Aortic Root Dilation and Aortic Elastic Properties in Children After Repair of Tetralogy of Fallot Wan-Yip Chong, MMedSc a , Wilfred H.S. Wong, MMedSc a , Clement S.W. Chiu, MBBS b , and Yiu-Fai Cheung, MD a, * Analyses of aortic specimens obtained from patients with tetralogy of Fallot (TOF) revealed elastic fiber fragmentation. This study sought to determine the prevalence of aortic root dilation and aortic regurgitation (AR) in children after TOF repair and tested the hypothesis that aortic elastic properties are altered and related to aortic root dilation in these patients. Aortic dimensions, adjusted for body surface area and expressed as z scores, and AR were assessed echocardiographically in 67 children 8.3  5.6 years after TOF repair. The aortic elastic properties were compared with those in 50 age-matched controls. The prevalence of aortic dilation (z score >2) was 88%, 87%, 61%, and 63% at the annulus, sinus of Valsalva, sinotubular junction, and ascending aorta, respectively. The z scores of the annulus (r  0.41, p <0.001) and sinus (r  0.33, p <0.01) were correlated with body surface area. Multivariate analysis identified the duration of follow-up after surgery as the only significant determinant of z scores of the annulus ( 0.41, p  0.001) and sinus ( 0.33, p  0.009). AR was present in 12% of patients who tended to have larger z scores at all aortic levels. Compared with controls, patients had significantly increased aortic stiffness (p <0.001) and reduced strain (p <0.001) and distensibility (p  0.002). Aortic stiffness was correlated positively, whereas aortic strain and distensibility were correlated negatively, with the aortic root z scores at all levels. In conclusion, this study shows a high prevalence of aortic root dilation in children after the repair of TOF. Aortic stiffening occurred in these patients and may play a role in progressive aortic root dilation. © 2006 Elsevier Inc. All rights reserved. (Am J Cardiol 2006;97:905–909) In the present study, we determined the prevalence of aortic root dilation and aortic regurgitation (AR) in children after corrective surgery for tetralogy of Fallot (TOF) and sought to identify predisposing risk factors. We hypothesized that the elastic properties of the aorta are altered and are related to aortic root dilation in patients with TOF despite total surgi- cal repair. To test the hypothesis, we compared the aortic elasticity indexes of patients with those of age-matched normal controls and determined the correlations between aortic elas- ticity indexes and aortic root dimensions. Methods Subjects: Sixty-seven patients (43 males) aged 11.5  6.4 years who had undergone total corrective surgery for TOF were recruited from the pediatric cardiac clinic con- secutively over a 4-month period. Those with pulmonary atresia or associated left ventricular outflow obstruction were excluded. From the clinical records, the following data were reviewed: previous palliative shunt operation, age at total surgical repair, the duration of follow-up since the operation, and residual cardiac lesions as documented by serial echocardiography. The aortic dimensions and aortic elastic properties of the patients were determined and com- pared with those obtained in 50 age-matched (10.0  4.8 years, p = 0.19) control subjects. The weight and height of the subjects were measured, and body surface area was derived accordingly. The institutional ethics committee ap- proved the study, and parents of all subjects gave written, informed consent. Echocardiographic examination: The left ventricular end-systolic and end-diastolic dimensions and wall thick- nesses were measured by M-mode echocardiography from the parasternal short-axis view. Left ventricular fractional shortening was calculated according to the standard formula. 1 The left ventricular dimensions were indexed by body sur- face area for subsequent analyses. Color-flow Doppler mapping was used to assess the severity of valvular regurgitation: (1) the degree of tricuspid regurgitation was graded as mild, moderate, or severe on the basis of the ratio of the area of the tricuspid regurgitant jet to that of the right atrium 2 ; (2) the degree of AR was graded as trivial (slight AR under the aortic valve), mild (AR not reaching the tip of mitral valve leaflet), moderate (AR a Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, and b Division of Cardiothoracic Surgery, Grantham Hospital, The University of Hong Kong, Hong Kong, China. Manuscript received August 10, 2005; revised manuscript received and accepted Sep- tember 26, 2005. * Corresponding author: Tel: 852-25182629; fax: 852-25539491. E-mail address: xfcheung@hkucc.hku.hk (Y.F. Cheung). 0002-9149/06/$ – see front matter © 2006 Elsevier Inc. All rights reserved. www.AJConline.org doi:10.1016/j.amjcard.2005.09.141