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  • Oral presentation
  • Open Access

Combined CMR and catheterization data in determining right ventricular-arterial coupling in children and adolescents with pulmonary arterial hypertension

  • 1,
  • 1,
  • 1,
  • 2,
  • 1,
  • 1, 2 and
  • 2
Journal of Cardiovascular Magnetic Resonance201416 (Suppl 1) :O43

https://doi.org/10.1186/1532-429X-16-S1-O43

  • Published:

Keywords

  • Pulmonary Arterial Hypertension
  • Cardiac Magnetic Resonance
  • Pulmonary Capillary Wedge Pressure
  • Vascular Reactivity
  • Receive Operating Characteristic Curve Analysis

Background

Pulmonary arterial hypertension (PAH) remains a disease with high morbidity/mortality in pediatrics. Understanding ventricular-arterial coupling, a measure of how well matched the ventricular and vascular function is, may elucidate the pathway leading to right heart failure.

Methods

This retrospective study included subjects with PAH who a cardiac magnetic resonance (CMR) study within 14 days of cardiac catheterization between January 2009-August 2013. The effective elastance (Ea, index of arterial load) and right ventricular maximal end-systolic elastance (Emax, index of contractility) were determined by a combination of CMR and hemodynamic data. Ea is defined as (mean pulmonary arterial pressure minus pulmonary capillary wedge pressure)/stroke volume. Emax is defined as mean pulmonary arterial pressure/end systolic volume. Ea/Emax ratio was derived. Additionally, a measure of non-invasive ventricular arterial coupling (assuming PWCP is insignificant, making Ea/Emax = end systolic volume/stroke volume) was derived from only CMR. Pulmonary vascular resistance indexed (PVRi) and pulmonary vascular reactivity, as defined by Barst criteria (decrease in mean pulmonary artery pressure of > 20%, unchanged/increased cardiac index, and decreased/unchanged pulmonary to systemic vascular resistance ratio), were also determined. Pearson correlation coefficients were calculated between PVRi and Ea, Emax, and Ea/Emax. Receiving operating characteristic (ROC) curve analysis determined the diagnostic value of Ea/Emax in predicting vascular reactivity.

Results

Sixteen subjects were identified for inclusion with equal gender distributions. Age ranged from 3 months to 23 years (mean 11.3+7.4 years). Ea and Ea/Emax increased with increasing severity defined by PVRi, with p < 0.001 for both. Ea/Emax (range 0.43-2.82) was highly correlated with PVRi (r = 0.92, 95% CI 0.79-0.97, p < 0.0001). Non-invasively derived ventricular arterial coupling was found to be significantly correlated with PVRi (r = 0.85, 95% CI 0.62-0.95, p < 0.0001), but with a lower correlation coefficient than with Ea/Emax derived from combined hemodynamic and CMR data. Regression of Ea/Emax and PVRi demonstrated differing lines when separated by reactivity, however, the lines were not significantly different (Figure 1). ROC curve analysis (Figure 2) revealed high accuracy of the Ea/Emax ratio in determining vascular reactivity. Ea/Emax of 0.85 had a sensitivity of 100% and a specificity of 80%. The area under the curve is 0.89 (p = 0.008), suggesting good discrimination between those who were and were not reactive.
Figure 1
Figure 1

Regression of ventricular arterial coupling ratio (Ea/Emax) and pulmonary vascular resistance indexed by reactivity. The shaded areas represent the 95% confidence interval for each regression line. The lines depict different trajectories based on reactivity, which approached, but not reach statistical significance (p > 0.05).

Figure 2
Figure 2

Receiver operating characteristic curve demonstrating an optimal threshold Ea/Emax ratio of 0.85. Using this criterion, is associated with a sensitivity of 100% and a specificity of 80%.

Conclusions

Measurement of ventricular arterial coupling, Ea/Emax, in pediatrics is feasible. Pulmonary vascular non-reactivity may be due to ventricular-arterial decoupling in which ventricular contractility fails to parallel increasing afterload in severe PAH. Use of Ea/Emax may have significant prognostic implication.

Funding

This work was supported by UL1 TR000154 from NCATS/NIH, 5R01HL114753 from NHLBI/NIH, as well as K25-094749 and K24-081506.

Authors’ Affiliations

(1)
Pediatric Cardiology, Children's Hospital Colorado, Aurora, Colorado, USA
(2)
Bioengineering, University of Colorado Denver Medical Campus, Aurora, Colorado, USA

Copyright

© Truong et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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