Disease Description (Causes and Symptoms)
- Definition summary: A condition that occurs when a blood clot formed in a vein, such as in the leg, travels through the bloodstream to the pulmonary artery and blocks the pulmonary artery or one of its branches, causing ventilation–perfusion imbalance in the lungs and placing strain on the right ventricle.
- Main causes/risk factors: Surgery·trauma·prolonged bed rest (immobility), cancer and anticancer treatment, history of venous thromboembolism, family history, pregnancy·postpartum period, oral contraceptives·hormone replacement therapy, obesity, smoking, medical conditions such as heart failure·renal failure, central venous catheters, etc.
- Pathophysiology (brief): When a distal pulmonary artery is blocked by a blood clot, perfusion to the blocked area decreases, causing ventilation–perfusion mismatch and impaired oxygen exchange. The increased strain on the right ventricle (increased pulmonary vascular resistance) may lead to right ventricular dysfunction·shock.
- Main symptoms: Sudden shortness of breath, chest pain (especially pleuritic·respiratory chest pain), tachycardia, sweating·anxiety, syncope or presyncope symptoms, hemoptysis (observed in approximately 20%), and cough. In severe cases, hypotension·shock or cardiac arrest may occur.
Treatment Methods
- Initial emergency treatment
- Oxygen supplementation and stabilization of vital signs. Emergency treatment and ICU management are required in cases of hypotension·shock.
- Anticoagulation therapy (basic treatment)
- Acute phase: Intravenous unfractionated heparin (LMWH) or unfractionated heparin (IV) is used.
- Oral anticoagulants: Warfarin (INR monitoring during maintenance treatment), or direct oral anticoagulants (DOACs: rivaroxaban, apixaban, etc.) — selected according to the patient’s condition and contraindications (pregnancy, severe renal impairment, etc.).
- Thrombolysis/mechanical removal
- Intravenous thrombolytic agents (e.g., tPA) may be considered in cases of hemodynamic instability (severe hypotension·shock or right ventricular failure) due to massive pulmonary embolism.
- If thrombolysis is contraindicated or fails, emergency thrombectomy (surgical pulmonary embolectomy) or catheter-directed clot removal may be performed.
- Supportive/preventive measures
- Inferior vena cava (IVC) filter placement: Considered when anticoagulation is impossible or in cases of recurrence.
- Rehabilitation·brisk walking exercise, compression stockings (for prevention; helpful in preventing DVT).
- Treatment duration (general guidelines)
- When caused by a clearly identified transient event (provoking factor), such as surgery: generally 3 months.
- When the cause is unknown (unprovoked) or the risk of repeated recurrence is high: Long-term (sometimes lifelong) anticoagulation may be considered (balancing the risk of bleeding is necessary).
- Precautions (during treatment)
- Risk of anticoagulation-related bleeding (risk assessment·monitoring required).
- When taking warfarin, drug·dietary interactions and periodic INR testing are necessary.
- Treatment strategies differ for special populations, including pregnant·breastfeeding patients and patients with cancer (consult a specialist).
- Risk of complications
- Acute: Shock, cardiac arrest, severe hypoxemia.
- Chronic: Secondary pulmonary hypertension, cor pulmonale (right ventricular hypertrophy/failure), pulmonary fibrosis·functional impairment after pulmonary infarction.
Checklist Before an Outpatient Visit (Including Items to Prepare and Sample Questions)
- Items/information to bring
- A list of currently taken medications (including prescription drugs·OTC medications·herbal medicines·supplements) and the time they were most recently taken
- Copies of previous test results (CT, V/Q scan, D-dimer, echocardiography, surgical records, etc.) or reports
- History of previous bleeding (gastrointestinal bleeding, cerebral hemorrhage, etc.) and history of transfusion
- Whether you are pregnant (or might be pregnant) and whether you are breastfeeding
- Time of symptom onset·course (when and how much the symptoms worsen), degree of shortness of breath (during activity·at rest), and characteristics of chest pain
- Changes in lifestyle patterns (recent long-distance travel·surgery·hospitalization·immobility, etc.)
- Checklist to organize before the outpatient visit
- Time of symptom onset and factors that worsen·improve symptoms
- Main symptoms currently experienced (shortness of breath, chest pain, hemoptysis, etc.)
- Whether bleeding symptoms are present (bruising, bleeding gums, hematuria, etc.)
- Risk factors for blood clots (cancer, hormone medication use, family history, etc.)
- Sample questions (items that patients may wish to ask their doctor)
- “If I have symptoms now, should I go to the emergency room?”
- “Do my current medications (e.g., aspirin) affect anticoagulation treatment?”
General Sample Questions to Ask the Doctor
- What are the expected effects and main side effects of this medication? (e.g., risk of bleeding, effects on the liver·kidneys, etc.)
- How long should anticoagulation treatment continue? What are the conditions for stopping it?
- How does treatment differ if I am pregnant or planning to become pregnant?
- In what cases are alternative treatments (such as an IVC filter) recommended when the risk of bleeding is high?
- When and how often should follow-up tests (CT/echocardiography/D-dimer, etc.) be performed?
Examples of Disease-Specific Questions
- Has right ventricular dysfunction (or increased pulmonary artery pressure) been confirmed on the current tests (echocardiography·CT, etc.), and how severe is it such that thrombolysis or active intervention is needed?
- The provoking factor for this pulmonary embolism is not clear. Should additional testing for thrombophilia (inherited·acquired) be performed? What types of tests are needed, and when should they be performed?