Lower extremity deep vein thrombosis is a common clinical venous reflux disorder, which is easily complicated by dangerous pulmonary embolism in the acute stage and often has sequelae such as varicose veins, limb swelling, calf skin pigmentation and ulcers in the later stage, which seriously affects the quality of work life of patients. In recent years, the incidence has a trend of increasing year by year.
Etiology.
The three major factors of thrombosis, stagnant venous blood flow, venous wall damage and blood hypercoagulation state. In recent years, through a large number of clinical and experimental observations, not only the specific content of each factor, but also the test method can be confirmed. However, among the three factors mentioned above, any single factor is often not sufficient to cause the disease; it must be a combination of various factors, especially slow blood flow and hypercoagulable state, that may cause thrombosis.
Clinical manifestations.
The most common major clinical manifestation is the sudden swelling of one limb. Patients with deep vein thrombosis of the lower extremity experience localized pain that increases with walking. In mild cases, the localized heaviness is only felt, and the symptoms are aggravated when standing.
Physical examination has the following features.
(1) Swelling of the affected limb.
The degree of development of swelling needs to be based on accurate daily measurement with tape measure and comparison with the thickness of the healthy lower limb to be reliable, relying solely on visual observation is unreliable. This sign is of high value in confirming the diagnosis of deep vein thrombosis, which often leads to increased tissue tension when the swelling of the lower leg is severe.
(2) Compression pain.
Pressure pain is often present at the site of venous thrombosis. Therefore, the lower extremities should be examined for calf muscles, N fossa, adductor canal and femoral vein below the groin.
(3) Homans sign.
When the foot is bent sharply to the dorsal side, it can cause pain in the deep calf muscle. Homans’ sign is often positive in the case of deep calf vein thrombosis. This is caused by the passive extension of the gastrocnemius and flounder muscles, which stimulates the thrombosed vein in the calf.
(4) Superficial venous dilatation.
Deep venous obstruction can cause elevated superficial venous pressure, and superficial venous dilatation is seen 1 or 2 weeks after onset.
The onset of the disease is rapid, with pain, tenderness, and significant swelling of the entire affected limb within a few hours. There is significant pressure pain along the femoral triangle and the internal femoral canal. In severe cases, the skin color of the affected limb is cyanotic, called “femoral cyanosis”, suggesting extensive thrombosis of the deep and superficial veins of the affected limb, accompanied by arterial spasm, sometimes leading to venous gangrene of the limb. The systemic symptoms are usually not obvious, the temperature does not rise above 39℃, and there may be mild tachycardia and tiredness. “Femoral cyanosis” is rarer.
Deep vein thrombosis of the lower extremities can occur in any part of the deep veins of the lower extremities. There are two common clinical types: calf muscle plexus thrombosis and iliofemoral vein thrombosis. The former is located in the calf and is called peripheral; the latter is located in the iliofemoral region and is called central. Either the peripheral or central type can involve the entire limb by extending in a cascading or retrograde fashion and is called the mixed type, which is the most common clinically.
Diagnosis.
1.Most commonly seen in postpartum, post-pelvic surgery, trauma, advanced cancer, coma or patients who are bedridden for a long time.
2.The onset of the disease is acute, the affected limb is swollen and hard and painful, which is aggravated after activity, often accompanied by fever and rapid pulse.
3, pressure pain at the thrombus site, swelling of the limb distal to the thrombus or the whole limb, flushing of the skin in the acute stage, increased skin temperature, weakening or disappearance of the dorsal foot and posterior tibial artery pulsation, and venous gangrene in severe cases. When the thrombus extends to the inferior vena cava, edema is evident in both lower extremities, buttocks, lower abdomen and external genitalia. When the thrombus occurs in the muscular plexus of the calf, Homans’ sign and Neuhof’s sign are positive.
4, Late thrombus absorption mechanization, often leaving venous insufficiency, superficial varicose veins, pigmentation, ulceration, swelling, etc., known as post-deep vein thrombosis syndrome. It is divided into.
(1) Peripheral type: blood backflow is the main cause.
(2) Central type: Blood reflux disorder is the main cause.
(3) Mixed type: both blood backflow and reflux obstruction.
