Normal values for paediatric biventricular volumes, ejection fraction and mass – influence of cardiovascular magnetic resonance analysis techniques

Background

Measurement of ventricular volumes and function by steady-state free precession (SSFP) cardiovascular magnetic resonance (CMR) is an important diagnostic tool in the treatment and follow-up of paediatric congenital heart disease. However, normal values are rare and the CMR analysis methods are inconsistent.

Aims

We sought to create two sets of ventricular normal values for different CMR analysis (contouring) methods.

Methods

In a retrospective study design, CMR data sets of 154 healthy children with an age range between 4 and 18 years from two centers in the UK and Germany were evaluated. Left and right ventricular end-diastolic and end-systolic volumes (LVEDV, LVESV, RVEDV, RVESV), ejection fraction (RVEF, LVEF) and myocardial mass (LVMM, RVMM) were analysed from short axis steady-state free precession images by using two different analysis techniques: 1) papillary muscles, myocardial trabeculations and the moderator band were included in the ventricular volume and excluded from the ventricular mass (Figure 1), 2) papillary muscles, myocardial trabeculations and the moderator band were excluded from the ventricular volume and included in the ventricular mass (Figure 2). Sex-specific reference curves were created separately for both ventricular contouring methods using the lambda mu sigma method. Correlations between variables were analyzed with the Spearman's rank correlation. Contouring methods were compared through Bland-Altman analysis.

Results

The mean age was 13.85±2.8 years (53 girls).

In children from 4 to 10 years average ventricular volumes and mass normalized for body surface area (BSA) measured:

In children from 11 to 18 years average ventricular volumes and mass measured:

Separate centile charts and centile tables for boys and girls for all cardiac parameters were created.

Conclusion

We provide paediatric CMR reference values for biventricular volumes, ejection and masses for two different CMR contouring methods. They can be used in the diagnosis and follow-up of congenital or acquired heart disease in children and for research purposes.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Bioelastic properties of the aorta in children, adolescents and young adults after cardiac transplantation: a cardiovascular magnetic resonance study

Background

Long-term complications after cardiac transplantation are common and typically include arterial hypertension and coronary allograft vasculopathy. Few studies also suggested that heart transplant recipients have an increased arterial stiffness.

Purpose

This prospective study aimed to assess the bioelastic properties of the aorta as well as LV function, morphology and structure in children and young adults after cardiac transplantation.

Methods

CMR studies from 34 patients (median age: 17.1 years, range: 8–24 years) who underwent cardiac transplantation in childhood were analysed. Aortic anatomy and distensibility were assessed at five locations of the thoracic aorta using steady-state free precession cine sequences. Pulse wave velocity (PWV) of the aortic arch and the descending thoracic aorta was measured from 2-dimensional phase contrast images. Size and function of the left atrium and the ventricles were assessed from a stack of short axis slices. Myocardial T1 times were determined using a standard MOLLI sequence.

Results

Cross-sectional areas of the ascending aorta and the aortic arch tended to be lower in patients compared to controls (ascending aorta 464.5±172.5 mm2 vs. 515.3±186.3 mm2, aortic arch 342.4±113.3 mm2 vs. 376.9±148.5 mm2) whereas cross-sectional areas of the descending aorta tended to be higher (aortic isthmus 283.7±102.1 mm2 vs. 257.9±89.5 mm2, aorta descendens diaphragmal 218.4±75.8 mm2 vs. 214.2±75.0 mm2) and showed a correlation with systolic blood pressure (r=0.33). PWV was higher in the aortic arch (4.8±2.4 m/s vs. 3.6±0.7 m/s).

Aortic distensibility was slightly higher at all measuring points in the study population compared to the control group and showed an increase with rising distance from the heart (ascending aorta 10.5±5.8 10–3 mm Hg-1, aortic isthmus 13.1±7.5 10–3 mm Hg-1, descending aorta 16.6±6.8 10–3 mm Hg-1). Biventricular volumes were slightly reduced in the patient group compared to the control group but this was not statistically significant. Only left ventricular mass messured during the systolic phase was higher in the study population compared to the control group (males 55.1 g/m2 vs. 53.0 g/m2, females 46.2 g/m2 vs. 45.2 g/m2). T1 mapping demonstrated increased T1 times in the heart-transplanted group compared to published data in healthy adults. In particular, T1 times of the lateral and inferior myocardial segments were higher.

Conclusion

Patients who underwent cardiac transplantation in childhood seem to have a reduced bioelasticity of the thoracic aorta. Increased myocardial T1 times suggesting alterations in myocardial structure.

Funding Acknowledgement

Type of funding sources: None.

Myocardial Perfusion in Hypoplastic Left Heart Syndrome

BACKGROUND

The status of the systemic right ventricular coronary microcirculation in hypoplastic left heart syndrome (HLHS) is largely unknown. It is presumed that the systemic right ventricle's coronary microcirculation exhibits unique pathophysiological characteristics of HLHS in Fontan circulation. The present study sought to quantify myocardial blood flow by cardiac magnetic resonance imaging and evaluate the determinants of microvascular coronary dysfunction and myocardial ischemia in HLHS.

