67Q: What is the ultimate danger of deep vein thrombosis?
A: Pulmonary embolism and post-thrombotic syndrome.
68Q: What is pulmonary embolism?
A: Pulmonary embolism is a clinical emergency caused by obstruction of the pulmonary artery or its branches by emboli, with pulmonary circulation and respiratory dysfunction as its main clinical and pathophysiological features.
69Q: What are the characteristics of pulmonary embolism?
A: The diagnosis rate is low, and the misdiagnosis and death rate are high. According to the literature, there are 650,000 pulmonary embolisms and 240,000 deaths from pulmonary embolism in the United States every year. In the UK, 40,000 non-fatal pulmonary embolisms occur each year, and about 20,000 inpatients die from pulmonary embolism.
70Q: What are the typical symptoms of pulmonary embolism of pulmonary embolism?
A: For dyspnea, chest pain, cough and hemoptysis.
71Q: What is the Wells score of pulmonary embolism?
A: Similar to deep vein thrombosis, pulmonary embolism also has no specific symptoms, making early diagnosis difficult. For this reason, Wells developed the pulmonary embolism score in 2000 for risk assessment of pulmonary embolism, and improved it in 2008. The details are.
72Q: How is the Wells score applied?
A: The risk of occurrence of pulmonary embolism is assessed according to the Wells score, and the clinical probability in 2000: low, 0-1; medium, 2-6; high, ≥7. ≤4, does not resemble PE; >4, resembles PE. 2008 clinical decision probability: ≤1, does not resemble PE; >l, resembles PE.
73Q: What is the gold standard for the diagnosis of pulmonary embolism?
A: Pulmonary arteriography is still the gold standard for the diagnosis of pulmonary embolism. Ventilation/perfusion scan is considered to be the preferred screening method, however, CT scan is more commonly used in actual clinical diagnosis and exclusion work.
74Q: How many types of pulmonary embolism are there?
Answer.
(1) Massive pulmonary embolism: acute pulmonary embolism with persistent hypotension (systolic blood pressure <90 mm Hg for more than 15 min and exclusion of arrhythmia, hypovolemia, sepsis, left ventricular insufficiency, bradycardia (heart rate <40 beats >90 mm Hg) in combination with right ventricular dysfunction or myocardial injury.
(2) Low-risk pulmonary embolism: those who exclude large and sub-large pulmonary embolism and have no clinical prognostic indicators of poor outcome.
75Q: Prevention of pulmonary embolism?
A: The literature reports that 80% to 90% of pulmonary embolism emboli originate from lower extremity deep vein thrombosis. Therefore, recognizing the high-risk factors of pulmonary embolism, identifying and determining the high-risk group of VTE, and implementing effective prevention strategies become the only effective way to reduce the incidence and morbidity and mortality associated with VTE, which is the basis of pulmonary embolism prevention and treatment. Once a deep vein thrombosis has formed, vena cava filter placement is currently used to prevent pulmonary embolism in clinical practice.
76Q: What is an inferior vena cava filter?
A: Inferior vena cava filter is a device made of metal wire, which is placed into the inferior vena cava through a special delivery device to intercept the larger thrombus in the blood flow to avoid entering the pulmonary artery with the blood flow and causing a fatal pulmonary embolism.
77Q: What are the indications for placement of a filter for pulmonary embolism?
A: Placement of filter can lead to complications such as filter displacement, obstruction, bleeding, etc., and the cost is high, so the clinical indications should be strictly controlled. The following cases can be considered for filter placement
①Deep vein thrombosis contraindicates anticoagulation therapy or anticoagulation therapy has serious bleeding complications.
②Pulmonary embolism despite anticoagulation treatment.
③Arterial thrombectomy or pulmonary artery thrombosis endothelial debridement.
④Residual deep vein thrombosis after the first pulmonary embolism.
⑤ Extensive large iliofemoral vein thrombosis. The route of inferior vena cava filter placement should be chosen from the healthy side, or via the right internal jugular vein if bilateral iliofemoral vein thrombosis is present.
78Q: What are the treatment methods for pulmonary embolism?
A: Anticoagulation, thrombolysis, interventional or surgical thrombectomy, and embolization.
79Q: What is the new concept of pulmonary embolism treatment?
Answer.
(1) 80% of pulmonary embolism is not fatal
. (2) When a patient dies suddenly and pulmonary embolism is highly suspected, “blind lysis” (static push of anticoagulant) can be used.
(3) In patients with confirmed pulmonary embolism and no contraindications, anticoagulation should be administered as early as possible, usually by subcutaneous injection of low-molecular heparin and concurrently with warfarin.
(4) In large pulmonary embolism combined with hypotension, thrombolysis should be actively performed.
(5) Combined with the risk of sudden death, catheter or surgical thrombolysis and thrombus retrieval can be considered.
(6)The anticoagulation time should be prolonged for primary pulmonary embolism.
(7) Chronic pulmonary embolism (pulmonary hypertension, CTPH) can be treated with lifelong anticoagulation + endothelial debridement.
80Q: What are the principles of thrombolysis in pulmonary embolism?
Answer.
(1) Thrombolysis can be considered in patients with acute major pulmonary embolism if they are at low risk of bleeding.
(2) Patients with acute submassive pulmonary embolism with evidence of poor clinical prognosis, including recent hemodynamic instability, worsening respiratory insufficiency, severe right ventricular insufficiency, and massive myocardial infarction, and for whom thrombolysis may be considered. Otherwise, thrombolytic therapy is not recommended.
(3) Thrombolysis is not recommended in patients with low-risk pulmonary embolism.
81Q: What are the principles of interventional procedures for pulmonary embolism?
A: In patients with acute massive or submassive pulmonary embolism, if thrombolysis is contraindicated or the condition is still unstable after thrombolytic therapy, catheter embolization, aspiration or surgical embolization can be considered when conditions permit.
82Q: What is post-thrombotic syndrome?
A: It is the most common and important complication of lower extremity deep vein thrombosis. During the mechanization of the thrombus, the venous valve is damaged or even disappears or adheres to the canal wall, resulting in secondary deep vein valve insufficiency, i.e., post-thrombotic syndrome.
83Q: What is the incidence of post-thrombotic syndrome?
A: The incidence of post-thrombotic PTS in patients with lower extremity DVT is as high as 20% to 50%. The choice and implementation of the starting treatment plan for patients with acute DVT can directly affect the occurrence and severity of PTS.
84Q: What are the clinical manifestations and risks of post-thrombotic syndrome?
A: Post-thrombotic syndrome occurs several months to years after the formation of deep vein thrombosis in the lower extremities. The main manifestations are chronic edema, pain, muscle fatigue (venous claudication), varicose veins, pigmentation, subcutaneous tissue fiber changes in the lower limbs, and in severe cases, local ulcers, which affect the quality of life of patients.
85Q: How to prevent post-thrombotic syndrome?
A: Patients with lower limb deep vein thrombosis should follow medical advice, wear elastic stockings after discharge, take oral anticoagulant drugs for 3 months to 6 months, avoid prolonged standing and sitting, and elevate the affected limbs during rest.
86Q: How to deal with post-thrombosis syndrome?
A: For patients with post-thrombotic syndrome, valve repair can be used if there is incomplete valve closure. Intraoperatively, pulse electrodes are used to stimulate the calf muscles to increase contraction to promote reflux, and postoperatively, the patient is encouraged to move the foot and toes actively.