A deep vein thrombosis—or DVT—is a serious condition. It occurs when a blood clot—or thrombus—develops in a vein deep within the body. Most commonly, DVT affects a vein in the thigh or calf. A DVT blood clot in the leg can cause leg swelling or warmth. Sometimes, people complain of achiness in the area, a calf cramp, or other cramping. Recognizing and treating a DVT is vital. Left untreated, DVT can lead to potentially life-threatening complications. Pulmonary Embolism A pulmonary embolism—or PE—is one of the most dangerous complications of DVT. It happens when a DVT blood clot breaks away and travels in the bloodstream to the lungs. The clot lodges in an artery in the lungs, blocking blood flow. Small clots can lead to damage to the lung tissue. Large clots can completely block blood flow to the lungs. This is a life-threatening situation. When blood isn’t flowing to the lungs, it can’t pick up oxygen. Without oxygen-rich blood, other organs and body tissues begin to die and sustain permanent damage. PE symptoms usually begin suddenly. When these symptoms develop, it is a medical emergency. Symptoms of PE include: Bluish lips or nails Chest pain Coughing up blood or bloody sputum Shortness of breath or rapid breathing Other symptoms can also occur, such as back pain, lightheadedness, or excessive sweating. PE can occur soon after a DVT blood clot develops or after several days. Seek prompt medical care if you have symptoms of DVT to prevent this potentially life-threatening complication. Pulmonary Hypertension Pulmonary hypertension is a consequence of a PE. When a PE blocks blood flow to the lungs, blood pressure builds behind the clot. This will eventually cause heart failure. To understand how, it helps to know how blood flows through the body. Blood returning from the body, such as the legs, flows back to the heart through veins. The heart pumps blood to the lungs to pick up oxygen. The oxygenated blood returns to the other side of the heart, then the heart pumps the oxygen-rich blood out to the body through arteries. High blood pressure behind a PE in the lungs means the heart has to work very hard to try to pump blood into the lungs. The heart will keep trying to pump against this pressure until it begins to weaken. With time, heart failure will occur. Symptoms of pulmonary hypertension and heart failure are very similar to PE. This includes shortness of breath, lightheadedness, fatigue, cough, and chest pain. People with pulmonary hypertension and heart failure may also have swelling of the ankles or belly and difficulty breathing when lying flat. Post-Thrombotic Syndrome Post-thrombotic syndrome—or PTS—happens when a DVT blood clot damages vein valves. Veins have small valves along their length that help keep blood flowing in one direction, back to the heart. Blocked blood flow from DVT can injure these valves when pressure builds. The valves begin leaking and can no longer control blood flow. The result of weakened valves is pooling of blood. Symptoms include chronic pain, swelling, redness or discoloration, skin changes, and ulcers on the leg. This usually affects the calf or ankle area. About 30% of people who have DVT will develop PTS. PTS ulcers can be very difficult to treat. This, along with other PTS symptoms, can greatly reduce your quality of life. Sometimes, PTS can lead to significant disability. Preventing DVT Complications Preventing DVT complications starts with following your treatment plan very carefully. This usually means taking anticoagulant medicines. These drugs will stop the DVT blood clot from growing larger and new clots from forming. With time, your body will break down the clot and absorb it. Your doctor may also recommend wearing compression stockings to support blood flow in your legs. Sometimes, more aggressive treatment is necessary. This may include placing a vein filter or using clot busting drugs. DVT prevention strategies involve changing risk factors. One of the main risk factors for DVT is being sedentary or on bed rest, such during hospitalization or extended travel. To reduce DVT risk, hospitals often use special leg compression equipment. You can do your part by moving and walking as soon as your doctor clears it. If you’re traveling, stop frequently to walk. If you’re on a plane, stand or walk when you can, do heel raises at your seat to exercise your calves, and wear support stockings. Other ways to prevent DVT include: Exercising regularly Losing weight if you are overweight Quitting smoking Talk with your doctor about your risk of DVT. This is especially important as people age, as the risk increases after age 60. But anyone can develop DVT, so have a conversation to find out if you are at risk and what you can do about it.