METHODS

One hundred nineteen HLHS patients (median age, 4.80 years) and 34 healthy volunteers (median age, 5.50 years) underwent follow-up cardiac magnetic resonance imaging ≈1.8 years after total cavopulmonary connection. Right ventricle volumes and function, myocardial perfusion, diffuse fibrosis, and late gadolinium enhancement were assessed in 4 anatomic HLHS subtypes. Myocardial blood flow (MBF) was quantified at rest and during adenosine-induced hyperemia. Coronary conductance was estimated from MBF at rest and catheter-based measurements of mean aortic pressure (n=99).

RESULTS

Hyperemic MBF in the systemic ventricle was lower in HLHS compared with controls (1.89±0.57 versus 2.70±0.84 mL/g per min; P<0.001), while MBF at rest normalized by the rate-pressure product, was similar (1.25±0.36 versus 1.19±0.33; P=0.446). Independent risk factors for a reduced hyperemic MBF were an HLHS subtype with mitral stenosis and aortic atresia (P=0.017), late gadolinium enhancement (P=0.042), right ventricular diastolic dysfunction (P=0.005), and increasing age at total cavopulmonary connection (P=0.022). The coronary conductance correlated negatively with systemic blood oxygen saturation (r, -0.29; P=0.02). The frequency of late gadolinium enhancement increased with age at total cavopulmonary connection (P=0.014).

CONCLUSIONS

The coronary microcirculation of the systemic ventricle in young HLHS patients shows significant differences compared with controls. These hypothesis-generating findings on HLHS-specific risk factors for microvascular dysfunction suggest a potential benefit from early relief of frank cyanosis by total cavopulmonary connection.

Ventricular and atrial function and deformation is largely preserved after arterial switch operation

OBJECTIVE

To test the hypothesis that ventricular and atrial function are different between patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) and healthy controls.

METHODS

103 consecutive patients with TGA (median age: 16.7 years, 4.3-39.6 years, 71.8% male) were compared with 77 controls (median age: 15.4 years, 6.3-43.2 years, 66.2% male). Biventricular and biatrial function were assessed using standard cardiovascular magnetic resonance (CMR) techniques and feature tracking. Group comparison was performed with conventional non-parametrical statistics and machine learning methods to find the variables most discriminative between patients and controls. These variables were used to build a multivariable logistic regression model to assess the case-control status.

RESULTS

Markers of left and right ventricular function (LV; RV) (ejection fraction, MAPSE, TAPSE, LV long-axis strain) as well as LV global longitudinal (-20.7 (-24.1; -17.9) vs -23.7 (-26.1; -21.6), p<0.001), circumferential (-29.4 (-32.2; -26.5) vs -30.5 (-33.6; 29), p=0.001) and atrial longitudinal strain (left atrium (LA): 23.3 (18.6; 28.8) vs 36.7 (30.7; 44), p<0001; right atrium: 21.7 (18.2; 27.8) vs 34.9 (26.9; 40.3), p<0.001) were reduced in patients compared with controls using non-parametrical testing. The logistic regression model including the most discriminative variables from univariate and machine learning analysis demonstrated significant differences between patients and controls only for TAPSE and LA global longitudinal strain.

CONCLUSIONS

Biventricular and biatrial function are largely preserved after ASO for TGA. Using a comprehensive CMR protocol along with statistical machine learning methods and a regression approach, only RV longitudinal function and LA function are significantly impaired.

Left ventricular noncompaction in pediatric population: could cardiovascular magnetic resonance derived fractal analysis aid diagnosis?

BACKGROUND

Cardiovascular magnetic resonance (CMR) derived fractal analysis of the left ventricle (LV) has been shown in adults to be a useful quantitative measure of trabeculation with high reproducibility and accuracy for the diagnosis of LV non-compaction (LVNC). The aim of this study was to investigate the utility and feasibility of fractal analysis in children.

METHODS

Eighty-four subjects underwent CMR: (1) 28 patients with LVNC (as defined by the Petersen criteria with NC/C ratio [Formula: see text] 2.3); (2) 28 patients referred by clinicians for assessment of hyper-trabeculation and found not to qualify as LVNC (NC/C [Formula: see text] 1.8 and < 2.3); (3) 28 controls. The fractal scores for each group were presented as global and maximal fractal dimension as well as for 3 segments of the LV: basal, mid, and apical. Statistical comparison of the fractal scores between the 3 groups was performed.

RESULTS

Global fractal dimension (FD) was higher in the LVNC group than in the hyper-trabeculated group: 1.345 (SEM 0.053) vs 1.252 (SEM 0.034), p < 0.001 and higher in hyper-trabeculated group than in controls: 1.252 (SEM 0.034) vs 1.158 (SEM 0.038), p < 0.001. The highest maximum FD was in the apical portion of the LV in the LVNC group, (1.467; SEM 0.035) whereas it was in the mid ventricle in the hyper-trabeculated (1.327; SEM 0.025) and healthy groups (1.251; SEM 0.042). Fractal analysis showed lower intra- and interobserver variability than the Petersen and Jacquier methods.

CONCLUSIONS

It is technically feasible to perform fractal analysis in children using CMR and that it is quick, accurate and reproducible. Fractal scoring accurately distinguishes between LVNC, hyper-trabeculation and healthy controls as defined by the Petersen criteria.

