Deep Vein Thrombosis Health Center

What Is Deep Vein Thrombosis and a Pulmonary Embolism?

A vein is a blood vessel that returns blood from the tissues of the body back to the heart. The body has two distinct systems of veins -- superficial and deep. The superficial system is made up of veins that are close to the skin. These are the blood vessels you frequently can see on your hand arms, or legs that can become more prominent when you exercise. The deep system is comprised of veins within the muscles of the body. The two systems are connected by small communicating veins. The body regulates the amount of blood going through both systems as a way of rigidly controlling the body's central temperature.  

Deep vein thrombosis (DVT) is a condition wherein a blood clot forms in a vein of the deep system. DVTs can occur anywhere in the body, but are most frequently found in the deep veins of the legs, thighs, and pelvis. They may infrequently arise from the upper extremities usually because of trauma, or from an indwelling catheter (tubing) or device.

Thrombophlebitis is a condition in which there is both inflammation and a blood clot in a vein. Thrombophlebitis can occur in either superficial or deep veins. Superficial thrombophlebitis occurs in veins close to the skin surface, and usually causes pain, swelling, and redness in the area of the vein. Superficial thrombophlebitis usually is treated with heat, elevation of the affected leg or arm, and anti-inflammatory medications. A thrombosis in a deep vein is a much more serious problem than one in a superficial vein, because a piece of the clot can  break off and travel through the deep veins back to the heart, and eventually be pumped by the heart into the arteries of the lung. When this happens, the condition is called pulmonary embolism (PE). Pulmonary embolisms occur in 30% of people with DVT, and cause 60,000 deaths annually, many of them unrecognized and labeled as heart attacks.