Duplication of the inferior vena cava with thrombotic complication: incidentally detected

Background

We report on a rare case of a successfully recanalised symptomatic iliofemoral vein thrombosis in a 37-year-old patient with an incidentally diagnosed duplication of the inferior vena cava (IVC) (IVCD).

According to the reported prevalence of 0.2 up to 3% in general population,1 the IVCD is considered to be the second or even most common IVC anomaly.2–4 Since this anomaly is usually asymptomatic, it is often an incidental finding in duplex ultrasound or radiographic examinations or during laparotomy. Therefore, the prevalence might even be underestimated.5 6

The IVC normally develops between the 6th and 10th weeks of gestation. The embryology of the IVC is a complex process involving fusion, regression and development of anastomosis of three pairs of the embryonic venous systems. The posterior cardinal veins appear first but only form the iliac bifurcation. The subcardinal veins appear next. The left subcardinal vein regresses, and the right subcardinal vein forms the suprarenal IVC. The Supracardinal veins appear last, the left supracardinal vein regresses and the right supracardinal vein forms the infrarenal IVC. The IVCD results from a normal persistence of the right supracardinal vein that creates the normal right-sided IVC and the failed regression of the left supracardinal vein that creates the anomalous left IVC.6 In addition, there is a failure of the regression of at least one of the normal midline anastomoses between the two infrarenal IVCs to become the suprarenal IVC. Consequently, the left and the right IVCs reunite typically at the level of the renal veins by a preaortic or retroaortic left renal vein or communicating vein to form the suprarenal IVC. Two anatomical types of IVCD are described.7 In one type, the left and right common iliac veins have no confluence and drain into the left and right IVC separately. In the other type, the left and right common iliac veins have a normal confluence in the right IVC before the left IVC arises from the right IVC. Often the left IVC is smaller (asymmetric duplication).

Patients with ICVD are often asymptomatic. However, in the case of a caval or iliofemoral thrombosis or pulmonary embolism, IVCD becomes clinically evident.

Case presentation

A 37-year-old male patient was referred because of an acute painful and swollen right leg. He underwent liver transplantation 3-year earlier due to sclerosing cholangitis, but no known previous episodes of thromboembolism, no dyspnoea, no immobilisation and no previous long-distance travels and no inappropriate water intake were noted. His family history was unremarkable. Tacrolimus was his only medication.

The examination revealed a pitting oedema of the right leg, with a 2 cm plus of circumference compared with the left leg. All other physical findings were normal: blood pressure 140/95 mm Hg, pulse 80 beats/min, body mass index 31.6 kg/m².

His laboratory data showed mild elevation of the transaminases (Alanine amino transferase (ALT) 76 µ/L, gamma glutamyl transferase (GGT) 111 µ/L), mild elevation of CRP (6.4 mg/L), normal haematology (thrombocyte 133 g/L, haemoglobin 15.5 g/L, leucocyte 7.84×10⁹/L), and renal function (serum creatinine 70 µmol/L). international normalised ratio (INR) was 1.1. No D-dimer test was performed due to a high pretest probability according to the Well’s score.

The patient voluntarily gave his consent for this paper.

Investigations

Duplex ultrasound revealed a deep vein thrombosis (DVT) of the right iliac and femoral vein. The infrarenal part of the orthotopic (right) IVC showed no flow, but an open left IVC was found. The review of previous CT scans confirmed the diagnosis of an IVCD (figure 1). The right infrarenal IVC was very small, doe to a filiforme-recanalised thrombus (figure 2). The left IVC was also small and emptied into the left renal vein. During the liver transplantation, only the perihepatic was exposed. Therefore, the duplication of the infrarenal IVC was not diagnosed.

Differential diagnosis

The main differential diagnoses of the IVCD on CT scans are aortic aneurysms, ascending lumbar veins, neoplasms, paravertebral lymphadenopathy, retroperitoneal cysts and left pyeloureteric dilatation.

Treatment

In accordance with the transplantation department, therapeutic intravenous unfractionated heparin was initiated, and a transfemoral catheter-directed thrombolysis was performed. Approximately 1 million units of urokinase were administered over 13 hours while the patient was observed in the intermediate care unit. Compression bandages of the legs were applied. In the control-venography, the external iliac vein was open. The right renal vein and the anastomosis of the liver transplantation were open. The catheter intervention was performed via femoral vein access with a 6F sheath. After predilatation, up to 10 mm, two overlapping stents (wallstent 12×60 mm and 14×40 mm) were implanted in the narrowed right IVC and dilated up to 14 mm. The stented segment extended from the common iliac vein to the junction of the renal vein (figure 3). The choice of the stent diameter was based on the experience of the interventionalist. Leg symptoms immediately improved. The liver transaminases normalised spontaneously.

The asymptomatic patient was discharged the next day with anticoagulation therapy with phenprocoumon at a target INR of 2–3 for 3 months.

Outcome and follow-up

The patient remained asymptomatic during the follow-up.

A phlebography performed 6 months later showed open stents with a prompt outflow of contrast medium. No pressure gradient between the IVC and the iliac veins was measurable. The stent remained open in follow-up control after 3 years showing adequate stent diameter.