Serial right ventricular assessment in patients with hypoplastic left heart syndrome: a multiparametric cardiovascular magnetic resonance study

OBJECTIVES

The aim of this study was to assess single right ventricular (RV) function in a large cohort of hypoplastic left heart syndrome (HLHS) patients after the completion of total cavopulmonary connection by analysing serial cardiovascular magnetic resonance (CMR) studies.

METHODS

CMR studies from 95 HLHS patients were analysed. RV end-diastolic and end-systolic volumes (RVEDV, RVESV), ejection fraction (RVEF) and long-axis strain (LAS) were measured from cine images.

RESULTS

All 95 patients had at least 2 CMR scans and 35 patients had 3 CMR scans. The median age (first quartile-third quartile) at the 3 examinations was 4.2 (3.3-6.1), 9.4 (6.1-11.4) and 14.6 (11.8-16.8) years. RV indexed volumes (RVEDVi and RVESVi) increased from first to the second and from the first and second examination to the third examination in patients with >10 years of age (P < 0.05). There was a slight decrease in RVEF and LAS throughout the examinations, but this was not statistically significant. Correlations were found between RVEF and LAS (r = -0.23; P < 0.01). Both RVEF and LAS correlated with RVEDVi and RVESVi (r = -0.17 to 0.43; P < 0.05).

CONCLUSIONS

Serial assessment of CMR studies in HLHS patients after total cavopulmonary connection completion demonstrate an increase in indexed RV volumes in older HLHS patients but only mild reduction in RVEF and LAS. The correlation of indexed RV volumes with RVEF and LAS together with the significant increase in RV volumes over time suggests that indexed RV volumes might be superior to RV functional markers to monitor the RV in HLHS patients.

Analysis of exercise capacity, quality of life and leisure sports in patients with a Fontan circulation

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Despite the improvement in survival, patients with a Fontan circulation are exposed to numerous complications as well as a reduced exercise capacity and quality of life. 

Purpose

To assess the influence of the type of single ventricle (right vs. left) and the amount of sporting activity on exercise capacity and health related quality of life (HRQol) in a large group of Fontan patients.

Methods

Retrospective analysis of standardised cardiopulmonary exercise tests (CPET) performed on a treadmill between 2014 and 2019. Questionnaires to measure HRQol and sporting activity were sent to study participants.

Results

79 patients were enrolled in this study (female, n = 31). 56 of them had a systemic right ventricle (SRV), 20 had a systemic left ventricle (SLV) and 3 had diverse anatomies. Median age at CPET was 12.2 years (range 6.2-34.4 years). The results for important exercise parameters were as follows: peak oxygen uptake (VO2max) 30.7 ± 6.2 ml/kg/min, oxygen uptake at anaerobic threshold (VO2-VAT) 24.7 ± 5.8 ml/kg/min, peak oxygen pulse 8.2 ± 3.4 mlO2/beat and VE/VCO2 slope 39.8 ± 9.1. There was no significant difference in VO2max, VO2-VAT, peak oxygen pulse and VE/CO2 slope between SRV and SLV patients: VO2max 30.2 ± 5.6 vs. 32.8 ± 7.5 ml/kg/min, p = 0.14; VO2-AT 24.4 ± 5.3 vs.25.7 ± 7.3 ml/kg/min, p = 0.53; peak oxygen pulse 7.8 ± 3.2 vs. 9.5 ± 3.9 mlO2/beat, p = 0.06; VE/CO2 slope 41.1 ± 9.6 vs. 36.9 ± 6.8, p = 0.10. Analyses of the questionnaires revealed that most of the patients do leisure sports (n = 60, 76%) with nearly half of them more than two hours per week (n = 26, 33%).

In a subgroup analysis of patients under 18 years (n = 51, 65%) we found that nearly all of them participate in school sports (n = 50) and have a good subjective healthiness (n = 47). VO2-VAT and VO2max correlated positively with subjective healthiness (VO2-VAT r = 0.32, p &lt; 0.05; VO2max r = 0.35, p &lt; 0.05) as well as with the amount of leisure sports activity (hours/week) (VO2-VAT r = 0.37, p &lt; 0.01; VO2max r = 0.50, p &lt; 0.01).

Conclusions

By analysing a large group of patients in Fontan circulation we could demonstrate that there is no difference in exercise capacity between SRV and SLV patients. Furthermore, most of the patients participate in leisure sports and have a good subjective healthiness. In a subgroup of paediatric patients, we were able to show that a better exercise capacity is associated with increased leisure sports activity and a better subjective healthiness.

