Doctors Revision

Cardiovascular System

Deep Vein Thrombosis/Pulmonary Embolism (DVT/PE)

Deep Vein Thrombosis (DVT) involves clot formation in deep veins (leg/pelvis). Pulmonary Embolism (PE) occurs when a clot dislodges and travels to the lungs. These conditions are often considered together as venous thromboembolism (VTE).

Also known as: DVT, PE, Blood Clot (Leg/Lung)

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Referral and warning signs

When to refer

Refer to hospital (H/RR) for diagnosis confirmation (ultrasound, CTPA) and initiation of anticoagulation. Urgent referral/consultation needed for suspected massive PE (hypotension, severe hypoxia) for consideration of thrombolysis/advanced care. Refer for management of bleeding complications or complex cases.

Red flags

  • Sudden onset severe shortness of breath, chest pain, haemoptysis
  • Hypotension, tachycardia, signs of shock (suggestive of massive PE)
  • Significant bleeding while on anticoagulation
  • Warm, swollen, painful limb unresponsive to initial measures

Signs and symptoms

  • DVT: Pain, swelling, warmth, redness of calf, thigh, or groin (may be unilateral). 50% clinically silent.
  • PE: Sudden onset dyspnoea (shortness of breath), tachycardia (rapid heart rate), pleuritic chest pain, cough (sometimes haemoptysis), hypotension, syncope (fainting). Half associated with silent DVT.

Risk factors

  • Immobilisation (prolonged bed rest, surgery, paralysis, long travel)
  • Surgery (especially orthopaedic, major abdominal/pelvic)
  • Trauma (blunt trauma, venous injury, cannulation)
  • Heart failure, Myocardial infarction
  • Malignancy and chemotherapy
  • Pregnancy and postpartum period
  • Oral contraceptive pills or hormone replacement therapy
  • Inherited thrombophilic states (e.g., Factor V Leiden)
  • Obesity
  • Increasing age
  • Previous DVT/PE

Diagnosis

Clinical assessment

Suspect DVT based on unilateral leg swelling/pain/warmth and risk factors (Wells score can help stratify risk). Suspect PE based on acute dyspnoea/chest pain/tachycardia/hypotension and risk factors. Differential diagnosis (DVT): Cellulitis, myositis, phlebitis, contusion, Baker's cyst rupture. Differential diagnosis (PE): Pneumonia, myocardial infarction, heart failure exacerbation, pneumothorax, anxiety.

Investigations

  • DVT: Compression ultrasound +/- Doppler of affected limb (Primary investigation).
  • PE: CT Pulmonary Angiogram (CTPA) (Primary investigation if available/patient stable). Ventilation/Perfusion (V/Q) scan (alternative).
  • D-dimer blood test: High negative predictive value (useful to rule out VTE in low-risk patients). Elevated in many conditions.
  • ECG: May show S1Q3T3 pattern, right heart strain, tachycardia (often non-specific).
  • Chest X-ray: Often normal in PE, may show atelectasis, effusion, or Hampton's hump/Westermark sign (rare). Rules out other causes.
  • Echocardiogram: Can show right heart strain in significant PE.
  • Activated Partial Thromboplastin Time (APTT): Monitor if using unfractionated heparin.
  • Prothrombin Time / International Normalized Ratio (INR): Monitor if using warfarin.

Diagnostic criteria

Clinical suspicion combined with positive imaging (Compression ultrasound for DVT, CTPA/VQ scan for PE) or supported by risk stratification and D-dimer testing.

Management

Non-pharmacological management

  • Early mobilisation after surgery/illness.
  • Graduated compression stockings (prevention/post-thrombotic syndrome).
  • Inferior Vena Cava (IVC) filter (in specific cases with contraindication to anticoagulation or recurrent PE despite anticoagulation - specialist decision).

Pharmacological treatment

  • Anticoagulation (Mainstay of treatment):
  • - Initial: Enoxaparin (LMWH) 1 mg/kg SC every 12 hours OR 1.5mg/kg SC once daily.
  • - OR Unfractionated Heparin (UFH) 5000 units IV bolus then infusion (e.g., 1000 units/hr, adjust per APTT) OR SC regimen (e.g., 17500 units Q12h or weight-based).
  • - Start Warfarin 5 mg PO daily concurrently with Heparin (overlap for at least 5 days AND until INR is therapeutic [2.0-3.0] for 2 consecutive days).
  • - Maintenance: Warfarin dose adjusted based on INR target 2.0-3.0 (Typical dose 2.5-10mg daily). Duration usually 3-6 months, longer or indefinite based on risk factors/recurrence.
  • - Alternative anticoagulants (Direct Oral Anticoagulants - DOACs like Rivaroxaban, Apixaban) are now often preferred where available (simpler dosing, no INR monitoring), but require specific protocols.
  • Thrombolysis (for massive PE with haemodynamic instability - specialist management).
  • Prophylaxis (High-risk patients - acutely ill medical, post-op): Enoxaparin 40 mg SC daily (or UFH 5000 units SC Q8-12h).

Monitoring

  • Monitor for signs of bleeding.
  • Monitor INR regularly (daily initially, then spaced out) while on Warfarin.
  • Monitor APTT if using UFH infusion.
  • Monitor platelet count if using Heparin (risk of HIT).
  • Monitor for symptom resolution and signs of post-thrombotic syndrome.

Complications

  • Pulmonary Embolism (from DVT)
  • Death (from massive PE)
  • Post-thrombotic syndrome (chronic leg pain, swelling, skin changes)
  • Chronic thromboembolic pulmonary hypertension (CTEPH)
  • Bleeding from anticoagulation
  • Heparin-Induced Thrombocytopenia (HIT)

Prevention

  • Early mobilisation post-surgery/illness.
  • Pharmacological prophylaxis (LMWH/UFH) in high-risk hospitalised patients.
  • Mechanical prophylaxis (compression stockings, intermittent pneumatic compression devices).
  • Avoid prolonged immobility during travel.
  • Manage underlying risk factors (obesity, smoking, HRT/OCP use).

Patient education

  • Explain DVT/PE and the purpose of anticoagulation.
  • Importance of adherence to medication (especially Warfarin and INR monitoring).
  • Signs and symptoms of bleeding to watch for and report immediately.
  • Need for regular INR checks if on Warfarin.
  • Dietary considerations with Warfarin (consistent Vitamin K intake).
  • Risk factor modification.
  • Signs of recurrence.
  • Importance of compression stockings if recommended.

Uganda-specific notes

LMWH (Enoxaparin) and Warfarin are the primary agents listed in UCG. INR monitoring capacity may be limited. Access to CTPA is restricted to higher centres. Clinical suspicion and early treatment initiation are crucial. Prophylaxis in high-risk patients is important.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 4, Section 4.1.1

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