The contact between the prosthetic valve and blood may cause platelet coagulation and thrombus formation, and in serious cases, the thrombus may be dislodged and cause vascular embolism in various organs, leading to hemiplegia, aphasia, lower limb artery embolism, etc. It may even jam the prosthetic valve leaflet and make the valve unable to open, leading to heart failure or sudden death. Therefore, a very important aspect after valve replacement is proper anticoagulation. Insufficient anticoagulation can easily lead to thromboembolism and other bad consequences, while too much anticoagulation can lead to bleeding, mainly nasal bleeding, dental bleeding, gastric bleeding, hematuria, menstruation, etc. Therefore, anticoagulation is a life-threatening issue. Therefore, anticoagulation is a life-threatening issue, and must be handled in close cooperation with medical personnel. 1.Anticoagulants and their use: (1) At present, the main anticoagulants are warfarin. Warfarin oral anticoagulation, 60kg weight patients, generally need about 3mg of warfarin once a day (domestic 2.5mg per tablet, imported 3mg per tablet). However, the sensitivity of anticoagulants varies from patient to patient, so regular blood tests for prothrombin time and activity are required. (2) Warfarin is absorbed through the gastrointestinal tract, and more than 90% of it is bound to plasma proteins and metabolized by the liver, which starts to work 12 hours after taking the drug and reaches its peak effect in 48 hours. The plasma half-life is 44 hours. It takes 5-7 days for the anticoagulant to reach steady state after taking once a day, so the maintenance dose should be changed every 5-7 days. The prothrombin time returns to normal 5-6 days after discontinuation of the drug. In severe bleeding, vitamin K can be used to counteract the effects of warfarin. The prothrombin time returns to normal after 12-24 hours after oral vitamin K. The prothrombin time returns to normal after only 3-5 hours after intravenous vitamin K. (3) Warfarin should be used for the first time 24-48 hours after the removal of pericardial and mediastinal drains, generally the first dose is 2 tablets (5mg), later the dose is adjusted according to the dynamic changes of prothrombin time and activity. (4) The normal value of prothrombin time is 12-14 seconds, and the activity is above 80%. After valve replacement, the prothrombin time should be maintained at 1.5-2.0 times the normal value (usually 18-24 seconds) or an activity of 35%-45%. The WHO (World Health Organization) now advocates an international standard for oral anticoagulant testing, the International Standard Ratio (INR). The INR should be controlled between 2 and 2.5 after valve replacement. (5) If the prothrombin time is more than 2 times normal or the activity is less than 30%, the dosage can be reduced by 1/4 or 1/8; if the activity is less than 25% or the prothrombin time is higher than 30 seconds, the dosage can be stopped once and adjusted after the next day’s laboratory test. Prothrombin time or activity should be measured 4-5 days after each dose adjustment. (6) If the dose is too high, pay attention to close observation. If there are signs of bleeding such as nasal obstruction, bleeding from teeth and eyes, hematuria, black stool, intra-abdominal bleeding manifestation (abdominal pain), intracranial bleeding manifestation (coma), etc., go to hospital for laboratory test immediately, reduce or stop taking warfarin, and if necessary, inject vitamin K against, or transfuse blood, plasma, platelets, etc. (7) If there is blunted valve tone, heart failure, hemiparesis, aphasia, painful arterial embolism of the limbs, etc., review the prothrombin time and activity, and increase the anticoagulant dose if thrombosis is diagnosed. (8) Generally, the maintenance dose of warfarin is about 3mg, but there are great differences among individuals. If the patient cannot achieve satisfactory anticoagulation effect after using 6mg of warfarin, it indicates that the patient is not sensitive to warfarin and other anticoagulants should be added, such as using aspirin, etc., 1-2 tablets should be added daily, and the prothrombin time and activity should be monitored. (9) During the period of hospitalization, the time or activity of prothrombin can be determined by the doctor according to the need, and after a period of time to find the appropriate maintenance amount, it can be changed to once every 3-5 days; if the measurement is still stable after 3-4 times, it can be changed to once a week; if the measurement is stable after 3-4 times, it can be extended to once every half month. And so on to 1 month, 3 months or half a year. Even if the conditions are poor, it should be measured once every six months to prevent thromboembolism or bleeding. If the dose is adjusted, it should be measured again within 4-5 days, and after it is stabilized, the interval of measurement should be extended appropriately. 