Single ventricle heart defects, where systemic and pulmonary venous returns mix in the single functional ventricle, represent the most complex form of congenital heart defect. Surgical repairs, termed """"""""Fontan Repairs,"""""""" reroute the systemic venous return directly to the pulmonary arteries, thus preventing venous return mixing and restoring normal oxygenation saturation levels. Unfortunately, these repairs are only palliative and Fontan patients are subjected to a multitude of chronic complications. Over the past 20 years, researchers have sought to understand the hemodynamics through this surgical construct in an effort to optimize its efficiency and minimize the imposed workload on the single ventricle. While this work has led to important advances in the surgical approach, including the development of the total cavopulmonary connection (TCPC), an integrated experimental and clinical approach relating these quantitative markers to ultimate patient outcomes has been lacking. Such a study would represent a critical step in the advancement of treatment efforts as it will identify the clinical markers that control outcomes, and elucidate the mechanisms of Fontan failure. Understanding these interconnections would also provide the means to develop optimal medical strategies to improve those outcomes. Therefore, the objective of this grant is to investigate the relationship between TCPC hemodynamics and ventricular function, and subsequently determine how those parameters impact patient quality of life (QOL). To achieve these objectives, the PI has assembled a multidisciplinary research team with a proven track record in the field, a novel set of established analytical tools, and the largest collection of single ventricle anatomy and flow data in the world. These assets will be utilized through the following synergistic approach: (1) we will perform a longitudinal analysis of TCPC hemodynamics and ventricular function;(2) we will compare the dynamics of the single ventricle and TCPC between rest and exercise using a CMR exercise protocol;and (3) we will conduct a cross-sectional assessment of patient QOL to quantify clinical outcomes, relate them to the measured hemodynamic and functional parameters, and determine which parameters are critical determinants and predictors of QOL. The novel components of this approach include the use of a CMR-compatible bike to obtain patient hemodynamic and function data under both resting and exercise conditions;the systematic quantification of TCPC hemodynamic (e.g. power loss) and cardiovascular function at rest and exercise in a cross-sectional study of over 150 patients;and the characterization of their temporal evolution in a longitudinal study. Correlation of these surrogates to quality of life measures will identify the strongest outcome predictors to be used for patient diagnosis. In parallel, combining these predictors with the simple mechanistic approaches will point to the cause of the deteriorating patient outcome. This will in turn help design improved surgical and clinical management strategies.

Public Health Relevance

This grant investigates the relationship between Fontan hemodynamics and ventricular function in patients born with single-ventricle heart defects. These surrogates will subsequently be correlated to quality of life measures to identify the strongest outcome predictors to be used for patient diagnosis. Understanding these interconnections will provide the means to develop optimal medical strategies to improve those outcomes.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL098252-03
Application #
8213473
Study Section
Clinical and Integrative Cardiovascular Sciences Study Section (CICS)
Program Officer
Burns, Kristin
Project Start
2010-02-01
Project End
2014-01-31
Budget Start
2012-02-01
Budget End
2013-01-31
Support Year
3
Fiscal Year
2012
Total Cost
$744,227
Indirect Cost
$110,226
Name
Georgia Institute of Technology
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
097394084
City
Atlanta
State
GA
Country
United States
Zip Code
30332
Wei, Zhenglun; Whitehead, Kevin K; Khiabani, Reza H et al. (2016) Respiratory Effects on Fontan Circulation During Rest and Exercise Using Real-Time Cardiac Magnetic Resonance Imaging. Ann Thorac Surg 101:1818-25
Restrepo, Maria; Luffel, Mark; Sebring, Jake et al. (2015) Surgical planning of the total cavopulmonary connection: robustness analysis. Ann Biomed Eng 43:1321-34
Vallecilla, Carolina; Khiabani, Reza H; Trusty, Phillip et al. (2015) Exercise capacity in the Bidirectional Glenn physiology: Coupling cardiac index, ventricular function and oxygen extraction ratio. J Biomech 48:1997-2004
Restrepo, Maria; Tang, Elaine; Haggerty, Christopher M et al. (2015) Energetic implications of vessel growth and flow changes over time in Fontan patients. Ann Thorac Surg 99:163-70
Khiabani, Reza H; Whitehead, Kevin K; Han, David et al. (2015) Exercise capacity in single-ventricle patients after Fontan correlates with haemodynamic energy loss in TCPC. Heart 101:139-43
Haggerty, Christopher M; Whitehead, Kevin K; Bethel, James et al. (2015) Relationship of single ventricle filling and preload to total cavopulmonary connection hemodynamics. Ann Thorac Surg 99:911-7
Haggerty, Christopher M; Restrepo, Maria; Tang, Elaine et al. (2014) Fontan hemodynamics from 100 patient-specific cardiac magnetic resonance studies: a computational fluid dynamics analysis. J Thorac Cardiovasc Surg 148:1481-9
Fogel, Mark A; Li, Christine; Nicolson, Susan C et al. (2014) Comparison by magnetic resonance phase contrast imaging of pulse-wave velocity in patients with single ventricle who have reconstructed aortas versus those without. Am J Cardiol 114:1902-7
Avitabile, Catherine M; Leonard, Mary B; Zemel, Babette S et al. (2014) Lean mass deficits, vitamin D status and exercise capacity in children and young adults after Fontan palliation. Heart 100:1702-7
Tang, Elaine; Restrepo, Maria; Haggerty, Christopher M et al. (2014) Geometric characterization of patient-specific total cavopulmonary connections and its relationship to hemodynamics. JACC Cardiovasc Imaging 7:215-24

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