3. Embryological Development of The Venous System
● The Sinus Venosus of the primitive heart tube receives 3 sets of paired (left &
right) systemic veins :
- Vitelline Vein
- Umbilical Vein
- Common Cardinal Vein
4.
5. Embryological Development of The Venous System
● Vitelline Veins : Return from the yolk sac. Distally, they regress and
proximally, they lose their connection with the sinus venosus by 6 weeks.
- Mid-portions contribute to hepatic and portal veins and a small portion of the
IVC
● Umbilical Veins : Carry oxygenated blood from the placenta to the right
atrium via ductus venosus. This blood is directed through the foramen ovale
into the left atrium & systemic circulation
6.
7. Embryological Development of The Venous System
● Cardinal Veins : Carry venous return from the embryo proper. Anterior and
Posterior cardinal veins join to form the common cardinal vein
- Anterior cardinal veins carry venous return from the upper body
- Posterior cardinal veins carry venous return from the lower body
● Right anterior and right common cardinal veins form the SVC in mature
circulation
● Left common cardinal vein forms the coronary sinus, which receives blood
from the coronary system
8. Embryological Development of The Venous System
● Formation of the IVC : Made up of five segments from urogenital, mesentric
and hepatic venous channels
● They fuse towards the right side of the spine and the left-sided segments
involute
● IVC interruption can occur at various segments; in such cases, one or more of
the venous connections that connect the upper and the lower body can
enlarge and shunt the blood to the SVC
11. Development of Systemic Venous Collaterals After Glenn
& Fontan Repair
● Functional correction of univentricular hearts relies on increased systemic
venous pressure as the driving force for blood to pass through the pulmonary
vascular bed without the support of a pumping ventricle
● Post Glenn anastomosis, there is creation of a pressure gradient between
the upper and lower body venous systems
● This pressure gradient may lead to opening up of rudimentary venous
collateral connections
12.
13. Development of Systemic Venous Collaterals After Glenn
& Fontan Repair
● These venovenous collaterals can lead to systemic arterial desaturation
● Resulting desaturation can in turn cause ventricular dysfunction
● Following three anatomical regions of the chest can serve as connections
between SVC and IVC :
- Anterior (Internal thoracic, Epigastric Veins)
- Middle (Pericardial Veins, Intercostal Veins)
- Posterior (Azygous/hemiazygous, lumbar or vertebral plexus veins)
14. Case Scenario
● 20/Female
● CHD IXL DILV with non inverted outlet chamber with severe PS with
moderate-sized OS ASD
● S/P Bilateral BDG (28/4/2016)
● Presented with progressive dyspnea on exertion for 3 months
● Baseline sPO2 : 77%
17. Take Home Message
● Progressive saturation is an indication for evaluation for venovenous
collaterals
● Catheter occlusion is the method of choice for management
● Systematic ligation of rudimentary veins especially at both brachiocephalic
angles should be performed during Glenn procedures
