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【Pregnancy puerperal vte(2/2)】

Question 4: Clinically suspicious deep venous thrombosis, what auxiliary examinations are needed for pulmonary embolism?

【Recommended and consensus】

4?1   Vascular compression ultrasound examination is preferred when suspicious deep venous thrombosis. (Evidence level: Level B)

4?2                                                             �

Vascular compression ultrasound examination (CUS) is the first choice when suspicious deep vein thrombosis. The veins that can be examined by vasopressor ultrasound examination include proximal vein (such as jugular vein, common femoral vein, femoral vein and popliteal vein) and distal vein (such as peroneal vein, anterior tibial vein, posterior tibial vein and intermuscular vein). Interpretation of results of vasopressor ultrasound examination:

(1) Positive: the vein loses its closure;

(2) Negative: All veins can be completely closed;

(3) Suspicious: Unsure whether there is deep venous thrombosis.

If the first ultrasound examination result is negative or suspicious, but is highly suspected in clinically, the examination should be conducted on the 3rd and 7th day, or other imaging examinations such as magnetic resonance venous angiography (MRV), venogram, etc.

When suspected acute pulmonary embolism, electrocardiogram is preferred and chest X-ray examination is the first choice. The electrocardiogram in about 40% of pregnant women with acute pulmonary embolism shows abnormalities (the most common is T-wave inversion, followed by right bundle branch block). Chest X-ray examination lacks sensitivity and specificity in the diagnosis of pulmonary embolism, but can show lung infection, pneumothorax, etc., which mainly provides support for clinical exclusive diagnosis. Diagnostic examinations of pulmonary embolism include nuclide pulmonary ventilation/perfusion (V/Q) scan and CT pulmonary angiography (CTPA).

Question 5:D?What is the value of dimers in screening and diagnosing venous thromboembolic disease during pregnancy and puerperal periods?

【Recommended and consensus】

5?1    D?dimer is not recommended as a reference indicator for screening, diagnosis, prevention or treatment of venous thromboembolic diseases in pregnant women. (Evidence level: Expert consensus)

The non-pregnancy D-dimer level in the normal range is helpful for the diagnosis of venous thromboembolic disease. However, since the D-dimer level generally increases during pregnancy, the value of using the D-dimer index to exclude venous thromboembolic disease during pregnancy and puerperal period is very limited. Research in my country also found that the plasma D-dimer level during pregnancy and early puerperal period is higher than that of normal people, and the plasma D-dimer level in early puerperal period is significantly higher than that in late pregnancy, and the postpartum time is prolonged, which shows a downward trend.

It is shown that the recommended plasma D-dimer reference value range (≤0.5      mg/L) for screening for venous thromboembolic disorders in non-pregnant populations is not suitable for women during pregnancy and childbirth. Therefore, D-dimer is not recommended as a screening or diagnostic indicator for venous thromboembolic disorders in pregnant women; it is not recommended to use elevated D-dimer levels as the basis for the prevention and treatment of venous thromboembolic disorders. However, it is still necessary to monitor D-dimer levels during the treatment of patients with clearly diagnosed venous thromboembolic disorders.

Question 6: Is it safe for mothers and children to undergo venous thromboembolic imaging tests during pregnancy?

【Recommended and consensus】

6?1     When a suspected pulmonary embolism requires relevant radioimaging examination, corresponding informed information should be made. (Evidence level: Expert consensus)

In the imaging examinations for diagnosing pulmonary embolism, chest X-ray, V/Q scan and CTPA are all radioactive tests. Low-dose radiation (<50     mSv) will not increase fetal mortality or teratogenicity. The exposure dose of fetals is <0.01    mSv, 0.1~0.5     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.66     mSv, 0.01~0.6 The exposure dose of female ** tissue is <1.0    mSv, 0.5~2.5     mSv. The consequences of misdiagnosis of pulmonary embolism may be very serious. Therefore, for pregnant women with clinically suspected pulmonary embolism, it is recommended to actively conduct relevant diagnostic examinations on the basis of informing the mother and child in detail about the potential risks.

The iodine in the contrast agent required for CT examination can enter the fetal circulation and amniotic fluid through the placenta, but there has been no reported teratogenic risk, and no adverse effects on the fetus after the thyroid absorption of iodine contrast agent have been observed. Its secretion in the *** and the gastrointestinal absorption rate of neonatal babies is <1%. Therefore, it is relatively safe to use iodine contrast agents for women with indications in pregnancy and puerperal periods.

3. Prevention of venous thromboembolic disease during pregnancy and puerperal period

Question 7: What are the preventive measures for venous thromboembolic disease during pregnancy and puerperal periods?

