Serial assessment of right ventricular function and deformation in patients with hypoplastic left heart syndrome: a cardiovascular magnetic resonance study

Background

In patients with hypoplastic left heart syndrome (HLHS), right ventricular (RV) dysfunction and failure is a major cause of adverse outcome. Most studies have assessed RV function and size during staged palliation but serial data about RV deformation and function after completion of the Fontan circulation are rare. We assessed RV function and deformation by analysing serial cardiovascular magnetic resonance (CMR) studies in a large cohort of HLHS patients after completion of the total cavopulmonary connection (TCPC).

Methods

CMR examinations of 105 HLHS patients (female: 31, male: 74) were retrospectively analysed. Short axis cine images were used to measure RVEF and end-diastolic myocardial mass indexed to body surface area (RVMMi). 2-dimensional CMR feature tracking (2D-CMR-FT) was performed using long-axis and short axis cine images to measure myocardial global longitudinal, circumferential and radial strain (GLS, GCS, GRS) values.

Results

From 105 patients, all had at least two CMR examinations after TCPC completion (mean age at TCPC: 2.7±0.8 years; mean interval between examinations 5.4±1.6 years). 36 patients had three examinations (mean interval between first and third scan 9.9±2.2 years). The first scan was performed at a mean age of 5.6±2.9 years. Global strain values and RVEF decreased from the first to the third examination with a significant decline in GLS from the first examination to the second examination (median and interquartile range (IQR): −18.6%, IQR −20.4 to −16.3 vs. −16.8%, IQR −19.2 to −14.7) and from the first to the third examination in 36 patients (−18.6%, IQR −20.8 to −16.1 vs. −15.9%, IQR −18.3 to −12.4) (all p-values <0.004). RVEF decreased significantly from the first to the third examination (55.9%, IQR 50.2–59.8 vs. 50.4%, IQR 45.0–57.6; p<0.002) and from the second to the third examination (55.1%, IQR 47.1–58.7 vs. 50.4%, IQR 45.0–57.6; p<0.0004). The decrease in RVEF between the first and second scan and the changes in GCS and GRS across the examinations did not reach statistical significance. Median RVMMi increased significantly between the first and second scan (47.4 g/m2, IQR 39.0–55.3 vs. 50.2 g/m2, IQR 42.6–61.7; p<0.0007) and slightly but not significantly between the first and third scan in patients with three examinations (47.4 g/m2, IQR 39.5–56.2 vs. 50.1 g/m2, IQR 45.3–60.4). Negative correlations between GCS and RVEF (r=−0.57 to −0.76; p all <0.0001) as well as between GLS and RVEF (r=−0.31 to −0.59; p all <0.002) at all three time points could be demonstrated.

Conclusion

Serial assessment of CMR studies in HLHS patients after TCPC completion demonstrates a significant reduction in global strain values and RVEF at mid-term follow-up. The significant reduction in GLS between the first two examinations with non-significant changes in RVEF suggest that 2D-CMR-FT might be a suitable technique for the detection of early myocardial dysfunction.

Funding Acknowledgement

Type of funding sources: None.

Normal values for paediatric atrial volumes assessed by steady-state free-precession cardiovascular magnetic resonance

Background

Measurement of atrial volumes by steady-state free precession (SSFP)cardiovascular magnetic resonance (CMR) is becoming increasingly important in the treatment and follow-up of paediatric congenital heart disease. It has prognostic value in terms of heart failure and cardiovascular death. However, CMR normal values for the clinically often used mono- and biplane area-length method in children are lacking.

Aims

We sought to create paediatric normal values for atrial volumes using the mono- and biplane area-length method.

Methods

In a retrospective study design, CMR data sets of 157 healthy children with an age range between 4 and 18 years from two centers in the UK and Germany were evaluated. In a four-chamber (4ch-) view, left and right atrial (LA, RA) endocardial borders were segmented during end-diastole and end-systole to calculate minimal and maximal atrial volumes (LAmin, LAmax, RAmin, RAmax) using the monoplane area-length method. Additionally, end-diastolic and end-systolic LA endocardial borders were segmented in a two-chamber (2ch-) view. Using the measurements from the 2ch- and 4ch-views, minimal and maximal LA volumes were calculated using the biplane area-length method. Atrial volumes were normalized for body surface area (BSA in m2). Sex-specific reference curves were created using the lambda mu sigma method.

Results

The median age was 13.8±2.81 years (53 girls).

In children from 4–10 years average atrial volumes measured: monoplane 4ch: LAmin 10.2±3.5 ml/m2, LAmax 28.8±7.4 ml/m2, RAmin 14.1±6.3 ml/m2, RAmax 27.0±11.4 ml/m2; monoplane 2ch: LAmin 10.9±4.1 ml/m2, LAmax 27.0±6.1 ml/m2; biplane: LAmin 10.2±3.3 ml/m2, LAmax 27.4±5.7 ml/m2.

