ABCs of DVTs and PEs

By Donna Smyers
Posted October 1st, 2006

How can an athlete have a circulatory problem?

Most athletes think they are protected against cardiopulmonary risks because of their aerobic fitness. They achieve a low heart rate, large lung capacity and high HDL cholesterol from all that exercise, so how can they have a circulatory problem? While athletes tend to have healthy hearts, lungs and arteries, trauma from impact, such as a bicycle accident, or microtrauma from running, can damage veins and put athletes at increased risk for a lesser-known circulatory problem – deep vein thrombosis (DVT).

A DVT is a blood clot that usually forms in the deep veins of the calf, knee, thigh or groin. Often, these clots may not be initially noticeable, but damage to the lining of a vein can initiate the clotting process. If the blood is moving sluggishly in that vicinity due to immobility, and/or if there is a genetic or medication-related propensity for blood to clot, clots are then more likely to be formed. A DVT by itself may be asymptomatic, or it may cause swelling and pain, but the real danger occurs when a clot breaks away from a vein in the leg, flows into and then lodges in the lungs, forming a pulmonary embolism (PE), which blocks blood flow in the lungs and can be fatal.

Why are athletes so at risk for a DVT? DVT is considered a standard post-surgical risk, which is actively addressed in hospitalized patients, but is unusual in young or healthy people. Apparently, competitive runners, triathletes, skiers, and cyclists may put themselves at greater risk by participating in an event that may create trauma and then get on an airplane to fly home. In a healthy population, air travel appears to create the highest risk for DVT (sometimes referred to as “economy class syndrome” ). I have seen figures of 100,000 deaths per year from air-travel-related DVTs and an estimated 85 percent of those affected by DVTs from air travel are athletes. Athletes’ low heart rates result in slower-moving blood through the veins. Combined with low oxygen pressure at high altitude, dehydration (from the event and/or dry cabin air), and cramped seating quarters, the risk of clots grows. In females, birth control pills or pregnancy increase the risk.

Although up to 50 percent of DVTs may be asymptomatic, you should recognize and be on the lookout for symptoms of a DVT: swelling, warmth, and pain in the calf or behind the knee. The swelling may come and go with exercise, or during rest and elevation. It usually hurts to flex the foot up toward your shin and is often mistaken for a calf muscle strain. Because most athletes initially conclude they have a strain, they do exactly what is most dangerous – massage or hot-tub therapy. Both are contra-indicated because they can help dislodge a clot and allow it to travel to the lungs, where it’s known as a pulmonary embolism. This is usually marked by shortness of breath or a persistent cough, but a large embolus may cause death within minutes or hours.

If you suspect a DVT, consult your doctor immediately for diagnostic testing. If the result is positive, treatment is imperative and consists of aggressive anticoagulant (anti-clotting) therapy. Patients are initially given IV heparin in the hospital, followed by two to six months of oral coumadin. During coumadin therapy (also known as a blood thinner), athletes may be prohibited from impact and contact sports due to the risk of excessive bleeding from new trauma.

There are several things you can do to prevent DVTs during air travel. Graduated compression stockings have been shown to prevent swelling and greatly decrease the risk of clots. I bought some for my trips to New Zealand and Hawaii for triathlons and now won’t fly without them. In addition, it is highly recommended that you move your legs and ankles frequently to keep the blood moving. Stay awake! Sleep is a risk factor since not only do you not move, but your blood oxygen levels fall, causing increased clotting factors. Interestingly, in one study, drinking extra water did not prevent the blood from thickening during air travel; however, drinking a sports drink with sodium and potassium (i.e. Gatorade or the equivalent) did maintain low viscosity.

My personal experiences with DVT
This article was inspired by the sudden death of Chuck Schultz this past July (see Editor’s Commentary, September, 2006). A prominent member of the Vermont cycling and skiing community, he died suddenly of a pulmonary thromboembolism. He had been in a serious bike accident, which created extensive bruising and trauma to his leg. Weeks later, he took an airline trip, and then returned to work, but he had said to a friend that his calf “was as big as his thigh.” Apparently, he did not recognize the danger or seek medical attention. Possibly, if he had known more about the diagnosis and treatment of DVTs, his death could have been prevented – we will never know.

I have known two athletes diagnosed with DVT progressing to PE who did survive. Many years ago, Kathy from Connecticut was a runner who enjoyed trail running. For about six months I heard her complain about a recurrent calf strain. Of course she did all the wrong things, including massage and heat. She was also on birth control pills. Finally, after developing a persistent cough, she was properly diagnosed and hospitalized to dissolve the clots in her lungs and leg.

My friend John showed up at Julio’s one night with a swollen leg. He had a persistent cough and trouble breathing, so he had convinced his doctor to give him antibiotics for an upper respiratory infection. He wondered why the antibiotics made his leg swell. My barstool diagnosis was that he definitely had a clot and that his breathing problem was not from a respiratory infection, but from PE. With my encouragement and his wife’s insistence, he ended up in the ICU that night on IV heparin, having been diagnosed with clots in four of the five lobes of his lungs, originating from an extensive clot in his leg.

While we will never know what caused John’s DVT, there are several indicators in his history. Approximately six months prior, he had been involved in a long distance running relay in Europe, followed by a long airplane ride home. That summer, he had quite a few leg cramps and calf injuries, although some were in the other leg. He also had been sick recently and spent two days in bed, avoiding drinking anything, because he didn’t want to have to get up (dehydration and lack of movement). Later it was discovered that he also had a genetic predisposition to clotting, so he remains on a low dose of coumadin to prevent future incidences.

From these stories, you can see that a variety of risks end up producing DVTs. For more information and personal accounts, I recommend these web articles I found during my research:

There is no need to panic next time you have a pain in your leg. Most of the time it is a calf strain. I treat them all the time. DVT is just one possibility to keep in the back of your mind when considering your, or someone else’s, symptoms, personal history, and risk factors.