A few lower extremity deep vein thrombosis can lead to fatal pulmonary embolism, so the treatment should include lower extremity venous thrombosis itself and how to prevent the occurrence of pulmonary embolism, the acute phase of the treatment methods are mainly surgical and non-surgical treatment of the 2 kinds of methods have their own characteristics, which method is better at present there is still a debate. In the chronic phase, there are medication, surgery, and compression therapy.
1.Acute treatment
(1)General treatment: once thrombosis occurs in the deep veins of the lower limbs, the patient should rest in bed to reduce the chance of pulmonary embolism due to dislodgment of the thrombus by walking around and avoid massaging and squeezing the swollen lower limbs. The affected limbs should be elevated above the heart level, which is conducive to blood reflux and prompts the swelling to subside. Bed rest time is usually about 2 weeks, after 2 weeks, wear step differential pressure compression stockings or use elastic bandage to wrap the affected limb, can accelerate the tissue swelling, reduce symptoms.
(2) Anticoagulation: Anticoagulation is the earliest and most widely used method in the treatment of venous thrombosis of the lower extremities. Anticoagulation itself can not dissolve the formed thrombus, but it can inhibit the spread of thrombus and cooperate with the body's own fibrinolytic system to dissolve thrombus, so as to achieve the therapeutic purpose, and at the same time, it can effectively reduce the incidence of pulmonary embolism, and it has a pivotal role in the prevention and treatment of pulmonary embolism. Other surgical or non-surgical treatments should generally be accompanied by anticoagulation as an adjunctive therapy. Anticoagulation can be used throughout the entire course of the disease, generally 1 to 2 months, some patients can be up to half a year to 1 year, and some even need lifelong anticoagulation. However, anticoagulation is contraindicated in the following cases: gastrointestinal ulcers, severe hepatic and renal insufficiency, recent cerebral hemorrhage, after abortion, congenital coagulation factor deficiency, and so on.
①Heparin: the most commonly used anticoagulant, its anticoagulant effect is mainly through the increase of antithrombin Ⅲ (AT Ⅲ) activity, inhibit thrombosis. Heparin has a fast onset of action, short half-life, and stable in vivo action. Heparin aqueous solvent is mainly 12500U/branch, equivalent to 100mg. 2 ways of administration are intravenous injection and subcutaneous deep fat layer injection, intramuscular injection is easy to occur at the injection site hematoma, should not be used. Subcutaneous deep fat layer injection method is simpler, but the concentration of heparin in the body is not easy to accurately control, the injection site is generally selected subcutaneous abdominal wall. Intravenous injection method utilizes micro-pump for continuous intravenous drug delivery, this method of heparin effect is fast, the dose is easy to control, the concentration of heparin in the body is more stable and easy to regulate, it is a more ideal method of drug delivery. The specific method is to inject heparin 50mg or 6250U intravenously, so that the concentration of heparin in the body reaches the peak value rapidly, and then the diluted solution of heparin (heparin 200mg or 25000U dissolved in 500ml of 5% glucose saline) is continuously dripped intravenously at 30ml/h. However, in the following cases, the dosage of heparin will be increased by micro-pumping. However, the dosage of heparin should be reduced to 20ml/h in the following cases: those who have had surgery within 2 weeks; those who have had stroke within 2 weeks; those whose platelet count is <100×109/L; and those who have a tendency to bleed.
Heparin dosage varies widely among individuals, so it should be adjusted according to laboratory monitoring. Currently the most commonly used heparin monitoring index is partial thromboplastin time (aPTT), during the administration of aPTT is controlled at 1.5 times the normal control or the upper limit of the normal value. aPTT is first detected after heparin 6250U intravenous injection, and then detected every 4-6 hours, and can be detected every 12 hours after stabilization.
The common side effects of heparin include: A. Bleeding, subcutaneous petechiae and ecchymosis should be taken seriously during the period of medication, if hematuria and gastrointestinal bleeding occurs, the medication should be reduced or discontinued, and if the bleeding volume is large, ichthyosin can be used to counteract the anticoagulant effect of heparin with a ratio of 1:1 intravenously. B. Thrombocytopenia, which may be related to the autoimmune reaction of the body induced by heparin, with an occurrence of 1% to 2%. B. Thrombocytopenia, may be related to autoimmune reaction caused by heparin, the incidence rate is 1%~2%, manifested as reduction of platelet count, and in serious cases, extensive thrombosis in arteries and veins may occur, resulting in death or mutilation of patients, which should be highly valued by clinics.
