Cor Pulmonale

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Referral

Definition

Cor pulmonale is right-sided heart failure caused by chronic pulmonary hypertension due to lung disease or pulmonary vascular disorders.

Aetiology

Common causes of cor pulmonale include:

  • Chronic lung diseases:
    • Chronic obstructive pulmonary disease (COPD) – most common cause.
    • Interstitial lung disease (e.g., pulmonary fibrosis).
    • Obstructive sleep apnoea (OSA).
    • Bronchiectasis.
    • Cystic fibrosis.
  • Pulmonary vascular disorders:
    • Chronic thromboembolic pulmonary hypertension (CTEPH).
    • Recurrent pulmonary emboli.
  • Chest wall and neuromuscular disorders:
    • Kyphoscoliosis.
    • Myasthenia gravis.
    • Motor neurone disease (MND).
  • High-altitude exposure: Chronic hypoxia leading to pulmonary hypertension.

Pathophysiology

Cor pulmonale develops due to chronic hypoxia, leading to:

  • Pulmonary vasoconstriction: hypoxia-induced narrowing of pulmonary arteries.
  • Pulmonary hypertension: increased resistance in the pulmonary circulation.
  • Right ventricular hypertrophy (RVH): the right ventricle thickens due to increased workload.
  • Right-sided heart failure: the right ventricle fails due to sustained pressure overload.

Risk factors

  • Chronic hypoxia (e.g., COPD, interstitial lung disease).
  • Obesity hypoventilation syndrome.
  • Obstructive sleep apnoea.
  • Recurrent pulmonary embolism.
  • Chronic mountain sickness (due to high-altitude exposure).

Signs and symptoms

Symptoms:

  • Progressive breathlessness.
  • Fatigue and weakness.
  • Exertional syncope (fainting due to reduced cardiac output).
  • Peripheral oedema (fluid retention in the legs and ankles).

Signs:

  • Elevated jugular venous pressure (JVP).
  • Right ventricular heave: due to right ventricular hypertrophy.
  • Loud P2 (pulmonary component of the second heart sound): due to pulmonary hypertension.
  • Hepatomegaly: enlarged liver due to venous congestion.
  • Ascites: fluid accumulation in the abdomen in severe cases.

Investigations

  • Blood tests:
    • Full blood count (FBC): may show polycythaemia (increased red cell mass due to chronic hypoxia).
    • B-type natriuretic peptide (BNP): raised in right heart failure.
  • Arterial blood gas (ABG): shows hypoxaemia and hypercapnia.
  • ECG:
    • Right axis deviation.
    • P pulmonale (tall P waves in lead II indicating right atrial enlargement).
    • Right ventricular hypertrophy (RVH).
  • Chest X-ray:
    • Enlarged right heart border.
    • Evidence of underlying lung disease.
  • Echocardiography (ECHO):
    • Confirms right ventricular hypertrophy and pulmonary hypertension.
  • CT pulmonary angiography (CTPA): to rule out chronic thromboembolic disease.
  • Right heart catheterisation: gold standard for diagnosing pulmonary hypertension.

Management

1. Treat Underlying Lung Disease:

  • Optimise COPD management (e.g., inhalers, pulmonary rehabilitation).
  • Treat interstitial lung disease with appropriate immunosuppression if indicated.
  • Manage obstructive sleep apnoea with CPAP.

2. Oxygen Therapy:

  • Long-term oxygen therapy (LTOT) if PaO₂ <7.3 kPa or evidence of right heart failure.
  • Target SpO₂ 88-92% in patients with chronic hypercapnia.

3. Pulmonary Vasodilators (if indicated in pulmonary hypertension):

  • Phosphodiesterase-5 inhibitors (e.g., sildenafil).
  • Endothelin receptor antagonists (e.g., bosentan) in selected cases.

4. Diuretics for Symptom Relief:

  • Furosemide 40 mg OD for fluid overload.
  • Monitor for electrolyte imbalances.

5. Anticoagulation:

  • For chronic thromboembolic pulmonary hypertension (CTEPH).
  • Consider lifelong anticoagulation.

Referral

Refer to secondary care in the following scenarios:

  • Respiratory specialist: if cor pulmonale is suspected but the cause is unclear.
  • Cardiology: if right heart failure is suspected and further cardiac imaging is needed.
  • Hospital admission:
    • Severe hypoxia requiring oxygen therapy.
    • Worsening right heart failure with significant fluid overload.
    • Signs of decompensation (e.g., hypotension, altered mental status).
 
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