Thrombosis occurs when the blood changes from a liquid to a solid state thereby producing a clot. Deep vein thrombosis (DVT) refers to the formation of a thrombus (blood clot) that develops in one of the major deep veins (a vein that accompanies an artery) of the body, usually in the leg (thigh or calf). A clot blocks blood circulation through these veins, which carry blood from the lower body back to the heart. Deep vein thrombosis causes pain, swelling and possible complications if it reaches the lungs. When a blood clot blocks blood flow to an artery in the heart or brain, a heart attack or stroke may result.
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