Basic cause

1. Cardiovascular endothelial injury
Vascular endothelial cell injury is the most important and common cause of thrombus formation, and it is more common in rheumatic and infective endocarditis, severe atherosclerotic plaque ulcers, traumatic or inflammatory arteriovenous injury sites, etc. There are also hypoxia, shock, sepsis and bacterial endotoxins that cause a wide range of endogenous diseases throughout the body.
After skin injury, the collagen under the endothelium activates the coagulation process, causing disseminated intravascular coagulation, and thrombus forms in the microcirculation of the whole body.

2. Abnormal blood flow
It mainly refers to the slowing down of blood flow and the generation of eddies in blood flow, etc., and the activated coagulation factors and thrombin reach the concentration required for coagulation in the local area, which is conducive to the formation of thrombus. Among them, veins are more prone to thrombus, which is more common in patients with heart failure, chronic illness and postoperative bed rest. In addition, the blood flow in the heart and arteries is fast, and it is not easy to form thrombus. However, when the blood flow in the left atrium, aneurysm, or branch of the blood vessel is slow and eddy current occurs during mitral valve stenosis, it is also prone to thrombosis.

3. Increased blood coagulation
Generally, the platelets and coagulation factors in the blood increase, or the activity of the fibrinolytic system decreases, leading to a hypercoagulable state in the blood, which is more common in hereditary and acquired hypercoagulable states.

4. Hereditary hypercoagulable state
It is related to hereditary coagulation factor defects, congenital defects of protein C and protein S, etc. Among them, the most common factor V gene mutation, the mutation rate of this gene can reach 60% in patients with recurrent deep vein thrombosis.

5. Acquired hypercoagulable state
Commonly seen in pancreatic cancer, lung cancer, breast cancer, prostate cancer, gastric cancer and other widely metastatic advanced malignant tumors, caused by the release of procoagulant factors by cancer cells; it can also occur in severe trauma, extensive burns, major surgery or postpartum In the event of massive blood loss, and in conditions such as gestational hypertension, hyperlipidemia, coronary atherosclerosis, smoking, and obesity.