2, the effect of food, drugs and other diseases on the anticoagulant effect: (1) the effect of food: foods rich in vitamin k can reduce the effect of anticoagulants. The following foods are rich in vitamin K. The content of vitamin K per 100 g of dry food is 4.4 mg of spinach, 3.2 mg of cabbage, 3.0 mg of cauliflower, 2.8 mg of peas, 0.8 mg of carrots, 0.6 mg of tomatoes, 0.16 mg of potatoes, 0.8 mg of pork liver, and 0.8 mg of eggs. Although the above foods are rich in vitamin K, as long as a balanced diet and regular measurement of prothrombin time and activity, it is possible to adjust the dose of anticoagulants, and there is no need to deliberately favor or prohibit certain foods. (2) The effect of drugs: drugs that enhance the effect of anticoagulants include: ① broad-spectrum antibiotics, which can reduce the intestinal production of vitamin K; ② aspirin, Antomin, sulforaphane, propofol, etc. can compete with warfarin for plasma protein binding sites, which increases the free blood concentration of the latter; ③ liquid paraffin can reduce the absorption of vitamin K; ④ chloramphenicol, metronidazole, meprobamate, ethanol, etc. can inhibit the degradation of (4) chloramphenicol, metronidazole, metamizole, ethanol, etc. can inhibit the enzymes that degrade warfarin, resulting in a relative increase in the concentration of warfarin; (5) phenytoin sodium, toluene, and sulfobutylurea have the same metabolic pathway; (6) aspirin and acetaminophen have anticoagulant synergistic effects; (7) salicylates, pautazone, chlorpromazine, and diphenhydramine have the effect of interfering with platelet function; (8) quinidine, thyroxine, phenylethylguanidine, and antamine have the effect of strengthening anticoagulants. Decrease the anticoagulant effect of drugs: ① abciximide in the intestinal tract can be combined with anticoagulants; ② hypnotics, rifampin, ashwagandha has the effect of increasing the activity of enzymes in the liver and accelerating the metabolism of warfarin; ③ estrogen and oral contraceptives can increase the content of clotting factors in the blood. (3) The effect of other diseases: diarrhea, vomiting can affect the absorption of drugs, heart failure or primary liver disease can reduce the synthesis of vitamin K, while reducing the metabolic rate of warfarin, the dosage of warfarin should be reduced. 3, post-transplantation bleeding and thromboembolism treatment: (1) mild bleeding, such as skin bruising, tooth bleeding, according to the prothrombin time and activity measurement results to reduce the amount of warfarin (reduce 1/4 or 1/8). (2)In case of obvious bleeding, such as rhinorrhea and hematuria, warfarin can be stopped for 1~2 days and the prothrombin time and activity can be measured in hospital immediately and adjusted gradually. (3) For severe bleeding, such as hemoptysis, vomiting blood, intracranial hemorrhage, vitamin K 120mg should be injected intravenously immediately and observed for 1~2 days after the bleeding stops, and then re-anticoagulated. (4) In critically ill patients with anemia, whole blood, fresh plasma or coagulation factors should be used to enhance coagulation function. (5) In normal women, if the menstrual flow is not much, the anticoagulant should be unchanged; if the menstrual flow is mildly increased, the amount of warfarin can be reduced; if there is a lot of bleeding, vitamin K can be injected to stop the bleeding; if the menstrual flow is irregular and persistent, menstrual regulating drugs should be taken; in rare cases of heavy bleeding, hysterectomy is required. 4.Whether you can have children after valve replacement: rheumatic heart disease patients can get married after heart function and physical strength recover very well after valve replacement. After marriage, we should pay attention to maintain good heart function. Female patients should use contraception after marriage because pregnancy and childbirth will increase the burden on their heart and may cause hemorrhage during childbirth due to anticoagulation, which may be life-threatening. However, if you become pregnant due to insistence on childbirth, you should go to a central hospital with cardiac surgery and decide whether to continue the pregnancy under the guidance of a doctor. Heparin has a large molecular weight, and animal and in vivo experiments have shown that it cannot pass through the placenta and has no teratogenic effect, while other oral anticoagulants may pass through the placenta and cause malformation in the baby.