②Low-molecular-weight heparin: As mentioned earlier, low-molecular-weight heparin has many superiorities over heparin. Since it mainly targets factor Xa, it is anticoagulant while the risk of bleeding is greatly reduced. With its good tissue absorption and long half-life, the method of administering the drug becomes simpler and the number of doses is reduced compared to heparin. There are several types of low molecular weight heparin sold on the market, and the composition and usage of the various products vary and cannot be generalized. Their ****similarity is that they are mainly injected subcutaneously, and in the case of deep vein thrombosis of the lower extremities, once every 12 hours.
Laboratory monitoring is generally not required with low-molecular-weight heparin, but like heparin, low-molecular-weight heparin can cause thrombocytopenia, and although its incidence is lower than that of heparin, testing of platelet counts can help in the early detection of this complication.
Because low-molecular-weight heparin is safer to use than heparin, it is now being used more and more in clinical practice and is gradually replacing heparin.
③Warfarin: Warfarin as an oral anticoagulant has been used for a long time in the clinic, and as an oral preparation, warfarin has become the first choice of outpatient anticoagulant therapy. Warfarin has a slow onset of action in the body, usually starting after 2 to 3 days of taking the drug, so it is often used together with heparin or low-molecular-weight heparin in the clinic, and heparin or low-molecular-weight heparin is discontinued when warfarin reaches its therapeutic effect.
Use: 7.5mg orally once on the first day, changed to 5mg orally once on the second day, 2.5mg/d orally on the third day, this dose is adjusted according to the prothrombin time (PT). Generally start to test PT 2 times a week to control the INR value at 2 to 3, then change to 1 time a week, and gradually transition to 1 time a month. The duration of warfarin in patients with lower extremity deep vein thrombosis is generally at least 2 months, and if there is a history of pulmonary embolism, the duration of warfarin can be extended to 1 year.
(3)Thrombolytic therapy: Thrombolytic therapy is the use of thrombolytic drugs to activate the body's fibrinogen, so that it becomes active fibrinolytic enzymes to promote the dissolution of thrombus, to achieve the purpose of removing fresh thrombus.
There are 2 main types of thrombolytic therapy, namely systemic therapy and local therapy. Systemic therapy is to inject thrombolytic drugs into the vein and then follow the blood flow throughout the body to dissolve the thrombus. Localized therapy is to inject thrombolytic drugs into the blood vessels through cannula to dissolve the thrombus in a certain area. Since collateral circulation is easily established after thrombosis in the lower extremity veins, the thrombolytic drug is not easily concentrated locally, so the infusion of thrombolytic drug at the distal end of the venous obstruction is not as effective as cannulation into the thrombus to dissolve the thrombus. There is valve obstruction in the vein, and it is sometimes difficult to reach the thrombus by cannulation from the healthy side, so it is usually done by puncture of the biliary vein from the affected side. In general, the bile vein on the affected side is punctured and inserted in a smooth way to the thrombus to continuously instill thrombolytic drugs. At present, most of the clinical use of systemic therapy.
Thrombolytic therapy is mainly for fresh thrombus, the earlier after the onset of the use of better results. For patients who have been ill for more than 3 days, the effect of thrombolysis will be reduced. Clinical observation is that some patients who have been ill for more than 3 days, after receiving urokinase treatment, the swelling of the limb also subsides rapidly, the possible mechanism is that urokinase dissolves the proximal and distal secondary fresh thrombus, which leads to the generation of collateral circulation, so that the swelling of the limb subsides, but the primary thrombus can not be completely dissolved. Even in patients less than 3 days old, due to the large extent of the thrombus and the fact that most of the thrombus had been more than 24 h from the time of consultation, the application of thrombolytic therapy can only partially dissolve the secondary fresh thrombus, and it is generally more difficult to completely dissolve the primary thrombus. Only in a very few very early cases, the thrombus may be completely dissolved.
The most common side effect of thrombolytic therapy is bleeding, which occurs in 12% to 45% of cases. Bleeding is related to the dosage of the medication, the way the medication is administered, and the duration of the medication. The higher the dose and the longer the duration of administration, the greater the risk of bleeding, and the risk of bleeding is greater with systemic than with localized medication. Superficial bleeding from the skin is easier to control, but the danger of deep bleeding from the organism, especially intracranial bleeding, is high, so thrombolytic therapy should be discontinued when bleeding manifests itself, and fresh plasma should be transfused to supplement coagulation factors if necessary. There is an increased chance of pulmonary embolism during thrombolytic therapy, and placement of a vena cava filter may be a better prophylactic method for this.
