Deep Vein Thrombosis

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, a superficial system and a deep system. 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. (More heat is lost when more blood flows through the superficial than the deep system.) A deep vein thrombosis (DVT) is a condition wherein a blood clot (thrombus) forms in a vein of the deep system.

A thrombosis in a deep vein is a much more serious problem than one in a superficial vein. The reason for this is that a piece of the clot in deep vein from a DVT 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). The blood clot is called an embolus (plural emboli), and the process of breaking off and traveling to the lungs is called embolism.

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.

DVT is a common condition that affects almost two million Americans each year. Among patients with DVT, pulmonary embolism will occur in 30%.