Cardiac MRI evaluation of aortic biophysical properties in paediatric Turner syndrome.

BACKGROUND: Aortopathy in Turner syndrome is associated with aortic dilation, and the risk of dissection is increased when the aortic size index is ≥ 2-2.5 cm/m2. We evaluated the aortic biophysical properties in paediatric Turner syndrome using cardiac MRI to determine their relationship to aortic size index. METHODS: Turner syndrome patients underwent cardiac MRI to evaluate ventricular function, aortic dimensions, and biophysical properties (aortic stiffness index, compliance, distensibility, pulse wave velocity, and aortic and left ventricular elastance). Spearman correlation examined correlations between these properties and aortic size index. Data was compared to 10 controls. RESULTS: Of 25 Turner syndrome patients, median age 14.7 years (interquartile range: 11.0-16.8), height z score -2.7 (interquartile range: -2.92 - -1.54), 24% had a bicuspid aortic valve. Turner syndrome had increased diastolic blood pressure (p < 0.001) and decreased left ventricular end-diastolic (p < 0.001) and end-systolic (p = 0.002) volumes compared to controls. Median aortic size index was 1.81 cm/m2 (interquartile range: 1.45-2.1) and 7 had an aortic size index > 2 cm/m2. Aortic and left ventricular elastance were greater in Turner syndrome compared to controls (both p < 0.001). Increased aortic size index correlated with increased aortic elastance (r = 0.5, p = 0.01) and left ventricular elastance (r = 0.59, p = 0.002) but not aortic compliance. Higher ascending aortic areas were associated with increased aortic compliance (r = 0.44, p = 0.03) and left ventricular elastance (r = 0.49, p = 0.01). CONCLUSION: Paediatric Turner syndrome with similar aortic size index to controls showed MRI evidence of abnormal aortic biophysical properties. These findings point to an underlying aortopathy and provide additional parameters that may aid in determining risk factors for aortic dissection.

Impaired Single Right Ventricular Function Compared to Single Left Ventricles during the Early Stages of Palliation: A Longitudinal Study.

BACKGROUND: Single right ventricles (SRV) are postulated to be disadvantaged compared with single left ventricles (SLV). We compared the evolution of SRV versus SLV function during infancy using conventional measures and speckle-tracking echocardiography (STE). We hypothesized that the SRV is mechanically disadvantaged during early infancy. METHODS: SRVs (n = 32) were compared with SLVs (n = 16) at the neonatal (presurgery) and pre-bidirectional cavopulmonary anastomosis (pre-BCPA) stages. Functional measures (fractional area change, indexed ventricular annular plane systolic excursion [iVAPSE], isovolumic acceleration [IVA], myocardial performance index, E and A velocities, tissue Doppler imaging annular velocities and STE-measured global longitudinal and circumferential strain, strain rate [SR], and early diastolic SR [EDSR]) were compared between SRV and SLV at each stage and between presurgery and pre-BCPA. RESULTS: Compared with SLV, presurgery SRV had lower circumferential strain (-10.6% vs -16.5%; P = .0002) and EDSR (1.41%/sec vs 2.13%/sec; P = .001). Pre-BCPA SRV had decreased IVA (1.2 vs 2.1 m/sec2; P = .006): longitudinal strain (-15.3% vs -19.1%; P = .001), SR (-0.97%/sec vs -1.53%/sec; P = .0001), EDSR (1.5%/sec vs 2.1%/sec; P = .001); circumferential strain (-10.6% vs -14.9%; P = .002), SR (-0.8%/sec vs -1.21%/sec; P = .0001), and EDSR (1.3%/sec vs 1.8%/sec; P = .009). SRV showed reduction of iVAPSE, IVA, s', e', a' velocities, longitudinal strain, SR, EDSR, and circumferential SR (P < .05) from presurgery to pre-BCPA, while circumferential strain was unchanged. SLV showed no significant change in these parameters during this interval. CONCLUSIONS: The progressive reduction in SRV longitudinal and circumferential function suggests that SRV may have a mechanical disadvantage from birth and progressive impairment with age.

Cardiac Magnetic Resonance Imaging in Pediatric Turner Syndrome.

OBJECTIVE: To compare the detection of cardiac lesions with the use of cardiac magnetic resonance imaging (CMR) and conventional echocardiography in children with Turner syndrome. STUDY DESIGN: Twenty-four girls with Turner syndrome, 8-18 years of age, were recruited through the Pediatric Endocrinology Program. Participants underwent CMR and echocardiography within a 2-year period, and discrepancies between the results of each modality were identified. RESULTS: Fifteen of 24 (63%) girls had a cardiac lesion identified on CMR or echocardiography. Both modalities identified the same lesion in 10 of 15 (67%); however, 6 of 15 (40%) participants had a lesion identified on CMR but not echocardiography. Participants with a missed lesion had a trend towards greater body mass index. Aortic dilation and bicuspid aortic valve were the most commonly missed lesions by echocardiography. CONCLUSIONS: CMR identifies significant cardiac lesions missed by echocardiography in pediatric patients with Turner syndrome, particularly along the aorta. These findings support the current guidelines that recommend screening CMR in addition to echocardiogram. Early identification of cardiac abnormalities in patients with Turner syndrome will allow for a greater understanding of the natural history in these patients and potentially identify candidates for earlier intervention.

Childhood presentation of interrupted aortic arch with persistent carotid ducts.

Interrupted aortic arch is a rare condition with typical presentation within the first few weeks of life, as the circulation is dependent upon patency of the arterial duct. Most cases are associated with intracardiac anomalies, the most common being a ventricular septal defect with some degree of hypoplasia and/or obstruction of the left ventricular outflow tract. Presentation beyond infancy is uncommon, and suggests the presence of well-developed collateral circulation. This case of childhood presentation of interrupted aortic arch and intact ventricular septum highlights the very unusual finding of bilateral collateral arteries consistent with persistent carotid ducts. Cardiac MRI angiography with three-dimensional reconstruction defined not only the site of interruption in the aortic arch but also the entire collateral circulation.