Thrombolytic therapy should be avoided during the operation of any damage to the blood vessels, thrombolytic therapy should be prohibited for patients with the following conditions: ① active bleeding in the body; ② stroke or intracranial foci within two months; ③ major surgery, organ biopsy or large trauma within two weeks; ④ perinatal women; ⑤ peptic ulcer or history of peptic hemorrhage (excluding hemorrhoids); ⑥ serious Liver and renal insufficiency; (7) uncontrolled hypertension; (8) patients with wall thrombus in the left heart; (9) patients with subacute endocarditis. Pregnant women, patients with atrial fibrillation, recently performed cardiopulmonary resuscitation, patients with diabetic retinopathy, recently underwent minor surgery, as well as patients with mild hepatic and renal insufficiency should be cautious of thrombolytic therapy.
Laboratory tests should be paid attention to during thrombolytic therapy, and commonly used tests include hematocrit, platelet count, prothrombin time (TT), partial thromboplastin time (APTT), fibrinogen, and fibrin degradation product measurements. In preparation for thrombolytic therapy, anticoagulation is stopped and the above laboratory indexes are measured, and the test is repeated every 3 to 4 h after the start of thrombolytic therapy.TT or APTT is controlled to be about 2 times the normal control, and the fibrinogen concentration should not be <1g/L (100mg/dl). Hematocrit, if decreased, should be considered to have hidden gastrointestinal bleeding. Attention should also be paid to the observation of the patient's mental changes, early detection of intracranial hemorrhage. Anticoagulation should not be carried out immediately after the end of thrombolytic therapy, usually need to wait for 2-3h, if heparin is used without the first shock dose.
The following thrombolytic drugs are commonly used.
①Streptokinase (SK): Streptokinase is produced by β-hemolytic streptococci, and was first found to have thrombolytic effect by Tillett and Garner in 1933. It first forms a streptokinase-fibrinogen complex with fibrinogen at a stoichiometric ratio of 1:1 in vivo, and then activates fibrinogen to become fibrinolytic enzymes with thrombolytic activity, and the streptokinase-fibrinogen complex is gradually transformed into streptokinase-fibrinolysis complex, which also has the effect of activating fibrinogen. Because streptokinase is not selective for the fibrinogen in the thrombus versus the fibrinogen in the circulating blood, a significant portion of it forms a complex with circulating fibrinogen when it is introduced into the body, thereby increasing the risk of bleeding.
Streptokinase is antigenic, and when it enters the body, it is easily neutralized by streptokinase antibodies. Those who have had hemolytic streptococcal infections in the recent past and those who have used streptokinase in the past six months have higher levels of streptokinase antibodies in their blood. Because of the antigenic nature of streptokinase, allergic reactions may occur in some patients, with an incidence of 1.7% to 18%. Therefore, an allergy test should be done before using streptokinase. After streptokinase enters the body, it is first neutralized by streptokinase antibody, and the remaining part combines with circulating fibrinogen to form an active complex, which activates fibrinogen into fibrinolysis. Fibrinolytic enzyme and excess free streptokinase form a complex, which is partially neutralized by circulating antifibrinolytic enzymes, and the rest binds to fibrin in the thrombus and breaks it down, which is the only part that actually acts as a thrombolytic agent. The half-lives of the streptokinase-fibrinogen complex and the streptokinase-fibrinolysis complex are 16 min and 83 min, respectively.
Streptokinase is administered as follows: 250,000 U of streptokinase is injected intravenously at a slow rate for 30 min, and then maintained at a rate of 100,000 U/kg. In addition to an allergy test that should be performed before streptokinase is administered, an intravenous infusion of 100 mg of hydrocortisone can help prevent or minimize allergic reactions. Streptokinase should not be used in patients who have had a recent hemolytic streptococcal infection or who have used streptokinase within six months.
②Urokinase (UK): Urokinase can be extracted from urine or from cultured human embryonic kidney cells. Unlike streptokinase, urokinase does not require the formation of a complex and can directly activate fibrinogen and dissolve thrombi. It is also non-selective as it is equally effective against circulating fibrinogen and fibrin-bound fibrinogen. Urokinase is non-antigenic and does not require allergy testing. Its half-life is 14 min.
