For a medical disorder affecting more than 250,000 Americans each year, researchers don’t know much more today about what causes blood clots in veins than they did over 100 years ago. But deep vein thromboses or DVTs are a serious health problem, especially in the elderly. When blood clots form in deep leg veins, they can permanently damage the venous system or even be fatal, if a blood clot, or pulmonary embolism, travels to the lungs.
