1. Hemodynamic comparison of the traditional Fontan baffle and Y-graft modification under
simulated exercise conditions
Kasey Rice, Ajit P. Yoganathan, PhD
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
Introduction
Materials and Methods
Results Conclusions
Patient-Specific Geometry and Boundary Conditions
Flow Field Diagrams for Y-Graft and Traditional Baffle
Exercise Performance (iPL) Comparison
Post-Simulation Analysis
Computational Fluid Dynamics (CFD) Simulation
Future Directions
Acknowledgments
A special thanks given to Children’s Healthcare of Atlanta (CHOA)
and Children’s Hospital of Philadelphia (CHOP) for providing MRI
patient data with confidentiality. Additional thanks to Phillip Trusty,
Dr. Zhenglun Wei, Dr. Maria Restrepo, Jaci Carithers and Dr. Ajit
P. Yoganathan for participation in the study. A special
acknowledgement given to my baby cousin Isaiah Deslauriers,
who was born with HLHS.
Correlations of iPL with Y-graft patient geometries
(1) Whitehead, K. K.; Pekkan, K.; Kitajima, H. D.; Paridon, S. M.; Yoganathan, A. P.; Fogel, M. A., Nonlinear Power Loss During Exercise in Single-
Ventricle Patients After the Fontan: Insights From Computational Fluid Dynamics. Circulation 2007, 116 (11 suppl), I-165-I-171.
(2) Khiabani, R. H.; Whitehead, K. K.; Han, D.; Restrepo, M.; Tang, E.; Bethel, J.; Paridon, S. M.; Fogel, M. A.; Yoganathan, A. P., Exercise capacity
in single-ventricle patients after Fontan correlates with haemodynamic energy loss in TCPC. Heart 2015, 101 (2), 139-143.
• Compare exercise performance for both TCPC types in real-
time (e.g. MRI-compatible cycle ergometer)
• Flow field diagram analysis
Literature Cited*
Fontan Procedure
• Routes blood around dysfunctional ventricle
• Last Stage for surgical procedure
Traditional Baffle
Y-Graft
Fontan
Anatomy
Boundary
Conditions
Patient MRI 3D Anatomy Meshed Geometry
CFD Simulation
• Navier-Stokes
Equation
• Inputs: Geometry
and Boundary
Conditions
Flow Field Results
• Anatomy Flow
Patterns
• Pressure Drop
• Particle
Resonance Time
Power Loss Calculations (𝟏)
• Macroscopic energy balance:
Patient MRI Velocity Segmentation
𝐸 =
𝑆𝑢𝑟𝑓𝑎𝑐𝑒
[𝜌 +
1
2
𝜌𝑢𝑗 𝑢𝑖] 𝑢𝑗 𝑛𝑗 𝑑𝑆 ≅ 𝜌 +
1
2
𝜌𝑣2
𝑄
𝐸 𝑑𝑒𝑙𝑡𝑎 = 𝐸𝑆𝑉𝐶 + 𝐸𝐼𝑉𝐶 − 𝐸𝐿𝑝𝐴 − 𝐸 𝑅𝑃𝐴
• Total Power Loss:
Correlations of iPL from intense exercise with iPL at rest
Y-GraftTraditionalSPSS
• Student t-test
• Mann Whitney
test
• Bivariate
comparisons
• Y-Grafts have significantly greater iPL which suggests
decreased exercise performance
• No strong correlation of iPL with patient geometry
• Exercise performance can be predicted for Y-graft patients
Patient
Demographics
Y-graft (n=20) LT/ECC (n=20) p-value
Age (years) 3.53±0.60 3.23±0.19 0.52
BSA (m2) 0.63±0.05 0.63±0.01 0.16
Male/Female 12/8 14/6 N/A
HLHS/non-HLHS 7/13 10/10 N/A
Systemic Venous
Flow (L/min)*
1.51±0.14 2.12±0.11 <0.01
PFD (% LPA) 48±4 44±3 0.49
Nakata Index
(mm2/m2)*
108±12 143±8 0.02
IVC Stenosis (%) 23±4 25±2 0.14
LPA Stenosis (%) 36±4 45±4 0.08
RPA Stenosis (%) 20±3 27±3 0.13
Overall PA
Stenosis (%)
26±3 35±3 0.05
R² = 0.118
0
0.1
0.2
0.3
0.4
0.5
0.6
0 5 10 15 20
iPL(3x) Minimum IVC size
R² = 0.23
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100 150 200 250
iPL(3x)
Nakata Index
R² = 0.40
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0 10 20 30 40 50 60
iPL(3x)
Overall Pa St. (%)
R² = 0.08
R² = 0.13
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0 5 10 15 20
iPL(3x)
Minimum LPA/RPA size
LPA min
RPA min
0.00
0.02
0.04
0.06
0.08
0.10
0.12
Rest Moderate
Exercise
Intense
Exercise
IndexedPower
Loss(iPL) Ygraft
Traditional
y = 0.9858x + 0.0028
R² = 0.98
y = 1.4028x + 0.0013
R² = 0.40
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2
iPL(3x)
iPL (1x)
Ygraft
Traditional
Rest Moderate
Exercise
Intense
Exercise