In recent years, urokinase has been administered by first injecting 4400 U of urokinase per kilogram of body weight intravenously over a 10-minute period, followed by maintenance at a rate of 4400 U/(kg-h). If intubation is used for interventional thrombolysis, the affected popliteal vein is punctured under ultrasound localization, and a straight-end multilateral orifice perfusion catheter is inserted into the thrombus in a parallel fashion, and urokinase is infused at a rate of 150,000 to 200,000 U/kg/h. X-ray imaging is performed every 12 hours to find out how the thrombus has been dissolved, and the position of the perfusion catheter is adjusted until the thrombus has been dissolved. If there is no sign of thrombus dissolution on examination after 12h of administration, the drug should be discontinued. Practical doses of urokinase have been reported by various authors to vary widely.
③Tissue-type fibrinogen activator (t-PA): many tissues of the human body can produce t-PA, t-PA in the absence of fibrin, its enzyme activity is very low; but when there is fibrin, its activity is significantly increased, the decomposition of fibrinogen into fibrinolytic enzymes, so t-PA can act selectively on the thrombus within the fibrinogen, and the risk of bleeding compared with the two above-mentioned The risk of bleeding is smaller than the above two thrombolytic drugs. Because of this selectivity, the thrombolytic effect of t-PA is obviously weakened when the fibrinogen bound to fibrin decreases rapidly, so its thrombolytic ability is relatively low compared with the non-selective thrombolytic drugs. Currently t-PA is mainly extracted from melanoma cells using genetic engineering and is called recombinant t-PA (rt-PA), which has a half-life of 4-7 min in the human body. t-PA is administered by intravenous injection of 40-50 mg every 2 hours until symptomatic relief.
④Others: At present, the above three thrombolytic drugs are mainly used in the clinic, and some other drugs are still under experimentation. Such as acylated streptokinase-fibrinogen complex, B-chain fibrinolytic enzyme-streptokinase complex, pre-urokinase, etc., these drugs in the half-life and selectivity have been improved.
(4) Surgery: Intravenous surgical thrombolysis was popular in the 1950s and 1960s, but since the 1970s, there have been more and more reports of thrombus recurrence after thrombolysis, which has led to a reappraisal of the value of thrombolysis, and a gradual increase in the safety of thrombolytic therapy, which has also led to some limitations on thrombolysis. However, some scholars still believe that thrombectomy is fast, safe and simple, as long as the indications are well mastered, the method is improved, and with anticoagulation, its success rate is still quite high. Other scholars believe that the effect of thrombectomy is close to that of drug therapy.
①Indications: A. Onset time is not more than 5 days, preferably within 72h; B. Lower extremity iliac and femoral vein thrombosis.
Color ultrasound or lower extremity venography should be performed before surgery to clarify the location of the thrombus, and attention should be paid to whether the thrombus is derived to the inferior vena cava.
②Surgical method: the operation is best performed in the operating room with X-ray fluoroscopy machine. If the thrombus is confined to one side of the iliac and femoral veins, make an incision in the groin of the affected side along the femoral vein, first reveal the saphenous vein, and then along the saphenous vein to find the junction of the saphenous and femoral veins, and then reveal the femoral vein. The common femoral vein, superficial femoral vein and deep femoral vein are carefully separated, and the operation is done gently to avoid artificially squeezing the thrombus off. An incision is made in the common femoral vein along the long axis of the vein, and a Fogarty catheter is inserted into the proximal end of the femoral vein to the inferior vena cava to dilate the balloon and pull out the thrombus, and this procedure is repeated several times until no thrombus is pulled out. Under X-ray fluoroscopy or angioscopy, the suction catheter was selectively inserted into the internal iliac vein, and the thrombus in the internal iliac vein was sucked out cleanly, and the venography confirmed that there was no thrombus left in the iliac vein. If localized stenosis of the left iliac vein is detected, balloon dilatation of the stenosis can be performed under X-ray fluoroscopy, and a stent can be placed in the stenosis if necessary. Squeeze the calf and thigh with a hemorrhage repellent belt or maneuver to squeeze out the distal venous thrombus. If it is found that it is difficult to remove the thrombus in the femoral vein, the superficial femoral vein can be ligated in order to prevent the distal venous thrombus from deriving to the proximal part. An embolization catheter is inserted into the deep femoral vein, and venous blood flow is restored after embolization. A branch of the saphenous vein is selected, cut and anastomosed proximally to the superficial femoral artery. The purpose of the arteriovenous fistula is to accelerate blood flow in the iliac veins and reduce the risk of rethrombosis. The arteriovenous fistula can be closed by interventional embolization of the fistula after 6 weeks or by surgical ligation of the fistula.