5.Pulmonary embolism can be caused by thrombus dislodgement.
6.Radioactive fibrinogen test, Doppler ultrasound and venous flow mapping can help to diagnose. Venography can confirm the diagnosis.
Differential diagnosis.
In the acute and chronic phases of lower extremity deep static thrombosis should be distinguished from the following diseases, respectively.
1. Acute arterial embolism.
This disease also often manifests as sudden pain of unilateral lower limb, which is similar to lower limb venous thrombosis, but there is no swelling of limb in acute arterial embolism, which mainly manifests as cold skin temperature of foot and lower leg, severe pain, numbness, movement disorder and loss of skin sensation, and the pulsation of dorsal foot artery and posterior tibial artery disappears, and sometimes the pulsation of femoral N artery also disappears, according to the above characteristics, it is easier to differentiate.
2. Acute reticulolymphangitis (dandruff).
The onset of this disease is also faster, the limbs are swollen, often accompanied by chills, high fever, red skin, elevated skin temperature and other symptoms, without superficial varicose veins, according to the above characteristics, it can be distinguished from deep vein thrombosis of the lower limbs.
3.Lymphedema.
There are similarities between this disease and the chronic phase of lower limb deep vein thrombosis, and the points of differentiation are as follows: medical history: the latter has an acute onset, often with a history of surgery, childbirth or trauma, while the former has a slow onset, often with a history of more than a few years; pain: the latter has pain in the acute phase, which gradually decreases later, while the former has no or slight dull pain and a feeling of heaviness in the affected limb; skin: the latter is not thickened, while the former is thickened in the late phase; color: the latter may be cyanotic, while the former has no changes; superficial veins: the latter dilated, the former not; ulcers and eczema: the latter often occur in the late stage, the former generally does not occur; edema: the latter soft, thigh, calf obvious, ankle, dorsal foot, toe is not obvious, the former hard and tough, thigh, calf, ankle, dorsal foot, toe are obvious; elevation of the affected limb: the latter edema subsides quickly, the former edema subsides slowly.
4. Other diseases.
Any patient who is bedridden due to postoperative, postpartum, severe trauma or systemic diseases and suddenly feels pain in the deep calf with pressure pain and positive Homans’ sign should first consider deep vein thrombosis in the calf. However, it should be differentiated from the following diseases: acute calf myositis, acute calf fibrillitis, calf muscle strain, calf deep vein rupture and hemorrhage, and Achilles tendon rupture. The latter are distinguished by a history of trauma, rapid onset, severe local pain and skin ecchymosis in the calf, especially in the ankle.
Treatment.
There are many different types of treatment for this disease, and the treatment differs between the acute and chronic phases. The treatment methods mainly include anticoagulation and thrombolytic therapy, surgery, interventional therapy and Chinese herbal medicine, etc. The interventional therapy includes interventional thrombolytic therapy, inferior vena cava filter placement, ultrasound ablation, percutaneous endovascular angioplasty and endovascular stent placement, etc.
1.Anticoagulant and thrombolytic drug therapy.
(1) Anticoagulation therapy: The purpose of anticoagulation therapy is to inhibit the coagulation process of the body, so that the hypercoagulable state can be controlled and thrombosis can be prevented, or the formed thrombus can not continue to develop. It is prohibited for people with bleeding disorders or bleeding tendency; recent trauma and major surgery; severe cardiac, hepatic and renal insufficiency and other conditions. Other anticoagulants, such as hirudin, anti-platelet factor III, dermatopoietin sulfate, etc. also have wide application prospects.
(2) Thrombolytic therapy.
It is forbidden to be used in coagulation disorders, bleeding disorders, those with major bleeding in the gastrointestinal tract within 3 months, within 5 days of major surgery, and liver and kidney insufficiency. Commonly used drugs include streptokinase (SK), urokinase (UK), tissue-type fibrinogen activator (t-PA) and thrombin.
(3) Anti-platelet therapy.
