Deep vein thrombosis of the lower extremities is a disease in which blood clots abnormally in the lumen of the deep veins of the lower extremities, blocking the lumen of the veins and leading to impaired venous return.
(A) Disease characteristics.
1. The disease can have causative factors, especially in patients who are bedridden for a long time, limb trauma, patients after major surgery (common ones are abdominopelvic surgery, joint replacement, spinal surgery), blood hypercoagulation state (long-term oral contraceptives, malignant tumor, nephrotic syndrome, pregnancy), and those who have venipuncture, intravenous placement or irritating drug infusion in the affected limbs. Iliac vein compression syndrome (cockette syndrome).
2.The main manifestation is sudden pain, swelling and superficial venous dilatation in one limb, especially in the left side, sometimes accompanied by systemic symptoms, such as fever, rapid pulse and elevated WBC. In severe cases, the affected limb is highly swollen and painful, and the femoral cyanosis may appear, that is, the artery is strongly spasmed due to extensive deep vein thrombosis, which is clinically manifested as severe pain in the affected limb on the basis of limb swelling, skin temperature drops, skin is dark purple, and arterial pulsation of the affected limb is weakened or disappears. The systemic reaction is obvious, and even shock and venous gangrene of the limb may occur and require amputation.
3. If the thrombus is dislodged, pulmonary embolism can be formed, resulting in cough, chest pain, dyspnea, hemoptysis, cyanosis, shock, and even sudden death in severe cases. This is a serious complication of the disease, which requires high attention to active prevention.
4.Late thrombosis mechanization often leaves venous insufficiency, superficial varicose veins, pigmentation, ulceration, swelling, etc., which is called post-deep vein thrombosis syndrome.
5.DVT includes lower limb and upper limb deep vein thrombosis, clinical mainly for lower limb deep vein thrombosis, the clinical manifestations and treatment principles of thrombosis in both parts are basically the same.
(B) Subtypes.
1, peripheral type: also known as calf muscle plexus thrombosis. The clinical manifestations of these patients may not be obvious, only mild swelling of the affected limb and mild pain in the calf, and Homans sign may be positive. (i.e. straight leg extension ankle test: when the patient is asked to straighten the lower limb and dorsiflex the ankle joint during the examination, the lesioned vein in the calf muscle is stimulated due to the passive elongation of the gastrocnemius and flounder muscles, causing deep pain in the calf muscle, which is positive.)
2. Central type: also called iliofemoral vein thrombosis. The swelling and heaviness of the affected limb is obvious, and there may also be mild pain in the affected limb. This type has a higher risk of pulmonary embolism caused by dislodged thrombus, and needs to be prevented.
3.Mixed type: Thrombosis of all the deep veins of the lower limbs including the muscular plexus of the calf. If it is caused by the development of peripheral type, the initial manifestation is mild, and then suddenly swelling. If it is caused by the expansion of central type, the clinical performance is not easy to distinguish from central type.
(C) Early diagnosis and importance of lower limb deep vein thrombosis.
Venous thrombosis is like cement, which can be flushed out early, but once it forms a clot, it cannot be dissolved. Although this analogy is not very appropriate, it is true that venous thrombosis starts to partially mechanize after tens of hours of formation. A mechanized vein clot is very difficult to resolve by thrombolysis. Surgical retrieval is also very unsuitable, as the mechanized thrombus is tightly adhered to the vein wall and forcible retrieval can lead to damage to the vein wall resulting in more extensive thrombosis. Therefore, early diagnosis is very important.
(d) How to diagnose early lower extremity deep vein thrombosis.
Although there are no obvious symptoms of early deep vein thrombosis, for experienced doctors, they can still find some clues through careful physical examination. For example, pain in the deep part of the calf when squeezing the calf stomach often indicates calf vein thrombosis (medically known as Homan’s sign). This is due to the sterile inflammation of the surrounding tissues during venous thrombosis, and by the same token, painful pressure at the base of the thigh often indicates femoral vein thrombosis. Of course, blood D2 aggregates are tested as early as possible once there is a suspicion of deep vein thrombosis. Color Doppler ultrasonography allows direct visualization of the diameter of the vein and the lumen, and can provide insight into the size of the thrombus and its location for a definitive diagnosis. In this way, most cases of deep vein thrombosis can be diagnosed early.
(E) Treatment modalities and indications of lower limb deep vein thrombosis.