Surveillance of Fontan Associated Liver Disease in Childhood and Adolescence

Fontan associated liver disease (FALD) has been recognized as a potentially serious sequela of the Fontan circulation. Prevalence of FALD among different age groups and risk factors for advanced changes were assessed. FALD screening included abdominal ultrasound and laboratory tests. A "liver disease score (LDS)" incorporating items from ultrasound and blood testing was calculated to grade FALD severity (5 items each, maximum score 10 points). 240 patients (male: n = 139, female: n = 101, systemic right ventricle: n = 160) underwent FALD screening 10 (IQR 7-15) years after Fontan surgery. Ultrasound was abnormal in 184 (76.6%) patients (surface nodularity / blunted liver edge: n = 133, 55.4%; heterogeneous parenchyma: n = 93, 38.8%; splenomegaly: n = 68, 28.3%; ascites: n = 23, 9.6%). At least one abnormal laboratory test was detected in 218 (90.8%) patients. Gamma-glutamyl-transpeptidase was elevated in the majority of patients (n = 206, 85.8%). Median LDS was 3 (2-4). Scores ≥5 were observed in 32 (13.3%) patients. Longer follow-up (15 (11-20) vs 9 (6-14) years, P <0.001), higher central venous (13 (11-15) vs 10 (9-12) mmHg, P <0.001) and end-diastolic pressure (8 (5-10) vs 6 (5-7) mmHg, P = 0.001), impaired ventricular function and absence of sinus rhythm were associated with LDS ≥5. Longer follow-up (OR 1.2 (1.1-1.3), P <0.001) and higher central venous pressure (OR 1.6 (1.3-2.1), p < 0.001) were the only independent predictors of advanced FALD. Abdominal ultrasound and laboratory abnormalities suggestive of FALD are common during routine follow-up already in childhood and adolescence irrespective of ventricular morphology. More advanced findings are associated with longer follow-up and higher central venous pressure.

Coronary artery ectasia in a child after arterial switch operation for transposition of the great arteries and suspected multisystem inflammatory syndrome in children associated with COVID-19: a case report

Background

Multisystem inflammatory syndrome in children (MIS-C) with features resembling Kawasaki disease has been reported in association with coronavirus disease 2019 (COVID-19).

Case summary

We report the rare case of a 22 months old boy with a history of operated simple transposition of the great arteries (TGA), who developed features of MIS-C likely to be associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection and involving the coronary arteries. Cardiovascular magnetic resonance imaging and cardiac catheterization showed long-distance ectasia of both coronary arteries after their origins and an origin stenosis of the right coronary artery with a perfusion defect. The patient was treated with oral anticoagulation together with antiplatelet therapy and remains under careful monitoring.

Discussion

This rare case demonstrates that also patients with TGA after the arterial switch operation (ASO) can develop coronary artery dilatation in association with MIS-C. The most interesting finding in this patient was that the origins of the reimplanted coronary arteries were not dilated. We speculate that scar tissue formation in the area of coronary artery transfer after ASO has prevented proximal coronary artery dilation.

Myocardial deformation in patients with a single left ventricle using 2D cardiovascular magnetic resonance feature tracking: a case-control study

Ventricular dysfunction is a well-known complication in single ventricle patients in Fontan circulation. As studies exclusively examining patients with a single left ventricle (SLV) are sparse, we assessed left ventricular (LV) function in SLV patients by using 2D-cardiovascular magnetic resonance (CMR) feature tracking (2D-CMR-FT) and 2D-speckle tracking echocardiography (2D-STE). 54 SLV patients (11.4, 3.1–38.1 years) and 35 age-matched controls (12.3, 6.3–25.8 years) were included. LV global longitudinal, circumferential and radial strain (GLS, GCS, GRS) and strain rate (GLSR, GCSR, GRSR) were measured using 2D-CMR-FT. LV volumes, ejection fraction (LVEF) and mass were determined from short axis images. 2D-STE was applied in patients to measure peak systolic GLS and GLSR. In a subgroup analysis, we compared double inlet left ventricle (DILV) with tricuspid atresia (TA) patients. The population consisted of 19 DILV patients, 24 TA patients and 11 patients with diverse diagnoses. 52 patients were in NYHA class I and 2 patients were in class II. Most SLV patients had a normal systolic function but median LVEF in patients was lower compared to controls (55.6% vs. 61.2%, p = 0.0001). 2D-CMR-FT demonstrated reduced GLS, GCS and GCSR values in patients compared to controls. LVEF correlated with GS values in patients (p < 0.05). There was no significant difference between GLS values from 2D-CMR-FT and 2D-STE in the patient group. LVEF, LV volumes, GS and GSR (from 2D-CMR-FT) were not significantly different between DILV and TA patients. Although most SLV patients had a preserved EF derived by CMR, our results suggest that, LV deformation and function may behave differently in SLV patients compared to healthy subjects.

Reference Values for Ventricular Volumes and Pulmonary Artery Dimensions in Pediatric Patients with Transposition of the Great Arteries After Arterial Switch Operation

BACKGROUND

Pulmonary artery (PA) anatomy in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) with Lecompte manoeuvre is different compared to healthy subjects, and stenoses of the PA are common. Magnetic resonance imaging (MRI) is an excellent imaging modality to assess PA anatomy in TGA patients. However, disease-specific reference values for PA size are scarce.

PURPOSE

To establish disease-specific reference ranges for PA dimensions and for biventricular volumes and mass.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 69 pediatric patients with TGA after ASO (median age 12.6 years; range 5-17.8 years; 13 females and 56 males).

FIELD STRENGTH/SEQUENCE

3.0 T, steady-state free precession (SSFP) and gradient echo cine sequences and four-dimensional time-resolved magnetic resonance angiography with keyhole.

ASSESSMENT

Right and left PA (RPA, LPA) were each measured at three locations during its course around the aorta. Ventricular volumes, mass, and ejection fraction were measured from a stack of short axis cine images.

STATISTICAL TESTS

The lambda-mu-sigma (LMS) method of Cole and Green, univariate and multivariate linear models, and t-test.

