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BackgroundStandardized methods for mapping the complex blood flow in vessels are essential for processing the large data volume acquired from 4D Flow MRI. We present a method for systematic and efficient analysis of anatomy and flow in large human blood vessels. To attain the best outcomes in cardiac surgery, vascular modifications that lead to secondary flow patterns such as vortices should be avoided. In this work, attention was paid to the undesired cancelation of vortices with opposite directions of rotation, known as Dean flow patterns, using hemodynamic parameters such as circulation and helicity density.MethodsOur approach is based on the multiplanar reconstruction (MPR) of a multi-dimensional feature-space along the blood vessel's centerline. Hemodynamic parameters and anatomic information were determined in-plane from the reconstructed feature-space and from the blood vessel's centerline. A modified calculation of circulation and helicity density and novel parameters for quantifying Dean flow were developed. To test the model performance, we applied our methods to three test cases.ResultsComprehensive information on position, magnitude and interrelation of vascular anatomy and hemodynamics were extracted from 4D Flow MRI datasets. The results show that the Dean flow patterns can be efficiently assessed using the novel parameters.ConclusionsOur approach to comprehensively and simultaneously quantify multiple parameters of vascular anatomy and hemodynamics from 4D Flow MRI provides new insights to map complex hemodynamic conditions.

BackgroundThe Norwood procedure is the first stage of correction for patients with hypoplastic left heart syndrome (HLHS) and may lead to an abnormal neoaortic anatomy. We prospectively studied the neoaorta's fluid dynamics and the abnormal twist of the neoaorta by MRI examinations of HLHS patients in Fontan circulation. This study for the first time investigates the hypothesis that the neoaorta twist is associated with increased helical flow patterns, which may lead to an increased workload for the systemic right ventricle (RV) and ultimately to RV hypertrophy.MethodsA group of forty-two HLHS patients with a median age of 4.9 (2.9-17.0) years, at NYHA I was studied along with a control group of eleven subjects with healthy hearts and a median age of 12.1 (4.0-41.6). All subjects underwent MRI of the thoracic aorta including ECG-gated 2D balanced SSFP cine for an axial slice stack and 4D-flow MRI for a sagittal volume slab covering the thoracic aorta. The twist of the neoaortic arch was quantified by the effective geometric torsion, defined as the product of curvature and geometric torsion. Fluid dynamics and geometry in the neoaorta, including the flow helicity index, were evaluated using an in-house analysis software (MeVisLab-based). Myocardial mass of the systemic ventricle at end-diastole was estimated by planimetry of the short-axis stack.ResultsCompared to the control group, the neoaorta in the HLHS patients shows an increased twist (P=0.04) and higher peak helicity density (P=0.03). The maximum helicity density was correlated with maximum effective torsion of the ascending neoaorta (P

BackgroundThe 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.MethodsOne 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).ResultsHyperemic 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

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The Fontan procedure provides relief from cyanosis in patients with univentricular hearts. A major clinical unmet need is to understand whether the venous flow patterns of the Fontan circulation lead to the development of congestive hepatopathy and other life-threatening complications. Currently, there is no consensus on whether heart beat or respiration is the main driving force of venous return and which one affects the periodic flow changes for the most (i. e., pulsatility). The present study, for the first time, quantified respiratory and cardiac components of the venous flow in the inferior vena cava (IVC) of 14 Fontan patients and 11 normal controls using a novel approach ("physio-matrix"). We found that in contrast to the normal controls, respiration in Fontan patients had a significant effect on venous flow pulsatility, and the ratio of respiration-dependent to the cardiac-dependent pulsatility was positively associated with the retrograde flow. Nevertheless, the main driving force of net IVC flow was the heart beat and not respiration. The separate analysis of the effects of respiration and heart beat provides new insights into the abnormal venous return patterns that may be responsible for adverse effects on liver and bowel of the patients with Fontan circulation.

Transposition of the great arteries (TGA) is caused by discordance between the great arteries and the ventricles. If left untreated, this anomaly has a disastrous perspective. More recent surgical approach for correction includes the Lecompte technique in which the pulmonary bifurcation is transposed anterior to the aorta, which may be less physiologic. Although the early results are excellent, there is potential for future problems involving the great arteries and semilunar valves1. These potential problems necessitate the development of other improved surgical techniques2. Here we report an MRI 4D flow study related to a case of simple TGA whose primary surgical correction - direct spiral arterial switch operation (DSASO) - was performed twenty years ago in an attempt to restore physiologic arrangement among the great arteries and semilunar valves.

