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Author Notes:

Corresponding Author: Ajit P. Yoganathan, 387 Technology Circle, Suite 232, Atlanta, GA, USA 30313, Ph. (404) 894-2849, Fax. (404) 894-1268 ajit.yoganathan@bme.gatech.edu

Subjects:

Research Funding:

This study was supported by the National Heart, Lung, and Blood Institute Grants HL67622, HL098252, and HL089647.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Cardiac & Cardiovascular Systems
  • Respiratory System
  • Surgery
  • Cardiovascular System & Cardiology
  • TOTAL CAVOPULMONARY CONNECTION
  • SUBDIAPHRAGMATIC VENOUS HEMODYNAMICS
  • FLOW

Respiratory Effects on Fontan Circulation During Rest and Exercise Using Real-Time Cardiac Magnetic Resonance Imaging

Tools:

Journal Title:

Annals of Thoracic Surgery

Volume:

Volume 101, Number 5

Publisher:

, Pages 1818-1826

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Background It is known that respiration modulates cavopulmonary flows, but little data compare mean flows under breath-holding and free-breathing conditions to isolate the respiratory effects and effects of exercise on the respiratory modulation. Methods Real-time phase-contrast magnetic resonance combined with a novel method to track respiration on the same image acquisition was used to investigate respiratory effects on Fontan caval and aortic flows under breath-holding, free-breathing, and exercise conditions. Respiratory phasicity indices that were based on beat-averaged flow were used to quantify the respiratory effect. Results Flow during inspiration was substantially higher than expiration under the free-breathing and exercise conditions for both inferior vena cava (inspiration/expiration: 1.6 ± 0.5 and 1.8 ± 0.5, respectively) and superior vena cava (inspiration/expiration: 1.9 ± 0.6 and 2.6 ± 2.0, respectively). Changes from rest to exercise in the respiratory phasicity index for these vessels further showed the impact of respiration. Total systemic venous flow showed no significant statistical difference between the breath-holding and free-breathing conditions. In addition, no substantial difference was found between the descending aorta and inferior vena cava mean flows under either resting or exercise conditions. Conclusions This study demonstrated that inferior vena cava and superior vena cava flow time variance is dominated by respiratory effects, which can be detected by the respiratory phasicity index. However, the minimal respiration influence on net flow validates the routine use of breath-holding techniques to measure mean flows in Fontan patients. Moreover, the mean flows in the inferior vena cava and descending aorta are interchangeable.

Copyright information:

© 2016 The Society of Thoracic Surgeons.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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