In recent years, due to the progress of research on platelet ultrastructure, platelet adhesion, aggregation and release functions, as well as arachidonic acid (AA), thromboxane (TXA) and prostaglandin (PGI) systems, antiplatelet agents have achieved better efficacy in preventing and treating thrombosis. Antiplatelet agents have long-lasting efficacy, can be taken for a long time, have no risk of bleeding, and do not require monitoring. They are indicated for hypercoagulable blood and thrombosis. There are no obvious contraindications. Commonly used drugs are aspirin, pansentin, thiaclopidine and prostaglandins PGE1 and PGI2.
2.Surgical treatment.
(1) Iliofemoral vein thrombectomy.
Applicable to acute DVT onset within 72 hours and femoral cyanosis and femoral leukomalacia. Early surgery has good effect. It is contraindicated for those with onset of DVT for more than 72 hours, those with secondary infection, those with history of DVT and those who cannot tolerate surgery. Currently, Fogarty catheter embolization is mostly used.
(2) Autologous saphenous vein diversion (also known as Palma-Dale procedure).
The principle of the procedure is to use the saphenous vein on the healthy side to anastomose with the distal iliofemoral vein through a subcutaneous tunnel in the suprapubic abdominal wall and the venous flow from the affected side flows back into the femoral vein on the healthy side through the saphenous vein. It is indicated for unilateral obstruction confined to the iliofemoral vein with severe swelling and distension of the lower extremity for more than 6 months. It is contraindicated in patients with poor venous return on the healthy side, those with significant foci of infection in the lower limbs or the whole body and those who cannot tolerate surgery.
(3) In situ saphenous vein-N vein diversion (also known as Husni’s procedure).
Applicable to patients with superficial femoral vein thrombosis or obstruction; patients with appropriate caliber of ipsilateral saphenous vein, no phlebitis and varicose veins, and good valve function; patients with obvious venous reflux disorders in the affected calf, such as swelling, superficial venous anger, stasis skin dystrophy, recurrent ulcers, etc., and poor results of elastic external support. It is forbidden for those with femoral or iliac vein occlusion, inferior vena cava obstruction, saphenous vein valve insufficiency, N vein and its distal vein occlusion.
3.Interventional treatment.
(1) Placement thrombolysis.
High concentration of thrombolytic drugs can be directly infused into the thrombus through the catheter to achieve the best thrombolytic effect and reduce the incidence of systemic bleeding complications. For the treatment of acute and non-acute deep vein thrombosis, it has shown better efficacy and has become a common method for the treatment of DVT. It is suitable for all kinds of symptomatic DVT, especially for iliofemoral or femoral N vein thrombosis, which is not suitable for surgical thrombosis. Contraindications are the same as for thrombolytic therapy. The methods of cannulation include reverse and cis placement. Both methods use the Seldinger puncture technique, and thrombolytic drugs are mostly urokinase, which is infused through the catheter sheath and catheter respectively with an infusion pump and maintained for 10–15 days. After thrombolysis is completed, anticoagulation therapy needs to be continued. Interventional thrombolysis can directly inject large doses of urokinase into the thrombus site or even into the inner part of the thrombus to increase the local drug concentration and prolong the time of drug action with the thrombus, thus the efficacy is higher.
(2) Inferior vena cava filter placement.
Pulmonary artery thromboembolism is a serious complication of deep vein thrombosis, even life-threatening. The introduction of inferior vena cava filter has been very effective in the treatment of deep vein thrombosis and prevention and treatment of pulmonary artery thromboembolism. Percutaneous puncture for placement of inferior vena cava filter is simple and safe, and has been widely adopted in recent years. It is suitable for DVT with contraindications to anticoagulation therapy, for those who have failed anticoagulation therapy and have recurrent pulmonary embolism, for chronic pulmonary hypertension, and for elderly people with recurrent thrombosis. It is contraindicated in people with severe blood coagulation disorders.
(3) Ultrasound ablation.
