Treating a 20 mm Hg Gradient Alleviates Myocardial Hypertrophy in Experimental Aortic Coarctation

Authors

David C. Wendell, Marquette UniversityFollow
Ingeborg Friehs, Harvard Medical School
Margaret M. Samyn, Medical College of WisconsinFollow
Leanne Harmann, Medical College of Wisconsin
John F. LaDisa, Marquette UniversityFollow

Document Type

Article

Language

eng

Publication Date

10-2017

Publisher

Elsevier

Source Publication

Journal of Surgical Research

Source ISSN

0022-4804

Abstract

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.

Comments

Accepted version. Journal of Surgical Research, Vol. 218 (October 2018): 194-201. DOI. © 2017 Elsevier Inc. Used with permission.

Recommended Citation

Wendell, David C.; Friehs, Ingeborg; Samyn, Margaret M.; Harmann, Leanne; and LaDisa, John F., "Treating a 20 mm Hg Gradient Alleviates Myocardial Hypertrophy in Experimental Aortic Coarctation" (2017). Biomedical Engineering Faculty Research and Publications. 514.
https://epublications.marquette.edu/bioengin_fac/514