【Recommended and consensus】

7?1 Dynamic evaluation of high-risk factors is an important means to prevent the occurrence of venous thromboembolic disease during pregnancy and puerperal periods. (Evidence level: Expert consensus)

7?2    Health education, physical methods are the first choice for preventing venous thromboembolic diseases during pregnancy and puerperal periods. (Evidence level: Expert consensus)

7?3    Pregnant and childbirth who have high-risk factors for venous thromboembolic disease during pregnancy and puerperal period should reasonably use preventive anticoagulant drugs. (Evidence level: Expert consensus)

The evaluation of risk factors for venous thromboembolic disease is the key to prevention. Compared with non-pregnancy periods, there are more and more complex risk factors for venous thromboembolic disease during pregnancy and postpartum periods. Although the risk assessment strategy for pregnant women has not been effectively verified, it is still recommended to evaluate the high-risk factors for venous thromboembolic disease for each pregnant woman, and adopt different prevention strategies based on the evaluation results to reduce the occurrence of deep venous thromboembolic disease and reduce pregnancy caused by venous thromboembolic disease.

Maternal death and adverse pregnancy outcomes. It is particularly important to emphasize here that the pregnancy and puerperal period are relatively long periods. As the pregnancy progresses and the puerperal period enters the puerperal period after delivery, the risk of venous thromboembolic disease will also change with the physiological changes and pathological conditions of the pregnant woman. Therefore, the risk of venous thromboembolic disease should be dynamically evaluated. It is recommended to evaluate it at the following nodes: when the first prenatal examination occurs, new pregnancy complications or complications appear, during hospitalization, and after delivery.

Health education with relevant knowledge is one of the effective measures to prevent venous thromboembolic disease. The education content includes informing pregnant women to eat reasonably, conducting pregnancy exercise regularly, avoiding dehydration, avoiding long-term bed rest or braking, encouraging early postoperative activities, identifying risk factors and early symptoms of venous thromboembolic disease, etc. The following physical methods can be used as preventive measures and auxiliary treatment methods for venous thromboembolic disease:

(1) Dorsiflexion of the foot;

(2) Anti-thrombosis gradient compressed elastic stockings: suitable for pregnant women who can move freely before or during puerperal period, or wear gradient compressed elastic stockings while receiving drug anticoagulation;

(3) Intermittent inflatable and pressurized device or sole venous pump: It is suitable for pregnant women who are in bed for a long time. There are high-risk factors for venous thromboembolic disease, especially those who have cesarean section. It is recommended to use it until at least the second day after delivery. Women who are not suitable for wearing gradient pressurized elastic stockings can consider using it all night.

However, if you are combined with severe peripheral artery disease or ulcer, recent skin transplantation, peripheral artery bypass transplantation, severe leg edema or pulmonary edema caused by congestive heart failure, allergies to known materials or products, severe local leg diseases (such as gangrene, dermatitis, untreated infectious incisions, fragile "paper-like" skin), etc., it is not appropriate to use the above physical methods. Pregnant and childbirth who have high risk factors for venous thromboembolic disease during pregnancy and postpartum period, the rational application of anticoagulant drugs can effectively prevent the occurrence of thromboembolic diseases. Drugs to prevent venous thromboembolic disease include ordinary heparin (UFH), low molecular weight heparin (LMWH), warfarin, direct 10a factor inhibitors, etc. Warfarin is a

Vitamin K antagonists are generally limited to anticoagulation treatment for pregnant women after cardiac mechanical valve replacement. Direct factor 10a inhibitors can pass through the placenta and are prohibited during pregnancy. Both ordinary heparin and low-molecular heparin do not pass through the placenta barrier. Because of its short half-life and high risk of bleeding, ordinary heparin is generally not used for the prevention of venous thromboembolic diseases. Low-molecular heparin mainly inhibits thrombosis through the action of the anticoagulant active factor 10a (F10a). While achieving effective anticoagulant effect, it can reduce adverse reactions such as bleeding caused by ordinary heparin, and is more safe. Therefore, low-molecular heparin is recommended as the first choice anticoagulant to prevent venous thromboembolic diseases during pregnancy and puerperal periods.

Question 8: How to implement preventive measures for venous thromboembolic disease during pregnancy and puerperal periods?

【Recommended and consensus】

8?1     Develop a screening table for high-risk factors for obstetric venous thromboembolic disease in this unit to guide the implementation of prevention measures for venous thromboembolic disease in pregnant women. (Evidence level: Expert consensus)

Including various risk factors and formulating corresponding evaluation tables can evaluate the risk of venous thromboembolic disease more comprehensively and objectively, and can also provide guidance on prevention strategies and stratified management of venous thromboembolic diseases during pregnancy and puerperal periods. However, the relevant domestic research data are currently scattered, and there is still a lack of high-level evidence-based medical evidence for the use of anticoagulant drugs in Chinese pregnant women to prevent venous thromboembolic diseases. Therefore, this consensus would like to draw on relevant domestic and foreign guidelines and combine the high-risk factors of venous thromboembolic disease to formulate implementation guidelines for preventive measures for pregnancy and puerperal periods for clinical reference.