The thrombus has already reached the inferior vena cava, and direct femoral vein dissection to remove the thrombus may increase the risk of pulmonary embolism at the time of surgery. The thrombus should be removed from the inferior vena cava under direct visualization, and then lower extremity vein thrombectomy should be performed. The specific method is to make a curved incision in the middle and lower abdomen of the affected side, and reveal the inferior vena cava and both renal veins through the retroperitoneal route. The inferior vena cava is incised longitudinally, and the thrombus in the inferior vena cava is removed cleanly, and then the venous incision is sutured. The iliac and femoral veins were then thrombosed and temporary arteriovenous fistulas were constructed using the methods described above.
Generally, the swelling of the affected limbs subsided soon after the surgery, and anticoagulation therapy was started from the day of the surgery with warfarin and heparin or low-molecular-weight heparin at the same time, and when the INR value of the prothrombin time reached 2-3, heparin or low-molecular-weight heparin was stopped, and the anticoagulation therapy was continued with warfarin for about half a year.
According to the statistics of Shanghai Renji Hospital, 118 patients with acute DVT of the lower limbs in the hospital, of which 59 limbs were surgically thrombosed, only 6 cases were confirmed to have patency of the trunk vein by postoperative collateral venography. The reasons for such a high rate of rethrombosis may include: the thrombus is too extensive to be removed, especially in small veins; the thrombus is too old and adherent to the venous intima, and the removal of the thrombus leads to intimal damage, collagen tissue exposure, and platelet adhesion causing rethrombosis. Venous thrombosis is common in the left iliac vein due to compression, and the Forgarty catheter makes it more difficult to remove all the thrombus in the vein, and thrombectomy does not remove the cause of thrombosis. Although the incidence of postoperative venous rethrombosis is high, it can remove a large number of thrombi at once, rapidly reduce the pressure in the vein, thereby rapidly relieving limb swelling and promoting the establishment of venous collateral branches, and actively cooperate with appropriate medication, which is expected to improve the efficacy of thrombectomy.
(5) Endoluminal intervention of inferior vena cava filter placement: the purpose is to place a filter in the inferior vena cava, so that the lower extremity venous thrombus will not cause pulmonary embolism after dislodging. This procedure is derived from inferior vena cava ligation. Since the mid-19th century, various methods of inferior vena cava isolation have been used in the clinic to prevent pulmonary embolism, however, surgical ligation or blockage of the inferior vena cava carries a certain degree of risk, and the morbidity and mortality rate of this procedure can reach 17% to 30%. 1969, Mobbin-Uddin firstly reported that placing umbrella-shaped filters inside the inferior vena cava effectively reduced pulmonary embolism. In 1969, Mobbin-Uddin first reported that the umbrella mesh was placed in the inferior vena cava and effectively reduced the incidence of pulmonary embolism. 1973, Kimray-Greenfield invented the Greenfield mesh, which brought the mesh technique to maturity and rapidly popularized its use in clinical practice. The biggest difference between the filters and traditional surgery is that the filters do not affect the inferior vena cava reflux, while the filters are placed through the peripheral veins through the unique release catheter, so the trauma is smaller than the traditional surgery, and the morbidity and mortality rate is significantly reduced. Most of the filter materials are stainless steel or titanium alloy, which has no rejection reaction in the body, and the titanium alloy material does not affect the magnetic **** vibration examination. Currently commonly used clinical filters include Greenfield stainless steel filters, Greenfield titanium alloy filters, bird's nest filters, Simon nickel titanium alloy filters and VenaTech filters.Greenfield filters are the most widely used in the clinic, and the continuous improvement of the process and materials enables Greenfield filters to pass 14F or even 12F The Greenfield screen is the most widely used in clinical practice. Continuous improvements in process and materials have allowed the Greenfield screen to be released through 14F and even 12F introducer sheaths, and is suitable for cases with inferior vena cava diameters up to <2.8cm. Bird's nest type filter has been used in the clinic since 1984, it is composed of 2 V-shaped brackets and a group of stainless steel wire, can be placed in the inferior vena cava as large as 4cm, but it will have a certain effect on the magnetic **** vibration examination.Simon nickel-titanium alloy filter due to the use of the characteristics of memory alloy, so that it can be released through the 9F sheath through the elbow vein of the upper limb or the external jugular vein, and it is not big on the influence of magnetic *** vibration, but during the release process of the guide sheath release. It has little effect on magnetic **** vibration, but during the release process the introducer sheath needs to be continuously filled with ice saline, and the possibility of displacement of the Simon screen has been reported to be higher than that of the other types.The VenaTech screen consists of two parts, the lower part of which serves as a fixation device, and the round cap-shaped screen, which is an alloy of eight metals, which serves as a filtration device. The ferromagnetism is small and therefore has little effect on magnetic **** vibration. The guide sheath is generally selected 12 or 9F.
