D-dimer is usually used as one of the important suspected indicators of PTE and DVT in clinical practice. How did it come about?

Plasma D-dimer is a specific degradation product produced by plasmin hydrolysis after fibrin monomer is cross-linked by activating factor XIII. It is a specific marker of fibrinolysis process. D-dimers are derived from cross-linked fibrin clots lysed by plasmin. As long as there is active thrombosis and fibrinolytic activity in the body's blood vessels, D-dimer will increase. Myocardial infarction, cerebral infarction, pulmonary embolism, venous thrombosis, surgery, tumor, disseminated intravascular coagulation, infection and tissue necrosis can lead to elevated D-dimer. Especially for the elderly and hospitalized patients, due to bacteremia and other diseases, it is easy to cause abnormal blood coagulation and lead to increased D-dimer.

D-dimer mainly reflects fibrinolytic function. Increased or positive seen in secondary hyperfibrinolysis, such as hypercoagulable state, disseminated intravascular coagulation, renal disease, organ transplant rejection, thrombolytic therapy, etc. Determination of the main factors of the fibrinolytic system is of great significance for the diagnosis and treatment of diseases of the fibrinolytic system (such as DIC, various thrombus) and diseases related to the fibrinolytic system (such as tumors, pregnancy syndrome), and monitoring of thrombolytic therapy.

Elevated levels of D-dimer, a fibrin degradation product, indicate frequent fibrin degradation in vivo. Therefore, fibrous D-dimer is a key indicator of deep vein thrombosis (DVT), pulmonary embolism (PE), disseminated intravascular coagulation (DIC).

Many diseases cause activation of the coagulation system and/or fibrinolytic system in the body, resulting in an increase in the level of D-dimer, and this activation is closely related to the stage, severity and treatment of the disease, so in these diseases Detection of the level of D-dimer can be used as an evaluation marker for disease staging, prognosis and treatment guidance.

Application of D-dimer in deep vein thrombosis

Since Wilson et al. first applied fibrin degradation products for the diagnosis of pulmonary embolism in 1971, the detection of D-dimer has played a huge role in the diagnosis of pulmonary embolism. With some highly sensitive detection methods, negative D-dimer Body value has an ideal negative predictive effect for pulmonary embolism, and its value is 0.99. A negative result can basically rule out pulmonary embolism, thereby reducing invasive examinations, such as ventilation perfusion scanning and pulmonary angiography; avoid blind anticoagulation therapy.D - The concentration of dimer is related to the location of the thrombus, with higher concentrations in the major branches of the pulmonary trunk and lower concentrations in the minor branches.

Negative plasma D-dimers rule out the possibility of DVT. Angiography confirmed DVT was 100% positive for D-dimer. Can be used for thrombolytic therapy and heparin anticoagulation medication guidance and efficacy observation.

D-dimer can reflect changes in thrombus size. If the content increases again, it indicates the recurrence of thrombus; during the treatment period, it continues to be high, and the size of the thrombus does not change, indicating that the treatment is ineffective.