The causes of thrombosis may be as follows:

1. It may be related to endothelial injury, and thrombus is formed on the vascular endothelium. Often due to various reasons of endothelium, such as chemical or drug or endotoxin, or endothelial injury caused by atheromatous plaque, etc., endothelial thrombus forms after injury;

2. For example, the coagulation of blood, the increase of platelet activity, or the abnormality of blood coagulation mechanism can also lead to the formation of thrombus;

3. The blood flow rate slows down or the blood volume decreases, and the blood concentration increases, which may also lead to the formation of thrombus, so there are many reasons for the formation of thrombus;

4. In addition to the above-mentioned reasons, the causes of thrombus also include increased activity of the fibrinolytic system. In addition, there is an increase in the number of platelets, which may lead to a thrombotic disease, so there are still many reasons.