RESULTS

Centile graphs and tables for PA dimensions, biventricular volumes, mass, and ejection fraction were created. Univariate linear analysis showed significant associations (P < 0.05) between body surface area (BSA), height, and weight with systolic MPA and RPA diameter. In multivariate linear analysis, only BSA remained a strong predictor for main PA and RPA diameters. For biventricular volumes, the univariate linear model revealed a strong influence of BSA, height, weight, and age (all P < 0.05). On multivariate linear analysis, only body height remained associated.

DATA CONCLUSION

Uni- and multivariate linear analyses showed a strong association between BSA and PA diameters, as well as between height and biventricular volumes, and therefore, centile tables and graphs are presented accordingly. Our data may improve MR image interpretation and may serve as a reference in future studies.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY STAGE: 2.

3D-printed, patient-specific intracranial aneurysm models: From clinical data to flow experiments with endovascular devices

PURPOSE

Flow models of intracranial aneurysms (IAs) can be used to test new and existing endovascular treatments with flow modulation devices (FMDs). Additionally, 4D flow magnetic resonance imaging (MRI) offers the ability to measure hemodynamics. This way, the effect of FMDs can be determined noninvasively and compared to patient data. Here, we describe a cost-effective method for producing flow models to test the efficiency of FMDs with 4D flow MRI.

METHODS

The models were based on human radiological data (internal carotid and basilar arteries) and printed in 3D with stereolithography. The models were printed with three different printing layers (25, 50, and 100 µm thickness). To evaluate the models in vitro, 3D rotational angiography, time-of-flight MRI, and 4D flow MRI were employed. The flow and geometry of one model were compared with in vivo data. Two FMDs (FMD1 and FMD2) were deployed into two different IA models, and the effect on the flow was estimated by 4D flow MRI.

RESULTS

Models printed with different layer thicknesses exhibited similar flow and little geometric variation. The mean spatial difference between the vessel geometry measured in vivo and in vitro was 0.7 ± 1.1 mm. The main flow features, such as vortices in the IAs, were reproduced. The velocities in the aneurysms were similar in vivo and in vitro (mean velocity magnitude: 5.4 ± 7.6 and 7.7 ± 8.6 cm/s, maximum velocity magnitude: 72.5 and 55.1 cm/s). By deploying FMDs, the mean velocity was reduced in the IAs (from 8.3 ± 10 to 4.3 ± 9.32 cm/s for FMD1 and 9.9 ± 12.1 to 2.1 ± 5.6 cm/s for FMD2).

CONCLUSIONS

The presented method allows to produce neurovascular models in approx. 15 to 30 h. The resulting models were found to be geometrically accurate, reproducing the main flow patterns, and suitable for implanting FMDs as well as 4D flow MRI.

Assessment of myocardial deformation in patients with a singule left ventricle using CMR feature tracking and speckle tracking echcardiography

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with a single ventricle are at risk for ventricular dysfunction in the long-term follow-up during and after completion of the total cavopulmonary connection (TCPC). Hence a detailed assessment of ventricular function is of high clinical relevance in those patients. Echocardiography and cardiovascular magnetic resonance (CMR) are routinely used to examine ventricular function with newer techniques, such as tissue tracking, enabling to determine regional and global myocardial deformation. Studies focusing on patients with a single left ventricle (SLV) are sparse. We assessed LV function in a larger cohort of SLV patients by using CMR feature tracking (FT) and speckle tracking echocardiography (STE).

Methods

56 SLV patients (mean age 12.0.5 ± 8.1 years) who underwent CMR as part of a routine clinical examination were included. The study population consisted of 20 patients with double inlet left ventricle (DILV), 25 patients with tricuspid atresia (TA) and 11 patients with various diagnoses. 36 patients had an echocardiographic examination within 3 months of the CMR study. Left ventricular longitudinal, circumferential and radial strain and strain rate were measured from short axis stacks at basal, midventricular and apical levels as well as from 4-chamber-views using FT. LV end-diastolic and end-systolic volumes (LVEDV, LVESV), ejection fraction (LVEF) and myocardial mass were determined from short axis images. 2D-STE was used to measure global peak systolic longitudinal strain and strain rate. In a subgroup analysis we compared patients with a DILV with patients who had TA.

Results

Apart from two patients, all patients were in NYHA class I. LVEF was preserved in the total group of patients (LVEF 56.1 ± 8.4%) and correlated well with global and regional circumferential strain (r= -0.38 to -0.74, p &lt; 0.01), global radial strain (r= 0.33, p &lt; 0.05) and global longitudinal strain values (r= -0.31, p &lt; 0.05). There was a mild association between LVEF and age at Fontan completion (r= -0.28, p = 0.04). There was no significant difference between the results for global longitudinal strain from FT and STE in the entire patient group. In the subgroup analysis there was no difference in LVEF, LV volumes and global strain and strain rate values from FT and STE between patients with DILV and TA.

Conclusion

SLV patients in this study had a preserved ejection fraction along with an overall good health. The correlation of global and regional strain values derived from CMR FT with LVEF demonstrates that FT might be valuable to assess ventricular function in SLV patients during long-term follow-up.

