DECATUR - Dr. Peter Eupierre remembers learning in medical school that deep-vein thrombosis was "very rare," but by the time he was in the middle of his residency, more and more cases began to appear.

"Deep-vein thrombosis is something that most people don't hear much about," said Eupierre, president of the Illinois State Medical Society. "It's a lot more common than we first thought, though, affecting up to 2 million Americans a year."

Although deep-vein thrombosis is preventable, more than 300,000 die each year from the condition and its primary complication, pulmonary embolism, Eupierre said.

March has been designated as Deep-Vein Thrombosis Awareness Month by the Coalition to Prevent Deep-Vein Thrombosis, with organizations such as the Illinois State Medical Society and Prairie Cardiovascular showcasing their support.

Deep-vein thrombosis occurs when a blood clot forms in a large vein, usually in the legs, which leads to partially or completely blocked circulation. If untreated, the clot has the potential to move into the lungs and create a pulmonary embolism, which occurs when clots block pulmonary blood vessels.

Symptoms of pulmonary embolism include shortness of breath, rapid pulse, sharp chest pain that worsens with deep breathing, low blood pressure or coughing up blood.

Several factors put individuals at risk for the condition, Eupierre said.

"Inactivity is for sure one risk factor," he said. "In the old days, we used to see it a lot after surgery because people would stay in bed for weeks and not be moving their legs. Birth control pills, obesity, smoking and high blood pressure are all increased risk factors for DVT."

Deep-vein thrombosis can be prevented, though, primarily by staying active and cutting down on your risks, Eupierre said. "If you travel by car, get out every two to three hours and walk around; if you're on a plane, walk around the plane. Keep moving, keep active - that's the best advice."

Courtney Klemm can be reached at cklemm@herald-review.com or 421-6968.