BEIJING, July 21 (Xinhuanet)- About one-fourth of patients with superficial blood clots may be at greater risk for life-threatening deep vein thrombosis, according to a new study.

    Austrian researchers said Monday, "varicose veins, thrombophilia (a disorder in which the blood clots too easily), use of oral contraceptives, trauma, malignancy or a period of immobility can cause blood clots near the surface of the legs.

    "In the past, not much interest has been focused on superficial vein thrombosis because of its generally benign course. However, recent investigations showed an unsuspected association of superficial vein thrombosis with deep vein thrombosis and thromboembolism [blockage of a blood vessel by a clot that has broken apart."

    Dr. Barbara Binder of the Medical University of Graz, Austria, and colleagues studied 46 patients-32 women and 14 men-- with superficial vein clots from November 2006 and June 2007. All had a diagnostic imaging test and other lab tests.
The team found deep vein thrombosis in 24 percent of patients, even though most had no other symptoms.
    
    Deep vein thrombosis most often occurred with superficial clots in the lower leg. In 73 percent of the patients, it occurred in the same leg as the superficial clot.
    
    "Usually, superficial vein thrombosis is regarded as a condition with an uncomplicated course and usually is not considered to be a severe or life-threatening disease. However, the occurrence of concomitant deep vein thrombosis and/or pulmonary embolism [blood clot that travels to the lungs] may lead to severe complications," the researchers said.
    
    The study is published Archives of Dermatology, one of the JAMA/Archives journals.

    
    (Agencies)