①Indications: A. There are contraindications to anticoagulation therapy of the lower extremity deep vein thrombosis patients; B. anticoagulation therapy in the process of the lower extremity deep vein thrombosis patients with more serious bleeding; C. formal anticoagulation therapy in the process of the lower extremity venous thrombosis patients still occurring in the course of the pulmonary embolism; D. multiple occurrences of pulmonary embolism in the patient; E. need to be carried out in the pulmonary arteriotomy thrombus of the lower extremity venous thrombosis patients; F. need to carry out pulmonary arteriotomy to take thrombus F. Patients with large floating thrombus clots proximal to the thrombus.
②Complications:
A. Thrombosis: venous puncture site can be secondary thrombosis, due to a variety of different devices, the incidence of its 5% to 27%, the thicker the release catheter, the greater the chance of venous thrombosis at the puncture site. In addition, the filter itself can also form a thrombus and cause inferior vena cava obstruction. In comparison, Greenfield filters have the lowest incidence at about 4%, while Simon filters and VenaTech filters have a higher probability of causing inferior vena cava obstruction, at 16% to 30%. Some patients with inferior vena cava obstruction do not show any clinical signs, and a few may develop femoral bruising.
B. Penetration of the vessel: The fixation hook of the filter penetrates the vessel and damages the surrounding tissue. In order to prevent displacement of the filter, most of the filters have barbs fixed to the wall of the inferior vena cava. If the fixation hooks penetrate the vessel wall and in turn damage the neighboring organs, the corresponding symptoms can be produced, with an incidence of about 9%. The organs that may be damaged include the duodenum, small intestine, abdominal aorta, and pancreas, and may cause retroperitoneal hematoma.
C. Filter displacement: the filter is usually placed under the renal vein, if the filter is not well fixed, it can be displaced with the blood flow, most of the displacement distance is less than 7cm, and very few can be displaced to the right atrium, right ventricle, and even to the pulmonary artery. Migration of the filter to the heart can cause cardiac arrest. If the filter moves below the renal vein, it generally does not affect renal function. Theoretically, if a thrombus forms in the renal vein, it could lead to renal failure, but this has not been reported clinically. Mislocalization of the filter may also be due to technical error.
D. It is less common for guide wires to get stuck and for filters to break.
3) Surgical approach:
A. The right femoral vein is usually chosen as the puncture point, and the right jugular vein or the left femoral vein can also be chosen; however, the jugular vein pathway carries the risk of air embolism, and the specificity of the left iliac vein anatomy makes the left femoral vein pathway more difficult than that of the right side.
B. After successful puncture, a 0.035-inch-diameter guide wire is fed into the inferior vena cava, the puncture needle is withdrawn, and the dilatation guide sheath is replaced with a dilatation sheath that is fed straight into the inferior vena cava, and the dilatation tube is withdrawn.
C. A filter release is inserted into the introducer sheath, and the tip of the release is placed at the level of the 2nd lumbar vertebrae under x-ray fluoroscopic positioning.
D. The catheter and outer sheath in the releaser are withdrawn and the mesh is released; once the mesh is released, no further attempts are made to move the mesh.
D. The introducer sheath is withdrawn with the releaser, and the puncture site is compressed to stop bleeding.
2. Chronic venous obstruction of the lower extremities treatment of venous thrombosis of the lower extremities, such as venous lumen is not recanalized or recanalization is incomplete that is the formation of chronic venous obstruction of the lower extremities, if the side branch venous compensation is insufficient, the affected limb is not easy to subside the swelling, the patient's life and work has a great impact. The treatment of chronic lower extremity venous obstruction should be non-surgical or surgical according to the patient's condition.