ObjectivesTo compare the Lecompte technique and the spiral anastomosis (complete anatomic correction) two decades after arterial switch operation (ASO).MethodsNine patients after primary ASO with Lecompte and 6 selected patients after spiral anastomosis were evaluated 20.8 ± 2.1 years after ASO versus matched controls. Blood flow dynamics and flow profiles (e.g. vorticity, helicity) in the great arteries were quantified from time-resolved 3D magnetic resonance imaging (MRI) phase contrast flow measurements (4D flow MR) in addition to a comprehensive anatomical and functional cardiovascular MRI analysis.ResultsCompared with spiral reconstruction, patients with Lecompte showed more vortex formation, supranatural helical blood flow (relative helicity in aorta: 0.036 vs 0.089; P < 0.01), a reduced indexed cross-sectional area of the left pulmonary artery (155 vs 85 mm²/m²; P < 0.001) and more semilunar valve dysfunctions (n = 5 vs 1). There was no difference in elastic aortic wall properties, ventricular function, myocardial perfusion and myocardial fibrosis between the two groups. Cross-sectional area of the aortic sinus was larger in patients than in controls (669 vs 411 mm²/m²; P < 0.01). In the spiral group, the pulmonary root was rotated after ASO more towards the normal left position (P < 0.01).ConclusionsIn this study, selected patients with spiral anastomoses showed, two decades after ASO, better physiologically adapted blood flow dynamics, and attained a closer to normal anatomical position of their great arteries, as well as less valve dysfunction. Considering the limitations related to the small number of patients and the novel MRI imaging techniques, these data may provoke reconsidering the optimal surgical approaches to transposition of the great arteries repair.

PurposeTo determine whether neglecting the flow unsteadiness in simplified Bernoulli's equation significantly affects the pulmonary transvalvular pressure drop estimation.Materials and methods3.0T magnetic resonance imaging (MRI) 4D velocity mapping was performed on four healthy volunteers, seven patients with repaired tetralogy of Fallot, and thirteen patients with transposition of the great arteries repaired by arterial switch. Pulmonary transvalvular pressure drop was estimated based on two methods: General Bernoulli's Equation (GBE), ie, the most complete form; and Simplified Bernoulli's Equation (SBE), known as 4V(2) . More than 2300 individual pressure drop measurements were used to compare the simplified and the general Bernoulli's methods. A linear mixed-effects model was employed for statistical analyses, fully accounting for clustering of observations among the methods and systolic phases.ResultsThe simplified Bernoulli's method systematically underestimated the pressure drop compared to general Bernoulli's method during the entire systolic phase (P < 0.05), including the peak systole, where on average ΔpSBE/ΔpGBE=78%.ConclusionThe simplified Bernoulli method underestimated the pressure drop during all systolic phases in all the studied subjects. Therefore, it is necessary to take into account the flow unsteadiness for more accurate estimation of the pressure drop. J. Magn. Reson. Imaging 2016;43:1313-1319.

