Inferior vena cava syndrome (IVCS) is not a primary diagnosis but is a consequence of any underlying pathology. As described in the pathophysiology section, the presentation of IVCS is dependent on the patient’s comorbidities and underlying diseases. Accurate diagnosis is based on a thorough history taking and physical examination.

The symptoms which a patient shows are in accordance with the pathophysiology of IVCS. It is important to inquire about other signs and symptoms, such as fatigue, dizziness, weight loss, abdominal pain, night sweats, anorexia, palpitations, diaphoresis, dizziness, shortness of breath on exertion. In addition, the history taking also has to get deep into previous illness history, including the history of abdominal surgeries, organ transplantation, lower extremity swelling and pain, family and past medical history of coagulopathy, prior deep venous thrombosis (DVT), as well as occupation and lifestyle.

A thorough physical examination will assist in the accurate diagnosis of IVCS. The vital signs will usually reveal hypotension, tachycardia, and possibly tachypnea with hypoxia. Signs of anemia, such as pallor or pale conjunctiva, might be the earlier sign of malignant disease, and with additional constitutional symptoms of malignancy can lead to the diagnosis of IVCS. 

While there are no specific tests with pathognomonic findings of IVCS, certain findings such as lower extremity edema, signs of DVT and pulmonary embolism (PE), cold and clammy extremities, abnormal neurological exam, hepatomegaly, and abdominal distention, lead to the decrease of venous return which then impair the perfusion of end organs.

Duplex ultrasound is the first line of modality can be used in a hemodynamically unstable patient. It is a rapid, accurate, and non-invasive modality to investigate the etiology of IVC obstruction. However, interference, i.e. obesity, limits the use of ultrasound in identifying the cause of obstruction. Esophagogastroduodenoscopy can also be used to reveal esophageal, gastric, or duodenal pathologies, especially tumor which compresses the IVC.[4]

CT abdomen and pelvis can then be used as an alternate non-invasive modality. Contrast venography, the standard for diagnosis, is used to assess the thrombotic obstructions of the abdomen in hemodynamically stable patients. Although it is an invasive procedure, it gives the most accurate finding of IVC obstruction and compression. Magnetic resonance (MR), a non-invasive but expensive instrument, can also be used to access obstruction of the IVC in hemodynamically stable patients and is replacing CT scans. Etiologies should be urgently obtained in hypotensive patients in order to prevent complications.[1]

The guideline treatment of inferior vena cava syndrome (IVCS) has not been clearly described. Therefore, treatment and management are determined by the etiology of the causative lesion and tailored to a patient’s condition. If the lesion is thrombotic, immediate treatment is focused on the prevention of propagation of the clot, causing a pulmonary embolism, and management of pain, edema, and the resulting hypotension. Either medical or surgical intervention can accomplish this. Medical treatments include anticoagulation using either low-molecular-weight heparin (LMWH), fondaparinux, or direct thrombin inhibitors. These medications reduce the buildup and propagation of the thrombosis but do not eliminate the primary thrombosis.

Endovascular procedures can subsequently be utilized to facilitate the introduction of thrombolytics to lyse the clot. These can include catheter-directed thrombolysis, pulse-spray pharmaco-mechanical thrombolysis, and then angioplasty with or without inserting stents, which increases patency of the IVC. Performing such procedures is required within a short period (within 14 days) of the onset of symptoms to minimize complications and decrease mortality rates. Surgical modalities such as thrombectomy, bypass, reconstruction/replacement, and ligation are used as a last resort due to the high invasive and significant intervention nature.[1]

If the stent placing is not advisable, placing IVC filters can alleviate symptoms for some time.[6] Recently, the use of IVC filters has increased, especially in advanced-stage cancer patients, in order to prevent the pulmonary embolus, although there is no explicit evidence of improved survival rate.[18] Temporary IVC filters are usually used in cancer patients during systemic chemotherapy.[19]

If lesions are due to non-thrombotic etiologies such as malignancy, then the treatment is directed to manage the underlying cause of the compression. This may include surgery, chemotherapy, radiation, or combination. Resection is a surgical option to remove tumor compression. However, resection is not possible to be done in unstable patients, thus, palliative care is provided. Another option is to place an intravascular stent or surgical bypass grafting, which increases the patency of the IVC to alleviate symptoms.[1][20] Recanalization of the occluded veins is usually done by implanting the metallic stents into the IVC from the superior vena cava via the right atrium.[21]

