Lower extremity deep vein thrombosis (DVT) is a disease caused by abnormal clotting of blood in the deep veins of the lower extremities, where blood return is obstructed and swelling, pain, and dysfunction of the lower extremities occur. DVT can cause pulmonary embolism, and if DVT is not effectively treated in the early acute stage, the thrombus plan often leaves venous insufficiency, which is called post-thrombotic syndrome (PTS). DVT is divided into central, mixed and peripheral types, among which the central and mixed types are more harmful to limb function. The implementation of catheter intervention for DVT should be considered in terms of safety, timeliness, comprehensiveness and long-term.
1.Safety: The implantation of filters before the intervention of long segment acute thrombosis can effectively prevent pulmonary artery embolism. The use of mechanical thrombus removal and transcatheter drug thrombolysis can significantly reduce the dosage of anticoagulants and thrombolytic agents and reduce the complications of visceral bleeding.
2.Timeliness: Once the diagnosis of acute DVT is clear, catheter thrombolysis should be done as soon as possible to shorten the course of the disease, improve the rate of complete recanalization of the official cavity, avoid or reduce venous valve adhesions, reduce the incidence of valve insufficiency and thrombosis recurrence, and try to prevent the course of the disease from entering the chronic and sequelae phase.
3.Comprehensive: Interventional thrombectomy such as catheter aspiration and mechanical ablation are often used for DVT. For DVT with iliac vein compression syndrome or with venous occlusion, PTA and stent implantation can be used in combination to rapidly restore blood flow and improve the efficacy of interventional treatment.
4.Long-term: After interventional catheter thrombolysis, it is advisable to continue anticoagulation for more than 6 months and regular follow-up and review to reduce the recurrence of DVT.
Indications for catheter thrombolysis
1.Acute DVT.
2.Sub-acute DVT.
3.Acute attack of DVT in chronic phase or sequela phase.
Contraindications
1, history of cerebral hemorrhage and surgery within 3 months, history of gastrointestinal and other internal bleeding and surgery within 1 month.
2, more serious infection in the affected limb.
3, acute iliofemoral vein or total lower limb DVT with a large amount of free thrombus in the vascular lumen without inferior vena cava filter placement.
4, refractory hypertension (blood pressure >180/110 mmHg).
5.Select with caution if you are over 75 years old.
The route of thrombolysis is divided into cascade and retrograde thrombolysis
Parallel thrombolysis: 1.
1.Placement of a tube through the N vein of the affected limb.
2.Femoral vein placement through the affected limb.
3.Saphenous vein dissection of the affected limb.
Retrograde thrombolysis: 1.
1.Intubation through the femoral vein on the healthy side to the iliofemoral vein on the affected side, and retention of the catheter for thrombolysis.
2.The internal jugular vein is cannulated to the iliofemoral vein, and the catheter is retained for thrombolysis.
The main thrombolytic agents are r-tPA and urokinase, and the duration of thrombolysis should not exceed 7 days.
Postoperative management
1, 2-3 days after intravenous retention catheter thrombolysis, the patient may have mild fever, this bout usually does not require special treatment, if necessary, the catheter can be replaced after strict sterilization.
2.Require outpatient follow-up at 1, 3, 6 and 12 months after surgery, and ultrasound to review the patency.
Prevention and treatment of complications
1.Hemorrhage and hemolysis During anticoagulation, closely observe the signs of subcutaneous, mucosal and visceral bleeding. If patients develop neurological symptoms, cerebral hemorrhage should be considered first, anticoagulation and thrombolytic drugs must be stopped immediately, and emergency cranial CT examination is recommended to clarify the diagnosis. If there is bleeding, additional hemostatic drugs can be used. For large amount of bleeding, puncture and drainage or surgical decompression and hematoma removal are feasible.
2. Residual thrombus and recurrence of thrombus The recurrence of thrombus in thrombolytic treatment is mostly related to the hypercoagulable state of blood caused by the underlying lesion, incomplete treatment and intravenous damage during treatment. It is advisable to inject heparin anticoagulation and subcutaneous injection of low molecular heparin during thrombolysis, and keep the catheter for 3-7 days.
3. Pulmonary embolism should be considered if symptoms such as dyspnea, cyanosis, chest tightness, coughing and coughing up blood, and decreased arterial oxygen saturation occur during thrombolysis. Before thrombolysis, for those who have fresh thrombus or floating thrombus in inferior vena cava and iliofemoral vein, implanting inferior vena cava filter to block the dislodged thrombus is an effective way to prevent pulmonary embolism. In younger age groups, the filter may be removed after surgery.
Efficacy evaluation: Catheter thrombolysis for DVT can be performed before and 6 months, 1 year, and 3 years after discharge, and the efficacy is classified into 4 grades according to the results of physical examination and contrast review.
Excellent: the circumference, tone and mobility of the affected limb are basically normal, the difference in circumference after treatment compared with the test is <1.0 cm, the imaging shows full or basic restoration of blood flow, the abnormal collateral vessels are not shown, there is no retention of contrast agent, and the wall of the tube is smooth.
Good: The circumference, tension and mobility of the affected limb are close to normal, with a circumference difference of 1.0-1.5 cm, and the imaging shows that blood flow is mostly restored, with a small number of collateral vessels, no significant retention of contrast agent, and smooth walls.
Moderate: The circumference, tone, and mobility of the affected limb improved significantly, and the imaging showed partial restoration of blood flow, more collateral vessels, mild retention of contrast agent, and a less smooth wall.
Poor: There was no significant improvement in the circumference, tone and mobility of the affected limb, the circumference difference was >2.0 cm, and the imaging showed no restoration of blood flow, a large number of collateral vessels, significant retention of contrast agent, and the wall of the tube was not smooth.
The treatment was effective for those rated as excellent, good or moderate.
Interventional treatment of DVT has many components and methods, and often needs to be used according to the staging and clinical stage of DVT. A combination of several methods of intervention can improve the efficacy. The catheter thrombolytic therapy for acute and subacute DVT must be emphasized to prevent the course of the disease from entering the chronic and post-acute phases as much as possible, and to adhere to the systemic medication after thrombolytic therapy to reduce the occurrence of deep venous insufficiency.