Background: Measurement of ventricular volumes and function using MRI is an important tool in pediatric congenital heart disease. However, normal values for children are sparce and analysis methods are inconsistent. Purpose: To propose biventricular reference values in children for two MRI postprocessing (contouring) techniques. Study Type: Retrospective. Subjects: A total of 154 children from two institutions (13.9 ± 2.8 years; 101 male) that were referred for a clinical MRI study. Field Strength/Sequence: 1.5 T; balanced steady‐state free precession (bSSFP) sequence. Assessment: Left ventricular (LV) and right ventricular (RV) end‐diastolic and end‐systolic volumes (LVEDV, LVESV, RVEDV, RVESV) and end‐diastolic and end‐systolic myocardial mass (LVEDMM, LVESMM, RVEDMM, RVESMM) were measured from short‐axis images using two contouring techniques: 1) papillary muscles, trabeculations and the moderator band were included in the ventricular blood volume and excluded from the myocardial mass, 2) papillary muscles, trabeculations and the moderator band were excluded from the ventricular volume and included in the ventricular mass. Statistical Tests: Univariable and multivariable linear regression models were used to evaluate relationships between sex, weight, height, body surface area (BSA) and age and volumetric results. Reference graphs and tables were created with the LMS‐method. Contouring techniques were compared by intraclass correlation, regression analysis and Bland–Altman plots. A P value < 0.05 was considered statistically significant. Results: Height and BSA were significantly associated with LVESV (method 1) and with LVEDV and RVEDV (method 2). LVESV (method 2), RVESV (both methods), RVEDV (method 1), and LVEDMM and RVEDMM (both methods), showed significant associations with height and weight. LVSV and RVSV (both methods) were significantly associated with BSA and weight. RVESV (method 1) was significantly associated with age. Gender showed significant associations for all parameters. Data Conclusion: The proposed pediatric reference values can be used in the diagnosis and follow‐up of congenital or acquired heart disease and for research purposes. Evidence Level: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES This is a comprehensive analysis of haemodynamics after valve-sparing aortic root replacement (VSARR) with anatomically curved prosthesis (CP) compared to straight prosthesis (SP) and age-matched volunteers (VOL) using 4D flow MRI (time-resolved three-dimensional magnetic resonance phase-contrast imaging). METHODS Nine patients with 90° CP, nine patients with SP, and twelve VOL were examined with 4D flow MRI. Analyses included various characteristic anatomical, qualitative and quantitative haemodynamic parameters. RESULTS Grading of secondary flow patterns was lower in CP patients than in SP patients (P  = 0.09) and more comparable to VOL, albeit not reaching statistical significance. However, it was easy to differentiate between VSARR patients and healthy volunteers: Patients more often had angular aortic arches (CP: 89%, SP: 100%; VOL: 17%; P  ≤ 0.002), increased average curvature (CP: 0.17/cm [0.15, 0.18]; SP: 0.15/cm [0.14, 0.16]; VOL: 0.14/cm [0.13, 0.16]; P  ≤ 0.007; values given as median [interquartile range]), and more secondary flow patterns (CP: 3 [2, 4] SP: 3 [2, 3] VOL: 2 [1, 2]; P  < 0.01). Maximum circulation (CP: 142.7 cm2/s [116.1, 187.3]; SP: 101.8 cm2/s [77.7, 132.5]; VOL: 42.8cm2/s [39.3, 65.6]; P  ≤ 0.002), maximum helicity density (CP: 9.6 m/s2 [9.3, 23.9]; SP: 9.7 m/s2 [8.6, 12.5]; VOL 4.9 m/s2 [4.2, 7.7]; P  ≤ 0.007), and wall shear stress gradient (e.g., proximal ascending aorta CP: 0.97 N/m2 [0.54, 1.07]; SP: 1.08 N/m2 [0.74, 1.24]; VOL: 0.41 N/m2 [0.32, 0.60]; P  ≤ 0.01) were increased in patients. One CP patient had a round aortic arch with physiological haemodynamic parameters. CONCLUSIONS The restoration of physiological aortic configuration and haemodynamics was not fully achieved with the curved prostheses in our study cohort. However, there was a tendency towards improved haemodynamic conditions in the patients with curved prostheses overall but without statistical significance. A single patient with a CP and near-physiological configuration of the thoracic aorta underlines the importance of optimizing postoperative geometric conditions for allowing for physiological haemodynamics and cardiovascular energetics after VSARR. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide Open in new tab Download slide 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

Abstract Background Aortic enlargement and impaired bioelasticity are of interest in several cardiac and non-cardiac diseases as they can lead to cardiovascular complications. Cardiovascular magnetic resonance (CMR) is increasingly accepted as a noninvasive tool in cardiovascular evaluation. Assessment of aortic anatomy and bioelasticity, namely aortic distensibility and pulse wave velocity (PWV), by CMR is accurate and reproducible and could help to identify anatomical and bioelastic abnormalities of the aorta. However, normal CMR values for healthy children and young adults are lacking. Methods Seventy-one heart-healthy subjects (age 16.4 ± 7.6 years, range 2.3 - 28.3 years) were examined using a 3.0 Tesla CMR scanner. Aortic cross-sectional areas and aortic distensibility were measured at four positions of the ascending and descending thoracic aorta. PWV was assessed from aortic blood flow velocity measurements in a aortic segment between the ascending aorta and the proximal descending aorta. The Lambda-Mu-Sigma (LMS) method was used to obtain percentile curves for aortic cross-sectional areas, aortic distensibility and PWV according to age. Results Aortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p Conclusions This study provides percentile curves for cross-sectional areas, distensibility and pulse wave velocity of the thoracic aorta in children and young adolescents between their 3rd and 29th year of life. These data may serve as a reference for the detection of pathological changes of the aorta in cardiovascular disease.

