Are you at risk for deep vein thrombosis?

Every year in Canada 200,000 people experience the painful malady known as deep vein thrombosis (DVT), and another 60,000 are hospitalized because of it. These clots, which are most common in the legs, can affect everyone — even the young and healthy, who often assume they're risk free.

The summer heat can cause mild swelling of the legs, ankles and feet, especially if you're not staying hydrated, so we thought it would be a good idea to focus more closely on DVT, and let you know when any pain and swelling are something to worry about.

The main misconception You may have heard of DVT because of its association with flying. ‘Economy class syndrome’, a term used to describe the health worries of air travellers stuck in cramped seats, is often touted as a major health issue. But did you know your likelihood of developing DVT during a 12-hour flight is actually extremely low?

According to Dr. Marc Rodger, a senior scientist at the Ottawa Hospital Research Institute, and a hematologist with an expertise in thrombosis, your odds are two in a million. “[Cramped] is a minor factor in DVT,” he says. “Something else is usually the main cause.”

Misconceptions such as this one about DVT are common, so let’s bust some myths and unveil the truths that could save your life.

The basics Your arteries pump blood from the heart through your body. Veins serve the opposite function, returning blood towards the heart. While arteries have muscle tissue that helps push blood, veins don’t. They rely on your body’s physical movements, specifically your calf muscle's contractions, to pump blood back towards your heart. If a lack of movement restricts the blood flow, and causes it to pool in a vein, blood clots can occur. If a blood clot floats through the heart and into the lungs, you could have a pulmonary embolism — a condition that can kill you.

Dr. Rodger says 50 percent of clots occur because of these factors: 1. Surgery within the last month 2. Wearing a cast for the past month 3. Being immobilized in bed for more than three consecutive days 4. A leg injury

Birth control, hormone replacement therapy, some chemotherapy treatments and being confined to a small space for more than 12 hours can put you at only a minor risk for DVT.

In fact, Dr. Rodger says that many individuals who develop blood clots while taking these medications or after travel, have recently experienced one of the four major risk factors, or have thrombophilia (an inherited blood clotting condition). Minor risk factors may contribute to DVT, but they’re not the principal cause.

Symptoms of DVT: 1. A pain in your leg or arm for more than an hour (similar to a charley horse) 2. Area swelling 3. Redness or a warm feeling over the affected area

If these symptoms continue after an hour, head to the emergency room immediately.

Symptoms of pulmonary embolism: 1. Chest pain that lasts more than 15 minutes 2. Unexplained shortness of breath that lasts more than 15 minutes 3. Fainting 4. A rapid pulse

Dr. Rodger says that 10 percent of people with a pulmonary embolism die before they get medical attention. If you experience these symptoms, head to the ER immediately.

DVT and pulmonary embolism require immediate treatment with blood thinning medications. “They reduce the risk of blood clots worsening by 90 to 95 percent,” says Dr. Rodger. Canada is a world leader in the treatment of DVT, and unlike many countries, the path to recovery doesn’t always include hospital admission. “About 80 percent of DVT patients, and 50 percent of pulmonary embolism patients are treated as out-patients because the treatments are so effective,” explains Dr. Rodger.

Preventing DVT: 1. If you’ve recently experienced one of the four main risk factors, ask your physician to prescribe blood thinners to prevent clots.

2. If you’re travelling by car, take breaks and get out of the vehicle. During air or rail travel, stand up, do stretches, avoid alcohol (it’s dehydrating) and drink plenty of water.

3. Don’t wear compression stockings. “The latest studies on whether compression stockings prevent blood clots suggest that the thigh-high ones don’t work, and the knee-high ones actually cause blood clots,” says Dr. Rodger.

4. “People who die of blood clots typically ignored their symptoms for days. The clots grew bigger, broke off, and went to the lungs where they’re fatal,” says Dr. Rodger. If you have symptoms, seek medical attention immediately.

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