Part 1: IVC Filter 101 - DVT, PE and Anticoagulants
IVC Filter 101 - DVT, PE and Anticoagulants
Why does someone get an IVC filter?
For most cases, it was designed to stop a potentially deadly embolism from traveling up the leg and into the heart and lungs.
A blood clot is also called a Thrombus.
When a blood clot has formed in a deep vein in the the leg (or sometimes in the pelvis or arm) it is called Deep Vein Thrombosis (DVT).
When the clot breaks off and starts traveling up the body it becomes an Embolism.
Once the embolism travels to the heart or lungs, it's called a Pulmonary Embolism (PE).
Blood clots are typically treated with anticoagulent medication, also known as Blood Thinners.
Patients who are contraindicated for blood thinner therapy may have an IVC Filter placed in their body. This includes patients who are scheduled for routine surgery in which it is dictated that anticoagulants (blood thinners) need to be stopped several days before surgery.
An IVC Filter is a small metal cage that is placed in the body by a vascular surgeon or interventional radiologist to catch a blood clot before it travels from the leg to heart and into the lungs.
Almost 1,000,000 people will be diagnosed with DVT per year and it is estimated that 200,000 of them will have an IVC filter placed in them each year.
IVC placement - watch video
Patients talk about their IVC filter
Most IVC filters are in place because of temporary DVT
- DVT occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in the legs.
- DVT can occur in anybody, at any age, although it is most common in adults over 60 years old and accompanied by an illness, injury or surgery.
- 1 out of 15 people are a genetic higher risk for developing DVT.
- Almost 1,000,000 people in the U.S. are diagnosed with a DVT each year.
- DVT often coincides with a serious illness like cancer, a leg injury or surgery like hip or knee surgery that causes lack of mobility.
- Decreased blood flow creates an easier environment for blood clots to form.
- Ultimately, the fear for doctors and patients is that a DVT might result in a deadly embolus (PE) that breaks off and travels to the heart and lungs. A pulmonary embolism can be sudden and unexpected and deadly.
- Anticoagulation (blood thinners) has been the primary therapy for DVTs - used to dissolve the clots over a short period of time, such as 2 weeks.
- Blood thinners like Heparin, Coumadin (Warfarin), Pradaxa, Xarelto or Eliquis are the most common treatment for DVT.
- Compression stockings are also often worn by people with DVT.
Deadly PE - Pulmonary Embolus
In a small number of people who have a DVT, a part of the blood clot breaks off. This travels in the bloodstream and is called an embolus. An embolus will travel in the bloodstream until it becomes stuck. An embolus that comes from a clot in a leg vein will be carried up the larger leg and body veins to the heart, through the large heart chambers, but will get stuck in a blood vessel going to a lung. This is called a pulmonary embolus.
- 100,000 Americans may die due to PE annually.
- 25% of PE deaths may be sudden.
Anticoagulent Therapy (Blood Thinners) is the Most Commonly Prescribed Treatment for DVT
The mainstay of medical therapy has been anticoagulation since the introduction of heparin in the 1930s. Warfarin was developed in the 1950s and a series of new blood thinners were introduced after 2010.
The Most Common Anticoagulent - Coumadin
Today, the most popular blood thinner continues to be the one that was developed in the the 1950's, Warfarin. It was first developed as a rat poison, but later approved for human use. It is well-known by the brand name Coumadin, manufactured by Bristol Meyers-Squibb. Coumadin has been the top anticoagulant medication since it was successfully used to treat President Dwight Eisenhower during the 1950's.
There are several new heavily-marketed blood thinners that are competing with Coumadin. The newer anticoagulants Pradaxa, Xarelto and Eliquis (since 2010) are more convenient than Coumadin which requires monthly blood tests and strict diet controls.
However, the newer medications are all currently part of mass torts alleging that they can cause excessive internal bleeding that can't be reversed with an antidote. Coumadin has an antidote.
TV Commercial for Blood Thinner
TV Commercial for Blood Thinner
Timeline of Treatment for Deep Vein Thrombosis (DVT) to Prevent Pulmonary Embolism (PE)
1900 - 1930
3. Warm Compresses
Prior to that bloodletting and experimentation with leeches and leech product was occasionally used.
1936 - The first anticoagulant, Heparin
Download and read more about Heparin in the pdf:
The History and Historical Treatments of Deep Vein Thrombosis
1948 - University of Wisconsin develops Warfarin as a Rat Poison
Since the late 1940's, DVTs have been commonly treated with the anticoagulants, Heparin and then Coumadin (Warfarin)
- They are often used sequentially - Heparin for immediate effectiveness in the hospital, then Warfarin for longtime home use.
- Warfarin was first licensed by entrepreneur Lee Ratner from the The Wisconsin Alumni Research Foundation (the independent patent arm of the University of Wisconsin) in 1948 as the primary chemical compound in D-Con, the world's best selling rat poison. It remained the primary active ingredient until the 1980's when mice began to show signs of warfarin resistance.
1954 - Warfarin deemed safe enough to use on humans (Coumadin)
- Warfarin for anticoagulation therapeutic use began in 1954 after it was deemed safe enough to use in humans.
- Warfarin is a type of VKA, or a Vitamin K antagonist.
- In 1956, it was used to treat President Eisenhower
1956 - Warfarin used to treat President Eisenhower
Today, Warfarin (marketed as Coumadin) continues to be the most widely prescribed anticoagulant although it is facing heavy competition and marketing from a new class of blood thinners including Xarelto, Pradaxa and Eliquis.
Go to Next: Part 2: IVC Filter 102 - History and Manufacturers of the IVC Filter