1.Bed rest and elevation of affected limb: bed rest for 1~2 weeks, avoid activities and forceful defecation, avoid squeezing and massaging the thrombus formation site to avoid dislodging the thrombus. Elevate the affected limb so that the lower limb is higher than the heart level, which can improve venous return and reduce edema and pain. When you start to get out of bed, you need to wear elastic stockings or use elastic bandage.
2.Anticoagulation therapy: anticoagulation therapy is an important method to treat deep vein thrombosis (DvT) by reducing or eliminating the coagulation of blood with drugs. It does not dissolve the formed thrombus, but can prevent the growth, reproduction and reoccurrence of thrombus by prolonging the clotting time, which is conducive to the autolysis of thrombus and promotes the more rapid re-tubulation of thrombosed veins. It is the currently accepted treatment for DvT and prevention and treatment of pulmonary embolism (PE), and low-molecular heparin and warfarin are mostly chosen clinically.
Low-molecular heparin (commonly used as sulpiride or coxsemide) does not require routine monitoring of coagulation during treatment. The course of treatment is generally 7-10 days, but can also be longer than a month.
3. Thrombolytic therapy.
The commonly used peripheral intravenous drug delivery method has limited amount to reach the local thrombus, and the chance of systemic bleeding complications will be increased. In our department, the drug is administered through the distal superficial vein of the affected limb, such as the dorsal foot vein on the affected side, so that the drug can reach the thrombus directly and increase the local drug concentration, and the thrombolytic effect is better than that of peripheral vein. In recent years, our department has adopted the minimally invasive technique of thrombolysis through the small saphenous vein and thrombolysis through the contralateral femoral vein to treat deep vein thrombosis in the lower limbs, and achieved good results. The minimally invasive technique inserts the thrombolytic catheter into the diseased vessel through the small saphenous vein in a downstream direction or through the contralateral femoral vein in the diseased vessel, which increases the contact area between the thrombolytic drug and the thrombus and shortens the time for the thrombolytic drug to reach the thrombus site, thus greatly improving the local concentration of the thrombolytic drug at the lesion site, enabling the highly concentrated thrombolytic drug to achieve the best thrombolytic effect in the shortest time, and reducing the complications of systemic It also reduces the occurrence of systemic bleeding complications, does not damage the venous valves, and preserves the normal function of the deep vein valves to the maximum extent. The greatest advantage of this method is that it is minimally invasive and does not damage the venous valves in the direction of blood flow.
To prevent the occurrence of pulmonary embolism due to thrombus dislodgement, an inferior vena cava filter should be routinely placed before catheter thrombolysis. Postoperative treatment with elastic stockings, anticoagulation and repulsion.
4.Stent recanalization and angioplasty.
Left iliac vein compression syndrome (cockette syndrome) has now become a common disease in vascular surgery, and many scholars have now found that most patients have iliac vein stenosis greater than 60% or occlusion during the treatment of acute lower extremity deep vein thrombosis, so it is believed that iliac vein lesions play an important role in the development of lower extremity deep vein thrombosis. Using interventional techniques, I can perform venography to clarify the diagnosis. A very thin guidewire can be tapped into the left iliac vein stenosis and dilated, and then a stent can be used to hold it open. Stenting of the iliac vein is a safe and effective method for the treatment of iliac vein stenosis or occlusion and can maintain long-term patency with good results. Interventional techniques can also be used to create a small channel for the thrombus with a guidewire, which is then propped up with a stent. After opening the thrombus and slowly releasing the stent, the stent expands and squeezes the thrombus, thus eliminating the blockage and restoring blood flow. It relieves the swelling, pain, and restricted movement of the limb due to the obstruction of the vein by the thrombus and the obstruction of blood return to the vein.
5.Venous thrombectomy.
Its indications are: central thrombosis, acute thrombosis of less than 7 days duration, good general condition of the body, life expectancy greater than one year, and exclusion of contraindications. Especially if thrombolysis is ineffective and bruising of the femur occurs, the thrombus should be actively removed. The embolism can be removed directly by incising the vein wall, and now the Fogarty catheter with capsule is mostly used to remove the embolism, which is a simple procedure. If inferior vena cava filter can be placed before embolization, the risk of pulmonary embolism can be reduced.
6.Inferior vena cava filter placement.
