Internal Medicine

Thrombosis prophylaxis

Synonyms in a broader sense

Thromboembolism prophylaxis
Thrombosis protection
Thrombosis prevention
thrombosis
Blood clots
embolism

Definition and introduction

Under the Thrombosis prophylaxis one understands preventive measures to minimize the risk Blood clot (thrombus) to build.
Blood clots can become particularly dangerous if this thrombus or parts of it detach from the vessel wall and are carried away with the bloodstream (embolism).

Read more about the topic here: Blood clotting

A distinction is made between arterial and venous thrombi. The aim of thrombosis prophylaxis is to three main causes of clot formation to counteract. The measures should therefore mainly Promote the venous return flow to the heart, prevent damage to the vascular wall and reduce the ability of the blood to clot.
It depends on the combination of different measures that are supposed to optimize the protection in synergistic cooperation. The risk of a Pulmonary embolism can be reduced by 60 - 80%.

In addition, a distinction is made between primary and secondary prophylaxis. The goal of the primary form is to prevent a patient who is at increased risk of thromboembolism from forming a blood clot.
Secondary prophylaxis affects patients who have a acute thrombosis or one post-thrombotic syndrome Suffer. It is primarily about preventing a relapse.

Read more on this topic: Post-thrombotic syndrome

Classification

In the Thrombosis prophylaxis a distinction is made physical and drug measures.

To the physical measures count among others:

Mobilization
storage
Stroking the veins
Vein compressions
Promotion of the return flow through gymnastics

A number of different drugs are available for drug intervention, which are intended to reduce the blood's ability to clot.
The points of attack are the various components of the coagulation system. The differentiated use and dosage of the Medication depend on the risk profile of the person concerned.

Blood clotting physiology

To better understand the various measures of thromboprophylaxis, it is helpful to know some basic facts about blood clotting.

The following are essentially responsible for blood clotting:

the nucleated blood platelets (thrombocytes)
the coagulation factors
as well as some other factors

One shares them Blood clotting (also hemostasis) into a primary and secondary hemostasis. Furthermore, the speed of the blood flow, the composition or the viscosity of the blood and the willingness to clot are of decisive importance (Virchow triad).
The Coagulation factors IX, X, VII and II are in their function of Vitamin K dependent. Primary and secondary hemostasis, as well as the endogenous and exogenous pathway, neither take place alone nor one after the other, but rather in parallel.

Primary hemostasis and platelet function

goal of primary hemostasis is the hemostasis through the formation of a platelet clot (thrombus). Platelets, of course, as well as a number of different factors (e.g. von Willebrand factor) and receptors. Does it come e.g. If a blood vessel is injured, it contracts in the primary reaction (vasoconstriction) in order to minimize blood loss and slow down blood flow.
The components of the tissue now exposed as well as the inner layer of the vessels (endothelium) now ensure that the platelets from the bloodstream can adhere precisely there.
The Platelets are further activated by clinging, emptying their content and changing their shape. With the formation of a plug (also called a white deposition thrombus), primary hemostasis is complete. It serves to "temporary waterproofing“.

Secondary hemostasis

For permanent closure, the plug must be replaced with a fibrin thrombus. This must be done in the inactive prepress in blood occurring Fibrinogen (or factor I of the blood coagulation cascade) can be converted to fibrin. This requires a relay-like activation of various coagulation factors in the blood.

This preceding blood coagulation cascade consists of an exogenous (or extrinsic) and an endogenous (or intrinsic) path, which represent different activation pathways and lead to a common end path.

To the endogenous way count the Factors XII, XI, IX, VIII such as Calcium as the most important components.

To the exogenous way count especially factors III and VII as well as likewise Calcium.

The common final section begins with the activation of factor X and the other factors V, II, XIII and I.

The fibrin, which is now activated at the end of the cascade, is cross-linked and glued and is ultimately called red thrombus referred to as the other components of the blood composition (e.g. the red blood cells) are caught in the fibrin network.