Pulmonary thromboembolism

Disease Description (Causes and Symptoms)

• Definition summary: Pulmonary thromboembolism (PE) is an acute condition that occurs when a blood clot formed in the deep veins, such as those in the legs, breaks loose and travels through the bloodstream to block a pulmonary artery or one of its branches. This blocks part of the blood flow to the lungs, causing impaired gas exchange and strain on the right ventricle.
• Main causes/risk factors: Surgery, trauma, prolonged immobility or paralysis, cancer (and cancer treatment), a personal or family history of embolism, pregnancy, childbirth, oral contraceptives, hormone therapy, obesity, smoking, central venous catheters, heart failure, kidney failure, and others.
• Key pathophysiology: Mechanical obstruction of the pulmonary artery → reduced perfusion in the affected area and ventilation/perfusion mismatch → hypoxemia and increased pulmonary vascular resistance → strain on the right ventricle (potentially causing heart failure or shock).
• Main symptoms (suspect immediately): Sudden shortness of breath, chest pain (which may worsen with inhalation), tachycardia, fainting or dizziness, hemoptysis (observed in approximately 20% of cases), sweating, anxiety, and cough. Massive embolism carries a risk of hypotension, shock, and cardiac arrest.

Treatment Methods and Precautions

• Treatment goals: Immediate prevention of death, prevention of recurrence, and prevention of long-term complications (e.g., chronic pulmonary hypertension).
• Acute, hemodynamically stable patients
  • First-line anticoagulation: Low-molecular-weight heparin (LMWH) is used initially, or unfractionated heparin (IV heparin) in patients with hypotension or hemodynamic instability. Switch to an oral anticoagulant after several days.
  • Direct oral anticoagulants (DOACs: rivaroxaban, apixaban, etc.) are widely used as standard options for the initial and maintenance treatment of non-cancer-associated VTE.
  • Warfarin (e.g., requires INR monitoring) is used when DOACs cannot be used or for special indications (such as mechanical heart valves).
• High-risk patients (massive embolism, hemodynamic instability)
  • Intravenous thrombolysis (thrombolytic therapy): Indicated in cases of hypotension or cardiogenic shock. The immediate risk of bleeding must be considered.
  • Catheter-based thrombectomy or surgical embolectomy (considered for massive embolism).
• In cases of recurrence, contraindication to anticoagulants, or treatment failure
  • Inferior vena cava (IVC) filter insertion: Considered temporarily or permanently when anticoagulants cannot be used or recurrent embolism occurs.
• Duration of anticoagulation (general recommendations)
  • Provoked VTE (e.g., surgery or air travel): Usually 3 months.
  • Unprovoked (idiopathic) VTE: At least 3 months, followed by an assessment of the balance between recurrence and bleeding risks to determine whether to extend treatment (often long-term or lifelong).
  • Cancer-associated VTE: Extended treatment duration (LMWH or a DOAC is often recommended for as long as the cancer remains active).
• Lifestyle management and precautions
  • Always be aware of the risk of bleeding during anticoagulant treatment: Consult a doctor before an injury or surgical procedure.
  • Check for interactions with alcohol and certain medications (such as antibiotics and antifungals).
  • If planning pregnancy, breastfeeding, or scheduled for surgery, consult healthcare professionals in advance about anticoagulant management (alternative treatment and when to stop the medication).
  • In an immediate emergency (severe shortness of breath, chest pain, fainting, significant hemoptysis, or hypotension), visit the emergency department.

Outpatient Visit Checklist (Including Preparations and Sample Questions)

• Items to prepare (to bring to the hospital/outpatient visit)
  • A list of all medications currently being taken (including prescription drugs, over-the-counter medications, and supplements)
  • Previous test results (recent chest CT, V/Q scan, D-dimer, INR, etc.) and imaging files (if possible, on a USB drive or as the original)
  • Medical history (recent surgery, trauma, pregnancy, history of cancer, or previous venous thrombosis)
  • Information about bleeding tendencies (previous bleeding, stomach ulcers, liver disease, etc.) and allergies
  • A record of when symptoms began, how they have changed (frequency and triggers of shortness of breath), and their impact on daily life
• Key information to tell the doctor directly during the outpatient visit
  • The time symptoms began and their progression, and whether there has been recent long-distance travel, surgery, or immobility
  • Possibility of pregnancy or use of contraceptive pills
  • Previous experience taking anticoagulants and whether there have been any bleeding problems

General Sample Questions to Ask the Doctor

• "Which anticoagulant is recommended for my current condition, and why?"
• "How long will I need to take the anticoagulant, and what are the criteria for stopping it?"
• "What are the main side effects of this medication, and what should I do if bleeding occurs?"
• "When should I visit the emergency department? (What are the specific warning symptoms?)"
• "What precautions should I take regarding lifestyle activities (exercise, alcohol consumption, travel, and dental treatment)?"

Examples of Condition-Specific Questions

• "I am planning to undergo surgery (or become pregnant) soon. How should my anticoagulant be adjusted?"
• "I have cancer (or reduced kidney function, etc.). Which anticoagulant would be safer and more effective for me?"

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