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© JAPI • august 2012 • VOL. 60
Case Report
Interrupted Inferior Vena Cava Syndrome
Ankur J Mehta1, Arvind H Kate1,2, Neelam Gupta3, Prashant N Chhajed1,2
Abstract
We report a case of interrupted inferior vena cava (IVC) as a rare developmental defect. Inferior vena cava
interruption is usually accompanied with azygos and hemiazygos continuation, and is asymptomatic.
Consequently, venous blood from the caudal part of the body reaches the heart via the azygous vein and superior
vena cava. A 50 year old female who came for routine health check-up was found to have pulmonary hypertension
on two dimensional echocardiography. On further investigations she also had restriction on pulmonary function
test. When computed tomography pulmonary angiography was done, showed dilated azygous vein without
pulmonary embolism. Computed tomography of the abdomen demonstrated interrupted inferior vena cava.
Such patients are at increased risk of deep vein thrombosis and pulmonary embolism.
A
Case Report
50 year old female came for routine health check up. The
only clinical symptoms she had was dyspnea on exertion
class I Medical Research Council dyspnea scale. Patient had two
normal pregnancy without any complications. She gave history
of diabetes mellitus since 18 years and was receiving insulin
therapy since six years. Family history was non contributory.
General examination revealed mild lower limb pedal edema.
Rest general examination was normal. Pulse - 88/min, BP –
130/90 mmHg, SpO2- 96% on room air. Respiratory Rate - 20/
min. Respiratory system examination revealed bilateral equal
breath sounds. Rest of the systemic examination was also
normal. The electrocardiogram was normal. Two dimensional
echocardiography revealed mildly dilated right atrium (42mm)
and dilated right ventricle (32mm), mild tricuspid regurgitation,
mild pulmonary hypertension (pulmonary artery systolic
pressure = 38 mmHg), no left ventricular regional wall motion
abnormality, no diastolic dysfunction, no left ventricular
hypertrophy and normal left ventricular systolic function
(left ventricular ejection fraction 55%). Pulmonary function
test revealed mild restriction. She was advised computed
tomography pulmonary angiography which revealed dilated
azygous vein and no evidence of pulmonary embolism.
Computed tomography of abdomen revealed inferior vena cava
continuing superiorly as the azygous vein (Figure 1), entering the
posterior mediastinum through the hiatus in the diaphragm for
the aorta (Figure 2), where it appeared slightly compressed with
no obstruction. Mal-rotation of the gut was noted. The duodenojejunal flexure and jejunum was observed to lie to the right of the
midline, most of the large bowel loops left of the midline and the
caecum in the midline. Polysplenia was also noted (Figure 3).
the hepatic vein. Systemic venous flow beyond this point is
accommodated by the dilated azygos and hemiazygos veins,
which eventually empty into the superior vena cava through
a dilated azygos arch.2 Our patient demonstrated the inferior
vena cava continuing superiorly as the azygous vein, entering
the posterior mediastinum through the hiatus in the diaphragm
for the aorta, where it appeared slightly compressed (Figures
4 and 5).
Embryologically, the morphologic features of the inferior
vena cava are the result of a dynamic process of development,
regression, anastomosis, and replacement of 3 paired venous
blood conduits (the posterior cardinal, supracardinal, and
subcardinal veins of the primary system) starting in the fifth
week. When the development of the venous system is complete, it
is possible to define the embryologic origins of all its components.
In particular, the superior vena cava originates from the right
superior cardinal vein. The azygos system is formed from the
more cranial portion of the right (azygos) and left (hemiazygos)
supracardinal veins. Blood from the subdiaphragmatic portion
of the embryo is channeled into a single inferior vena cava,
flowing to the paramedian right. In caudal to cranial order, these
segments are the iliac veins from the posterior cardinal veins,
the subrenal (postrenal) segment from the right supracardinal
vein, the renal segment from anastomosis between the right
supracardinal and subcardinal veins, the suprarenal (prerenal)
segment from the right subcardinal vein, and the hepatic segment
Discussion
Infrahepatic interruption of the inferior vena cava with
azygous continuation is a rare congenital anomaly seen in
0.6–2% of patients with congenital heart disease1 and in less
than 0.3% of otherwise normal individuals. This developmental
anomaly results in termination of the inferior vena cava below
1
Institute of Pulmonology, Medical Research and Development,
Mumbai; 2Lung care and Sleep Center, 3Radiology, Fortis-Hiranandani
Hospital, Vashi, Navi Mumbai
Received: 30.12.2010; Accepted: 18.01.2011
Fig. 1 : Azygous continuation on lung window
© JAPI • august 2012 • VOL. 60 Fig. 2 : Azygous continuation on abdominal window
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Fig. 5 : Infrarenal normal inferior vena cava on axial view
from the hepatocardiac canal.3
Fig. 3 : Polysplenia
Interrupted inferior vena cava is associated with congenital
heart disease in approximately 85% of cases, and frequently
with the polysplenia syndrome.4 Our patient demonstrated
polyspenia. Other associated cardiac anomalies include atrial
septal defect, pulmonary stenosis or atresia, double-outflow
right ventricle, atrioventricular canal, cor biloculare, and
anomalously connecting pulmonary disease.1 Also documented
is the presence of mirror- image dextrocardia, dextroversion,
situs inversus, partial inversion of the abdominal viscera, and
bilateral superior vena cava.2 In our patient two dimensional
echocardiography showed mildly dilated right atrium and
right ventricle, mild pulmonary hypertension with normal left
ventricular parameters.
Failure of the hepatic and prerenal segments to fuse is the
most common developmental anomaly of the inferior vena cava
and results in infrahepatic inferior vena cava interruption. The
infrahepatic inferior vena cava may continue as the azygos vein
or may continue as the hemiazygos vein to the left superior vena
cava, intrathoracic veins or anomalous intrahepatic veins. The
dilated azygos vein may be misinterpreted as a paracardiac or
mediastinal mass on chest radiography. Our patient presented
for a routine health check up. During investigations, pulmonary
function tests revealed mild restriction and two dimensional echo
revealed mild pulmonary hypertension. Further investigations
by means of computed tomography pulmonary angiogram
and computed tomography of abdomen and pelvis permitted
the confirmation of the diagnosis. Although, the patient as yet
had not manifested any complications related to this anomaly,
this diagnosis is important as such it may be associated with
deep vein thrombosis of the lower limbs,5 bilateral venous
insufficiency or with sick sinus syndrome. The other potential
issues or complications such patients may face include
procedural difficulties during right heart catheterization,
electrophysiological studies, cardiopulmonary bypass surgery,
femoral vein catheter advancement, inferior vena cava filter
placement, and temporary pacing through the transfemoral
route.
Conclusion
Fig. 4 : Infrarenal normal inferior vena cava on coronal view
To our knowledge this is the first report in which further
investigation of mild restriction on pulmonary function test and
mild pulmonary hypertension during routine health check led
to the diagnosis of interrupted inferior vena cava syndrome.
The knowledge of this congenital anomaly is important so that
deep vein thrombosis measures may be advised during high
risk situations and also alternative sites be used for cardiac
catheterization other than the femoral vein.
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© JAPI • august 2012 • VOL. 60
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