BackgroundAortic 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.MethodsSeventy-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.ResultsAortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p < 0.001; PWV: r = 0.25 to 0.32, p = 0.047 to 0.009; aortic distensibility r = -0.43 to -0.62, p < 0.001) correlated with height, weight, body surface area, and age. There were no significant sex differences.ConclusionsThis 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.

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Background-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. ; 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). Methods and Results Conclusions-Reduced

BackgroundThe 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.MethodsFifty-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.ResultsIn 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).ConclusionsPatients 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.

In 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.

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.

Purpose: To determine whether neglecting the flow unsteadiness in simplified Bernoulli's equation significantly affects the pulmonary transvalvular pressure drop estimation. Materials and Methods: 3.0T 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 Ber-noulli'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. Results: The simplified Bernoulli's method systematically underestimated the pressure drop compared to general Bernoul-li's method during the entire systolic phase (P < 0.05), including the peak systole, where on average Dp SBE =Dp GBE 578%. Conclusion: The 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 2015;00:000-000. P ulmonary valve stenosis is a common anomaly in patients with congenital heart defects. Quantitative assessment of the severity of pulmonary valve stenosis is mainly based on the pulmonary transvalvular pressure drop, 1 commonly estimated by continuous-wave Doppler 2 and recently by magnetic resonance imaging (MRI) phase contrast flow measurements. 3 The accuracy of noninvasive measurements of the transvalvu-lar pressure drop has been debated. 4-11 Several studies have investigated the correlation between MRI measurements and echocardiography with catheterization for the estimation of the pressure drop in pulmonary circulation. The results have been inconsistent. 3,12-14 Cardiac catheterization is the current standard for estimating the transvalvular pressure drop; however , this method is not practical for routine follow-ups due to View this article online at wileyonlinelibrary.com.

BackgroundPatients 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 ResultsSeventy‐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).ConclusionsChildren 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.