(1) Mechanical physiotherapy: Due to the obstruction of venous blood return in the lower limbs, resulting in venous stagnation and tissue swelling, the use of elastic bandage or elastic stockings can significantly improve the patient's symptoms, reduce the feeling of pain in the affected limbs, accelerate the swelling to subside, and can effectively prevent the late complications of deep vein thrombosis. Compression stockings should be selected with stepped differential pressure medical compression stockings, from the ankle upward pressure is gradually reduced, daytime should adhere to wear, remove before going to bed. This method is simple and easy to accept, but it should be disabled in the acute stage of lower extremity venous thrombosis to prevent pulmonary embolism caused by thrombus dislodgement.
(2) drug therapy: chronic venous obstruction of the lower extremities of the patient should still be given anticoagulant therapy, because patients with a history of thrombosis has a great chance of thrombosis, anticoagulant therapy can effectively prevent thrombosis again. Generally use oral anticoagulation therapy, such as warfarin, can also be used to anti-platelet aggregation of drugs such as aspirin, ticlopidine (against keloid). Traditional Chinese medicine blood-activating drugs such as Salvia miltiorrhiza help the establishment of collateral circulation.
(3) Endoluminal intervention: mainly for large blood vessels, such as iliac vein and inferior vena cava. When venous thrombosis is incomplete recanalization, local stenosis is easily formed. After the site of stenosis is clarified by using venography, the femoral vein from the contralateral side is cannulated to the stenosis, dilated with a balloon catheter, and a stent is placed to restore the internal diameter of the lumen. The endoluminal intervention method is simple, but it is only suitable for short-segment stenosis of large veins, and the stent placed into the lumen of the vein is itself a factor that induces thrombosis, and the long-term effect is not yet certain.
(4) Surgical treatment: chronic venous obstruction of the lower limbs generally do not need surgical treatment, surgical treatment is mainly re-establishment of venous bypass, due to the special characteristics of venous blood flow, making the bypass blood vessels long-term patency is not as good as the arterial vascular, so the surgical treatment should be strictly controlled indications. Color ultrasound, magnetic **** vibration venography or conventional venography before surgery can help to clarify the location and scope of venous lesions, and pelvic CT examination can exclude the possibility of tumor compression.
①Indications for surgery: lower extremity venous obstruction that is ineffective after conservative treatment and has obvious symptoms.
②Factors affecting the long-term patency of venous bypass vessels:
A. Bypass vessel material: the same as arterial bypass surgery, bypass vessels preferred to autologous veins, autologous veins have a better long-term patency rate than artificial blood vessels. The most commonly used is the saphenous vein, which, if dissected longitudinally and then sutured in a spiral arrangement, can be made into a larger diameter vessel for iliac vein or even inferior vena cava bypass surgery. The contralateral superficial femoral vein is sometimes used as a bypass vessel, but this may result in swelling or other complications in the contralateral lower extremity. Upper extremity veins and jugular veins are also occasionally used. Cryopreserved human allograft veins are also beginning to be used in the clinic, but their long-term effects have yet to be proven. Among the artificial blood vessel materials, expanded polytetrafluoroethylene (ePTFE) is the most used because ePTFE artificial blood vessels can be made of any caliber and length, no pre-coagulation is needed for use, artificial blood vessels with support rings are less likely to collapse and become angular after compression, and ePTFE artificial blood vessels have better anti-thrombotic properties than other materials.
B. Temporary arteriovenous fistula: In 1953, Kunlin first proposed to build an arteriovenous fistula at the distal end of the bypass vessel, which can accelerate blood flow in the bypass vessel and reduce the chance of thrombosis. Practice shows that temporary arteriovenous fistula can improve the long-term patency rate of bypass vessels. However, in patients with cardiac insufficiency, the increase in return blood volume will increase the burden on the heart.Menawat believes that the ratio of the caliber of the fistula to the diameter of the bypass vessel should not be >0.3.The arteriovenous fistula can be wrapped around a non-absorbable 2-0 thread and loosely tied in a knot, with the end of the thread buried under the skin so that it is easy to recognize the ligature and close the fistula at a later date. Fistula closure can also be accomplished by interventional embolization. Fistula closure usually occurs 6 months after surgery.