Serial right ventricular assessment in patients with hypoplastic left heart syndrome patients (HLHS): a cardiovascular magnetic resonance study

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with hypoplastic left heart syndrome (HLHS) are at risk for right ventricular (RV) dysfunction over the course of the three-stage surgical palliation with the final step being the completion of the total cavopulmonary connection (TCPC). However, less is known about RV function during follow-up after TCPC completion. We assessed RV function by analysing serial cardiovascular magnetic resonance (CMR) studies in a large cohort of HLHS patients.

Methods

CMR studies from 95 HLHS patients (67 males) were retrospectively analysed. Short axis cine images were used to measure RV end systolic and end diastolic volumes and ejection fraction (RVEF). Oblique cine images showing the atria and right ventricle in a similar manner like a standard "4-chamber view" were used to measure tricuspid annular plane systolic excursion (TAPSE) and long axis strain (LAS).

Results

From the 95 patients, all had at least two and 32 patients had three CMR scans. The first scan was performed at a mean age of 4.9 ± 2.8 years, the second scan at a mean age of 9.3 ± 4 years and the third at a mean age of 14.3 ± 3.7 years. The mean values of RV end diastolic and end systolic volume indexed to body surface area (REDVi, RVESVi) as well as RV ejection fraction (RVEF) at the three time points were: 1) REDVi 92.6 ± 21.9 ml/m2, RVESVi 43 ± 15.1 ml/m2, RVEF 54.2 ± 7.1%; 2) REDVi 93.9 ± 25.6 ml/m2, RVESVi 44.6 ± 18.3 ml/m2, RVEF 53.6 ± 7.8%; 3) REDVi 110.9 ± 41.9 ml/m2, RVESVi 58.1 ± 35 ml/m2, RVEF 50.1 ± 10.1%. There was a statistically significant increase in RVEDVi and RVESVi from the first and the second scan to the third scan (p &lt; 0.01). RVEF was lower at the time of the third scan compared to the first and second scan, but this difference was not statistically significant. TAPSE increased slightly from the first to the third scan (p &lt; 0.05). There was no change in stroke volume and LAS from the first to the third scan. Strong correlations were found between RVEF and LAS as well as between RVEF and TAPSE (r = 0.49 and r=-0.50; p &lt; 0.001, respectively).

Conclusion

Serial assessment of CMR studies in HLHS patients after TCPC completion could demonstrate an increase in indexed RV volumes over time, whereas RV stroke volume, RVEF and LAS largely remain stable.

Ventricular and atrial function in transposition of the great arteries after arterial switch operation - a comprehensive cardiovascular magnetic resonance study

Funding Acknowledgements

Type of funding sources: None.

Background

Although good long-term results after arterial switch operation (ASO) in patients with transposition of the great arteries (TGA) have been described, a few studies suggest that patients can develop ventricular dysfunction. We established a comprehensive cardiovascular magnetic resonance (CMR) analysis protocol to evaluate biventricular and atrial function markers in a large cohort of paediatric and adult TGA patients after ASO.

Methods

103 TGA patients (median age 16.7 years, range 4.3-39.6 years) who underwent ASO were retrospectively included. 66 patients had simple transposition and 37 patients had associated anomalies (ventricular septal defect (VSD) n= 30, aortic coarctation n= 11). 77 healthy subjects were enrolled as controls (median age 15.4 years, range 6.3-43.2 years). 

Biventricular volumes, wall thickness as well as ventricular and atrial functional and deformation parameters were assessed using standard CMR analyses techniques as well as CMR feature tracking (FT). For statistical analysis each clinical variable was evaluated by standard nonparametrical tests and jointly assessed with machine learning methods (random forest, Boruta). The significant variables were used to build a logistic regression model for predicting the case-control status

Results

Results from Mann-Whitney-U test revealed that both, left and right ventricular function markers (left ventricular ejection fraction (LVEF); right ventricular ejection fraction (RVEF); MAPSE; TAPSE; LV long-axis strain) were reduced in patients compared to controls. In addition, left ventricular global longitudinal (-21.18 ± 4.49 / -23.93 ± 3.41; p &lt; 0.001) and circumferential strain values (-29.28 ± 4.30 / -31.32 ± 3.63; p = 0.001) as well as longitudinal strain values for both atria (LA: 24.18 ± 8.04 / 37.81 ± 10.30; p &lt; 0001; RA: 23.89 ± 11.12 / 34.47 ± 10.87; p &lt; 0.001) were lower in patients compared to controls. Segmental FT analysis revealed that the interventricular septum appeared most affected. The logistic regression model demonstrated significant differences for MAPSE, TAPSE (Figure), left atrial global longitudinal strain and basal inferoseptal radial strain. Strong correlations were found between MAPSE and TAPSE (Figure) as well as between left atrial global longitudinal strain and MAPSE (r= 0.54, p &lt; 0.001).

Conclusions

TGA patients after ASO are at risk for ventricular and atrial dysfunction. Using a comprehensive CMR analysis protocol along with statistical machine learning methods and a regression approach, we could demonstrate that especially biventricular longitudinal function, left atrial function and basal septal deformation is impaired.

Abstract Figure

Cardiovascular magnetic resonance (CMR) normal values for pulmonary arteries in healthy children and adolescents

Funding Acknowledgements

Type of funding sources: None.

