When Procedures Make Intuitive Sense, Despite the Data (or Lack of)…About IVC Filters and Vertebroplasty

Today’s (April 08, 2013) issue of JAMA Internal Medicine brings forth a new controversy regarding another common and popular interventional radiology procedure  – retrievable IVC filter placement.

A review of data in a new retrospective study on the efficacy of IVC filters, has shown that there is only one randomized control trial published in 1998 that showed a reduction in the rate of symptomatic pulmonary embolism in those with filters but with no significant long-term difference in the death rate at 8 years and with an increase in the rate of deep vein thrombosis in those who had filters.

This new retrospective study published in JAMA Internal Medicine concludes, “that the use of IVC filters for prophylaxis and treatment of venous thrombotic events, combined with a low retrieval rate and inconsistent use of anticoagulant therapy, results in suboptimal outcomes due to high rates of venous thromboembolism”

Another study in the same issue discusses the differing rates of use of this technique in California, the main factor being the particular hospital that is providing care. The Society of Interventional Radiology guidelines [4] for the use of an IVC filter list four absolute indications – “recurrent VTE (acute or chronic) despite adequate anticoagulation, contraindication to anticoagulation, complication of anticoagulation, inability to achieve/maintain therapeutic anticoagulation”.  However there is a long list of relative indications with little consensus and that is where there is significant variability, depending on the aggressiveness of the program.

It happened with vertebroplasty when two studies by Kallmes et al and Buchbinder et al, comparing sham procedures with actual procedures showed no significant difference in pain scores between the two groups at all time points. This kicked up a huge storm in the interventional radiology and spine communities, but also forced us to examine our data more objectively and spurred more hospitals and groups to perform their own double-blind control studies, a few of which like the Vertos II trial, have shown that vertebroplasty is better than controlled medical treatment, though there has been no comparison with sham procedures since the 2009 studies.

We all want to believe that “doing” something that is intuitive (cement in an acute fracture, IVC filter stopping downstream emboli) has to help, just like Dr. Zamboni’s belief in treating patients with multiple sclerosis by dilating areas of venous narrowing because of the theory he ascribes to that chronic cerebrospinal venous insufficiency is the cause of multiple sclerosis.

Procedures sometimes quickly become mainstream without data, simply because “they make sense”. Cardiac CT angiography found adopters in patients and celebrities like Oprah Winfrey, simply because it made sense to see the coronary arteries without a catheter, despite the lack of any kind of initial data.

In the end though, we as radiologists need to create compelling stories for the use of techniques, modalities and procedures by making sure that there are enough controlled studies that demonstrate efficacy and safety.

Hopefully in the near to medium future, there will be more date regarding the efficacy (or not) of IVC filters that will clear the air and help patients and the treating doctors make better decisions.

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