C. Thromboprophylaxis: Anticoagulant drugs and intermittent leg inflation compression, as described previously, are effective in preventing thrombosis. During the operation, 1 subsidiary branch was found in the vein distal to the bypass vessel, a thin catheter was inserted, and the other end was led out of the body. heparin diluent was continuously titrated after the operation, and the partial thromboplastin time (APTT) was measured so that it did not exceed two times of the normal control. the catheter was removed after 48 h, and heparin anticoagulation was continued to be given through the body vein, and it was gradually switched to oral anticoagulation therapy.
D. Close observation of bypass vessels: During surgery when bypass vessels are established, examination with color ultrasound or venography helps to determine the patency of the anastomosis, and corrects problems promptly if found. Determine the distal venous pressure, compare the change of venous pressure before and after blocking the bypass vessel, and understand the effect of the bypass vessel on hemodynamics. One day after the operation, contrast examination was performed through the indwelling catheter of the vein belonging to the branch, and the patency of the bypass vessel could be understood in time. Regular ultrasound follow-up after discharge is necessary to correct problems as soon as possible.
③Surgical methods:
A. Saphenous vein - popliteal vein bypass (May-Husni procedure): first designed by Warren and Thayer in 1954, but not popularized. It was not popularized until the 1970s when it was reintroduced and popularized by May and Husni. This procedure is indicated in cases of occlusion of the superficial femoral vein alone or the proximal popliteal vein. The ipsilateral saphenous vein is left in reserve, the distal popliteal vein is exposed, and the saphenous vein is cut off and anastomosed with the distal popliteal vein, end to side. The anastomosis should be performed as delicately as possible without damaging the endothelium, and should be closed continuously with 6-0 or 7-0 non-absorbable, non-invasive sutures. Temporary arteriovenous fistulas can be selected at the ankle by anastomosing one of the posterior tibial veins or by anastomosing the saphenous vein to the posterior tibial artery end-to-end. This procedure is now rarely performed because of the small number of patients with simple superficial femoral vein thrombosis and the poor rate of long-term patency of the bypass vessels after the procedure.
B. Suprapubic vein bypass (Palma-Dale procedure): This procedure was first reported by Uruguayan physician Palma in 1960 and popularized by Dale. This procedure is suitable for cases in which the iliac vein on one side is obstructed, the iliofemoral vein on the opposite side is normal and the vein below the inguinal ligament on the affected side is free of thrombus, and there is no lower extremity venous valvular insufficiency. In addition, only cases with a difference of 4 cm or more between the circumferences of the two lower limbs were selected for surgery. The saphenous vein on the healthy side was used as the bypass vessel, and the circumference of the saphenous vein was required to be more than 4mm, and the varicose vein should not be used. The saphenous vein on the healthy side is separated from the femoral vein, and the saphenous vein is cut off and ligated, leaving 25-30cm of the saphenous vein at its distal end, and the saphenous vein is led to the femoral vein on the affected side through the suprapubic subcutaneous tunnel, and the saphenous vein is expanded with diluted heparin and poppy alkaline, and then anastomosed to the femoral vein end-to-end with 5-0 or 6-0 non-damaging non-absorbable sutures. One collateral branch of the affected saphenous vein or femoral vein was selected to establish a temporary arteriovenous fistula with the femoral artery, and another collateral branch was selected to insert a fine catheter to serve as a conduit for continuous heparin infusion and postoperative imaging (Figure 10). If the condition of the autogenous vein is not ideal, an 8-mm caliber ePTFE artificial blood vessel can also be chosen as a bypass vessel. This procedure is still performed in many medical centers because of the satisfactory long-term patency rate.
C. Femoral vena cava, iliac vena cava, and vena cava-atrial vein bypass: It is suitable for unilateral or bilateral iliac vein thrombosis and inferior vena cava thrombosis cases that cannot undergo Palma Dale operation. Femoral-caval vein bypass is performed with a 10-12 mm PTFE prosthetic vessel, and a temporary arteriovenous fistula should be created (Figure 11). For iliac-caval vein bypass, a 14-mm PTFE artificial blood vessel is used, and for inferior vena cava-inferior vena cava bypass or cavernous-atrial bypass, a 16-20-mm artificial blood vessel is used, which generally does not need to establish a temporary arteriovenous fistula, and the artificial blood vessel used should be equipped with an external support ring. Because the operation is large and the long-term patency rate is not yet ideal, the indications should be strictly controlled, and cases with severe symptoms and ineffective treatment by other methods should be selected.
(II) Prognosis
There is no relevant content described.