Anticoagulation is a medical therapy with medication that inhibits blood clotting. Anticoagulation can be used for both preventive and therapeutic purposes. The medication used for blood clotting is called an anticoagulant or anticoagulant. It influences the plasmatic coagulation, i.e. the coagulation factors in the blood plasma.
Here you will find further information and selected anticoagulation specialists.
Anticoagulation is commonly understood to mean "blood thinning". However, this does not mean that blood is diluted with additional liquid (as in boiling). Rather, it means that by administering certain medications (anticoagulants)
coagulation factors in the blood are inhibited. Literally translated, the technical term anticoagulation means "directed against (anti) clotting (coagulation)". It is therefore not so much a blood thinning as an inhibition of coagulation.
Anticoagulants are drugs whose active ingredients bind to enzymes in the blood plasma, the so-called coagulation factors. This special binding, which fits exactly like a key in a lock, inhibits the coagulation factors and thus the formation of clots.
Otherwise, activated coagulation factors ultimately bind to the blood cells (red and white) and platelets (thrombocytes) in several steps (cascades), whereupon they stick together. This leads to the formation of a blood clot, also known as a blood clot. Clotting is activated, for example, when the vessel wall is injured, whereupon the blood clot seals the damage to the vessel wall, literally "sealing it off" and thus preventing further blood loss.
Treatment with anticoagulants (= anticoagulants) is always necessary if there is increased clot formation in the blood. This can be caused by three conditions and risk factors, which are summarized in Virchow's triad. Rudolf Virchow (1821 - 1902) was a German doctor and pathologist who worked intensively on research into blood clotting. He discovered three factors that lead to increased coagulation. These are changes
If one (or all three) factors are altered, this results in increased (pathogenic) coagulation, which can lead to blood clots(thrombosis) and/or the spread of these clots (embolism).
Anticoagulation therapy may be indicated for all conditions that are associated with a coagulation disorder. A distinction is made between preventive and therapeutic indications.
Preventive anticoagulation is mainly used in the vicinity of operations or in bedridden patients. The blood thinning is intended to prevent both thromboses and pulmonary embolisms.
Cardiac arrhythmia is the most common indication for anticoagulation for therapeutic purposes. Irregular heartbeats can cause clots to form in the heart, which are then carried into the body by the bloodstream. This is known as an embolism, and a coagulation disorder therefore leads to an increased risk of embolism.
An embolism can lead to serious complications, such as a stroke if the clot is carried upwards into the brain, or a "cold leg" if it is carried downwards. Blood thinning can significantly reduce the risk of embolism.
Another common reason for anticoagulation therapy is thrombosis of the leg veins. These occur in the case of congenital coagulation disorders, after major operations, prolonged sitting (e.g. air travel) or malignant tumors. Women of childbearing age who smoke also have an increased risk of thrombosis.
Patients can inject themselves with heparin © cristianstorto | AdobeStock
In the case of thrombosis, temporary anticoagulation therapy for 3-6 months is often sufficient. In rare cases, however, lifelong anticoagulation may also be advisable. This is the case, for example, with repeated thromboses or congenital blood clotting disorders. Patients who have an artificial heart valve implanted usually also require lifelong anticoagulation. The same applies to cardiac arrhythmias.
As already mentioned at the beginning, the various anticoagulants are often referred to colloquially and in educational discussions as "blood thinners". Strictly speaking, however, this is not correct. Anticoagulants do not reduce the viscosity (= flow properties) of the blood or the concentration of blood cells or blood protein.
When blood is thinned, the liquid part of the blood, the so-called blood plasma, is increased. This can be done using special fluids, so-called plasma expanders ("blood thinners"). This significantly increases the volume of plasma and therefore also dilutes it. However, these plasma expanders are not used to increase the formation of clots in the blood, but to reduce the volume in the circulation. The most common cause of a lack of blood volume is blood loss in the event of an accident or injury. Plasma expanders are always infused.
There are different drugs that inhibit blood clotting. The most obvious distinguishing feature is certainly the way in which they are administered, namely as
Outside of hospital, which is also known as outpatient treatment, tablets are generally preferred. However, injections can also be administered temporarily.
In hospital, especially in an emergency situation or after an operation, infusions are most common.
Many patients with circulatory disorders take tablets containing the active ingredient acetylsalicylic acid (ASS®, Godamed®, Aspirin®). However, this is not an anticoagulant in the narrower sense, but a so-called platelet aggregation inhibitor. It is a medication that inhibits the blood platelets (thrombocytes) and thus prevents them from clumping together.
A distinction is made in the mode of action between
Direct anticoagulants inhibit the coagulation factors directly, whereas indirect anticoagulants do this indirectly.
Indirect anticoagulants have been successfully administered since the middle of the last century and have revolutionized vascular medicine. The classic representatives of indirect anticoagulants are phenprocoumon(Marcumar®) and heparin (e.g. Clexane®). Marcumar® is administered in tablet form and must be dosed according to blood values that are regularly determined. It inhibits the production of certain vitamin K-dependent coagulation factors, which is why its full effect usually only occurs after 5-10 (sometimes even later) days. Marcumar® is also known as a vitamin K antagonist.
Heparins, on the other hand, have an immediate effect and are administered as injections or infusions. They bind to coagulation factors present in the blood plasma (so-called cofactors) and thus lead to an inhibition of coagulation, which occurs within a very short time. For this reason, heparins are mainly administered in emergency situations or to bridge the gap until an emergency operation. Vascular operations, such as bypass operations, are only possible if heparin is administered during the operation, whereby it is injected directly into the opened artery. The advantage of heparin is that it takes effect immediately and can be stopped by another drug called protamine.
Heparin is also administered as so-called "thrombosis injections" after operations (such as the insertion of an artificial joint) in order to reduce the risk of thrombosis. The likelihood of this occurring is increased due to the naturally reduced physical activity in the first phase after an operation.
Direct anticoagulants are still relatively new, which is where the name "new oral anticoagulants" (NOAC) comes from. DOAC (direct oral anticoagulants) is also a common abbreviation.
The best-known preparations in the field of direct anticoagulants are
They are administered in tablet form and take effect after around 6-10 hours.
The advantage of direct anticoagulants is that they are easier to dose, i.e. 1-2 tablets a day depending on the active ingredient. In the case of Marcumar®, regular blood tests must be carried out, which then determine the dosage (experience shows that 0.25 - 1.5 tablets per day).
The greatest risk associated with anticoagulant therapy is the risk of bleeding . Cerebral hemorrhage, for example, is particularly dangerous as it causes bleeding inside the skull.
There are various risk scores to estimate the risk in advance. They indicate how high the risk of a cerebral hemorrhage is in an individual case. The use of anticoagulants should be critically questioned, particularly in older, frail people with a tendency to fall.
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