IVCS patients of intrahepatic obstruction due to malignant hepatic enlargement are usually treated using strip radiotherapy to the intrahepatic IVC, with or without a hepatic arterial infusion of chemotherapy.[22] The IVC obstruction is generally managed by crossing the tumorous lesion with either a guidewire or Brockenbrough needle along with a Mullins sheath assembly, and then a balloon dilatation was done with the help of Inoue or Mansfield balloon.[23]

In some mild compression etiologies like pregnancy, physical maneuvers to move the uterus away from the IVC can be applied.[7]

Inferior vena cava syndrome (IVCS) is characterized by tachycardia, hypotension, tachypnea, hypoxemia, and shortness of breath. The differential diagnosis of IVCS is broad, mainly because it is rarely ever diagnosed as a primary disease process. The differential diagnosis of IVCS are: 

• Chronic venous insufficiency
• Shock
• IVC compression
• Malignancy[5]
• Deep vein thrombosis
• Iliocaval syndrome
• Aortocaval syndrome[7]

Prognosis of inferior vena cava syndrome (IVCS) depends on the underlying patient condition, including the hemodynamic status of the patient, the severity of compression or vein obstruction, the grading of the malignancy, and previous comorbidities. The outcome of patients who have inferior vena cava thrombosis overall relates to the embolic risk associated with DVT. If the IVC is occluded, pulmonary embolism does not present a significant risk. However, if the IVC lumen remains, embolization may occur.

Complications of inferior vena cava syndrome (IVCS) depend on the underlying comorbidity and patient's risk factors for the following but include:

• Pulmonary embolism (PE)[24]
• Deep vein thrombosis[25]
• Chronic venous insufficiency (CVI)
• Post-thrombotic syndrome (PTS) progressing to venous ulceration, venous gangrene
• Hemodynamically instability[1] leading to cardiac arrests and possibly death.

Patient education should be focused on modifiable risk factors and finding the etiology of the syndrome. Patients with an increased risk of thrombosis such as pregnancy, obesity, oral contraceptive pills (OCPs), smoking, venous insufficiency, immunocompromised, diabetes, or hypertension are at risk for developing obstruction of the IVC and an increased risk of malignant neoplasm development. Education needs to be tailored more towards mobility, weight loss, dietary modification, smoking cessation, stop alcohol consumption, and a healthier lifestyle.[15]

Inferior vena cava syndrome (IVCS) is not a primary diagnosis, but rather a diagnosis of exclusion. It mimics a variety of etiologies, and the signs and symptoms can overlap with other lethal conditions. So a prompt diagnosis can prevent significant morbidity and mortality. In addition to imaging, a thorough history and physical examination are vital to the diagnosis of IVCS. Although IVCS can predispose to thrombus formation, it protects against pulmonary embolism coming from the lower limbs deep vein thrombosis.[26]

Because of inferior vena cava syndrome (IVCS) is not a primary diagnosis; it is often missed and leads to adverse outcomes for the patients. Superior vena cava syndrome (SVCS) is a better-recognized entity because of its specific presentation: right upper extremity swelling with skin discoloration and signs of decreased blood return to the right heart. In contrast, IVCS causes bilaterally lower extremity swelling, which can be misdiagnosed as congestive heart failure exacerbation, nephrotic syndrome, lymphangitis, or varicose veins.

IVCS can also be accompanied by symptoms consistent with hemodynamic instability, which can mimic several conditions such as circulatory shock, cardiogenic shock, pulmonary embolism, acute heart failure, acute pulmonary edema, etc. As a result, the responsibility of the entire interprofessional team, which includes both primary care providers, specialists such as trauma surgeons, transplant surgeons, hematologists, oncologists, and general surgeons, to name a few, nurses, social workers, pharmacists to counsel regarding medications that can cause prothrombotic states to advise the patients on how to reduce the risk of thrombosis, counsel on the importance of medications compliance if the patient is on anticoagulation or antiplatelet therapy, and to promote lifestyle modifications to reduce the risk of thrombosis as well as obstruction of the IVC, which can cause severe morbidity and increased risk of mortality.