Background

Changes in the right ventricular outflow tract (RVOT) and pulmonary arteries (PAs) are often seen in paediatric patients with congenital heart disease (CHD), pulmonary hypertension or genetic disorders (e.g. Marfan syndrome, Loeys-Dietz syndrome, Williams syndrome, DiGeorge syndrome). Cardiovascular magnetic resonance (CMR) imaging is an excellent method to visualize the RVOT and PAs without the use of ionizing radiation and contrast media but for the interpretation of CMR data in the paediatric population the knowledge of normal values is crucial. However, normal values for pulmonary arteries from contrast-free cine CMR images are lacking.

Purpose

The aim of this retrospective multicentre study was to establish reference ranges for the diameters of the mean PA (MPA), right PA (RPA) and left PA (LPA).

Methods

163 CMR scans of healthy children and adolescents (mean age 13.8 ± 2.9 years; range 5-18 years) from two centres in the UK and Germany were included. The diameter of the MPA was measured in sagittal-oblique RVOT cine images and transaxial cine stacks, whereas the diameter of the RPA and LPA were measured from transaxial stacks and specific pulmonary artery branch cine images.

Results

Mean systolic and diastolic diameters for the MPA were 22.1 ± 2.8 mm (14.4 ± 2.2 mm/m²)/ 17.2 ± 2.3 mm (11.3 ± 1.9 mm/m²) measured in RVOT cine stacks. Mean systolic and diastolic diameters for the RPA and LPA were:  1) RPA, 12.4 ± 1.7 mm (7,9 ± 1,6 mm/m²)/ 9.8 ± 1.6 mm (5.9 ± 1.8 mm/m²) and 2) LPA, 13.3 ± 1.5 mm (8.3 ± 2.1 mm/m²)/ 10.8 ± 1.5 mm (6.8 ± 1.8 mm/m²). Separate centile charts for boys and girls for the MPA were created.

Conclusions

We established CMR normal values for the MPA, RPA and LPA for children and adolescents. Our data might be useful for the detection of PA stenosis and dilatation and may serve as a reference in future studies.

Cardiovascular magnetic resonance normal values for pulmonary arteries and ventricular volumes in paediatric patients with transposition of the great arteries after arterial switch operation

Funding Acknowledgements

Type of funding sources: None.

Background

The anatomy of the pulmonary arteries (PA) in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) with Lecompte manoeuvre is different compared to healthy subjects and stenoses of the PA are known to occur. Cardiovascular magnetic resonance (CMR) imaging is an excellent imaging modality to assess PA anatomy in TGA patients. However, disease specific normal values for PA size do not exist. Furthermore, the impact of pulmonary artery size, age and gender on ventricular volumes and function is unknown. Therefore, we sought to establish disease specific normative ranges for PA dimensions as well as biventricular volumes and function.

Methods

70 CMR scans of paediatric patients with TGA after ASO with Lecompte manoeuvre (mean age 12.3 ± 3.6 years; range 5-18 years; 57 males) were included. Cine CMR sequences as well as contrast-enhanced magnetic resonance angiography (CE-MRA) data were used to measure pulmonary artery dimensions. Right and left PA were each measured at three locations during its course around the aorta. Ventricular volumes, mass and ejection fraction were measured from a stack of short axis cine images.

Results

Mean systolic and diastolic diameters of the MPA were 15.0 ± 2.3 mm (10.5 ± 2.7 mm/m²) / 13.2 ± 2.9 mm (9.2 ± 2.9 mm/m²) and mean cross-sectional MPA area was 286.7 ± 81.7 mm². Mean systolic and diastolic diameters for the RPA and LPA at the narrowest point were: RPA 10.5 ± 2.8 mm (7.8 ± 2.4 mm/m²)  / 8.1 ± 2.2 mm (6.0 ± 1.9 mm/m²); LPA 8.4 ± 2.8 mm (6.2 ± 2.1 mm/m²) / 7.4 ± 2.3 mm (5.4 ± 1.6 mm/m²). Mean values for biventricular volumes, ejection fraction and mass were as follows: 1) left  ventricular (LV) end-diastolic volume (EDV) 89.0 ± 20.3 ml/m² and end-systolic volume (ESV) 35.1 ± 11.7 ml/m², 2) right ventricular (RV) EDV 76.4 ± 15.4 ml/m² and ESV 32.4 ± 9.1 ml/m², 3) LV and RV ejection fraction 61.1 ± 6.5 % / 58.9 ± 6.1 % and 4) LV and RV mass 59.6 ± 15.2 g/m² / 23.3 ± 7.4 g/m². Separate centile charts for boys and girls for PA dimensions as well as biventricular volumes, mass and ejection fraction were created.

Conclusion

We established disease specific CMR normal values for the PA dimensions as well as for ventricular volumes, mass and ejection fraction in paediatric patients with TGA after ASO. Our data will improve CMR image interpretation and may serve as a reference in future studies.

The interplay of systemic atrial and ventricular function in patients with transposition of the great arteries after arterial switch operation

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: The role of systemic atrial (LA) function and its interplay with the systemic ventricle (LV) in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) is currently not well defined.

Purpose

Investigate the role of LA function and its interplay with the LV.

