The aryl hydrocarbon receptor (AhR), a ligand activated transcription factor, is the receptor for the polycyclic aromatic hydrocarbons found in tobacco smoke, polychlorinated biphenyls, and the environmental pollutant, dioxin. To better understand the role of the AhR in the heart, echocardiography, invasive measurements of aortic and left ventricular pressures, isolated working heart preparations, as well as morphological and molecular analysis were used to investigate the impact of AhR inactivation on the mouse heart using the AhR knockout as a model. Cardiac hypertrophy is an early phenotypic manifestation of the AhR knockout. Although the knockout animals were not hypertensive at the ages examined, cardiomyopathy accompanied by diminished cardiac output developed. Despite the structural left ventricular remodeling, the hearts of these animals exhibit minimal fibrosis and do not have the expected increases in surrogate molecular markers of cardiac hypertrophy. The anatomic remodeling without typical features of molecular remodeling is not consistent with hypertrophic growth secondary to pressure or volume overload, suggesting that increased cardiomyocyte size may be a direct consequence of the absence of the AhR in this cell type.

Background-Supravalvar pulmonary stenosis (SVPS) is frequently observed after arterial switch. Traditionally the coronary arteries are removed from the neopulmonic root by excising the entire sinus of Valsalva. As a result, reconstruction of the neopulmonic root requires a pericardial patch encompassing two-thirds of the anastomosis between the neopulmonic root and pulmonary artery. We present a technique where the coronary arteries are removed as limited buttons of sinus tissue, leaving the transected edge of the neopulmonic root intact. We hypothesize that maintaining native arterial tissue in the anastomosis between the neopulmonic root and the pulmonary artery bifurcation reduces postoperative SVPS. Methods and Results-We performed a retrospective review of neonates with D-transposition of the great arteries undergoing arterial switch procedure from 1996 to 2009. Charts were reviewed, and clinical outcomes recorded for each patient. Most recent echocardiograms were evaluated for right ventricular outflow tract obstruction. A total of 120 patients received arterial switch using this technique. There was 99% survival and no injuries to the coronary arteries regardless of anatomy. Total follow-up was 564 patient-years. Mean follow-up at last clinical visit was 66Ϯ46 months. Evaluation of the most recent outpatient echocardiogram revealed an average peak instantaneous gradient across the neopulmonic root of 22.5Ϯ5 mm Hg. Only 7 (5%) patients required reintervention (balloon dilation, nϭ5; surgery, nϭ2). Conclusions-Our technique of removing the coronary arteries as limited buttons, and anastomosis of the pulmonary artery using only native arterial tissue provides excellent midterm results with minimal SVPS. (Circulation. 2012;126[suppl 1]:S118 -S122.)

Objective To investigate racial differences in central blood pressure and vascular structure/function as subclinical markers of atherosclerotic cardiovascular disease (CVD) in children. Study design This cross-sectional study recruited 54 African-American children (18 female, 36 male; age 10.5 ± 0.9) and 54 white children (27 female, 26 male; age 10.8 ± 0.9) from the Syracuse City community as part of the Environmental Exposures and Child Health Outcomes (EECHO) study. Participants underwent blood lipid and vascular testing on two separate days. Carotid artery intima-media thickness (IMT) and aortic stiffness were measured via ultrasonography and carotid-femoral pulse wave velocity (PWV), respectively. Blood pressure (BP) was assessed at the brachial artery and estimated in the carotid artery using applanation tonometry. Results African American children had significantly higher PWV (4.8 ± 0.8 m/s) compared with white children (4.2 ± 0.7 m/s; p<0.05) which remained significant after adjustment for confounding variables including socioeconomic status. African-American children had significantly higher IMT (African-American 0.41 ± 0.06, white 0.39 ± 0.05 mm), and carotid systolic BP (African-American 106 ± 11, white 102 ± 8 mmHg; p<0.05) compared with white children, although these racial differences were no longer present after covariate adjustments for height. Conclusions Racial differences in aortic stiffness are present in childhood. Our findings suggest that racial differences in subclinical CVD occur earlier than previously recognized.

For aortic coarctation repair in infancy, a strategy designed to directly address aortic arch hypoplasia results in excellent intermediate-term results with normal BP, physiologic arm:leg BP relationship, and near normal descending aortic blood flow velocities by Doppler.

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