Diagnosis
Duplication of the inferior vena cava
Findings
The original venogram was obtained by right common femoral approach.
No thrombus was seen within the inferior vena cava (IVC), and the
caliber of the cava was normal. However, the entire left border of the
vessel was smooth and continuous, and inflow from the left common iliac
was not appreciated (Figure 1).
The CT scan demonstrated a double
IVC (Figure 2) with thrombus in the right external iliac vein (not
shown). The filter legs were expanded and no significant filter tilt was
seen.
Using a right internal jugular approach, we advanced a
pigtail catheter into the right common iliac vein and obtained a
venogram. The venogram confirmed both right and left IVC moieties and
communication via pelvic collaterals (Figure 3). We then positioned the
pigtail catheter into the left IVC. Venography demonstrated a
similar-caliber left IVC terminating in the left renal vein and then
communicating with the common suprarenal IVC (Figure 4). We placed a
second filter in the left IVC (Figure 5).
Discussion
Given the complex embryogenesis of the IVC, it is not surprising to
encounter anatomic variations. Duplication of the IVC occurs in up to
2.8% of the population.1 Failure of the left caudal
supracardinal vein to regress results in persistent communication
between the left common iliac vein and the left renal vein. The left
renal vein then typically crosses anterior to the aorta to join the
right IVC. Though asymptomatic, double IVC has important clinical
implications when attempting caval filtration or when retroperitoneal
surgery is performed. The left IVC can also be misdiagnosed as
lymphadenopathy on cross-sectional imaging.
Inferior vena cava
filtration is commonly performed to prevent pulmonary embolism in
patients with hypercoaguable states or documented venous thromboembolic
disease and contraindications to anticoagulant therapy. The Günther
Tulip vena cava filter may be deployed by the femoral or jugular
approach and can be used as a retrievable or permanent filter. Ideally,
caval filters are placed below the renal veins. However, in cases of
congenital anomalies of the IVC and its tributaries, alternative
placement locations or additional filters must be considered to combat
embolization through accompanying pathways. Venography is routinely
performed prior to filterplacement. In addition to determining the level
of the renal veins, cavography allows measurement of caval diameter and
detection ofIVC and renal vein anomalies. Cavograms have revealed that
in 15% of the cases there are abnormalities that significantly affect
the placement of the filter.2 Clues to duplication of the IVC
on cavography include lack of visualization of the left iliac inflow
and larger-than-expected left renal vein inflow.
Caval
interruption options in patients with duplicated IVC include single
filter deployment in each IVC limb, single filter deployment in the
unpaired suprarenal IVC, and filter placement in the right IVC with
concurrent embolization of the left moiety or point of communication
with the duplicated segment.3 In our case, we elected to deploy an additional filter in the left IVC.
Conclusion
Anatomic variations of the inferior vena cava and its tributaries are
generally asymptomatic, but they must be recognized during vena cava
filter placement because collateral pathways for emboli to bypass the
filter may exist. Double IVC occurs in up to 3% of the population and
necessitates a single suprarenal or paired caval filters.
- Anne N, Pallapothu R, Holmes R, Johnson MD. Inferior
vena cava duplication and deep venous thrombosis: Case report and review
of the literature. Ann Vasc Surg. 2005;19:740–743.
- Martin KD, Kempczinski RF, Fowl RJ. Are routine inferior vena cavograms necessary before Greenfield filter placement? Surgery. 1989;106:647–651.
-
Vo NJ, Wieseler KW, Burdick TR, et al. The use of paired optionally
retrievable Gunther Tulip filters in trauma patients with anatomical
variants. Semin Intervent Radiol. 2007;24:20-28.