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Congenital malformations of IVC

Congenital malformations of the inferior vena cava

Doppler ultrasound image of inferior vena cava (Credit: Nevit Dilmen)
The prevalence of IVC is approximately 4% and these anomalies are usually asymptomatic and are incidentally diagnosed during investigations for other medical conditions

Although congenital malformations of the inferior vena cava (IVC) are rare and underreported, they can be a risk factor for deep venous thrombosis (DVT) as a result of inadequate venous drainage of the lower extremities through collateral circulation. In this systematic review, ‘The Typical Presentation Spectrum of Deep Vein Thrombosis Associated with Inferior Vena Cava Malformations’, published in Thrombosis, describes the typical presentation of IVC malformations, their management, and the management of their associated DVT.

The prevalence of IVC is approximately 4% and these anomalies are usually asymptomatic and are incidentally diagnosed during investigations for other medical conditions. According to the authors, most reported anatomic anomaly in this case series is IVC agenesis ranging from 1/100 to 1/200,000 in the general populationand in 5% of deep venous thrombosis (DVT) patients younger than 30 years and the evidence has shown that patients with agenesis of inferior vena cava (AIVC) are prone to develop DVT of the lower extremities at a younger age.

“A high index of suspicion for inferior vena cava anomalies should be considered in young patients presenting with deep vein thrombosis."

“This warrants investigating IVC malformation as an etiologic factor in young patients diagnosed with idiopathic DVT,” the authors state. “…This paper attempts to report all cases of DVT in patients with IVC anomalies in the literature along with a review of symptomatology, diagnosis, and treatment. We aim to raise awareness of IVC anomalies as a risk factor in young patients with idiopathic DVT.”

They authors conducted a systematic search focusing on the demographic data of the patients with IVC anomalies, clinical DVT presentation, comorbidities, contribution of thrombophilia screening, and therapeutic management.

They identified 188 patients with IVC malformation presenting with DVT with a mean age at diagnosis of DVT of 27.5±11.4 years (min. 9, max. 72); 138 patients (73.4%) were under 30 years of age (male to female ratio, 4:1).

All patients were diagnosed with one of the following IVC anomalies: prerenal IVC agenesis (13.8%), infrarenal IVC agenesis (17%), postrenal IVC agenesis (0.5%), infrahepatic IVC agenesis (7%), IVC hypoplasia (4.2%), IVC duplication (2.7%), and IVC agenesis not further classified (54.8%). In 15 cases, associated anomalies were also present, largely right kidney aplasia (seven patients) and left kidney aplasia (five patients). The others were polysplenia (two patients) and right hepatic lobe agenesis (one patient).

After initial imaging, 168 patients (90%) were screened for genetic blood coagulation disorders with positive findings in 68 (40.5%). The most prevalent was factor V Leiden mutation in 19 patients followed by prothrombin G20210A mutation (8 cases), protein C or protein S deficiency (four cases), and lupus anticoagulant (four cases). The others had one of the following:

  • antiphospholipid antigens
  • hyperhomocysteinemia
  • factor VIII elevation;
  • and antithrombin III deficiency.

Twenty-four patients were found positive for two or three thrombophilic factors.

Management mostly consisted of anticoagulation with unfractionated heparin (35.2%) or low molecular weight heparin (LMWH) (22.1%). DVT management in 35 patients required one of the following surgical procedures: prosthetic bypass (11.7%), pharmacomechanical catheter-directed thrombolysis (PCDT) (8.4%), surgical thrombectomy (1.9%), or IVC Greenfield filter (0.6%) as summarized in Table 3. Almost all patients (99%) were discharged on vitamin K antagonists (VKA), mainly warfarin, and/or elastic compression stockings for a period of at least 6 months. Factor Xa inhibitors (Rivaroxaban and Apixaban) were prescribed in two cases.

Sixty cases were followed up with imaging studies, mainly duplex venous ultrasound (US), for a mean period of 12.9±12.4 months (range: 30 days - five years) and recurrence was demonstrated in 23 and resolution in 37 patients.

The literature reports that 90% of IVC anomalies involve the suprarenal segment and only 6% involve the renal or infrarenal segments, making absent infrarenal IVC the rarest congenital anomaly. Nevertheless, in the authors own case series, infrarenal IVC agenesis was the most prevalent among the IVC anomalies (17%), followed by prerenal and infrahepatic IVC, and they state that it is important to note that IVC agenesis was not further classified in 54.8% of the cases.

Treatment

Once the DVT associated with IVC anomalies is confirmed, the researchers report that their patients are treated either conservatively with unfractionated heparin and LMWH (35.2% and 22.1% in their case series) or surgically for severe venous insufficiency not correctable with anticoagulation alone manifested by non-healing lower extremity ulcers. Surgical options included:

  • prosthetic bypass (11.7%)
  • pharmacomechanical catheter-directed thrombolysis (PCDT) (8.4%)
  • surgical thrombectomy (1.9%)
  • IVC Greenfield filter (0.6%)

They report that PCDT compared to systemic anticoagulation alone, significantly decreased the thrombus burden and incidence of recurrent DVT in patients with extensive iliofemoral DVT.

“PCDT could be a treatment option in patients with symptomatic iliofemoral DVT, good functional status, life expectancy of one year or more, and low risk of bleeding,” the authors note. “However, studies focusing on the long-term outcomes following PPCDT are desperately needed as evidence is lacking.”

In the outpatient setting, they report that adjustment of modifiable risk factors (i.e., oral contraceptive pills, immobilization, and major physical activity), compression stockings, and long-term anticoagulation were the treatments of choice. In the authors case series, patients were prescribed oral vitamin K antagonists, mostly warfarin, with a target international normalized ratio (INR) range of 2-3. Factor Xa inhibitors (Rivaroxaban and Apixaban) were prescribed in two cases, with 17% of patients were prescribed compression stockings. However, there was no consensus concerning the duration of anticoagulation.

In their own case series, 11 patients discontinued oral anticoagulation therapy at six months and eight patients at one year. All others were on long-term anticoagulation that was decided on case-by-case basis. At least three to six months of anticoagulation is required for DVT associated with IVC agenesis.

“While the majority of patients might have other risk factors, prolonged oral anticoagulation and compression stockings are recommended. Follow-up, mainly by US, aims at detecting DVT recurrence. Currently, no data exists on long-term morbidity and mortality following DVT associated with IVC abnormalities,” they conclude. “A high index of suspicion for inferior vena cava anomalies should be considered in young patients presenting with deep vein thrombosis. We suggest being liberal in screening for IVC anomalies in this high risk group.”

The study authors were from Vita-Salute San Raffaele University, Milan, Italy, Virginia Mason Medical Center, Seattle, WA, Washington University in St Louis, St. Louis, MO, USA, Ente Ospedaliero Cantonale, Lugano, and Ente Ospedaliero Cantonale, Bellinzona, Switzerland.

The article was edited from the original article, under the Creative Commons license.

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