DVT Device Breaks Up Dangerous Clots

DVT Device Breaks Up Dangerous Clots

CREATED Jan 28, 2014

CHICAGO (Ivanhoe Newswire) - Every year, 2 million people develop deep vein thrombosis—a large blood clot in the leg that can be fatal. In the past, blood thinners were the only option, but the medication doesn't help dissolve the clot itself. Now, a new device is changing that and helping prevent complications.

Constant road trips Mallory Click took in college, nearly took her life. At just 21 she developed deep vein thrombosis, a large blood clot that can develop from sitting for long periods of time.

"I woke up early that morning and my leg was swollen. It was just crazy how much bigger it was than my other leg," Mallory told Ivanhoe.

Vascular surgeon Heather Hall says part of the clot had traveled to Mallory's lung, which can cause sudden death.

"It was very serious," Heather Hall, MD, Vascular Surgeon, Weiss Memorial Hospital, told Ivanhoe.

Blood thinners can help prevent future clots, but the clot itself can take months to clear up. That can lead to permanent damage for up to 50 percent of patients with DVT within one year.

"So the sooner that you clear that clot from the vein, the more functional that vein is going to be long term," Dr. Hall said.

That's where the Trellis system comes in. A catheter traps the clot between two balloons. Then, clot dissolving medication can be delivered directly to the site and broken up with a handheld motor, clearing the vein.

"These patients are going to have quicker resolution of their symptoms and also that long term their veins are going to be functional," Dr. Hall said.

It was lifesaving for Mallory, who's now paying more attention to her body on the road.

"I will definitely be more careful and take rest stops as much as possible," Mallory said.

Devices like the Trellis device are now being researched in a national study, that's currently enrolling patients to determine the best treatment for blood clots.  To learn how you can enroll or to find a study site near you, go to http://attract.wustl.edu.


BACKGROUND: Deep vein thrombosis (DVT) is a condition where a blood clot forms in one or more of the deep veins in the body, usually in the legs.  It can cause leg pain, but can occur without any symptoms.  DVT can develop if you're sitting still for a long time, like traveling in a car or plane, or if you have certain medical conditions that affect how your blood clots. Because a blood clot can break loose and travel through the bloodstream to the lungs, DVT is considered a serious condition. (Source: www.mayoclinic.com)

SYMPTOMS:  In almost half of all patients, DVT occurs without any noticeable symptoms.  However, when there are symptoms present they can include: 

  • Changes in skin color, like turning pale, red, or blue.
  • Swelling in the affected leg, including in the ankle and foot.
  • Warmth over the affected area.
  • Pain in the affected leg, which can include pain in the ankle and foot.  The pain usually starts in the calf and can feel like a charley horse.

If you develop symptoms of DVT, then you should contact your doctor for guidance.  However, if you develop signs of a pulmonary embolism (a life-threatening complication of DVT), then you should seek medical attention immediately.  Approximately 200,000 people die annually as a result of pulmonary embolism. Warning signs of a pulmonary embolism include: unexplained sudden shortness of breath, rapid pulse, sweating, coughing up blood, anxiety or nervousness, feeling lightheaded or dizzy, or chest pain or discomfort that worsens when you breathe deeply.  (Source: www.mayoclinic.com andhttp://www.sirweb.org/news/newsPDF/2008am/Mon/DVT_Final.pdf)

NEW TREATMENT: The goal of DVT treatment is threefold: stopping the blood clot from getting any bigger, preventing the clot from breaking loose and causing a pulmonary embolism, and reducing the chances of DVT from happening again.  Treatment options may include blood thinners, clot busters, filters, and/or compression stockings.  The latest treatment option is called the Trellis device.  Studies have shown that treatment with the device breaks up a blood clot in most patients quicker than using just a drug.  Using imaging, the device is guided directly to the clot via a catheter in the vein.  The Trellis removes the clot and restores blood flow much quicker than the current catheter-directed thrombolysis technique, which uses a drug alone and can take as long as two to three days to be effective with the patient in an ICU.  The Trellis combines the use of clot busting drugs with a drug dispersion device to break up the clot.  Because the device disperses the drug throughout the clot, it allows the clot-dissolving drug to work much more quickly and often less drug is used.  (Source:http://www.sirweb.org/news/newsPDF/2008am/Mon/DVT_Final.pdf)  


Heather Hall, MD, Vascular Surgeon, Weiss Memorial Hospital, talks about a new way to treat deep vein thrombosis.

What causes DVT?

Dr. Hall: There are a lot of risk factors for DVT. Anything that's going to restrict someone's movement and make them less mobile can put them at risk for DVT. So, if you think about it things like increasing age, being overweight, or surgery, anything that's going to make you less mobile is going to put you at risk. The reason is that the blood is flowing from the leg towards the heart and if you're less active the blood flow through those veins is slower, putting you at risk for developing a clot. Other things that can make you at a higher risk for developing a DVT are things like medical conditions or habits that make the blood more likely to clot; so things like cancer, pregnancy, smoking, and some inherited blood disorders.

Does it affect women more often than men?

Dr. Hall: It does affect women more often than men and part of that is due to estrogen. So, other risk factors are birth-control pills that contain estrogen or hormone replacement therapy that includes estrogen. Those components put women at a higher risk.

