1.What is deep vein thrombosis? The so-called deep vein thrombosis usually refers to the thrombosis that occurs in the deep veins of human body. The substances that form and dissolve blood clots are produced in the blood of human body all the time. These two substances are indispensable to maintain the normal life of the body. If there is less thrombus-forming substance, the blood flow will not stop after an injury, which can be life-threatening in serious cases. If there is less substance to dissolve the blood clot, it will easily produce blood clots and cause harm to the body. There are three major risk factors for venous thrombosis: slow blood flow, damage to the vein wall and the hypercoagulable state of the blood. Due to the reason that the human body walks upright, the lower extremity veins return to the heart blood flow more slowly, so the lower extremity deep vein thrombosis is the most common. 2.Who is prone to deep vein thrombosis? There are many causes of deep vein thrombosis, the common ones are as follows. (1) Malignant tumor, oral contraceptives, pregnancy and postpartum – these people are usually in the state of blood hypercoagulation, and thrombosis has occurred. (2) Prolonged bed rest, long distance travel – blood flow is slow. (3) Trauma, surgical factors – human trauma caused by surgery and car accidents can cause human physiological functions to be in a very disturbed state for a short period of time, making it easy for deep vein thrombosis to occur. (4) Some hereditary diseases. For example, some people are born with less anti-thrombotic substances in their bodies and have already developed thrombosis, and these patients usually develop thrombosis at a very young age. Deep vein thrombosis is usually the result of a combination of causes. For example, a woman who has just given birth to a child, a patient who has had a stroke and is bedridden for a long time is prone to thrombosis. 3, prevention of deep vein thrombosis There is a famous saying in Chinese medicine, “A good doctor treats the untreated disease, a Chinese doctor treats the treated disease, and a lower doctor treats the last disease. This saying is very philosophical. The best way to treat a disease is to prevent it from happening. “Life is exercise” is very useful to prevent blood clots. For example, after giving birth to a child, women should get out of bed frequently, and if they cannot get out of bed, they should ask their family members to help them move their legs frequently, for 1 to 5 minutes every 2 hours to prevent the formation of deep vein thrombosis in the lower limbs. This is also true for patients who are bedridden for a long time due to surgery or other reasons. However, patients with leg or pelvic fractures or other reasons requiring lower extremity braking should strictly follow the doctor’s instructions to avoid damage. The high pace of life in modern society has significantly reduced the amount of human exercise, making some healthy people also suffer from deep vein thrombosis. When you travel long distances by airplane or train, you should get up every 2 hours or so to move around. When you work in front of the computer, don’t forget to get up and move around often. I met a lot of healthy people who suffer from lower limb DVT due to long time fixed in one posture in the clinic, such as long-distance bus drivers, travelers and IT people. 4.Harm of deep vein thrombosis to human body The vascular system of human body is divided into venous system and arterial system. Arterial blood contains high concentration of oxygen, which is pumped out by the left heart to supply the body with oxygen and other nutrients. The venous blood is recycled by the body and pumped into the lungs through the right heart – the pulmonary artery for the exchange of oxygen and carbon dioxide, etc. to make the blood nutritious again. Oxygen is extremely important to people, and brain death can occur within 5 minutes of oxygen deprivation in the average person. The most fatal danger of deep vein thrombosis is that a large clot is dislodged from the vein wall and pumped into the pulmonary artery through the right heart, thus blocking the pulmonary artery and causing a fatal pulmonary embolism. Large pulmonary artery embolism will prevent venous blood from entering the pulmonary circulation for blood oxygen exchange, resulting in death due to lack of oxygen. This is the so-called disease in the limbs, the danger is in the lungs. Only when a large thrombus is dislodged and blocks the main pulmonary artery will it cause a fatal pulmonary embolism. Because the body’s compensatory function is very strong, embolism of smaller branches of the pulmonary artery is usually not fatal. Other hazards such as causing discomfort such as swelling and pain in the affected limb are generally not fatal. This is the reason why the doctor seems not to be particularly concerned about the swollen limb when the patient is seen, but keeps asking the patient if he has any cough, chest tightness and other discomfort. 5.Treatment of deep vein thrombosis (1) Acute deep vein thrombosis Acute deep vein thrombosis generally refers to thrombosis with an onset time of less than 2 weeks. The timing of acute DVT treatment is very important, the earlier the treatment, the better the effect. If a thigh is suddenly found to be swollen, seek immediate medical attention and do not engage in strenuous activity to avoid pulmonary embolism caused by the dislodgement of the newly created thrombus! If there is no contraindication to thrombolytic therapy, catheter thrombolysis should be pursued. This treatment method has been used on a large scale for less than 20 years and has a better efficacy than the traditional surgical removal of the clot from the vein. Surgical thrombectomy is rarely used nowadays because it can damage the intima of the vein and the valve of the vein, and is prone to thrombosis and poor recovery of limb function after surgery. For patients with contraindications to thrombolytic therapy, such as deep vein thrombosis complicated by cerebral hemorrhage, they should be treated by experienced vascular specialists. (2) Treatment of chronic deep vein thrombosis. Chronic thrombosis is longer and generally no longer suitable for thrombolytic therapy, but anticoagulation therapy is needed, generally anticoagulation therapy for more than 3 months, and when to stop the specific drug should be under the guidance of doctors. (3) What is an intravenous filter and what kind of patients need to put it? A venous filter generally refers to a vena cava filter, which is usually placed in the inferior vena cava. It is a metal screen placed in the inferior vena cava to prevent fatal pulmonary embolism caused by dislodged deep vein thrombosis. The upper veins of the human body are thin and even if a thrombus is dislodged it rarely causes a fatal pulmonary embolism, so filters placed in the superior vena cava are very rare in clinical practice. This screen can effectively intercept larger clots and prevent fatal pulmonary embolism; however, some smaller clots cannot be effectively intercepted. Of course, small clots do not usually cause fatal pulmonary embolism. A venous filter does not treat pulmonary embolism or dissolve the clot, but is only a device to prevent fatal pulmonary embolism. (4) The side effects of placing the filter are so far very limited in human knowledge of itself. Most of the drugs or devices or treatments used to treat diseases nowadays have some side effects, and some of them are very serious. More importantly, each person is very different, and the same treatment method has good therapeutic effects for some people, but for others there are serious side effects, which are often unpredictable. Venous filters are no exception. (5) Long-term medication for DVT Generally, patients with DVT need to take medication for a longer period of time. The more commonly used drugs are warfarin and rivaroxaban. There is no significant difference in the final efficacy between the two. The former has a long duration of application, exact efficacy, and is very inexpensive; the disadvantages are more side effects of bleeding, the need for frequent blood tests to adjust the drug dosage during the use of the drug, and more dietary and drug contraindications, as specified in the drug instructions. The latter has been used for a shorter period of time and is a new type of drug. The advantage is that the side effects of bleeding are smaller and frequent blood tests are not needed; the disadvantage is that it is expensive. Patients should choose the treatment plan according to their own economic conditions, and should not think that what is expensive is necessarily effective. It is important to emphasize that you must live a regular life and take your medication on time and in quantity when you are on long-term medication. The medication is only part of the treatment plan prescribed by your doctor, but the precautions in your life and changes in your diet are equally important.