By Riyaz Bashir, MD, FACC, RVT
In a recent paper in JACC Cardiovascular Interventions,1 my colleagues and I describe the etiology, diagnosis and treatment of inferior vena cava thrombosis in an effort to raise awareness of this rare yet morbid condition, which remains under-diagnosed. Up to 90 percent of those with untreated IVC thrombosis experience post-thrombotic syndrome and 45 percent experience disabling venous claudication. The mortality rate is twice that of deep vein thrombosis (DVT) of the lower extremities. IVC thrombosis also occurs in 60 to 80 percent of patients with congenital IVC defects (who make up 0.5 to 1 percent of the population).
In the United States, overuse of inferior vena cava filters for DVT may increase IVC thrombosis risk. Up to 30 percent of patients with IVC filters experience late filter thrombosis.2 These filters are implanted in up to 17 percent of venous thromboembolism patients and more than 40 percent of those with high bleeding risk—a rate 25 times higher than in Europe. While many filters are designed to be retrieved, in practice the highest reported mean retrieval rate is 34 percent.3 This puts a relatively large number of venous thromboembolism patients at risk of filter-induced IVC thrombosis.
No official guidelines exist for diagnosing IVC thrombosis; it often has vague symptoms at onset, including scrotal swelling in males, back or abdominal pain, and symptoms similar to those for lower extremity deep vein thrombosis—including leg pain, heaviness or swelling. More frequently, IVC thrombosis remains undiagnosed until the clot migrates or embolizes into the lungs or renal veins, leading to dyspnea or kidney failure. Patients with lower-extremity deep vein thrombosis can also develop IVC thrombosis by clot propagation, although the majority do not. Based on the literature review, we recommend IVC duplex screening in patients with unretrieved IVC filters, known congenital anomalies, unexplained back pain or renal failure, renal cell carcinoma or Budd-Chiari syndrome, or proximal or bilateral DVT.
Dedicated IVC duplex ultrasound, CT or MR imaging are very helpful diagnostic tools, although availability and cost may limit the use of MR scans. A catheter venogram can provide definitive results, although it is more invasive.
Most patients diagnosed with IVC thrombosis receive systemic anticoagulant therapy. This may be combined with other therapeutic approaches, including minimally invasive catheter-directed thrombolysis (CDT), angioplasty and stenting for patients with a low bleeding risk. These catheter-based approaches offer significant potential benefits, including faster resolution of symptoms and reduction in post-thrombotic complications, and do not appear to have the same risks as surgical thrombectomy or systemic thrombolysis. However, research on CDT and stenting specifically for IVC thrombosis is still limited.4 Further clinical trials and societal guidelines are required; until then, physicians should employ careful patient selection and good judgment when using endovascular therapies for IVC thrombosis.