Abstract 14436: Patent Ductus Arteriosus Ameliorates Hypertensive Changes in the Aorta of Neonates and Infants with Coarctation
Objective: Despite adequate relief of obstruction, a significant proportion of patients with coarctation of the aorta (CoA) present with late hypertension. However, the etiology of late hypertension following repair is unknown. Prior to repair, the presence of a patent ductus arteriosus (DA) limits upper-body blood pressure and the gradient through the coarctation. We hypothesized that in infants, a patent DA limits the hypertensive changes in the aortic arch when compared to infants with a closed DA.
Methods: In 16 patients < 90 days of age at repair, we analyzed the arm:leg blood pressure gradient and collected mRNA from the aorta proximal to the coarctation. Quantitative PCR was used to determine the expression patterns of collagen-I, Transforming Growth Factor β (TGFβ), elastin and smooth muscle actin (SMA) to determine arterial stiffness, elasticity and smooth muscle hypertrophy. All genes were normalized to ribosomal-18s.
Results: Of 16 infants, 12 had a patent DA, and 4 had a closed DA. There was no difference in mean age between groups (25.2±22 vs. 26.7±24 days, p=0.8). Collagen-I expression was greater in patients with a closed vs. open DA (4.9±1.0 vs.0.9±0.3 fold, p=0.03). Similarly, TGFβ expression was also higher in patients with a closed DA (3.76±0.6 vs. 1.34±0.2 fold, p=0.04). Elastin expression was also higher in patients with a closed DA(9.95±1.3 vs. 0.9±0.5). There was no difference SMA expression between patients. There was a linear correlation between the arm:leg blood pressure gradient and collagen-I(R2=0.9, p=0.05) expression in patients with a closed DA.
Conclusion: Our findings provide the first evidence that pre-operative vascular changes occur in the proximal aorta of neonates prior to coarctation repair, particularly if the DA is closed. These changes may contribute to the development of hypertension and provide further evidence for early repair.
- © 2012 by American Heart Association, Inc.