The cardiovascular system develops from the mesoderm. The cardiogenic field is established around 18-19 days and develops into a fully functional heart by 8 weeks. The venous system develops from the vitelline veins, umbilical veins, and cardinal veins. These veins drain different areas of the developing embryo and undergo remodeling to form the adult venous structures, including redirection of blood flow through the liver into the inferior vena cava. Variations and anomalies can occur during this complex developmental process.

1. The cardiovascular system is
mesodermally derived
Specifically, lateral
splanchnic mesoderm…
Gilbert fig 14.1

2. The cardiogenic field is established in the mesoderm just after gastrulation
(~18-19 days) and develops into a fully functional, multi-chambered heart by
the 8th week
angiogenic cell clusters
(angioblasts/hemangioblasts)
(right dorsal aorta)
(right endocardial tube)
blood islands
(developing blood vessels)
cardiogenic field
pericardial cavity
Langman’s fig 12-1

3. Fusing cardiac primordia
“conotruncus”
(outflow tract)
future
ventricles
future
atria
septum transversum
(liver & diaphragm primordium)
21 days 22 days
Langman’s fig 12-7

4. Venous system development
cardinal veins
vitelline veins umbilical veins
sinus venosus
Langman’s fig 12-41

5. Vitelline and umbilical veins change
during liver development
• R hepatocardiac channel
 hepatic portion of IVC
• R umbilical V regresses
• proximal L umbilical V regresses
• distal L umbilical V persists
and then  round ligament of the liver (ligamentum teres hepatis)
• ductus venosus  ligamentum venosum
L vitelline V
umbilical V
sinus
venosus
cardinal V
hepatic
sinusoids
duodenum
duodenum
yolk sac
L hepatocardiac
channel
R hepatocardiac
channel
ductus
venosus
portal V
superior
mesenteric V
splenic V
hepatic portion of
inferior vena cava
hepatic V
(R vitelline V) hepatic V
4 weeks 5 weeks
6 weeks
8 weeks

6. posterior cardinal veins
anterior cardinal veins
Systemic venous development
Langman’s fig 12-41

7. Week four: SYMMETRY
Umbilical Veins drain the chorion
Vitelline Veins drain the yolk sac
Cardinal Veins drain the body of the
embryo. All three pairs of veins open
to the right and left horn of the sinus venosus
- at this stage the liver buds begin to develop
from the ventral endodermal wall of the
foregut
- these cells invade mesenchymal tissue,
called the septum transversum
Umbilical Veins
anterior cardinal veins
Vitelline Veins

8. 5 – 8 weeks of gestation
- liver cords growing into the septum transversum
- interrupt the cranial portion
of both vitelline (first)
and umbilical veins (day 32) between the liver and the
heart with an extensive vascular network
– the hepatic sinusoids
vitelline anastomoses

9. 5–8 weeks of
development
the asymmetric stage with
intrahepatic
umbilico–portal–ductus venosus
anastomosis
main portal vein
duodenum
left and right portal veins
left ant. cardinal vein
left ant. cardinal vein
hepatocardiac segment of
inferior v. cava
1. Left proximal vitelline vein disappears
2. Right proximal vitelline vein give rise to
hepatocardiac segment of inferior v. cava
3. Distal sections of vitelline veins become
portal vein
4. Other segments disappear
Hepatic vein
ductus venosus
-joining of hepatic sinusoids
-draining into IVC

10. Changes in umbilical veins at 5-8
weeks
- changes of vitelline veins are accompanied by
changes in umbilical veins
1. Entire right umbilical vein diappears
2. Cranial segment of left umbilical vein
disappears
left
left
right
left Umbilical Vein becomes
- dominant conduit of blood from placenta
left umbilical vein
8th week
- intrahepatic portion of the Vitelline Vein (left portal branch), forms an
anastomosis between the intrahepatic segment of the left Umbilical Vein
- and forms an anastomosis with ductus venosus
main portal vein
ductus venosus
left umbilical vein
hepatocardiac segment of inferior
v. cava from right vitelline vein

11. Cardinal veins, subcardinal and
supracardinal veins
- anterior and posterior Cardinal Veins drain the embryo body, draining the cranial and caudal
parts of the body
- both veins empty into the Common Cardinal Veins – the third venous system entering the
sinus venosus of the embryonic heart
- as the embryo is growing in size, cardinal veins are supplemented by a range of bilateral
longitudinal venous channels that anastomose with posterior cardinal system and with each
other: subcardinal, supracardinal

12. Cardinal veins,
subcardinal and
supracardinal veins

13. Fate of Cardinal veins, subcardinal and
supracardinal veins
-left subcardinal vein
-subcardinal anastomosis
-left supracardinal vein
-left posterior cardinal vein
-iliac anastomosis of posteror cardinal veins
-sub-supracardinal anastomosis
(renal collar)
1. From the 5th week the posterior cardinal branches are obliterated
- only the most caudal part persists
giving rise to the common iliac vein
- and most caudal segment of Inferior Vena Cava: sacral
segment
-left anterior cardinal vein
-left common cardinal vein

14. Fate of Cardinal veins, subcardinal and
supracardinal veins
-left subcardinal vein
-subcardinal anastomosis
-left posterior cardinal vein
-iliac anastomosis
of posteror cardinal veins
hepatocardiac segment
of inferior v. cava (VV)
1. From the 5th week the posterior cardinal branches are obliterated
- only the most caudal part persists
giving rise to the common iliac vein
- and most caudal segment of Inferior Vena Cava: sacral
segment
-left anterior cardinal vein
-left common cardinal vein
anastomosis between
anterior cardinal veins

15. Fate of subcardinal veins, cardinal veins,
and supracardinal veins
hepatocardiac segment
of inferior v. cava (VV)
- subcardinal veins form in the ventromedial parts of mesonephric
ridges (5-7 weeks)
- become connected to postcardinal veins by a number of
vessels
- drainage of mesonephros
By the 8th–9th week
- the proximal left subcardinal vein
obliterates
and connects with the right branch:
renal–hepatic (suprarenal) segment of the IVC
- anastomosis between the subcardinal veins forms:
proximal part of left renal vein
-subcardinal anastomosis
gonadal veins
-sub-supracardinal anastomosis
(renal segment)

16. Fate of supracardinal veins, cardinal veins, and
subcardinal
- supracardinal veins form dorsolateral to the aorta
- supracardinal veins drain the thoracic wall and the iliac veins
- inferior portion of the left supracardinal vein obliterates
-and connects to the right subcardinal vein,
- forming the sacrorenal (prerenal) segment of the IVC
- superior segment of the supracardinal vein is divided:
- into the left branch, called the hemiazygos vein,
which forms a cross anastomosis to the right branch:
called the azygos vein,
which drains into the superior vena cava
-sub-supracardinal anastomosis
(renal segment)
postrenal segment
prerenal segment
renal vein
gonadal vein

17. Superior and inferior vena cava
- proximal left anterior Cardinal Vein
-regresses and disconnects from the sinus venosus
-a shunt to the right anterior Cardinal Vein is formed:
left brachiocephalic vein
- right anterior Cardinal Vein is transformed into:
right brachiocephalic vein
- segment between the junction of the left and right
brachiocephalic veins and the right atrium develops
meanwhile into:
Superior Vena Cava
-right common cardinal vein
-proximal part of right anterior cardinal vein
– coronary sinus
oblique vein
-left sinus horn

18. Systemic venous development: shift to the right
7 weeks Adult
L. brachiocephalic anastomosis
What if the brachiocephalic anastomosis fails?
Moore & Persaud

19. Double inferior
vena cava
Absent inferior
vena cava
Langman’s fig 12-45

20. Left superior
vena cava
Double superior
vena cava
viewed from behind
Langman’s fig 12-46

21. ANOMALIES OF SYSTEMIC
VENOUS SUPPLY
• Anomalies of Caval Veins
• Anomalous Connection with Normal
Drainage
1. Superior caval vein
a. Left superior caval vein to coronary
sinus—with or without connecting vein

22. BILATERAL SUPERIOR VENAE CAVA
WITH NORMAL DRAINAGE TO THE
RIGHT ATRIUM

24. COURSE OF LSVC
follows the course of the embryonic left cranial cardinal vein. It enters the pericardial cavity
to the left of the left upper pulmonary veins, and runs posterior to the dome of the left
atrium, having the mouth of the left atrial appendage to its left side. As it passes inferiorly,
it accepts the hemiazygos vein and descends medially into the inferior atrioventricular
groove. In nine-tenths of cases, the persistent left superior caval vein drains into the
morphologically right atrium through an enlarged mouth of
the coronary sinus

25. • THE SIZE OF THE LSVC VARIES
• LEFT INNOMINATE VEIN MAY BE PRESENT IN
60%
• THE LSVC STARTS AT THE JUNCTION OF THE LEFT
JUGULAR AND LEFT SUBCLAVIAN VEINS
• JOINS THE CORONARY SINUS IN THE POSTERIOR
LEFT AV GROOVE

26. CLINICAL MANIFESTATIONS
• PHYSIOLOGY IS USUALLY NORMAL AND NO
CLINICAL MANIFESTATIONS
• ENLARGEMENT OF THE CORONARY SINUS MAY
INTERFERE WITH BLOOD FLOW FROM THE LA
INTO THE LV
• AN INCREASE IN THE MAGNITUDE OF THE LEFT
TO RIGHT SHUNT AT THE ATRIAL LEVEL WAS
FOUND IN PATIENTS WITH SECUNDUM ASD
PERSISTENT LSVC AND DILATED CORONARY
SINUS

27. • CHEST X-RAY : SHADOW ALONG THE LEFT UPPER
BORDER OF THE MEDIASTINUM

28. BILATERAL SVC WITH AN UNROOFED
CORONARY SINUS
• COMMON WALL BETWEEN THE LA AND
CORONARY SINUS IS ABSENT
• PERSISTENT LSVC DRAINS INTO THE LEFT ATRIUM
• IN PATIENTS WITH A NORMAL INTER ATRIAL
SEPTUM, THE ORIFICE OF THE UNROOFED
CORONARY SINUS WILL FUNCTION AS AN
INTERATRIAL COMMUNICATION

29. CLINICAL MANIFESTATIONS
• MOST PATIENTS HAVE A LARGE CORONARY SINUS OSTIUM THAT
FUNCTIONS AS AN INTERATRIAL COMMUNICATION (RAGHIB
SYNDROME)
• IN MOST PATIENTS, ARTERIAL OXYGEN SATURATION RANGES
BETWEEN 85-95%
• THEY ARE AT RISK OF PARADOXICAL EMBOLI, BRAIN ABSCESS,
STROKE
• WHEN RIGHT ATRIAL OUTFLOW STENOSIS OR ATRESIA COEXISTS
WITH A PERSISTENT LSVC TO AN UNROOFED CORONARY SINUS,
THE SHUNT IS FROM RIGHT TO LEFT

30. • REPAIR IS DONE TO AVOID COMPLICATIONS OF
CYANOSIS
• IF THE LSVC OS RELATIVELY SMALL AND THERE IS
AN ADEQUATE SIZED LEFT INNOMINATE VEIN,
THE LSVC CAN BE LIGATED AND THE INTERATRIAL
COMMUNICATION CLOSED.
• IN THE ABSENCE OF AN ADEQUATE SIZED
BRIDGING LEFT INNOMINATE VEIN, THE
CORONARY SINUS IS REROOFED.

31. ABSENCE OF RIGHT SUPERIOR
CAVAL VEIN
• The anomaly results from involution of the right,
instead of the left, superior cardinal vein during
embryonic life. It is known to exist both as an
isolated anomaly and in association with other
cardiac malformations. Abnormalities of rhythm
are common, more so with coexisting cardiac
malformations, and are more pronounced in older
patients
• RHYTHM DISTURBANCES INCLUDE: AV block, SA
node dysfunction, VT, LBBB And RBBB, SVT

32. Issues that make diagnosis important
are
• Implantation of transvenous pacemaker
• placement of a pulmonary artery catheter for
intraoperative or postoperative monitoring
without the use of flouroscopy
• systemic venous cannulation for ECMO, CPB

33. Absent Bilaterally Superior Caval Veins
On rare occasions, both superior caval veins can be absent.
The blood from the head and arms drains to the inferior
caval vein via the azygos or hemiazygos systems. Although
the exact morphogenesis remains unclear, we presume that
this anomaly results from failure of development of the
superior cardinal venous system. Since the drainage of blood
remains unobstructed, it remains clinically silent, as has been
the case in most reported examples, coming to attention
only during pacemaker implantation or central line insertion

34. INFERIOR CAVAL VEIN
A. Absence of the Hepatic Segment of Inferior Caval
Vein With Azygos Continuation
This is the most common anomaly involving the inferior caval vein. It
exists because of the absence of the infrahepatic portion of the inferior
caval vein (INTERRUPTED IVC). The blood from the lower part of the body
reaches either the left or right superior caval vein via the dilated azygos
venous system
Hepatic veins drain blood from Liver to Morphological RA
occurs dur to Abnormal development of right subcardinal vein which fails
to anastomose to right vitelline vein.

35. • Supracardinal venous system normally forms
Azygous vein which provides drainage to
developing superior caval vein
• INCIDENCE: 0.6%
• It is most relevant in the setting of patients
having functionally univentricular hearts who
are undergoing construction of a
cavopulmonary connection. The mere
connection of the superior caval vein to the
pulmonary arteries in this setting is equivalent
to a near total cavopulmonary connection. This
is so-called Kawashima repair

36. Anomalous Systemic Venous Connection With
Anomalous Drainage
• SYSTEMIC VEIN DRAIN - MORPHOLOGICALLY LA
• DIRECT DRAINAGE - BLOOD AWAY FROM
PULMONARY CIRCULATION ( DECREASES
EFFECTIVE PULMONARY FLOW)
• RISK OD PARADOXICAL EMBOLISATION AND
STROKE
• ARTERIAL DESATURATION DISPROPORTIONATE TO
CO-EXISTING CARDIAC MALFORMATION

37. LSVC TO LA
• The left superior caval vein can rarely communicate directly and
anomalously to the left atrium. In most of these instances, the
communication is through a combined deficiency of the adjacent
walls of the left atrium and coronary sinus. The spectrum of
fenestration of the coronary sinus is also described as unroofing of
coronary sinus
• Unroofed coronary sinus almost always is associated with a
persistent LSVC
• A CS defect without an associated LSVC, and the physiology is same
as in ASD

38. RIGHT SVC DRAINING INTO LA
• IT REPRESENTS A SINUS VENOSUS
DEFECT OF THE SVC TYPE IN ASSO.
WITH ATRESIA OF THE RIGHT SVC
ORIFICE
RESULTS FROM DEF. OF COMMON WALL
BETWEEN SVC AND RUPV
THIS DEFECTS UNROOF THE RUPV AND
ITS BRANCHES INTO RIGHT SVC
THE UNROOFED RUPV THEN DRAINS
INTO SVC AND ITS LA ORIFICE BECOMS
INTERATRIAL COMMUNICATION

39. CLINICAL MANIFESTATIONS OF
R-SVC IN LA
• CYANOSIS
• SYMPTOMS MAY NOT DEVELOP UNTIL LATE
CHILDHOOD OR ADOLSCENCE
• THE RISKS OF RT TO LT SHUNT SEQUELAE
INCREASE WITH AGE

40. • TREATMENT
• THE RIGHT SVC FLOW IS SURGICALLY DIVERTED INTO
THE RA
• IN THE PAST THIS WAS DONE BY CREATING AN ASD AND
REDIRECTING SVC FLOW INTO RA AND PULMONARY
BLOOD INTO LA
• PREFERRED SURGICAL APPROACH IS TRANSECTION OF
THE RIGHT SVC ABOVE THE ENTRANCE OF THE RUPV
AND ANASTOMOSIS OF THE TRANSECTED CAVAL END TO
THE RA APPENDAGE

41. BILATERAL INFERIOR VENAE
CAVA
• BILATERAL SUPRAHEPATIC IVCs (i.e. A NORMAL
IVC AND A CONTRALATERAL HEPATIC VEIN) A
FREQUENT FINDING IN CASES OF VISCERAL
HETEROTAXY WITH ASPLENIA
• B/L SUPRAHEPATIC IVCs ALSO CAN OCCUR
RARELY IN PATIENTS WITH A NORMAL VISCERAL
SITUS
• THE LEFT SIDED HEPATIC VEIN IN THOSE CASES
CASES DRAINS INTO A NORMAL CS

42. INFERIOR VENA CAVA DRAINAGE TO
THE LA
• DURING FETAL LIFE ABOUT HALF OF THE UVC BLOOD
THAT ENTERS THE RA IS DIRECTED TOWARDS THE LA
WITH HELP OF TWO VENOUS VALVES, THE EUSTACHIAN
VALVE ANDD VALVE OF THE FORAMEN OVALE
• A LEFT ATRIAL IVC ALSO OCCUR IN CASES IN WHICH ALL
THE SYSTEMIC AND ALL THE PVs DRAINED INTO THE
LEFT SIDED ATRIUM

43. CLINICAL MANIFESTATIONS
• PARTIAL OR COMPLETE DRAINAGE OF THE IVC NTO THJE
LEFT ATRIUIM RESULTS IN CYANOSIS
• THE CLINICAL MANIFESTATIONS ARE THE RESULT OF RIGHT
TO LEFT SHUNTING, INCLUDING POLYCYTHEMIA, BRAIN
ABSCESS, AND PARADOXICAL EMBOLI
• TREATMENT : IVC BLOOD IS SURGICALLY REDIRECTED INTO
THE RIGHT ATRIUM

44. TOTALLY ANOMALOUS SYSTEMIC
VENOUS CONNECTION
• CONNECTION OF ALL SYSTEMIC VEINS, ALONG WITH
THE PVs, TO MORPHOLOGIC LA --> RARE, PARTICULARLY
WHEN ATRIAL ARRANGEMENT IS USUAL
• WHEN PRESENT AS ISOLATED ANOMALY LEFT TO RIGHT
SHUNT (ASD/VSD/PDA) PROVIDES BLOOD TO LUNGS-->
DETERMINES SPO2
• AMOUNT OF LEFT TO RIGHT SHUNT GOVERNS GROWTH
OF RA/RV
• SMALL SHUNTS-HYPOPLASIA OF RIGHT CHAMBERS-
INTENSE CYANOSIS

45. • LARGE SHUNT: GOOD OXYGENATION, GROWTH OF RV,
PERMITTING COMPLETE SURGICAL REPAIR
• PRESENCE OF CYANOSIS DESPITE OF L--> R SHUNT
ACROSS ASD, HYPOPLASTIC RV, CONCORDAND AV + VA
CONNECTIONS --> ALMOST DIAGNOSTIC OF TASVC
• DIAGNOSIS IS MISINTERPRETED AS SINGLE
VENTRICULAR PHYSIOLOGY
• ONLY 1 CAVAL VEIN GENERALLY SVC MAYBE
CORRECTLY IDENTIFIED BECAUSE SALINE CONTRAST
ECHO IS PERFORMED FROM UPPER LIMB

46. FINDINGS
• INTENSE CYANOSIS, CLUBBING
• JVP: NOT ELEVATED
• NO CARDIOMEGALY, LIVER NORMAL SIZE
• ECG: POOR RV FORCES
• ECHO: AV+VA CONCORDANCE, ALL PVS TO LA, DRAINAGE OF CAVAL
VEINS NOT CLEARLY VISUALIZED USUALLY, HYPOPLASTIC RA/RV,
DILATED LA/LV
• AGITATED SALINE INJECTED IN RIGHT ARM: IMMEDIATE + INTENSE
FILLING OF LA FOLLOWED BT RA
• CARDIAC CATH: CONTRAST INJECTION IN CAVAL VEINS CONFIRMS
SVC+IVC+HEPATIC VEINS CONN. TO LA, SWAN GANZ CATHETER
INSERTED THROUGH RFA>AO VALVE>LV>MV>LA>ASD>RA

49. ANOMALIES OF DUCTUS VENOSUS
• 1. ANOMALOUS TERMINATION OF THE UMBILICAL VEINS
AND ABSENT DUCTUS VENOSUS
• 2. POSTNATAL PERSISTENCE OF THE DUCTUS VENOSUS
• 3. PERSISTENT VALVES OF THE SINUS VENOSUS

50. • 1. ANOMALOUS TERMINATION OF THE
UMBILICAL VEINS AND ABSENT DUCTUS
VENOSUS:
• PERSISTENT LEFT UMBILICAL VEIN
TERMINATES DIRECTLY INTO THE CS, BY WAY
OF THE LEFT PORTAL VEIN OR INTO THE ILIAC
VEIN
• PERSISTENT RIGHT UMBILICAL VEIN
TERMINATES DIRECTLY INTO THE RA, INTO
THE IVC, INTO THE RIGHT PORTAL VEIN AND
INTO RIGHT SVC

51. • CLINICAL MANIFESTATIONS:
• USUALLY DO NOT PRODUCE SYMPTOMS
• INTRAUTERINE OBSTRUCTION OF THE
UMBILICAL VEIN FLOW AND POSTNATAL
INTESTINAL OBSTRUCTIONS SECONDARY TO
THE ANOMALOUS TERMINATION OF THE
UMBILICAL VEIN MAY OCCUR

52. POSTNATAL PERSISTENCE OF
THE DUCTUS VENOSUS
• CONGENITAL POSTNATAL PERSISTENCE OF THE DUCTUS
VENOSUS BECAUSE THE SHUNT WAS AWAY FROM THE
PORTAL VENOUS SEPTUM PROXIMALLUY TO THE DISTAL
HEPATIC VEINS OR IVC DISTALLY
• THESE INTRAHEPATIC PORTO-SYSTEMIC SHUNTS ARE
DUE TO ABNORMAL PERSISTENCE OF ELEMENTS OF THE
OMPAHALOMESENTRIC SYSTEM
• THREE OF THE TEN CASES REPORTED RESULTED IN
PORTO-SYSTEMIC ENCELOPATHY

53. • DIAGNOSIS: ULTRASOUND OR CT
DEMONSATRATES A LARGE TORTOUS VESSEL
ORIGINATING FROM THE PORTAL VEIN THAT
CONNECTED TO THE HEPATIC VEIN OR IVC
• TREATMENT: IN THE ABSENCE OF
ENCEPHALOPATHY, T/T MAY NOT BE INDICATED.
IF LIGATION OF THE DUCTUS VENOSUS IS
CONTEMPLATED ONE SHOULF ESTABLISH THE
INTERGRITY OF THE PORTAL SYSTEM. IF IT IS
NOT INTACT, LIGATION COULD LEAD TO
MESENTRIC VENOUS CONGESTION > BOWEL
ISCHEMIA

54. EXTRAHEPATIC POSTOSYSTEMIC SHUNT (
ABERNETHY MALFORMATION)
• Uncommonly, the blood from the splanchnic circulation reaches
the IVC via abnormal vascular communications. These anomalous
portosystemic shunts (Abernethy malformation)
• Have hemodynamic and clinical implications comparable to those
produced by persistent patency of the venous duct. However, the
communication is located outside the liver.
• Well known to exist with hypoplasia of intrahepatic portal venous
system. The variant with absent portal vein is more common in
females. If suspected, the diagnosis can be easily made by
ultrasound and or computed tomographic angiography. While liver
transplantation is the only treatment available when the
intrahepatic portal veins are absent, closure or ligation of the shunt
can be performed in the setting of hypoplasia

55. ANOMALIES OF THE CORONARY
SINUS
• CORONARY SINSUS DEFECT AND UNROOFED CS
• CORONARY SINUS ORIFICE ATRESIA
• UNROOFED CORONARY SINNUS ALMOST ALWAYS IS
ASSOCIATED WITH A PERSISTENR LSVC
• A CS DEFECT WITHOUT AN ASSOCIATED LSVC, AND THE
PHYSIOLOGY IS THE SAME AS IN ASD

56. CORONARY SINUS ORIFICE
ATRESIA
• INCIDENCE IS RARE
• THE CS IS USUALLY WELL FORMED, THE
ORIFICE IS COVERED BY A THIN MEMBRANE
LIKE TISSUE
• ALTERNATIVE EXIT FOR CORONARY
VENOUS BLOOD RETURN-
– A SMALL LSVC, LARGE THEBASIAN VEIN
– CS SEPTAL DEFECT, CONNECTION WITH THE
IVC IN ONE CASE

57. • It is also possible for the thebesian valve to persist and to
produce atresia of the orifice of the sinus. In this situation,
coronary venous drainage will be to a persistent left superior
caval vein, which may well be relatively hypoplastic.
Intraoperative ligation of the caval vein in this setting was
described as producing coronary ischemia and death. In some
of these cases with atresia of the orifice of coronary sinus, an
associated fenestration in the walls of the sinus permits
drainage of coronary venous blood to the left atrium.