Four-dimensional flow MR imaging showed abnormal helical systolic flow in the ascending aorta of patients with a BAV, including those without aneurysm or aortic stenosis. Identification and characterization of eccentric flow jets in these patients may help identify those at risk for development of ascending aortic aneurysm.
Purpose: To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation.Materials and Methods: Time-resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers.Results: Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r ¼ 0.99, limits of agreement ¼ À20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation.Conclusion: 4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair.
The objective of this study was to explore the current practice and attitudes of pediatric cardiologists in the United States and Europe on the transfer and transition of children with congenital heart disease (CHD). A survey among pediatric cardiology programs in the United States and Europe was undertaken. Sixty-nine centers completed and returned the 61-item questionnaire that was specifically devised for this survey. Of 69 participating centers, 74% reported that they transfer their patients to adult-focused care. When a center transfers its patients, 80% transfer them to a formalized Adult Congenital Heart Disease Program. The median age of transfer is 18 years. Comorbidities, pregnancy, and patient/family request to leave pediatric cardiology were identified as initiators for transfer. Complexity of the heart defect was relatively less important when deciding whether to transfer patients. Only one-third of the centers that transfer their patients provide a structured preparation for patients and family. Development of a formal transition program is planned at 59% of the centers that transfer patients. In conclusion, timely transfer and a structured transition process of children with CHD are not implemented in all pediatric cardiology programs. Health-care providers working in pediatric cardiology should make their transfer policies explicit and transition programs ought to be developed.
T ime-resolved, 3D, phase-contrast magnetic resonance imaging (4D flow) is an effective means of evaluating dynamic multidirectional blood flow in the thoracic aorta. 1 We have used the technique for characterization of abnormal flow features in a 14-year-old boy with aortic coarctation and bicuspid aortic valve (BAV) but without evidence of aortic stenosis or regurgitation. In addition to the expected flow disturbance in the region of the juxtaductal coarctation (Figure 1), we show an unusual flow feature in the ascending aorta that has not been previously reported in this clinical setting and that may be unique to BAV: 2 discrete nested helices of midsystolic blood flow in a nonaneurysmal aorta (Figure 2).Exaggerated helical flow has been described in the context of ascending aortic aneurysm, with the majority of cases seen in patients with aneurysmal dilation Ͼ4 cm. 2 Our patient, however, had only mild dilation of the ascending aorta (3.2 cm at the level of the main pulmonary artery).BAV occurs in 1% to 2% of the population and may account for more morbidity and mortality than all other congenital cardiac malformations combined. One theory for the elevated risk of aortic aneurysm in these patients is that an increased hemodynamic load is placed on the proximal aorta, resulting in progressive aortic dilatation. 3 Previous work has demonstrated that supraphysiological hemodynamics in the form of elevated shear stress, as seen in the radial artery proximal to an arteriovenous dialysis fistula, lead to an increase in vessel size. 4 The pronounced helical flow and eccentric systolic jet in the ascending aorta that we have demonstrated may represent an increased hemodynamic bur- Figure 1. Fourteen-year-old boy with BAV and aortic coarctation. A, Three-dimensional contrast-enhanced magnetic resonance angiography that demonstrates a focal juxtaductal coarctation and prominent internal mammary and intercostal arteries, consistent with collateral flow. B and C, Views of the right and left aspect of the aortic arch respectively with streamlines to visualize the 4D flow data set in midsystole. Streamlines are imaginary lines aligned with local vector fields and represent the flow field at a given moment in the cardiac cycle. They are color-coded for velocity. Marked flow disturbance is seen in the descending aorta at and distal to the coarctation, with acceleration of flow and regions of signal dropout secondary to aliasing. Additionally, note the eccentric right-sided flow jet and prominent helical flow in the ascending aorta, flow features that have been reported in association with ascending aortic aneurysms. 2 D, Oblique sagittal T1 spin-echo image in the same orientation as Image C, which demonstrates only mild dilation of the ascending aorta (3.2 cm at the level of the main pulmonary artery).
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