In children from 11–18 years average atrial volumes measured: monoplane 4ch: LAmin 13.6±4.9 ml/m2, LAmax 34.1±9.1 ml/m2, RAmin 19.2±6.8 ml/m2, RAmax 34.2±9.6 ml/m2; monoplane 2ch: LAmin 13.2±4.9 ml/m2, LAmax 31.4±9.7 ml/m2; biplane: LAmin 12.9±4.4 ml/m2, LAmax 31.8±8.8 ml/m2.

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

Conclusion

We provide paediatric CMR reference values for atrial volumes. 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.

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.

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 < 0.05; VO2max r = 0.35, p < 0.05) as well as with the amount of leisure sports activity (hours/week) (VO2-VAT r = 0.37, p < 0.01; VO2max r = 0.50, p < 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.

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 < 0.01), global radial strain (r= 0.33, p < 0.05) and global longitudinal strain values (r= -0.31, p < 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 < 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 < 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 < 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 < 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 < 0001; RA: 23.89 ± 11.12 / 34.47 ± 10.87; p < 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 < 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 < 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/m²] 37.8 (29.9-42.9) 42.02 (38.3-51.6) 0.002 LAVI total emptying [ml/m²] 16.8 (13.7-20.8) 24.3 (20.6-29.4) <0.001 LAVI conduit emptying [ml/m²] 10.3 (8.1-13.9) 17.5 (15.2-20.8) <0.001 LAVI active [ml/m²] 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) <0.001 LA-EF-conduit [%] 28.1 (23.4-34.3) 42.5 (35.4-45.8) <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) <0.001 LA active/total ratio 0.38 (0.29-0.47) 0.27 (0.22-0.30) <0.001 Differences in left atrial function between TGA and control patients Abstract Figure. Fig. 1A and B

Erworbenes von-Willebrand-Syndrom bei Kindern mit hämodynamisch relevantem Vitium

Das erworbene von-Willebrand-Syndrom (VWS) ist eine seltene Gerinnungsstörung im Rahmen anderer (z. B. kardiovaskulärer) Erkrankungen, die bei operativen oder interventionellen Eingriffen zu starken Blutungen führen kann. Zur Verdachtsdiagnose führen die prädisponierende Grunderkrankung, die leere Blutungsanamnese und die pathologisch veränderten von-Willebrand-Faktor-Parameter. Wir berichten über zwei Patienten mit kongenitalen Vitien und negativer Blutungsanamnese, bei denen präoperativ durch erweiterte Gerinnungsdiagnostik die Diagnose eines erworbenen VWS gestellt wurde.

[Acquired von Willebrand syndrome in two children with congenital heart defects and abnormal haemodynamics]

Acquired von Willebrand syndrome is a rare bleeding disorder associated with other primary diseases such as cardiovascular disorders which can cause severe haemorrhage during surgery or interventional procedures. It should be suspected if there is no history of bleeding and abnormal von Willebrand factor (VWF) values in patients with predisposing disorders. We present two children with congenital heart defects and no personal or family history of bleeding. In these patients we preoperative diagnosed acquired von Willebrand syndrome with coagulation tests including analysis of the VWF multimeric pattern.

[Osteosynthesis after sagittal division of the mandible. Biomechanical stability of various methods in a pig mandibular model]

Forty years after the introduction of sagittal split osteotomy for transposition of the mandible according to Obwegeser, very different procedures for osteosynthesis are still discussed and practised. In a simple biomechanical model in the porcine mandible, five different methods for osteosynthesis using metallic screws (titanium, cobalt-chromium-molybdenum alloy) and one using a polymer screw (polylactic acid-copolymer blend), as well as the use of miniplates, were studied with regard to the stability of the compound. The Kruskal-Wallis H-test (variance analysis by ranks) showed statistically highly significant differences (P = 0.00017) regarding maximum stability. Osteosynthesis by miniplates was very stable with regard to the maximum load (Fmax = 234 N +/- 47), but not so in terms of three-dimensional stability of the osteosynthesis itself. The highest stability of osteosynthesis with screws only (Fmax = 183 N +/- 65) was found for a 2.7-mm titanium screw in triangular geometry. The use of 2.7-mm cobalt-chromium-molybdenum screws (Fmax = 173 N +/- 42) and 3.5-mm titanium screws (Fmax = 160 N +/- 76) did not make an statistical difference (P = 0.37). The mechanical values of 2.0-mm titanium screws in linear (Fmax = 113 N +/- 37) or triangular (Fmax = 136 N +/- 62) geometry and of 3.5-mm polylactic acid-copolymer blend screws (Fmax = 121 N +/- 33) did not differ statistically from each other (P = 0.75) but they did from the previous group (P = 0.019). In consideration of the low biting forces following sagittal split osteotomy, all tested procedures of osteosynthesis meet the mechanical requirements for clinical practice.