Pulmonary artery to aorta ratio is associated with cardiac structure and functional changes in mild-to-moderate COPD
Authors Cuttica MJ, Bhatt SP, Rosenberg SR, Beussink L, Shah SJ, Smith LJ, Dransfield MT, Kalhan R
Received 31 December 2016
Accepted for publication 9 March 2017
Published 12 May 2017 Volume 2017:12 Pages 1439—1446
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Charles Downs
Peer reviewer comments 3
Editor who approved publication: Dr Richard Russell
Michael J Cuttica,1 Surya P Bhatt,2 Sharon R Rosenberg,1 Lauren Beussink,3 Sanjiv J Shah,3 Lewis J Smith,1 Mark T Dransfield,2 Ravi Kalhan1
1Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 2Division of Pulmonary, Allergy & Critical Care Medicine, University of Alabama-Birmingham, Birmingham, AL, 3Division of Cardiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
Background: The ratio of the diameter of the pulmonary artery (PA) to the diameter of the aorta (PA:A) on computed tomography (CT) imaging is associated with both COPD exacerbation and pulmonary hypertension. The mechanisms of PA enlargement in COPD are poorly understood.
Methods: In this retrospective, single center study we evaluated pulmonary function, CT scans, right heart catheterizations, and echocardiography in 88 subjects with mild-to-moderately severe COPD. A sensitivity analysis was performed in 43 subjects in whom CT scan and echocardiogram were performed within 50 days of each other. To evaluate the association between PA:A ratio and echocardiographic parameters and hemodynamics, we performed simple correlations and multivariable linear regression analysis adjusting for lung function, age, sex, race, and diastolic function.
Results: All subjects had preserved left ventricular (LV) systolic function (LV ejection fraction 62.7%±5.5%). Among them, 56.8% had evidence of diastolic dysfunction. There was no association between PA:A ratio and the presence of diastolic dysfunction. In a multivariable model, PA:A ratio was associated with right ventricular (RV) chamber size (β=0.015; P<0.003), RV wall thickness (β=0.56; P<0.002), and RV function (–0.49; P=0.05). In the subgroup of subjects with testing within 50 days, the association with RV chamber size persisted (β=0.017; P=0.04), as did the lack of association with diastolic function. PA:A ratio was also associated with elevated PA systolic pressures (r=0.62; P=0.006) and pulmonary vascular resistance (r=0.46; P=0.05), but not pulmonary arterial wedge pressure (r=0.17; P=0.5) in a subset of patients undergoing right heart catheterization.
Conclusion: In patients with mild-to-moderately severe COPD and preserved LV function, increased PA:A ratio occurs independent of LV diastolic dysfunction. Furthermore, the PA:A ratio is associated with right heart structure and function changes, as well as pulmonary hemodynamics. These findings indicate that PA:A ratio is a marker of intrinsic pulmonary vascular changes rather than impaired LV filling.
Keywords: COPD, diastolic dysfunction, pulmonary artery
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]