Clinical application of blood coagulation in cardiovascular and cerebrovascular diseases(2)

Why should D-dimer, FDP be detected in cardiovascular and cerebrovascular patients?

1. D-dimer can be used to guide the adjustment of anticoagulation strength.
(1) The relationship between D-dimer level and clinical events during anticoagulation therapy in patients after mechanical heart valve replacement.
The D-dimer-guided anticoagulation intensity adjustment treatment group effectively balanced the safety and efficacy of anticoagulation therapy, and the incidence of various adverse events was significantly lower than that of the control group using standard and low-intensity anticoagulation.

(2) The formation of cerebral venous thrombosis (CVT) is closely related to the thrombus constitution.
Guidelines for the diagnosis and management of internal vein and venous sinus thrombosis (CVST)
Thrombotic constitution: PC, PS, AT-lll, ANA, LAC, HCY
Gene mutation: prothrombin gene G2020A, coagulation factor LeidenV
Predisposing factors: perinatal period, contraceptives, dehydration, trauma, surgery, infection, tumor, weight loss.

2. The value of combined detection of D-dimer and FDP in cardiovascular and cerebrovascular diseases.
(1) D-dimer increase (greater than 500ug/L) is helpful for the diagnosis of CVST. Normality does not rule out CVST, especially in CVST with isolated headache only recently. It can be used as one of the indicators of CVST diagnosis. D-dimer higher than normal can be used as one of the diagnostic indicators of CVST (level III recommendation, level C evidence).
(2) Indicators indicating effective thrombolytic therapy: D-dimer monitoring increased significantly and then decreased gradually; FDP increased significantly and then decreased gradually. These two indicators are the direct basis for effective thrombolytic therapy.

Under the action of thrombolytic drugs (SK, UK, rt-PA, etc.), the emboli in the blood vessels are rapidly dissolved, and the D-dimer and FDP in the plasma are significantly increased, which generally lasts for 7 days. In the course of treatment, if the dosage of thrombolytic drugs is insufficient and the thrombus is not completely dissolved, D-dimer and FDP will continue to be at high levels after reaching the peak; According to statistics, the incidence of bleeding after thrombolytic therapy is as high as 5% to 30%. Therefore, for patients with thrombotic diseases, a strict drug regimen should be formulated, the plasma coagulation activity and fibrinolytic activity should be monitored in real time, and the dose of thrombolytic drugs should be well controlled. It can be seen that the dynamic detection of D-dimer and FDP concentration changes before, during and after treatment during thrombolysis has great clinical value for monitoring the efficacy and safety of thrombolytic drugs.

Why should patients with heart and cerebrovascular diseases pay attention to AT?

Antithrombin (AT) deficiency Antithrombin (AT) plays an important role in inhibiting thrombus formation, it not only inhibits thrombin, but also inhibits coagulation factors such as IXa, Xa, Xla, Xlla and Vlla. The combination of heparin and AT is an important part of AT anticoagulation. In the presence of heparin, the anticoagulant activity of AT can be increased by thousands of times. The activity of AT, so AT is an essential substance for the anticoagulant process of heparin.

1. Heparin resistance: When the activity of AT decreases, the anticoagulant activity of heparin is significantly reduced or inactive. Therefore, it is necessary to understand the level of AT before heparin treatment to prevent unnecessary high-dose heparin treatment and the treatment is ineffective.

In many literature reports, the clinical value of D-dimer, FDP, and AT is reflected in cardiovascular and cerebrovascular diseases, which can assist in the early diagnosis, condition judgment and prognosis evaluation of the disease.

2. Screening for the etiology of thrombophilia: Patients with thrombophilia are clinically manifested by massive deep vein thrombosis and repeated thrombosis. Screening for the cause of thrombophilia can be performed in the following groups:

(1) VTE without obvious cause (including neonatal thrombosis)
(2) VTE with incentives <40-50 years old
(3) Repeated thrombosis or thrombophlebitis
(4) Family history of thrombosis
(5) Thrombosis at abnormal sites: mesenteric vein, cerebral venous sinus
(6) Repeated miscarriage, stillbirth, etc.
(7) Pregnancy, contraceptives, hormone-induced thrombosis
(8) Skin necrosis, especially after using warfarin
(9) Arterial thrombosis of unknown cause <20 years old
(10) Relatives of thrombophilia

3. Evaluation of cardiovascular events and recurrence: Studies have shown that the reduction of AT activity in patients with cardiovascular disease is due to endothelial cell damage that leads to a large amount of AT being consumed. Therefore, when patients are in a hypercoagulable state, they are prone to thrombosis and aggravate the disease. The activity of AT was also significantly lower in the population with recurrent cardiovascular events than in the population without recurrent cardiovascular events.

4. Assessment of thrombosis risk in non-valvular atrial fibrillation: low AT activity level is positively correlated with CHA2DS2-VASc score; at the same time, it has a high reference value for assessing thrombosis in non-valvular atrial fibrillation.

5. The relationship between AT and stroke: AT is significantly reduced in patients with acute ischemic stroke, the blood is in a hypercoagulable state, and anticoagulation therapy should be given in time; patients with stroke risk factors should be regularly tested for AT, and early detection of patients' high blood pressure should be performed. The coagulation state should be treated in time to avoid the occurrence of acute stroke.