What are the diagnostic steps and treatment options for pulmonary hypertension?

Diagnostic Steps and Treatment Options for Pulmonary Hypertension

Echocardiography is the recommended first-line diagnostic investigation for pulmonary hypertension, followed by a systematic diagnostic algorithm to determine the specific type and cause, with treatment tailored to the underlying etiology. 1

Diagnostic Algorithm for Pulmonary Hypertension

Step 1: Initial Assessment

• Echocardiography: First-line non-invasive diagnostic test when PH is suspected 1

  • Assess for:
    • Tricuspid regurgitation velocity
    • Right ventricle/left ventricle basal diameter ratio >1.0
    • Flattening of interventricular septum
    • Right ventricular outflow Doppler acceleration time <105 msec
    • Pulmonary artery diameter >25 mm
    • Right atrial enlargement (area >18 cm²)

• Probability Classification based on echocardiographic findings 1:

  • Low probability: No further testing if no risk factors present
  • Intermediate probability: Further assessment needed
  • High probability: Proceed to confirmatory testing

Step 2: Identify Underlying Cause

• For intermediate/high probability cases, evaluate for:

  • Left heart disease and lung diseases through:
    • ECG
    • Pulmonary function tests with DLCO
    • Chest radiograph
    • High-resolution CT
    • Arterial blood gases

• If left heart/lung disease confirmed:

  • Treat underlying condition if no signs of severe PH/RV dysfunction
  • Refer to PH expert center if severe PH/RV dysfunction present

• If left heart/lung disease not confirmed:

  • Perform V/Q scan to assess for CTEPH 1

Step 3: Confirmatory Testing

• Right Heart Catheterization (RHC): Gold standard for definitive diagnosis 1, 2

  • Diagnostic criteria: mPAP ≥25 mmHg, PAWP ≤15 mmHg, PVR >3 Wood units

• Additional Testing based on suspected etiology:

  • For CTEPH: CT pulmonary angiography, pulmonary angiography 1
  • For PAH: Comprehensive blood work including:
    • Routine biochemistry, hematology
    • Immunology, HIV testing
    • Thyroid function tests
    • Abdominal ultrasound for portal hypertension 1

Classification and Risk Assessment

PH Classification

1. Group 1: Pulmonary arterial hypertension (PAH)
2. Group 2: PH due to left heart disease
3. Group 3: PH due to lung diseases
4. Group 4: Chronic thromboembolic PH (CTEPH)
5. Group 5: PH with unclear/multifactorial mechanisms

Risk Stratification

• Low risk (<5% 1-year mortality):

  • No clinical signs of RV failure
  • WHO FC I-II
  • 6MWD >440m
  • BNP <50 ng/L or NT-proBNP <300 ng/L

• Intermediate risk (5-10% 1-year mortality):

  • WHO FC III
  • 6MWD 165-440m
  • BNP 50-300 ng/L or NT-proBNP 300-1400 ng/L

• High risk (>10% 1-year mortality):

  • Clinical signs of RV failure
  • WHO FC IV
  • 6MWD <165m
  • BNP >300 ng/L or NT-proBNP >1400 ng/L 2

Treatment Approach

General Measures

• Oxygen therapy: For patients with arterial O₂ <60 mmHg 2
• Diuretics: For right ventricular failure with fluid retention
• Anticoagulation: Consider for idiopathic PAH
• Effective contraception: Strongly recommended for women with PAH due to high maternal/fetal mortality risk (30-50%) 2

Specific Treatment Based on PH Group

Group 1 (PAH)

• Low/Intermediate Risk Patients:

  • Initial oral combination therapy targeting multiple pathways:
    • Endothelin receptor antagonist (ERA) + PDE-5 inhibitor
    • Preferred combinations: Ambrisentan + Tadalafil or Bosentan + Sildenafil 2

• High Risk Patients:

  • IV epoprostenol as first-line therapy 2, 3
  • Consider adding ERA and/or PDE-5 inhibitor

Group 2 (Left Heart Disease)

• Optimize treatment of underlying heart condition
• PAH-specific therapies not recommended 1

Group 3 (Lung Disease)

• Optimize treatment of underlying lung disease
• Long-term oxygen therapy
• Conventional vasodilators not recommended (may impair gas exchange) 1

Group 4 (CTEPH)

• Pulmonary endarterectomy (PEA): Treatment of choice, potentially curative 2
• For inoperable CTEPH:
  • Riociguat (soluble guanylate cyclase stimulator)
  • Balloon pulmonary angioplasty in expert centers 2

Advanced Options

• Lung transplantation: For inadequate response to maximal medical therapy
• Balloon atrial septostomy: As palliative procedure or bridge to transplantation in select cases 2

Follow-up and Monitoring

• Regular assessments every 3-6 months in stable patients 1
• Monitoring parameters:
  • Functional class
  • Exercise capacity (6MWD)
  • BNP/NT-proBNP levels
  • Echocardiographic parameters
  • Hemodynamics when indicated 1

Common Pitfalls to Avoid

• Excessive fluid administration worsening right heart failure
• Delayed escalation of therapy leading to poor outcomes
• Using calcium channel blockers without vasoreactivity testing
• Monotherapy for high-risk patients
• Failure to refer to specialized PH centers 2

All patients with confirmed PH should be managed at specialized centers with multidisciplinary expertise in pulmonary hypertension for optimal outcomes.