Blood Clots, Travel and Deep Vein Thrombosis (DVT)

The holidays are upon us. In a few weeks we will be celebrating Christmas, Hanukkah (which starts this year on Dec. 25), Kwanzaa (which starts on Dec. 26) and a New Year. Tens of millions of people will be traveling to visit family and friends. Hours of sitting in a plane, bus or car can lead to an unwelcome guest: blood clots in the large veins of the legs. A deep vein thrombosis (DVT) can sneak up on you after returning home. Clots can arise days or even weeks after travel.

What is Deep Vein Thrombosis (DVT)?

When you sit or remain inactive for many hours, blood flow in leg veins may slow down. It’s not just air travel that is risky. We know people who hate to stop on the Interstate. They drive for 6 to 8 hours without a pitstop. That may be just as dangerous as sitting in a cramped airplane seat while flying across the ocean. Even a long bus trip could put you at increased risk for a DVT.

Thrombosis means the development of a clot in a blood vessel such as a vein or artery. The clot itself is called a thrombus. Medicalese often originates from Greek and Latin. The Greek word thrombos loosely translates to clump.

When a clump of blood cells gang together in a vein deep in the legs or thighs you’ve got a deep vein thrombosis (DVT). When the clot restricts blood flow through a vein it is called venous thromboembolism (VTE). If part of the thrombus breaks loose and travels to the lungs it is a pulmonary embolism (PE). Wherever the clot lodges, it can spell big trouble.

A New and Worrisome Risk for Blood Clots!

It’s not just long periods of sitting that may increase your risk for a blood clot. Microplastic particles circulating in your blood stream could also pose a problem. A study published in Scientific Reports (December 6, 2024) reveals that almost all of the subjects tested had microplastics in their blood.

The investigators found an association between microplastic particles in the blood and a greater risk for blood coagulation. It remains to be determined if microplastics will increase the risk of blood clots. The authors conclude that there is a need to reduce exposure to microplastics and to better understand their connection with blood coagulation and cardiovascular risks.

To give you some idea of how much plastic there is in the world, the authors cite these stats:

“Due to their affordability, ease of processing, and chemical stability, plastics have dramatically increased over time—from a global production of approximately 1.5 million tons in 1950 to about 390 million tons in 2021.”

How do microplastic particles get into us?

The authors reports that plastic food containers, reusable food pouches and water bottles are all contributing microplastics (MPs) to our bodies.

The authors state:

“The human body is exposed to MPs [microplastics] through ingestion, inhalation, and skin exposur. MPs are present in food, drinking water, and food packagin. Products closely associated with daily life, such as plastic teabag, feeding bottle, and snacks have been reported to contain MPs. MPs have been investigated in various human biological samples, including colectomy specimens, saliva, sputum, lungs, liver, breast milk, and feces. The detection of MPs in systemic tissues suggests that MPs may also be detected in the bloodstream, which supplies the entire body.”

We are being slowly plasticized. MPs could be increasing our risks for blood clots.

How Common is Deep Vein Thrombosis (DVT)?

We suspect that most health professionals think that DVTs and PEs are relatively rare. They would be wrong. Life threatening DVTs are more common than some of our most common health conditions. More about that in a moment. In truth, good statistics about venous thromboembolisms are hard to come by. The CDC admits as much. Here is the overview from this highly regarded public health institution:

“• The precise number of people affected by DVT/PE is unknown, although as many as 900,000 people could be affected (1 to 2 per 1,000) each year in the United States.
• Estimates suggest that 60,000-100,000 Americans die of DVT/PE (also called venous thromboembolism).

• 10 to 30% of people will die within one month of diagnosis.
• Sudden death is the first symptom in about one-quarter (25%) of people who have a PE.

• Among people who have had a DVT, one-half will have long-term complications (post-thrombotic syndrome) such as swelling, pain, discoloration, and scaling in the affected limb.
• One-third (about 33%) of people with DVT/PE will have a recurrence within 10 years.”

Deaths from DVT:

We have searched the medical literature to try and verify the number of people who die annually from a venous thromboembolism (VTE). We were shocked to read this acknowledgement from leading authorities (American Journal of Preventive Medicine, April, 2010)

“Presently, there is no national surveillance of VTE, and current prevalence and incidence estimates are likely underestimates…Further, PE often presents as sudden death. Given that the number of autopsies performed in the U.S. is low, and that PE may be misdiagnosed as heart failure, current estimates of the number of PE events are probably low.”

We have looked high and low for more information on missed diagnoses and DVT. You can read about our research in our book, Top Screwups. We suspect that annual mortality rates for VTE may be substantially higher than CDC estimates.

An article in the journal Cureus (Jan. 31, 2022) suggests that at least 100,000 patients die from pulmonary embolism annually:

“PE [pulmonary embolism] is also considered the most common cause of preventable hospital death.”

The National Blood Clot Alliance goes on to state:

• “100,000 to 300,000 deaths from blood clots occur each year, which is greater than the total number of people who lose their lives each year to AIDS, breast cancer, and motor vehicle crashes combined.”

STOP! Go back and reread that sentence. Did you know that mortality from blood clots exceeds that of breast cancer, HIV and motor vehicle accidents combined? We didn’t think so. We too were shocked. This is serious stuff!

