The meaning of the following items is much more than what I have said, and what I have said is the meaning that is closely related to the diseases in our department: Item 1: prothrombin activity (PT%): still an index calculated from PT and NP, which is the opposite direction of change from PT, i.e. PT% decreases when PT value increases. Item 2: Activated partial thromboplastin time (APTT): a commonly used indicator for monitoring the endogenous coagulation system in clinical practice. In vascular surgery, it is mainly used to monitor the effect of anticoagulation therapy with common heparin, and the higher the measured value, the better the anticoagulation effect. In general, it is more effective and safe to make the APTT value 1.5-2.5 times higher than the normal value after using heparin. Item 3: prothrombin time (TT): in vascular surgery, increased TT is mostly seen in reduced plasma fibrinogen content, increased fibrin (original) degradation products and after the use of heparin. shortening of TT has no clinical significance. Item 4: Fibrinogen (FIB): In vascular surgery, increased FIB is mainly seen in the pre-thrombotic state, but is not a specific indicator (i.e., increased FIB may not necessarily indicate a pre-thrombotic state, but other disorders such as malignancy, after major surgery, stress and acute infection can also lead to its elevation), in addition, persistent increase in FIB may induce atherosclerosis; decreased FIB is seen in diffuse intravascular FIB is reduced in diffuse intravascular coagulation (DIC) and hyperfibrinolysis, etc. Item 5: Antithrombin III activity (AT-III): It is a very important physiological anticoagulant in the body, which can bind to some of the coagulation factors and thus produce anticoagulation. It is worth noting that when AT-III binds to heparin, its conformation changes and its ability to bind to coagulation factors increases thousands of times, which is also the mechanism by which heparin produces anticoagulant effects in vivo. It should be noted that the effect of heparin decreases when AT activity is below 70%; below 50% is a significant decrease in the effect of heparin; below 30% is ineffective heparin treatment. Item 6: D-dimer (D-Dimer): is one of the products of cross-linked fibrin degradation and is increased in secondary fibrinolysis, but not in the early stages of primary fibrinolysis. In vascular surgery, the main significance of D-dimer is that when its value is increased, the patient cannot be identified with thrombotic disorders (others such as malignancy, heart attack, post-surgery, acute inflammation can also be increased), while when it is negative, venous thrombosis can be basically excluded.