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. [ABSTRACT FROM AUTHOR]

Background Optimal pulmonary perfusion is crucial for a well-functioning Fontan circulation in patients with hypoplastic left heart syndrome (HLHS). To obtain an adequate size of the left pulmonary artery (LPA), patch enlargement is a routine part of the hemi-Fontan procedure in our center. However, LPA patch enlargement at the time of the modified Norwood procedure may have surgical advantages. Therefore, the aim of this study was to evaluate whether anatomic and functional effects of the new approach are superior. Methods A total of 51 consecutive HLHS patients underwent a cardiovascular magnetic resonance imaging study including assessment of LPA anatomy and lung perfusion. The LPA of 20 patients was enlarged during the modified Norwood procedure (group N) and of 31 patients during the hemi-Fontan procedure (group HF). Results The median indexed cross-sectional area of the LPA in group N was significantly higher than in group HF (49.5 versus 27.9 mm 2 /m 2 , p < 0.0001). The regional pulmonary perfusion as measured by first-pass, contrast-enhanced signal intensity upslope was significantly improved in group N (left side 0.67 s −1 versus 0.40 s −1 , p = 0.002; right side 0.84 s −1 versus 0.52 s −1 , p = 0.01). The total hemi-Fontan bypass and procedure times were significantly shorter in group N (both p < 0.001). Conclusions These first magnetic resonance imaging data show that HLHS patients after LPA patch enlargement during the modified Norwood procedure have significantly higher LPA cross-sectional areas and show improved lung perfusion and shorter overall procedure time as compared with LPA patching during second stage (hemi-Fontan). Therefore, this promising surgical technique may improve blood flow dynamics of the Fontan circulation in the long run. [ABSTRACT FROM AUTHOR]

Background: The increased cardiovascular morbidity of adults with late repair of aortic coarctation (CoA) has been well documented. In contrast, successful CoA repair in early childhood has a generally good prognosis, though adverse vascular and ventricular characteristics may be abnormal, which could increase long-term risk. This study sought to perform a comprehensive analysis of aortic elasticity and left ventricular (LV) function in patients with aortic coarctation (CoA) using cardiovascular magnetic resonance (CMR). In a subgroup of patients, we assessed structure and function of the common carotid arteries to probe for signs of systemic vascular remodeling. Methods: Fifty-one patients (median age 17.3 years), 13.9 ± 7.5 years after CoA repair, and 54 controls (median age 19.8 years) underwent CMR. We determined distensibility and pulse wave velocity (PWV) at different aortic locations. In a subgroup, common carotid artery distensibility, PWV, wall thickness and wall area were measured. LV ejection fraction (EF), volumes, and mass were measured from short axis views. Left atrial (LA) volumes and functional parameters (LAEFPassive, LAEFContractile, LAEFReservoir) were assessed from axial cine images. Results: In patients distensibility of the whole thoracic aorta was reduced (p < 0.05) while PWV was only significantly higher in the aortic arch (p < 0.01). Distensibility of the descending aorta at the level of the pulmonary arteries and PWV in the descending aorta, both correlated negatively with age at CoA repair. LA volume before atrial contraction and minimal LA volume were higher in patients (p < 0.05). LAEFPassive and LAEFReservoir were reduced (p < 0.05), and LAEFReservoir correlated negatively with aortic arch PWV (p < 0.05). LVEF, volumes and mass were not different from controls. Carotid wall thickness and PWV were higher in patients compared to controls (p < 0.05). Conclusions: Patients after CoA repair have impaired bioelastic properties of the thoracic aorta with impact on LV diastolic function. Reduced descending aortic elasticity is associated with older age at time of CoA repair. The remodeling of the common carotid artery in our sub-study suggests systemic vessel wall changes. [ABSTRACT FROM AUTHOR]

We read with interest the letter to the editor by Van den Eyde I et al. i [[1]] regarding our recently published study presenting the results from serial right ventricular (RV) assessment with cardiovascular magnetic resonance (CMR) in patients with hypoplastic left heart syndrome (HLHS) [[2]]. As discussed by Van den Eyde I et al. i , physiological changes due to puberty might play an important role in RV deterioration. Cyanosis is common in HLHS patients, if the fenestration in the Fontan tunnel is patent, and is a known factor that contributes to heart failure in congenital heart disease patients [[6]]. [Extracted from the article]

