It’s bad enough when you’re sick in bed. And here, in addition to the actual illness, a great danger looms: thrombosis. People who sit a long time and a lot also have an increased risk of thrombosis. Overall, about two out of every 1,000 people in Western countries get a thrombosis every year. These blood clots preferentially form in the deep veins of the legs and pelvis, and less frequently in the arteries. There is an increased risk of thrombosis even weeks after surgery, especially in elderly patients.
Blood clots – fortunately
If blood did not have the fascinating ability to clot, we would bleed to death from the slightest injury. Both internal and external injuries are treated by the body with lightning speed, first by constricting the blood vessels and then by attaching platelets, or thrombocytes, to the edge of the vascular injury. Together with numerous clotting factors of the blood and tissue, they seal the wound. However, this protective mechanism has the opposite effect in certain diseases, when blood clots in the body, or more precisely in the vascular system. This can lead to the formation of a blood clot, a so-called thrombus, in a vessel. The thrombus can seal the vessel completely – no more blood flows at all. But when blood stops flowing, the supply of oxygen stops. The result: tissue dies, and there may even be partial failure of certain organs.
The veins are particularly affected
Thromboses primarily affect the veins. Veins are the part of the vascular system that carries deoxygenated blood back to the heart. From there, it is pumped first through the lungs and then back into the systemic circulation via the arteries to resupply oxygen to all organs. Unlike the arteries, the veins are equipped with valves inside them, which are very important for transporting blood to the heart. The valve pockets of the calf veins are in the vast majority of cases the starting point of thrombosis. One form of blood clot is familiar to everyone: varicose veins. These are dilated veins just under the skin. One in five of all German citizens suffer from them, mostly women. If a blood clot develops there, this is usually harmless.
Symptoms of thrombosis
The symptoms of venous thrombosis are severely painful swelling in the leg, usually it also feels overheated and is blue in color. Read how to recognize thrombosis here. Due to the constant blood stasis, this can develop into a chronic venous condition – not infrequently with open legs (ulcus cruris).
Embolus: when a thrombus migrates
However, a thrombus can also be carried away by the bloodstream and become a “wanderer,” or embolus. In this case, it is washed away from the site of origin and blocks a vessel somewhere else – resulting in a life-threatening embolism. Every effort is made to prevent this. This is where the “anticoagulants” come into play. There are various clotting factors in the body, which are named with Roman numerals in the order of their discovery.
Anticoagulant factors
Clotting factors are blood proteins and are made in the liver. Anticoagulants delay blood clotting by decreasing the body’s production of certain clotting proteins. This specifically prolongs the clotting time and prevents the formation of unwanted clots that can block a blood vessel. Patients with artificial heart valves, for example, have to take the active substance coumarin. Patients who have to lie down for a long time because of surgery are given the unloved thrombosis stockings and the daily heparin injection.
Heparin and thrombosis stockings
Heparin is a drug that inhibits blood clotting and is injected just under the skin. Patients who have to lie down a lot at home because of a broken leg, for example, inject their own medication – usually into the abdominal wall below the navel. The use of acetylsalicylic acid is repeatedly recommended, but its effectiveness in preventing travel thrombosis is controversial because it only affects arteries, not veins. Thrombosis stockings, also known as compression stockings, are used as a preventive measure: they support the veins by increasing tissue pressure from the outside, thus facilitating blood return. They are also recommended for high-risk patients who travel by air for long periods.
Treatment of thrombosis
Treatment of thrombosis should be given as soon as possible to prevent further progression of thrombosis and to reduce the risk of sometimes life-threatening complications. Bed rest for thromboses from the back of the knee upward, while activities such as walking around are among the first measures for thromboses of the lower leg veins. Until swelling subsides, the legs are wrapped with bandages, after which a compression stocking must be worn. Restoration of blood flow can be achieved by dissolving the thrombus with medication. Large blood clots can also be removed surgically, and sometimes the blocked section of the vessel is bridged by a vasculoplasty called a bypass.
Risk factors for thrombosis
The following factors confer an increased risk of thrombosis:
- Prolonged bedriddenness
- Lack of exercise, such as sitting for long periods on long-distance flights or in the car
- Lack of fluids
- Congenital coagulation disorders
- Increased tendency to blood clotting after major surgery or childbirth
- Arteriosclerosis and varicose veins, often in older age.
- Women taking the birth control pill.
- Pregnancies
- Obesity
- Smoking
If thrombosis is suspected, you should contact a doctor immediately.