For those who fail to meet the indications for preventive medication after evaluation, non-drug methods are recommended to prevent venous thromboembolic disease; for those who meet the indications for preventive medication after evaluation, non-drug methods and anticoagulants are recommended to use combinations of non-drug methods and anticoagulants to prevent venous thromboembolic disease; for pregnant women who have high risk factors for bleeding and venous thromboembolic disease, non-drug methods are recommended to use non-drug methods to prevent bleeding until the risk of bleeding is reduced, and then evaluate whether combined anticoagulants are needed to prevent venous thromboembolic disease.

4. Treatment of venous thromboembolic disease during pregnancy and puerperal period

Question 9: What are the treatment measures for venous thromboembolic disease during pregnancy and puerperal periods?

【Recommended and consensus】

9?1      Once the venous thromboembolism during pregnancy and puerperal period is diagnosed, multidisciplinary consultations should be initiated as soon as possible and comprehensive treatment measures based on anticoagulation treatment should be taken. (Evidence level: Expert consensus)

After clinically suspicious or confirmed venous thromboembolism during pregnancy and puerperal periods, relevant specialties should be consulted for multidisciplinary consultation, including vascular disease specialties, respiratory, imaging, ICU, neonatal department, etc. Embolization of the intracranial venous system also requires consultation in the neurology department to jointly evaluate the condition, formulate diagnosis and treatment plans, determine whether to continue pregnancy or terminate pregnancy, the timing of termination of pregnancy, and subsequent treatment plans to ensure the safety of mother and child. The main measures include: anticoagulation therapy, physical therapy, percutaneous vena cava filter (IVCF), thrombolytic treatment, etc.

1. Anticoagulant therapy: Multidisciplinary physicians jointly formulate anticoagulant drugs and their dosage selection based on the time of thrombosis and high-risk factors. At this time, the use of anticoagulant drugs is to treat the thrombus that has occurred, and the dosage will be greater than the dose of preventive drugs. Therefore, medication should be taken under the guidance of multidisciplinary consultation opinions, and the side reactions related to anticoagulant should be closely monitored.

2. Physical treatment: including dorsiflexion of the foot, gradient pressurized elastic stockings, intermittent inflatable pressurization devices or sole venous pumps, etc. See the specific methods for 7.

3. Percutaneous vena cava filter: The use of percutaneous vena cava filter in pregnancy is limited, and there are few related research. We need to weigh the pros and cons and make careful decisions.

4. Thrombolytic treatment: At present, there are only cases of thrombolytic treatment during pregnancy, and it may increase the risks of major bleeding and intracranial bleeding. Therefore, it is not recommended to use it in patients with acute pulmonary embolism with deep venous thrombosis and hemodynamic stability. It can only be considered in patients with acute pulmonary embolism with hemodynamic unstable acute pulmonary embolism.

Question 10: How to determine the activation and timing of discontinuation of anticoagulants?

【Recommended and consensus】

10?1    The activation and discontinuation of anticoagulants based on the high-risk factors and time of occurrence, timing of delivery and method of delivery, whether there are side effects of drugs, etc. (Evidence level: Expert consensus)

The activation of anticoagulants during pregnancy depends on the extent of risk factors and the time of occurrence. Anticoagulants need to be discontinued during use:

(1) Anticoagulant-related side reactions occur during medication use (bleeding in different parts, thrombocytopenia, liver function abnormalities, allergic reactions, etc.);

(2) Signs of temporary labor occur;

(3) Planned delivery: Disable low-molecular heparin for at least 12 to 24 hours before planned delivery.

The timing of re-initiating low-molecular heparin during the puerperal period depends on the number and type of risk factors of venous thromboembolic disease. Before activation, the risk of venous thromboembolic disease must be re-evaluated and the risk of bleeding must be ruled out. The specific implementation methods of low-molecular heparin during the puerperal period and the timing of postpartum discontinuation are referred to Table 1.

Question 11: How to evaluate the risk of venous thromboembolic disease in pregnancy and puerperal periods in patients with hereditary thromboembolism?

【Recommended and consensus】

11?1   The occurrence of venous thromboembolic disease during pregnancy and puerperal periods in patients with hereditary thromboembolic disease is related to the type of risk factors and whether there is a family history of venous thromboembolic disease. (Evidence grade: B    )

The occurrence of hereditary thrombopathy is related to race, and it is rare in this type of patient in my country. Relevant laboratory test indicators mainly include antithrombin, Leiden mutation (FVL), prothrombin gene G20210A mutation, protein C or protein S, etc. According to the above indicators, hereditary thrombopathy can be divided into two types: high-risk and low-risk. High-risk hereditary thrombopathy mainly includes antithrombin deficiency, homozygous mutation of FVL, homozygous mutation of prothrombopathy G20210A, heterozygous mutation of FVL, heterozygous mutation of prothrombopathy G20210A, heterozygous mutation of FVL, heterozygous mutation of prothrombopathy G20210A, and protein C or protein S deficiency; while low-risk hereditary thrombopathy mainly includes heterozygous mutation of FVL, heterozygous mutation of prothrombopathy G20210A, etc.
Chapter completed!