1. The modified Fontan procedure: morphometry and surgical implications
Maria G Kiaffas, MD, Richard Van Praagh, MD, Chrysoula Hanioti, MD, Douglas W Green, MD 
The Annals of Thoracic Surgery 
Volume 67, Issue 6, Pages (June 1999)
DOI: /S (99)

2. Fig 1
The ratio of the Fontan area (FA) relative to the systemic venous area (SVA), ie, the FA/SVA index, varied with the operation performed and the presence or absence of a left superior vena cava (LSVC). (A) With an atriopulmonary anastomosis, FA/SVA index = c/a + b. (B) With a lateral tunnel cavopulmonary anastomosis, FA/SVA index = d + b ± c/a + b ± c. a, cross-sectional area of the inferior vena cava (IVC); b, cross-sectional area of the right superior vena cava (RSVC);c, cross-sectional area of FA in A; c, cross-sectional area of LSVC in B; d, cross-sectional area of lower RSVC anastomosed to inferior surface of right pulmonary artery (RPA);LPA, left pulmonary artery; LT, lateral tunnel; MPA, main pulmonary artery; RA, morphologically right atrium; ±, with or without.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

3. Fig 2
(A) Comparison of normal tricuspid valve area (TVA) with systemic venous area (SVA), ie, normal TVA/SVA indices shown with white circles, and Fontan area (FA) to SVA, ie, FA/SVA indices shown with black circles. There is almost no overlap between the normal and the much smaller Fontan indices. (B) Comparison of normal TVA to body surface area (BSA), ie, normal TVA/BSA indices (white circles) and FA/BSA indices (black circles). There is no overlap between the normal and the much smaller Fontan indices.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

4. Fig 3
Obstructive Fontan procedure in a year-old boy. (A) Anastomosis between the lower superior vena cava (SVC) and the undersurface of the right pulmonary artery (RPA); cross-sectional area 55 mm2. (B) Anastomosis of the upper SVC with the superior surface of the RPA; cross-sectional area 77 mm2. The inferior vena cava at its junction with the right atrium (RA), not shown; cross-sectional area 902 mm2. The FA/SVA ratio = 132/979 (0.1348, or 13.48%). The area of the lower SVC-RPA anastomosis in A is 93.9% less than that of the IVC. The area of the left-sided tricuspid valve is 396 mm2. The summed cavopulmonary anastomoses shown in A and B = 132 mm2, 67% less than the area of the left-sided tricuspid valve (the only functioning atrioventricular valve). (C) Same patient also had restrictively small bulboventricular foramen (BVF), indicated by 1-mm probe. BVF measures 8 × 6 mm; cross-sectional area 37.7 mm2, resulting in subaortic stenosis (treated with Damus-Kaye-Stansel procedure) and marked left ventricular hypertrophy (13 mm in thickness). Diagnosis: single left ventricle (LV) with infundibular outlet chamber, transposition of the great arteries {S, L, L}, double-inlet LV, right-sided mitral valve patched closed, atrial septum closed. FW, free wall; PV, pulmonary valve; RL, right lung; TV(L), tricuspid valve, left-sided; VS, ventricular septum.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )