This document discusses a rare case of an anomalous right superior vena cava (RSVC) draining directly into the left atrium. The key points are: 1. Embryological development explains how the RSVC could anomalously connect to the left atrium. 2. A 34-year-old woman presented with hypoxemia and was found to have this rare condition. 3. Surgical correction was performed to reroute the RSVC into the right atrium, resolving the hypoxemia.

1. RIGHT SUPERIOR VENA
CAVA DRAINING TO LEFT
ATRIUM –
REVIEW OF REPORTED
CASES
Discussed By –
Dr Kunwar Sidharth Saurabh

2. • The most commonly encountered systemic thoracic venous anomaly
is a persistent left superior vena cava that drains into the right atrium
via the coronary sinus.
• A much rarer systemic venous anomaly is that of isolated anomalous
drainage of a normally positioned right superior vena cava (RSVC) into
the left atrium (LA). This has been reported in very few patients.

3. Embryology of SVC
• During the fourth week of
gestation, two major
symmetrical vein systems, the
right and the left precardinal
veins, drain the upper portion of
the embryo.
• Each precardinal vein drains into
a common cardinal vein before
entering the embryological
heart.

4. Cont..
• By the eighth week of gestation,
a vein anastomosis connects the
two precardinal veins and the
left common cardinal vein
atrophies progressively until
complete regression.

5. Cont..
• With this regression, the anastomotic vein between the two
precardinal veins becomes the left innominate (brachio-cefalic) vein
and the right precardinal vein and the right common cardinal vein
form the SVC.

6. Proposed Hypothesis
• Posterior deviation of the common cardinal vein will lead to fusion
between the posterior wall of the RSVC and the anterior wall of the
embryonic LA.

8. • The patient presented with dizziness, mild cyanosis, polycythemia
and normal cardiac and pulmonary findings.
• This condition should be suspected if cyanosis, clubbing, and a
"normal" cardiac examination coexist and if the more common
pulmonary and hematological causes of this triad have been
excluded.
• The first major diagnostic clue in this confusing clinical presentation
was an unsuccessful lung perfusion scan in which intravenous tracer
consistently bypassed the lungs.

9. • His mother noted him to be cyanotic from a young age.
• The patient's wife reported a 10-year history of decreasing memory
and attentiveness.
• Twenty months before this admission, the patient had a well
documented, uncomplicated inferior myocardial infarction with
subsequent vague, intermittent chest pain that did not appear to be
ischemic in etiology.
• He was found at another hospital to have a hematocrit of 64.5 with
an erythropoietin level twice normal. A primary etiology for the
polycythemia was not found

10. • Physical examination on admission to this hospital revealed a normally
developed man with striking central cyanosis and clubbing of the fingers
and toes.
• On auscultation the only notable finding was a single second heart sound.
• Other systemic examinations were normal with no splenomegaly,
hepatomegaly etc,
• Chest radiograph revealed normal-sized heart and unremarkable lung
fields.
• The hemoglobin was 19.2, hematocrit 60, platelet count 266,000, white
cell count 5,200, and blood smear normal.

11. • Along with other investigations, the patient underwent lung
perfusion scan in which intravenous tracer consistently bypassed
the lungs.
• The diagnosis of SVC to LA in this particular case was made by cardiac
catheterisation in which the green dye injected in SVC appeared in
Femoral artery after few seconds, while also, the catheter could be
seen traversing from SVC to LA.

12. • At operation, The right atrium was opened. There was no atrial septal
defect. The atrial septum was incised superiorly with the incision
extending into the superior vena cava. A pericardial patch was
fashioned so as to divert the superior vena caval blood into the right
atrium and the pulmonary venous return into the left atrium.
• The right atrium was also patched with the pericardium to increase
its size.
• The patient also had SVD (RCA Prox 100%), which was bypassed using
RSVG.

14. • Difficulty was experienced weaning the patient off the bypass pump.
• After using the intraaortic balloon and inotropic agents, he was
successfully separated from the bypass pump. His hemodynamic
status improved. By the fifth postoperative day the intraaortic balloon
was successfully removed.
• The patient, however, had sustained acute renal failure early in his
postoperative course, requiring hemodialysis. While renal function
was improving, he became septicemic and died three weeks after the
operation.

16. Important points -
• The findings are clearly consistent with adult survival, but whether
life expectancy is shortened is not clear.
• The quality of life may be adversely affected. There is evidence that
the changes in cognitive functions can be there, presumably a result
of chronic hypoxia.
• Patient can also complain of shortness of breath and dizziness, also
probably on the basis of hypoxia.

17. Important Points –
• A potential danger in these patients results from the direct
communication of the superior vena cava with the systemic
circulation, which poses the increased risk of systemic emboli.
• Hence, It is recommended that intravenous infusions utilizing veins
of the upper body should be avoided if a patient with this syndrome
is recognized.
• Other cardiac and hematological causes must be excluded.

19. Findings and Management
• After inspecting the RA cavity very carefully,they could not find the
RSVC orifice in the normal position. The LA cavity was carefully
inspected through the large Sinus Venosus ASD, and the RSVC orifice
was found at the right-side roof of the LA.
• Furthermore, the right upper pulmonary vein orifice was found in the
RSVC.
• After dealing with SVASD, and rerouting the pulmonary venous
channel, The cephalic edge of the atrial appendage flap was
anastomosed to the anterior external wall of the SVC beyond the
SVC-RA junction to avoid injury to the sinus nodal artery. Then the
extracardiac rerouting of RSVC flow was completed.

22. Findings
• This was the first prenatal ultrasound diagnosis of abnormal RSVC
drainage into the left atrium
• Neonatal transthoracic echocardiography confirmed the diagnosis
and showed an abnormal connection of the right pulmonary veins to
the RSVC. Right-to-left shunt due to anomalous drainage of the RSVC
into the left atrium associated with an atrial septal defect and
anomalous pulmonary venous return were diagnosed on
echocardiography and confirmed by angiography.

23. • The importance of prenatal recognition of this rare anomaly (RSVC
draining into the left atrium) is due to the fact that usually this
anomaly is responsible for mild-to moderate cyanosis and arterial
desaturation, and it is often diagnosed only after serious
complications such as brain abscesses.
• This is because, in normal conditions, two thirds of the right atrial
inflow comes from the inferior vena cava, which mitigates the risk of
moderate-to-severe hypoxemia and delays diagnosis until
adulthood.

26. Significant points
• A case of a 34-year-old woman who presented with asymptomatic
hypoxemia in the peripartum period.
• Spontaneous rupture of membranes and evidence of fetal distress
developed, and an urgent cesarean section was performed. Despite
intubation before the procedure, the patient became hypoxic, with an
oxygen saturation that was measured at 78% in the operating room.
The baby was successfully delivered by cesarean section, after which
the patient was extubated; her oxygen saturation levels ranged from
85% to 94%, even upon the administration of 10 L of oxygen through
a nasal cannula.

28. Significant points-
• The association vein of Galen aneurysmal malformation, with
congenital heart disease has been described.
• The vein of Galen aneurysmal malformation (VGAM) is a congenital
vascular malformation. It manifests in the first year of birth with high
output cardiac failure.
• Any connection between the venous and arterial systems poses a
substantial risk of brain abscess and paradoxical embolization.

30. • Young female who presented with cerebral abscess and seizures.
• The uniqueness of the case lay in the manner in which her
neurological symptoms completely diverted attention from the
intracardiac lesion.
• The RA appendage (RAA) was anastomosed to SVC using side-biting
clamps. The use of such a clamp, assisted by the large caliber of the
SVC, ensured that there were neither deleterious pressure variations
in the venous system nor the possibility of venous brain oedema. SVC
and LA junction was ligated with umbilical tape without transecting
the SVC. CPB was NOT used for the procedure.

32. Significant points
• There were no concerns, apart from circumoral cyanosis during episodes
of crying that was noted by her parents.
• Despite this small inter-atrial communication, patient had minimal clinical
symptoms except for mild cyanosis. Most likely, this is explained by the
presence of the bridging vein connecting the right SVC to the left SVC,
which is the relatively larger systemic upper vein.
• We also report this case to demonstrate and confirm the persisting
importance of using pulse oximetry in the evaluation of pediatric
patients.
• With pulse oximetry screening before discharge becoming the standard of
care on the detection of critical CHD in newborns ,the finding of a
borderline oxygen saturation needs full medical work-up, including a
thorough echocardiography study.

33. First Reported Case to be Diagnosed by CECT

37. • Computed tomography showed bilateral superior vena cavae (SVC)
connected by a bridging vein. The left SVC drained to the coronary sinus.
The right SVC drained to the right upper pulmonary vein (RUPV) and into
the LA. A smaller caliber remnant of the right SVC connected the RUPV to
the right atrium.
• Angiography confirmed the connections.
• Balloon occlusion of the lower right SVC did not alter pressure in the upper
right SVC.
• A 14-mm Amplatzer Vascular Plug II (St. Jude Medical, St. Paul, Minnesota)
was deployed in the right SVC at the SVC-RUPV junction. A 10-mm
Amplatzer Vascular Plug II was deployed in the inferior remnant of the right
SVC at the SVC-RUPV junction.

38. • Percutaneous closure of a left SVC draining to the LA and surgical
correction of a right SVC draining to the LA have been described.
• This is the first report describing percutaneous closure of a right SVC
to LA connection.

40. Differential Diagnosis
• Differential diagnosis of hypoxemia-
• primary lung disease
• intracardiac right-to-left shunt
• pulmonary arteriovenous malformation
• pulmonary embolus
• Hemoglobinopathy
• Methemoglobinemia.
• Commonly associated malformations-
• Atrial or ventricular septal defect
• Single atrium or single ventricle
• Eisenmenger complex
• Tetralogy of Fallot
• Transposition of the great vessels.
• Associated extracardiac abnormalities
• Coarctation of the aorta
• Pulmonary arterio- venous fistula
• Patent ductus arteriosus
• Abnormalities of the IVC

41. NOTE
• Regardless of clinical presentation, surgical correction is indicated
once the diagnosis of a systemic venous connection to the LA is
determined