species. The influence of host phylogeny varies considerably among measures of parasite load, with the greatest influence exerted on parasite diversity. These results reveal that both host morphology and biotic interactions are key determinants of host-parasite associations, and that consideration of multiple aspects of parasite load is required to fully understand patterns in parasitism