Methods

Between 2007 and 2018 patients with TGA corrected by ASO and control patients of comparable age, sex, height but without known cardiovascular disease were included in this prospective single centre analysis of 3 Tesla cardiac magnetic resonance cine imaging studies of atrial and ventricular function. Additionally, in TGA patients extracellular volume fraction (ECV) was assessed by T1 mapping and global longitudinal strain (GLS) by feature tracking.

Results

Overall, 81 TGA (16.3 [IQR 10.5-21.2] years, 32% female) and 30 control patients (11.9 [IQR 8.7-22.5] years, 63% female) were included in the current analysis. TGA patients had smaller LA maximum volume index, and reduced total atrial and conduit volume emptying. This resulted in a reduced LA reservoir and conduit function compared to controls. In TGA, a higher LA active/conduit and active/total ratio indicated impaired passive filling of the LV. (Table 1)

The median ECV was 28.3% (IQR 25.8-33.9) and the median GLS -24.2% (IQR -28.6- -20.4) in TGA patients. LA reservoir (Fig. 1A), conduit and contractile function showed a negative correlation with GLS (r=-0.470, p &lt; 0.001, r=-0.270, p = 0.022 and r=-0.257, p = 0.030, respectively). Interestingly, the LA active/conduit ratio (Fig. 1B) and the active/total ratio showed a positive correlation with ECV (r = 0.418, p = 0.002 and r = 0.339, p = 0.013, respectively).

Conclusion

Impaired LA function is frequent among patients with TGA following ASO. The impairment of LA function is linked to both LV dysfunction and fibrosis.

Table 1 Variable TGA (n = 81) Control (n = 30) p-value LAVI max.[ml/m&sup2;] 37.8 (29.9-42.9) 42.02 (38.3-51.6) 0.002 LAVI total emptying [ml/m&sup2;] 16.8 (13.7-20.8) 24.3 (20.6-29.4) &lt;0.001 LAVI conduit emptying [ml/m&sup2;] 10.3 (8.1-13.9) 17.5 (15.2-20.8) &lt;0.001 LAVI active [ml/m&sup2;] 6.7 (4.1-8.6) 6.4 (5.0-7.9) 0.984 LA-EF-reservoir [%] 46.6 (42.0-50.5) 57.2 (51.2-60.1) &lt;0.001 LA-EF-conduit [%] 28.1 (23.4-34.3) 42.5 (35.4-45.8) &lt;0.001 LA-EF-active [%] 24.11 (17.9-29.1) 25.7 (21.5-29.7) 0.339 LA active/conduit ratio 0.60 (0.41-0.90) 0.37 (0.28-0.44) &lt;0.001 LA active/total ratio 0.38 (0.29-0.47) 0.27 (0.22-0.30) &lt;0.001 Differences in left atrial function between TGA and control patients Abstract Figure. Fig. 1A and B

Cardiovascular magnetic resonance normal values in children for biventricular wall thickness and mass

BACKGROUND

Pediatric patients are becoming increasingly referred for cardiovascular magnetic resonance (CMR). Measurement of ventricular wall thickness is typically part of the assessment and can be of diagnostic importance, e.g. in arterial hypertension. However, normal values for left ventricular (LV) and right ventricular (RV) wall thickness in pediatric patients are lacking. The aim of this study was to establish pediatric centile charts for segmental LV and RV myocardial thickness in a retrospective multicenter CMR study.

METHODS

CMR was performed in 161 healthy children and adolescents with an age range between 6 and 18 years from two centers in the UK and Germany as well as from a previously published CMR project of the German Competence Network for Congenital Heart Defects. LV myocardial thickness of 16 segments was measured on the short axis stack using the American Heart Association segmentation model. In addition, the thickness of the RV inferior and anterior free wall as well as biventricular mass was measured.

RESULTS

The mean age (standard deviation) of the subjects was 13.6 (2.9) years, 64 (39.7%) were female. Myocardial thickness of the basal septum (basal antero- and inferoseptal wall) was 5.2 (1.1) mm, and the basal lateral wall (basal antero- and inferolateral) measured 5.1 (1.2) mm. Mid-ventricular septum (antero- and inferoseptal wall) measured 5.5 (1.2) mm, and mid-ventricular lateral wall (antero- and inferolateral wall) was 4.7 (1.2) mm. Separate centile charts for boys and girls for all myocardial segments and myocardial mass were created because gender was significantly correlated with LV myocardial thickness (p < 0.001 at basal level, p = 0.001 at midventricular level and p = 0.005 at the apex) and biventricular mass (LV, p < 0.001; RV, p < 0.001).

CONCLUSION

We established CMR normal values of segmental myocardial thickness and biventricular mass in children and adolescents. Our data are of use for the detection of abnormal myocardial properties and can serve as a reference in future studies and clinical practice.

Pulmonary sling in a patient with common arterial trunk

We report a rare association of common arterial trunk with left pulmonary artery sling and highlight the importance of cross-sectional imaging in complex congenital cardiac lesions. The patient was antenatally diagnosed with common arterial trunk and underwent surgical repair in the neonatal period. At the age of 20 months, the patient presented with respiratory symptoms and increased right ventricular pressure. Multislice computed tomography demonstrated a pulmonary sling with compression of the distal trachea. Surgical correction of the pulmonary sling and change of the right ventricular to pulmonary artery conduit to a bigger size was performed.