By Suzanne Rostler
NEW YORK, Oct 14 (Reuters Health) -- Deep vein thrombosis (DVT), a disorder in which clots form in the veins found deep in the legs and groin, may be a more frequent cause of pulmonary embolism than previously believed, suggest two reports in the October issue of the journal Chest.
People who are inactive, such as during a long plane trip or during convalescence after surgery, are at risk for DVT. Muscle activity in the legs helps to keep blood circulating. Without activity, blood flow can become sluggish, increasing the risk of clots forming. The potentially life-threatening disorder occurs when a clot breaks free from the leg veins and travels through the circulation to the lungs, where it may interfere with breathing.
"If someone is going to die from DVT, they will have a pulmonary embolism that will be fatal," Dr. Barbara Alving, a hematologist and director of the Blood Disease and Resources division of the National Heart, Lung, and Blood Institute, told Reuters Health.
In one study, a team of researchers from France analyzed the medical records of 213 patients with pulmonary embolism. Eighty-two percent of patients with acute pulmonary embolism were found to have DVT when they were diagnosed with the embolism.
Only 42% of patients with DVT experienced symptoms, which can include pain and swelling in the leg.
"These original data constitute a unique and reliable basis for clinicians and researchers designing new diagnostic and therapeutic strategies in various subgroups of patients with suspected or proven acute pulmonary embolism," conclude lead author Dr. Philippe Girard and colleagues.
Another study found that 400 of 175,730 patients (0.23%) admitted to hospitals over a 5-year period were diagnosed with pulmonary embolism.
Age was found to correspond with the incidence of pulmonary embolism: more than half of patients diagnosed were between the ages of 65 and 85.
In patients over 50 years, investigators observed a higher incidence of pulmonary embolism among women. The use of oral contraceptives and childbearing had no effect on the frequency of pulmonary embolism.
Alving told Reuters Health that the studies suggest physicians could be more aggressive in trying to prevent DVT. Current prevention strategies to prevent DVT in surgical patients include clot-busing drugs such as heparin.
According to the American College of Chest Physicians, which publishes the journal Chest, about 2 million Americans experience DVT each year.
