Thrombosis and hemostasis are important physiological functions of the human body, involving blood vessels, platelets, coagulation factors, anticoagulant proteins, and fibrinolytic systems. They are a set of precisely balanced systems that ensure the normal flow of blood in the human body. Continuous circulation of flow, neither spilling out of the blood vessel (hemorrhage) nor coagulation in the blood vessel (thrombosis).

The mechanism of thrombosis and hemostasis is usually divided into three steps:

Initial hemostasis is mainly involved in the vessel wall, endothelial cells, and platelets. After vessel injury, platelets quickly gather to stop bleeding.

Secondary hemostasis, also known as plasma hemostasis, activates the coagulation system to convert fibrinogen into insoluble cross-linked fibrin, which forms large clots.

Fibrinolysis, which breaks down the fibrin clot and restores normal blood flow.

Each step is precisely regulated to maintain a state of balance. Defects in any link will lead to related diseases.

Bleeding disorders are a general term for diseases caused by abnormal hemostasis mechanisms. Bleeding disorders can be roughly divided into two categories: hereditary and acquired, and the clinical manifestations are mainly bleeding in different parts. Congenital bleeding disorders, common hemophilia A (deficiency of coagulation factor VIII), hemophilia B (deficiency of coagulation factor IX) and coagulation abnormalities caused by fibrinogen deficiency; acquired bleeding disorders, common There are vitamin K-dependent coagulation factor deficiency, abnormal coagulation factors caused by liver disease, etc.

Thromboembolic diseases are mainly divided into arterial thrombosis and venous thromboembolism (venousthromboembolism, VTE). Arterial thrombosis is more common in coronary arteries, cerebral arteries, mesenteric arteries, and limb arteries, etc. The onset is often sudden, and local severe pain may occur, such as angina pectoris, abdominal pain, severe pain in the limbs, etc.; it is caused by tissue ischemia and hypoxia in the relevant blood supply parts Abnormal organ, tissue structure and function, such as myocardial infarction, heart failure, cardiogenic shock, arrhythmia, disturbance of consciousness and hemiplegia, etc.; thrombus shedding causes cerebral embolism, renal embolism, splenic embolism and other related symptoms and signs. Venous thrombosis is the most common form of deep vein thrombosis in the lower extremities. It is common in deep veins such as the popliteal vein, femoral vein, mesenteric vein, and portal vein. The intuitive manifestations are local swelling and inconsistent thickness of the lower extremities. Thromboembolism refers to the detachment of thrombus from the formation site, partially or completely blocking some blood vessels during the process of moving with the blood flow, causing ischemia, hypoxia, necrosis (arterial thrombosis) and congestion, edema ( pathological process of venous thrombosis). After the deep vein thrombosis of the lower extremity falls off, it can enter the pulmonary artery with the blood circulation, and symptoms and signs of pulmonary embolism appear. Therefore, the prevention of venous thromboembolism is particularly important.