Symptoms of Deep Vein Thrombosis (DVT):

When blood clots break loose from veins and migrate to the lungs, the result can be life threatening. Sudden death might be the first symptom of PE. Up to one third of those diagnosed with DVT/PE die within a month of being diagnosed.

That is why it is so important to recognize the symptoms of a possible blood clot as early as possible. Swelling, redness, tenderness and pain in one leg can be an early tip-off.

If the clot lodges in the lungs (PE), it can cause chest pain, shortness of breath, rapid breathing, trouble breathing, chest pain after deep breaths, irregular heart rhythms, lightheadedness, low blood pressure or coughing up blood. Do NOT delay. Sudden death can be a consequence of a pulmonary embolism!

DVT/PE A Leading Diagnostic Mistake

It can be challenging to uncover the most common diagnostic errors made by health professionals. No one likes to admit making a mistake. But if doctors are given the opportunity to discuss this issue anonymously, they often reveal some interesting information.

A survey of 310 internists, specialists and emergency physicians conducted at 22 institutions revealed that the most frequently missed diagnosis was pulmonary embolism or PE (Archives of Internal Medicine, Nov. 9, 2009).

We discovered that diagnostic mistakes involving pulmonary embolism were also a major cause of malpractice claims. That is why it is so important for patients and families to be vigilant when it comes to symptoms of deep vein thrombosis (DVT) or pulmonary embolism (PE).

Preventing DVTs and PEs:

People who are immobile for a long time are more susceptible to DVT. One reader wrote about this experience:

“I took a long car trip (over 20 hours), only stopping for gas. I developed DVT in my leg and am now on blood thinners, apparently for life. Was the trip partly the cause?”

While traveling can sometimes be responsible for clot formation, lying still in a hospital bed is also a risk. Another reader related:

“I had bilateral knee surgery and developed a clot (DVT). As a result, I now take Xarelto. This drug made me short of breath and gave me muscle fatigue after even the slightest activity. The doctors insisted it wasn’t the drug, but when I was able to discontinue it, I felt much better.”

Knee or hip replacement surgery pose serious risks for blood clots. It is essential that patients discuss preventive strategies BEFORE undergoing surgery. Here is a link to an article about this very topic:

Many health professionals are surprised to learn how effective aspirin can be at preventing blood clots after joint replacement surgery (Bone Joint Journal, Nov. 2017). Again, medical supervision is essential!

Treating Deep Vein Thrombosis (DVT):

When a person is diagnosed with a blood clot in a deep vein in the thigh, the treatment is usually anticoagulant medication. Heparin is a common anticoagulant that is used in hospitals. Although drugs such as apixaban (Eliquis), rivaroxaban (Xarelto) or warfarin (Coumadin) don’t dissolve such clots, they keep others from forming.

Another treatment that appears helpful to prevent complications is compression therapy (Blood, Nov. 22, 2018). Special elastic hosiery that squeezes the legs has been shown to help reduce some of the adverse effects of a DVT.

Preventing Blood Clots During Hospitalization:

After surgery, patients often have reduced mobility for several days. This can increase the risk for blood clot formation. If a patient has to lie in a hospital bed without moving, doctors sometimes order intermittent pneumatic compression (IPC). These flexible sleeves fit around a patient’s legs. They periodically fill with air, squeeze the legs and improve blood flow through veins.

There is even a portable leg wrap (CIRCUL8) from Precision Medical Products. It can be operated through an app on a cell phone. The rhythmic compression while riding on an airplane or in a car can help reduce the risk of clots. You may need to ask your doctor for a prescription and check to make sure your insurance company will pay for this device. We suspect it is pricey. Those at risk, however, should be covered.

For those who are especially susceptible to blood clots, low-dose aspirin may also be beneficial. A study of people who were at high risk of developing a recurrent DVT or PE reported that low-dose aspirin could be protective (European Journal of Internal Medicine, Jan. 2014). Do not try this without medical supervision!

Aspirin vs. Xarelto (Rivaroxaban)

We were astonished to learn that aspirin was as good as the far more expensive drug Xarelto when it came to preventing blood clots after knee or hip replacement surgery. If you would like to read more about this intriguing study, here is a link.

Travel Smart!

Even people who have never had a deep vein thrombosis (DVT) may benefit from precautions when traveling. Standing up and walking around every hour or so gets the blood flowing. If you are especially susceptible to blood clots ask your physician whether you need to take prophylactic medicine before traveling.

Moving your legs or wearing compression hose on a long trip could help holiday travelers get home safely. We suggest consulting a health professional about the right kind. Such stockings are measured by the pressure they exert: mm (millimeters) of Hg (mercury). It is recommended that people who are vulnerable wear 15 to 30 mm below-the-knee compression stockings if they have to travel for many hours. Not everyone should wear elastic stockings, however. Support hose that is too tight may cause vein thrombosis or cut off blood flow in susceptible individuals.

The experts at the Cleveland Clinic recommend that long-distance air travelers:

“exercise the legs by flexing and extending the ankles at regular intervals. Walk about the cabin periodically, 5 minutes for every hour on longer duration flights (> 4 hours). Drink adequate amounts of water and fruit juices.”

Share Your Own Experience!

Have you ever had a blood clot? Please share your story with other readers in the comment section below. We fear that most people do not appreciate the significance of a deep vein thrombosis (DVT) or pulmonary embolism (PE). Prevention is always the best medicine. If you want to learn more about microplastics, here is a link to a recent podcast interview you may find helpful.