Treating a 20 mm Hg gradient alleviates myocardial hypertrophy in experimental aortic coarctation. J Surg Res 2017 Oct;218:194-201
Date
10/08/2017Pubmed ID
28985849Pubmed Central ID
PMC5679105DOI
10.1016/j.jss.2017.05.053Scopus ID
2-s2.0-85020927176 (requires institutional sign-in at Scopus site) 5 CitationsAbstract
BACKGROUND: Children with coarctation of the aorta (CoA) can have a hyperdynamic and remodeled left ventricle (LV) from increased afterload. Literature from an experimental model suggests the putative 20 mm Hg blood pressure gradient (BPG) treatment guideline frequently implemented in CoA studies may permit irreversible vascular changes. LV remodeling from pressure overload has been studied, but data are limited following correction and using a clinically representative BPG.
MATERIALS AND METHODS: Rabbits underwent CoA at 10 weeks to induce a 20 mm Hg BPG using permanent or dissolvable suture thereby replicating untreated and corrected CoA, respectively. Cardiac function was evaluated at 32 weeks by magnetic resonance imaging using a spoiled cine GRE sequence (TR/TE/FA 8/2.9/20), 14 × 14-cm FOV, and 3-mm slice thickness. Images (20 frames/cycle) were acquired in 6-8 short axis views from the apex to the mitral valve annulus. LV volume, ejection fraction (EF), and mass were quantified.
RESULTS: LV mass was elevated for CoA (5.2 ± 0.55 g) versus control (3.6 ± 0.16 g) and corrected (4.0 ± 0.44 g) rabbits, resulting in increased LV mass/volume ratio for CoA rabbits. A trend toward increased EF and stroke volume was observed but did not reach significance. Elevated EF by volumetric analysis in CoA rabbits was supported by concomitant increases in total aortic flow by phase-contrast magnetic resonance imaging.
CONCLUSIONS: The indices quantified trended toward a persistent hyperdynamic LV despite correction, but differences were not statistically significant versus control rabbits. These findings suggest the current putative 20 mm Hg BPG for treatment may be reasonable from the LV's perspective.
Author List
Wendell DC, Friehs I, Samyn MM, Harmann LM, LaDisa JF JrAuthors
John F. LaDisa PhD Professor in the Pediatrics department at Medical College of WisconsinMargaret Mary Samyn MD Professor in the Pediatrics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsAortic Coarctation
Disease Models, Animal
Hypertrophy, Left Ventricular
Magnetic Resonance Imaging
Male
Rabbits
Random Allocation
Ultrasonography