Can you talk about how many people are impacted by this every year?

Dr. Hall: So, DVT in the United States is actually a huge health problem. Some estimates say that about 300,000 to 600,000 people per year in the United States will develop a DVT or blood clot. More recent estimates put that at about 2 million cases per year. The average person has about a one in 1,000 risk per year of getting a blood clot, and as you add different risk factors that risk increases.

Can this become fatal?

Dr. Hall: DVT can cause symptoms in the leg like pain and swelling, but it's when that clot breaks off and travels to the lung and becomes a pulmonary embolism that it can be fatal. Even though there may be about 2 million cases of DVT per year in the United States, there's probably about 100,000 cases of fatal pulmonary embolism per year in the United States. That is more than the deaths from breast cancer and AIDS combined.

How many of those would you say realistically could be prevented?

Dr. Hall: I think a great number of those could be prevented. So you know the way to reduce your risk from developing a pulmonary embolism or having a death from a pulmonary embolism is recognition of a DVT. If a person experiences very sudden pain or swelling in their leg, they need to seek care from their doctor right away. Their doctor will ask them a series of questions about their symptoms. If they think that the likelihood of them having a DVT is high, they'll refer them for a diagnostic ultrasound.

So let's say that someone does have a clot what are the treatments that they can look at?

Dr. Hall: We can treat DVT with blood thinners for anticoagulation and that's been the standard of care for decades. The sooner that the blood thinner is started the better for the patient. That treatment however is somewhat flawed if you think about it. The way that a blood thinner works is that it prevents the clot from getting bigger. It also reduces the chance of that person getting more clots in the future, but blood thinners don't completely dissolve the clot. That is where the treatment falls a little bit short.

More recently there have been other ways to treat these blood clots. In Mallory's case, she is a healthy young woman who was a college student and developed pain and swelling in her leg. She might have initially thought this is probably something benign and hopefully this will go away, but that pain and swelling persisted and so luckily for her she recognized this as being an abnormal thing and came to the emergency room to be evaluated. Mallory was in a long car ride from St. Louis to Chicago and was sitting in the car the entire time trying to make good time on the highway and didn't take any breaks. We also know from Malory's case that once we were able to do some blood work on her, we saw that she did have a factor in her blood that made her more prone to clot than the average person. When Mallory came in, she was evaluated by the emergency rooms team and was found to have pain and swelling and redness in her leg and was quickly evaluated with an ultrasound. An ultrasound is really the most sensitive way to diagnose DVT and ultrasound also allows us to pick up when these blood clots are in these larger veins, again the thigh and pelvis. So, it allows us to select patients that are good candidates for the more advanced treatment. She was started on blood thinners right away, but we saw that she had large clots within her thigh veins and her pelvic veins. Because of her young age and her desire to be active, we discussed the risks and benefits of this advance therapy of giving the clot busting medications and decided to go ahead and treat her.

So she's been a success?

Dr. Hall: Yes. In Mallory's case we did get her started on the blood thinners right away and we were able to also treat her with the lytic medication and the trellis device to physically break up the clot. We were able to get good clearance of her veins within 24 hours and she was able to be discharged home simply on a blood thinner. She's done very well since her procedure, she's active, and has minimal symptoms left in that leg.

What's the recovery time like with a device may be versus just taking blood thinners?

Dr. Hall: With the traditional therapy with blood thinners, some patients will get the blood thinner in the emergency room and if they're young and they're reliable they'll get discharged from the emergency room just with the blood thinner. Patients that have more extensive clots or patients that have pulmonary embolism typically will be admitted to the hospital and those patients will be seen by a vascular surgeon. However, the therapy itself can be done within a 24 hour period; so even though it may involve an overnight stay in the hospital, it still gets patient's home with a significantly decreased clot burden and significantly reduced symptoms.

Is there a difference between recovery times or is it about the same?

Dr. Hall: Recovery times can be shorter using lytic medication on larger clots.

So I understand there's some that can be resolved with blood thinners and some are going to require clot busting medications. How does the device with the clot busting medication compare to just using the clot busting medication? Is there a difference in resolution of the symptoms or is it the same?

Dr. Hall: That's the problem. We know that patients that have extensive DVT in their leg are more likely to have this post thrombotic syndrome. So about a third to a half of patients that develop extensive DVT are going to develop post thrombotic syndrome, where even though the clot is resolved they continue to have pain and swelling and discomfort in that leg for the rest of their life. If we use these clot busting medications and resolve the clot sooner, fewer patients are going to have this post thrombotic syndrome. So their leg is not only going to feel better sooner, but they're less likely to have complications down the road.

Once you get it are you predisposed to getting it again in the same leg?

Dr. Hall: Yes. So, any individual that has a DVT they have a risk of having recurrent DVT at some time in their life. For example, if someone has a major operation and has a DVT after that, that's a transient risk factor; so they are less likely to get a DVT later in life. If you have someone that has a genetic disorder, like being overweight or obese, then if that person develops a DVT, they're more likely to have a recurrence because their risk factors are ongoing.


Caren Perlmuter
Marketing & Community Outreach
Weiss Memorial Hospital