Clinical presentation can vary depending on the extent and location of the thrombus within the IVC. Typically, patients complain of leg heaviness, pain, swelling, and cramping. Symptoms can also be nonspecific such as abdominal, flank or back pain. Men may present with scrotal swelling. The vague nature of symptoms may delay diagnosis until clot migration to the lungs, and renal veins occur, which leads to shortness of breath and oliguria, respectively. The presence of bilateral lower extremity edema and dilated superficial abdominal veins suggests the possibility of an IVC thrombus. Overall, given the ambiguous presentation, there are not pathognomonic history and physical exam findings to diagnose IVC thrombosis consistently across all patients.[6]

There are currently no societal guidelines available to aid in the diagnosis and management of IVC thrombosis.  Multiple imaging modalities are potentially useful when IVC thrombosis is suspected. These include ultrasound, CT, MRI, and catheter venography.

IVC duplex ultrasound can be used to visualize a potential thrombus, but there are limitations to this modality. Overlying bowel gas and patient obesity may make visualization very difficult. Ultrasound should still be a consideration as an initial test given the low-risk profile. Case studies have reported IVC thrombosis identification using ultrasound in the emergency department. Sonographic signs that indicate a potential thrombus include a monophasic waveform by doppler, a choppy sign indicating increased blood velocity, and inability to compress the vessel.

Computer tomography (CT) can also be used to visualize the location of the thrombus. However, MRI is the most reliable technique for visualizing the presence and extent of the thrombus. Given the poor general availability and the high cost of MRI, it should not be the initial imaging choice. Direct catheter venography is the most common imaging technique to arrive at a definitive diagnosis.

Once the diagnosed, there should be a consideration for imaging dedicated to potential complications from the IVC thrombus. Approximately 12% of patients diagnosed with an IVC thrombus will develop pulmonary emboli. Therefore, dedicated CT angiogram of the thorax may be needed to evaluate for pulmonary emboli. If there is a concern for renal involvement, nuclear renal scanning can be used to assess for renal vascular compromise.  

Initial management consists of anticoagulation. Heparin can be started in the emergency department with the goal of bridging to warfarin or a newer generation anticoagulant. Additional treatment options depend on the acuity of the thrombus. There may be a benefit to catheter-directed thrombolysis or thrombectomy if the IVC thrombus is acute (<14 days), subacute (15 to 28 days), and for a patient who is not at high risk of bleeding. Percutaneous transluminal angioplasty with stenting is also a consideration. However chronic (>28 days) IVC thrombosis may benefit more from stenting than catheter-directed thrombolysis. Ultimately, when evaluating the patient in the emergency department, starting heparin is crucial. Consulting vascular surgery is necessary for other potential treatment options.  If the IVC thrombus is due to an extrinsic cause, such as a tumor, then further diagnostic testing will be needed.[3][7]

The differential diagnosis possibilities for a patient with suspected IVC thrombosis are broad. The differential diagnosis may include nephrolithiasis, renal cell carcinoma, pancreatic cancer, DVT, liver disease, spinal pathology, pulmonary emboli, bowel obstruction, and urinary retention.

The overall prognosis hinges on the underlying cause of the thrombus. If a patient has a hereditary hypercoagulable disease, they are predisposed to the development of thrombi. However, if they are compliant with their anticoagulation therapy, their prognosis will be favorable. Alternatively, if the patient is diagnosed with progressive cancer such as pancreatic cancer that has extended and compressed the IVC, their prognosis is likely poor.

Children who have had catheterization have gone on to develop unilateral leg swelling and chronic pain. Finally, there is the potential of pulmonary embolus if the inferior vena cava has a floating embolus.

If untreated, patients can suffer from a post-thrombotic syndrome, which consists of venous stasis changes leading to ulceration in the lower extremities. Other complications include pulmonary emboli and renal ischemia due to the extension of the thrombus. Thus, if IVC thrombosis is a consideration, imaging should not be delayed.

The most important factor in determining patient education would be targeting patients who have modifiable risk factors. Patients who are at increased risk of thrombus formation are those who are obese, using oral contraceptive pills, and have a smoking history.  Education and prevention of these modifiable risk factors will make the most significant difference. For those patients who have a hereditary disorder such as Factor V deficiency, the importance of long-term anticoagulation must be discussed to prevent thrombus formation.

The image shows an IVC filter in a patient with common iliac vein injury from the use of a trocar during lap cholecystectomy. The right common iliac vein had to be ligated and an IVC filter placed via the RIJ. A crossover saphenous vein graft bypass is planned to help decompress the right leg.

Interprofessional communication is the key to success for patient care. Most medical errors that occur are secondary to a lack of communication. All team members must be at liberty to speak up when they have concerns. For IVC thrombosis, coordination of care by physicians is necessary. An emergency medicine physician may initially evaluate the patient, but they must be able to contact the vascular surgery, nephrologist, etc. for further management. In addition to communication skills is the importance of knowing one's limits. There must be a willingness to ask for help when needed to improve healthcare outcomes. Excellent communication and awareness of personal limitations among all team members are critical.