What is haemostasis?
Haemostasis is how the delicate balance of blood flow in our vessels is maintained. If the balance is disturbed thrombosis or bleeding might occur.
What are the risks?
When a wound arises in a vessel wall, a clot must form at the site of the injury to prevent bleeding. The first reaction in this process is vasoconstriction, where the muscles in the vessel wall contract to decrease the blood flow and the amount of blood loss. The exposure of endothelium cells recruit platelets, the smallest cell fragments in the blood. The activated platelets connect and attach themselves to each other via pseudopods, and those clumps of platelets attach themselves to the site of injury with collagen. (This is known as the von Willebrand factor) They then use fibrinogen to form a temporary plug. In the third step the temporary plug is strengthened by the formation of a fibrin network together with other blood cells, creating a more stable clot. This stable clot stops the bleeding and activates the wound to start healing the cell walls. Finally, fibrinolysis sets in at the same time as the wound is healing. This is the normal procedure during a haemorrhage – the entire process prevents bleeding whilst simultaneously creating a sufficient clot.
Disturbance in the blood and in the vascular system may cause cardiovascular diseases. Some of the known risk factors are high blood pressure, high cholesterol, diabetes, smoking, and family history. Many cardiovascular diseases can be prevented by changing lifestyle, e.g. quitting smoking, maintaining a healthy BMI, exercising regularly, eating healthily, and reducing stress.
A disturbed blood balance eventually results in bleeding or thrombosis. If the blood is diluted, it is impossible for a clot formation to form, and blood loss is an inevitable result if there is an injured vessel wall. This event might be caused by haemophilia, a deficiency of coagulation factors, or thrombocytopenia, which is a low number of platelets.
If the blood throughout the vessel has a high viscosity, and the blood flow is substantial decreased due to a thrombosis, and if this takes place in a coronary vessel that supplies the heart with oxygen, angina pectoris will most likely occur.
The cause of cardiovascular diseases and thrombosis are most often due to inflammation in the vascular system, a process called arteriosclerosis. The inflammation gives incorrect signals to the blood that there might be a haemorrhage in the vessel wall and will probably result in an unrestrained thrombus. In this case, the affected person is at high risk of an embolism, and will most likely be perscribed oral anticoagulants, such as warfarin or NOAC’s/DOAC’s. Monitoring the drug dose is crucial in patient treatment as the side effects of anticoagulant therapy include excessive bleeding. The patient needs to visit the care centre at least every other month to have the PT-INR measured, which determines the anticoagulant concentration in the blood. INR can be determined by two methods, either PT Owren’s or PT Quick.