1. Optimal Conduit Size of the Extracardiac Fontan Operation Based on Energy Loss and Flow Stagnation 
Keiichi Itatani, MD, Kagami Miyaji, MD, PhD, Takahiro Tomoyasu, MD, Yayoi Nakahata, MD, Kuniyoshi Ohara, MD, PhD, Shinichi Takamoto, MD, PhD, Masahiro Ishii, MD, PhD 
The Annals of Thoracic Surgery 
Volume 88, Issue 2, Pages (August 2009)
DOI: /j.athoracsur
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
(A) Geometry of the extracardiac Fontan computational flow dynamic model. Mean values of 17 patients are used to create the geometry. The right and left pulmonary arteries (PA) are assumed to be the same diameter, and the mean values of the bilateral pulmonary artery diameters are used. A 9.6 mm diameter is equivalent to the pulmonary artery index (PA index, Nakata's index) 273. The radius of conduits varied from 14 to 22 mm. Conduits were anastomosed to the pulmonary artery at a distance equal to one superior vena cava (SVC) radius from the center of the Glenn anastomosis site. The conduit curve was determined as though the middle level of the conduit deviated 6.6 mm from the axis of the inferior vena cava (IVC). (B) Time varying function of boundary conditions. The SVC and IVC flow were given by the previously reported MRI flow study [12]. The pressures of the bilateral pulmonary arteries were given as 11 mm Hg, which dropped to 20% in the inspiratory phase.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
Flow features and stagnation areas at rest. Flow features of inspiratory and expiratory phases for each conduit size are shown. The color contours represent the velocity magnitude, and the indicators (arrowhead) represent the flow directions. Penetration of the superior vena cava flow into conduits is detected in conduits larger than 20 mm. Backflow in the expiratory phase at the lateral portion of the conduits is detected in conduits larger than 18 mm.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

4. Fig 3
Clinical manifestations of Fontan flow. Angiographic study (superior vena cava [SVC]) of a patient after the extracardiac Fontan operation in the expiratory phase. Iopamidol was injected in the SVC above the bifurcation site of innominate vein and right carotid vein using a 4 Fr. pigtail catheter at the velocity 6 mL/second. Flow from the SVC penetrates into the conduit, as if the conduit were something like a flow reservoir.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

5. Fig 4
Change in flow features during the 0.5 W/kg exercise. The upper half indicates flow features on the expiratory phase and the lower half on the inspiratory phase. The 14, 18, and 22 mm conduits are compared on two exercise levels.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

6. Fig 5
Change in flow features during the 1.0 W/kg exercise. The upper half indicates flow features in the expiratory phase and the lower half in the inspiratory phase. The 14, 18 and 22 mm conduits are compared on two exercise levels.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions

7. Fig 6
Graphs of energy loss and stagnation volume at rest and during exercise. (A) Energy loss at rest and on two exercise levels. (B) The rate of energy loss per inlet energy. (C) Stagnation volume at rest. (D) Stagnation volume during 0.5 W/kg exercise. (E) Stagnation volume during 1.0 W/kg exercise.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2009 The Society of Thoracic Surgeons Terms and Conditions