Dr. Nation on Knowing Your Risk for DVT

During the summer months, cases of DVT (deep vein thrombosis) can be more frequent as people embark on road trips and air travel for their getaways and vacations. What is the link between DVT and sitting in cars or airplanes?

This potentially serious venous disorder occurs when blood thickens due to poor circulation and forms a solid clot, typically in the legs. These blood clots could prove dangerous, or even life-threatening, if they travel to your heart or lungs.

The CDC estimates that as many as 900,000 people in the United States are affected by DVT each year.

Many people wonder: how do you know if you are prone to getting DVT? We asked board-certified vascular surgeon and vein specialist Dr. David Nation to address this question.

Here’s what he had to share in response to common concerns about DVT risk factors, a new link between it and COVID, and what to do if you suspect you have developed a blood clot:

 What are the risk factors of DVT and how can they potentially lead to DVT?

The risks of DVT are often referred to as Virchow’s triad:  endothelial injury (injury to the lining of the blood vessel), stasis (lack of movement of blood flow), and hypercoagulable state (tendency of blood to clot more easily). 

 More specifically, risk factors for DVT include prolonged immobility, recent trauma or major surgery, narrowing or compression of larger veins, and anything that can cause hypercoagulability, or tendency of the blood to clot more easily. 

Anything that causes blood to move more slowly or become stagnant can increase clots, such as immobility. Stasis is also the main factor when a clot develops due to an anatomic narrowing or compression of the vein, such as that seen in thoracic outlet syndrome or iliac vein compression syndrome. 

Trauma and major surgery can also increase risk of DVT, both due to associated immobility but also due to injury to the vessel walls, which leads to endothelial injury and release of factors that increase clotting in response to injury.  There is also an overall inflammatory response in these conditions which activates the clotting cascade and leads to blood clot development. 

Finally, there are numerous factors that tend to make blood clot more easily, causing what we call a hypercoagulable state.  These include genetic conditions that can be inherited, as well as acquired hypercoagulable states such as seen with some cancers, certain medications, or COVID-19. 

What is the link between COVID and the increased risk of DVT?

COVID may increase risk of DVT by multiple pathways, although this is still not yet fully understood.  The virus creates an inflammatory state which can lead to hypercoagulability, and it also causes direct endothelial injury to the lung tissue, which can release signals into the bloodstream that stimulate clot formation.  There has also been some suggestion that the virus may also directly activate the clotting cascade by interactions within the bloodstream.  All of these effects are more prominent in patients with severe COVID symptoms and much less common with mild cases. 

People who have had COVID should be aware of the symptoms to watch for that can signal development of a clot, such as new onset leg swelling (usually just on one side), or chest pain/shortness of breath, and they should seek medical attention if these symptoms occur.   

The risk of DVT after a mild case of COVID is still fairly low, and usually medical therapy is not needed unless a clot develops.  Patients who have a history of blood clots or known hypercoagulability may be at higher risk and should talk with their doctor about whether any additional prophylactic treatment could be necessary. 

If you suspect that you have DVT, when should you check with your doctor (or perhaps go to an emergency room), and how will it be treated?

If you develop new leg swelling, or new chest pain or shortness of breath, you should see your doctor or go to the emergency room.  For leg swelling, an ultrasound is done to evaluate for DVT.  If you have chest pain or shortness of breath, a CT scan will usually be done to check for blood clots in the lungs, or pulmonary emboli.  If you are found to have a clot, blood thinners will be started to prevent the clot from worsening or causing a life-threatening situation.  For severe cases, other interventions may be considered. 

Are there any common misconceptions about DVT?

DVT can be a potentially life-threatening problem due to the risk of pulmonary embolism.  The clot in the leg is not directly fatal itself but can lead to bothersome symptoms and decreased quality of life.  It is important to seek an evaluation right away if you develop any symptoms of DVT.

Please contact us here for a consultation with one of our board-certified vein specialists if you have concerns about DVT or other venous disorders such as varicose veins and spider veins. To schedule an appointment in Austin, please call 512.452.VEIN (8346), or call 512.501.4287 for our clinic in Georgetown.

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