This method is to deliver high-energy, low-frequency ultrasound waves to the thrombus site through a catheter probe made of special materials, which generates cavitation and leads to powerful vortex sound. This vortex action pulls the thrombus toward the tip part of the probe, which acts continuously at high speed for a short time to completely dissolve the thrombus into blood components. This method is characterized by fast, safe and pathologically damage-free lysis, which means that the thrombus is dissolved into normal blood components (red blood cells, white blood cells, platelets, etc.) within 1 – 3 minutes of time, and without any damage to the vessel wall. It is suitable for patients with DVT within 3 months, those with poor or failed results of drug thrombolysis or catheter clot retrieval, those with contraindications to drug thrombolysis, those with bruised femur, and those with acute onset of DVT in chronic lower limbs. Intravascular ultrasound ablation also has its limitations, the scope of ablation for lesions without thrombus is small, the degree of tissue ablation is limited, and the size of the lumen diameter depends on the size of the ultrasound ablation probe.
(4) Percutaneous endoluminal angioplasty and endovascular stenting.
Percutaneous transluminal angioplasty (PTA) is a non-surgical treatment that involves the percutaneous puncture and introduction of balloon catheters, metal endoprostheses and other devices to dilate and other minimally invasive treatments to recanalize narrowed and occluded vessels. Among them, if treated with balloon catheter dilation alone, it can be called balloon dilation, which is commonly referred to as percutaneous transluminal angioplasty. In contrast, when treated with a metal endoprosthesis, it can be referred to as endovascular stenting. PTA alone is not effective in the long term, so it is often necessary to place an endoprosthesis after PTA. It is indicated for vascular stenosis or occlusive disease that affects the function of organs and tissues. It is prohibited in cases of severe cardiac, hepatic and renal insufficiency, abnormal coagulation mechanism, active stage of aortitis, etc.
4.Chinese herbal medicine treatment.
Chinese medicine believes that this disease is caused by blood clotting and dampness obstruction in the ligaments, and is often treated by activating blood circulation, removing blood stasis, and promoting the circulation of dampness. The main treatment methods are internal treatment, external treatment, oral administration of Chinese medicine, static injection of Chinese medicine and acupuncture point injection therapy, etc.
(1) Internal treatment method.
According to TCM diagnosis and treatment, this disease is mostly identified as three types: damp-heat infusion, blood stasis and dampness, and spleen and kidney yang deficiency. The damp-heat infusion type is equivalent to the acute stage of DVT, and the treatment is to clear heat and dampness, activate blood circulation, etc. The blood stasis and dampness type corresponds to the inflammatory phase of DVT, and the treatment is to activate blood circulation and remove blood stasis, activate dampness and open the ligaments. Spleen and kidney yang deficiency type is equivalent to the DVT sequelae stage, the treatment is to warm the kidney and strengthen the spleen, promote dampness and open the ligaments.
(2) External treatment methods.
①External treatment.
In the acute stage, add ice chips l0g for every 500-1000g of mannitol, mix it into a cloth bag and apply it externally to the inflammation of the lower leg and femur, and then change it after the medicine is wet and clumped. It has the effect of reducing water and swelling, anti-inflammatory and pain relief, etc.
② Fumigation therapy.
After the acute inflammation subsides, can apply the decoction of blood swelling wash, blood pain relief, alum wash, etc. or dissolve, fumigate the affected area while hot, 1 – 2 times a day. It has the functions of eliminating blood stasis and swelling of limbs, relieving pain and promoting the establishment of collateral circulation.
(iii) Treatment of ulcers.
Late in the course of the disease, those who have left chronic ulcers in the lower leg for a long time, can apply ulcer wash to wash the affected area externally, after washing, cover with yu hong cream oil gauze or clean change of medicine to promote ulcer healing.
In acute DVT, Fogarty catheter embolization, interventional thrombolytic therapy, early anticoagulation thrombolytic therapy and oral Chinese medicine treatment are feasible and effective; in case of pulmonary embolism or recurrent thrombosis, inferior vena cava filter placement is feasible. For subacute and chronic DVT, placement thrombolysis, ultrasonic ablation, lower extremity DVT PTA, stent placement and TCM treatment are feasible; for post-DVT syndrome, autologous saphenous vein diversion or in situ saphenous vein-N vein diversion and TCM internal and external treatment are feasible. In conclusion, there are a variety of treatment methods for lower extremity DVT, and many new treatment methods are still being explored. It can be seen that interventional therapy has a wide development and application prospect in the treatment of DVT of lower extremities.