OBJECTIVES In patients after completion of the total cavopulmonary connection (TCPC) with an intra-atrial lateral tunnel, deviations of the tunnel from an ideal straight tubular shape were observed. However, little is known about frequency and adverse effects of such shape deviations. We sought to analyse tunnel anatomy, dimensions and blood flow using cardiac magnetic resonance imaging (CMR). METHODS Fifty-four patients with hypoplastic left heart syndrome (HLHS; mean age 6.0 ± 2.4 years) underwent CMR with gradient-echo cine sequences, 2D- and 3D-phase-contrast imaging. We analysed anatomy, diameters, cross-sectional areas, volumes and blood flow of the tunnel. RESULTS Twenty-five patients had a tubular tunnel. In 29 patients, bulging and/or narrowing of the tunnel were present. Cross-sectional areas and volumes of the tunnel were not significantly different between the two groups. There were also no differences for the mean blood flow and the mean and maximal flow velocity (P = 0.05–0.6). In all the patients, the normalized tunnel volume was related to age (r = 0.44; P = 0.002) and body surface area (BSA; r = 0.42; P = 0.005). The mean tunnel blood flow correlated with age (r = 0.73; P = 0.001) and BSA (r = 0.83; P < 0.0001). CONCLUSIONS A considerable percentage of patients with an intra-atrial lateral tunnel develop mild deviations of the tunnel from ideal tubular shape. The correlation between tunnel volume and mean blood flow with age and BSA suggests that the capacity of the tunnel adjusts to body growth, independent of tunnel shapes that deviate from a fluid-dynamically favourable shape. Follow-up CMRs are needed to detect long-term effects of irregular tunnel shapes on flow dynamics. [ABSTRACT FROM AUTHOR]

The elastic function of the aorta in patients with transposition of the great arteries after arterial switch operation (ASO) is suspected to be important for long-term prognosis.Fifty-one patients and 34 controls were studied at 3.0 Tesla with MRI. Forty-three patients (12.8±6.9 years) underwent 1-stage ASO, 8 patients (23.8±6.9 years) had prior pulmonary artery banding (2-stage ASO). Aortic dimensions, distensibility, pulse wave velocity, aortic arch angle, left ventricular (LV) mass, LV systolic function and left atrial (LA) volumes, and LA passive emptying function as marker of LV diastolic function were assessed. Compared with controls, patients had increased aortic root areas (602.6±240.5 versus 356.8±113.4 mm2/m; P<0.01) and reduced distensibility of the thoracic aorta most pronounced at the aortic root (3.2±2.0 versus 9.1±4.7×10-3 mm Hg-1; P<0.01). Aortic distensibility correlated negatively with the aortic areas (P<0.01). Pulse wave velocity was higher in adults after ASO (5.0±1.0 versus 3.8±1.3 m/s; P<0.01). In contrast to controls pulse wave velocity and distensibility correlated with age in patients (P=0.04 to <0.01), LV mass was higher in patients (P=0.02). LA volumes correlated negatively with aortic root and ascending aortic distensibility and positively with pulse wave velocity (P<0.05). In patients, LA passive emptying function was lower (27.3±8.9 versus 41.1±6.0; P<0.01) and correlated with aortic root distensibility (P=0.004).Reduced aortic bioelasticity and aortic root dilatation are present in transposition of the great artery patients post ASO and are likely to contribute to LV diastolic dysfunction. Impaired aortic bioelasticity was strongly associated with age, suggesting the usefulness of follow-up studies for early onset of degenerative cardiovascular disease. [ABSTRACT FROM AUTHOR]

Background: Patients with hypoplastic left heart syndrome after a Norwood operation show dilatation and reduced distensibility of the reconstructed proximal aorta. Cardiac magnetic resonance imaging (CMR) and angiographic examinations indicate that the native descending aorta (DAo) is also dilated, but this has not been studied in detail. Methods and Results: Seventy‐nine children with hypoplastic left heart syndrome in Fontan circulation (aged 6.3±3.2 years) and 18 control participants (aged 6.8±2.4 years) underwent 3.0‐tesla CMR. Gradient‐echo cine and phase‐contrast imaging was applied to measure cross‐sectional areas (CSAs), distensibility, pulse wave velocity, and the incremental elastic modulus of the thoracic aorta. CSA of the DAo in patients was also compared with published percentiles for aortic CSA. Patients had significantly larger CSA of the DAo at the level of pulmonary artery bifurcation (229.1±97.2 versus 175.7±24.3 mm/m2, P=0.04) and the diaphragm (196.2±66.0 versus 142.6±16.7 mm/m2, P<0.01). In 41 patients (52%), CSA of the DAo was >95th percentile level for control participants, and the incremental elastic modulus of the aortic arch and the DAo was higher than in patients with normal CSAs (arch: 90.1±64.3 versus 45.6±38.9 m/s; DAo: 86.3±53.7 versus 47.1±47.6 m/s; P<0.01). Incremental elastic modulus of the aortic arch and the DAo correlated with the CSA of the DAo (arch: r=0.5; DAo: r=0.49; P<0.01). Conclusions: Children with hypoplastic left heart syndrome frequently show dilatation of their DAo associated with increased stiffness of the aortic arch. Higher aortic impedance increases the afterload of the systemic circulation and likely contributes to the burden of the systemic right ventricle.