Carotid artery stenosis

Disease Description (Causes and Symptoms)

• Definition and pathophysiology
  Pulmonary thromboembolism (PE) occurs when a thrombus formed mainly in peripheral veins (deep veins), such as those in the legs, breaks off and travels through the bloodstream to obstruct the pulmonary artery or its branches. Partial blockage of pulmonary blood flow causes ventilation–perfusion mismatch, and reduced oxygenation and increased pulmonary vascular resistance may lead to right ventricular overload and right heart failure. A massive embolism can cause hemodynamic instability and progress to shock and cardiac arrest.
• Main causes (risk factors)
  Older age, surgery or trauma, prolonged immobility/paralysis, cancer (including chemotherapy), a personal or family history of embolism, pregnancy and childbirth, oral contraceptives or hormone replacement therapy, obesity, smoking, central venous catheterization, heart failure, respiratory failure, renal failure, and others.
• Main symptoms and signs
  Sudden shortness of breath, chest pain (pleuritic chest pain), tachycardia, tachypnea, sweating and anxiety, syncope or orthostatic hypotension, hemoptysis (observed in approximately 20%), and shock (systolic blood pressure < 90 mmHg or a sudden drop in blood pressure). A shock index (pulse/systolic blood pressure) > 1 suggests severe disease.

Treatment Methods

• Principles of acute (emergency) treatment
  1. Start anticoagulant therapy immediately (as soon as possible unless there is a risk of systemic bleeding) to prevent progression of existing thrombi and recurrence.
  2. In cases of hemodynamic instability (massive PE, hypotension, or shock), consider thrombolysis (systemic or catheter-directed), catheter-based mechanical removal, or surgical embolectomy.
  3. If right ventricular dysfunction is confirmed, prompt intensive treatment is required (including thrombolysis) — echocardiographic findings are important for prognosis and treatment decisions.
• Drug treatment
  • Initial (acute phase): Use low-molecular-weight heparin (LMWH) or intravenous unfractionated heparin (particularly when renal failure or preoperative use is involved).
  • Long-term oral anticoagulation: Direct oral anticoagulants (DOACs: rivaroxaban, apixaban, edoxaban, etc.) or warfarin (target INR 2.0–3.0). DOACs are often the first choice for many patients because of their convenience and safety (but may be limited in pregnancy, severe renal impairment, certain drug interactions, and other situations).
  • Thrombolytics: Systemic alteplase (e.g., 100 mg over 2 hours, according to guidelines) or catheter-directed local thrombolysis. Indicated for hemodynamic instability caused by massive PE.
• Procedures and surgery
  • Catheter-directed thrombus removal/thrombolysis (for severe cases or when systemic thrombolysis is contraindicated)
  • Surgical embolectomy (in emergencies, massive embolism, or when other methods fail)
  • Inferior vena cava (IVC) filter: Consider when anticoagulant therapy is contraindicated or when recurrence occurs despite appropriate anticoagulant treatment.
• Treatment duration (general recommendations)
  • Provoked thrombosis (temporary risk factor): Usually 3 months of anticoagulation.
  • Unprovoked (idiopathic) thrombosis or persistent risk factors: Usually 6–12 months or longer; long-term (lifelong) anticoagulation may be considered when the risk of recurrence is high or in the presence of specific predispositions (such as inherited thrombophilia). An individualized risk–benefit assessment is required.
• Lifestyle management and precautions
  • Follow instructions for taking anticoagulants (medication, dosage, and regular testing).
  • Contact a medical institution immediately if signs of bleeding (hematuria, black stools, gum bleeding, etc.) occur.
  • Consider prophylactic anticoagulation and mechanical prevention (compression stockings) during long-distance flights, surgery, or prolonged immobility.
  • Consult a healthcare professional about the effects of anticoagulants when planning pregnancy or choosing contraception.

Checklist Before an Outpatient Visit (Including Preparation Items and Example Questions)

• Items to bring (recommended for outpatient visits)
  • A list of medications currently being taken (including anticoagulants and antiplatelet agents), recent doses, and start dates
  • Medical history: previous VTE (venous thromboembolism), bleeding tendency, surgical history, pregnancy and childbirth history, and whether hormone medications are being taken
  • Copies of recent test results, if available (blood tests, INR records, D-dimer, chest CT/scan/echocardiography findings, etc.)
  • Time of symptom onset and progression (symptom diary): record changes in shortness of breath, chest pain, strength, syncope, etc.
  • Lifestyle habits (smoking, alcohol consumption, activity level) and records of recent long-distance travel or immobility
• Items to check at the outpatient visit
  • Recent bleeding and bleeding risk factors (peptic ulcer, history of cerebral hemorrhage, etc.)
  • Kidney and liver function (important for selecting medications and determining dosage)
  • Possibility of pregnancy or whether currently pregnant
  • Treatment adherence and presence of medication side effects

General Example Questions to Ask the Doctor

• What are the main side effects of this medication (the currently recommended anticoagulant), and what signs of bleeding should I watch for?
• How long should anticoagulant treatment continue? What are the criteria for stopping it?
• What precautions should I take during regular activities (exercise, driving, travel) or in daily life?
• I am planning a pregnancy. Which anticoagulant is safe?
• Are there any interactions with other medications (prescription, OTC, or herbal medicines) or foods?

Examples of Disease-Specific Questions

• In my case (e.g., cancer, impaired renal function, plans for pregnancy), which anticoagulant is most appropriate and why?
• If my current symptoms worsen or recurrence is suspected, what specific signs (e.g., changes in blood pressure or oxygen saturation thresholds) mean that I should go to the hospital immediately?

(Brief summary) Key testing and diagnostic points: Clinical assessment (Wells/Geneva score) → D-dimer (useful for ruling out disease when clinical suspicion is low; general cutoff 500 μg/L) → Imaging (CTPA is preferentially used; V/Q scanning is useful in specific situations). Echocardiography is important for assessing right ventricular function and hemodynamics. Treatment consists of immediate anticoagulation, thrombolysis or mechanical/surgical removal in cases of hemodynamic instability, and determining the duration of anticoagulation according to the cause. Long-term follow-up and management are necessary because complications may include chronic thromboembolic pulmonary hypertension (CTEPH), pulmonary infarction, and right heart failure.