Lower limb deep vein thrombosis is a common clinical disease, and the dislodged thrombus can produce pulmonary embolism (PE), and the dislodged large thrombus can lead to the obstruction of main branches of pulmonary artery and endanger the life. Implanting an inferior vena cava filter to stop a potentially dislodged thrombus in the inferior vena cava with a filter can effectively prevent pulmonary embolism, a serious complication. It has been proven to be a safe and effective preventive measure. Inferior vena cava filters have been commonly used in the past 20 years both at home and abroad, with approximately (30-40) million filters implanted annually in the United States.
The generally accepted indications for inferior vena cava filter implantation are:
① those with DVT formation or those with contraindications to PE anticoagulation therapy.
(ii) Those who develop PE recurrence despite adequate anticoagulant administration.
(iii) those who need to discontinue anticoagulation due to bleeding complications in the course of anticoagulation for DVT formation or PE.
④ those who have failed other inferior vena cava block procedures and have PE recurrence
(⑤) Those with massive thrombosis in the iliac or femoral veins or in the inferior vena cava.
⑥People at high risk of DVT with PE in the lower extremities. The proportion of preventive use of inferior vena cava filters is increasing year by year, mainly used in patients with severe limb trauma, pregnancy with DVT or PE, and DVT formation in the lower extremities before surgical retrieval or interventional thrombolytic therapy.
The duration of non-permanent filter placement varies depending on the type of filter and can be 3-6 weeks to a maximum of 12 weeks. Permanent filters are indicated for patients at risk of progressive or permanent thrombosis and for patients with long-term or permanent contraindications to anticoagulation therapy.
Vena cava filter placement is simple, effective, with few complications and minimal trauma. It is a painless procedure using minimally invasive techniques, inguinal puncture under local anesthesia and filter placement with a fine guidewire, leaving only needle marks after the procedure. Our department has mastered the technique of filter insertion and temporary filter retrieval. It has effectively prevented the risk of fatal pulmonary embolism (PE) for nearly 100 patients with lower extremity deep vein thrombosis. The application of this technique has provided strong support for interventional thrombectomy, pharmacological thrombolysis and stent revascularization in our department. It makes the ideal treatment of deep vein thrombosis more effective.
(vi) Treatment of post-deep vein thrombosis syndrome of lower limbs.
At the later stage, the intravenous thrombus is mechanized and recanalized, the diseased vein is narrowed, dilated and tortuous, the venous valve is destroyed, the blood in the deep vein flows backward to the superficial vein, causing the superficial vein of the lower extremity to stagnate, the venous pressure rises, the tissue is hypoxic, and finally the post-thrombosis syndrome of the deep vein of the lower extremity (Deep
Vein Thrombosis Syndrom (PTS), whose main clinical manifestations are recurrent lower limb swelling, varicose veins, skin pigmentation, eczema-like dermatitis, secondary infection and chronic venous ulcers of lower limbs. It is clinically difficult to treat, and some affected limbs are in a long-term sick state, which seriously affects the quality of life of patients.
Treatment clinically mainly includes.
Compression therapy. The effect of compression therapy is better than drug therapy. The pressure gradient in the deep veins of the lower extremities gradually increases from top to bottom, and pressure therapy is to achieve the treatment purpose by eliminating this pressure.
The commonly used compression therapy methods are classified as.
(1) Intermittent inflatable pump compression therapy.
(2) compression stockings with a pressure gradient. Intermittent inflatable pump compression therapy is more effective than compression stockings.
(3) Medication. Strictly speaking, there are no medications that are medically effective in treating the sequelae of deep vein thrombosis. However, the effect of treatment can be increased by using some drugs as an adjunct to compression therapy. Generally speaking, the medications used in clinical practice include: Avalanche, Desiccated, Mizarin, and Chinese herbal medicine. Among them, Avalanche has the best effect, is the most convenient to take and the cheapest, and is recommended by international clinical guidelines. However, the effect of treatment with drugs alone is not good, and must be combined with pressure treatment.
The treatment program developed by our department in recent years has the advantages of rapidly reducing edema, preventing lower limb ulcers, and accelerating deep vein thrombosis recanalization.
The specific program is as follows.
(1) Intermittent inflatable pump compression therapy twice a day for more than 15 minutes each time.
(2) Wearing elastic stockings with intermediate or higher compression after air pump compression therapy.
(3) Taking two tablets of Evelam orally once a day.
(4) Patients with acute thrombosis require anticoagulation therapy with heparin and warfarin. Deep vein ultrasound is repeated every 6 months for recanalization, and iliac vein CT is repeated after one year.