What is the recommended diagnostic approach and initial management for a patient with suspected pulmonary hypertension presenting with unexplained dyspnea, fatigue, or syncope?

Diagnostic Approach and Initial Management for Suspected Pulmonary Hypertension

Begin with transthoracic Doppler echocardiography as the primary screening tool when pulmonary hypertension is suspected, followed by right heart catheterization for definitive diagnosis in patients with high probability of PH or symptomatic patients with risk factors. 1

Clinical Suspicion: When to Consider PH

Suspect pulmonary hypertension in patients presenting with:

• Unexplained exertional dyspnea (most common presenting symptom, occurring in 60% at presentation) 2
• Fatigue and weakness reflecting impaired oxygen transport 2
• Syncope or presyncope (occurs in ~40% of patients, especially with exertion) 2
• Chest pain/angina (reported by ~40% during disease course) 2

Physical examination findings that raise suspicion include: 1

• Left parasternal lift (right ventricular heave)
• Accentuated pulmonary component of S2
• Pansystolic murmur of tricuspid regurgitation
• Jugular venous distension, hepatomegaly, peripheral edema (indicating advanced disease with right ventricular failure)
• Lung sounds are typically normal 1

High-risk populations requiring heightened suspicion: 1

• Connective tissue disease
• Portal hypertension/liver disease
• HIV infection
• Congenital heart disease with systemic-to-pulmonary shunts
• Family history of pulmonary hypertension

Initial Diagnostic Workup

First-Line Screening Tests

Transthoracic Doppler echocardiography is the investigation of choice for detecting elevated pulmonary pressures and should be performed first. 3, 4 The echocardiogram stratifies probability as: 1

• "PH unlikely": No further workup if asymptomatic and no risk factors; echocardiographic follow-up if symptomatic 1
• "PH possible": Right heart catheterization may be considered if symptomatic with risk factors 1
• "PH likely" with symptoms: Right heart catheterization is mandatory (Class I recommendation) 1

Chest radiograph should be obtained early but has limited sensitivity for mild PH. 1 Findings include:

• Central pulmonary artery enlargement with peripheral "pruning"
• Right heart chamber enlargement
• Right interlobar artery >15 mm in women (>16 mm in men) 1
• Normal chest X-ray does NOT exclude PH 1

Electrocardiogram provides supportive evidence: 1

• Right ventricular hypertrophy (present in 87% of IPAH)
• Right axis deviation (79% of IPAH)
• Sensitivity only 55%, specificity 70% - inadequate as screening tool alone 1

Essential Laboratory and Imaging Studies

All patients with suspected PAH require: 1

• Routine biochemistry, hematology, immunology, and thyroid function tests (Class I recommendation) to identify associated conditions 1
• Abdominal ultrasound for screening portal hypertension (Class I recommendation) 1
• Ventilation/perfusion (V/Q) lung scan in all patients with unexplained PH to exclude chronic thromboembolic PH (CTEPH) - this is a Class I recommendation 1, 4
• High-resolution CT should be considered in all patients (Class IIa recommendation) 1

Pulmonary function tests and arterial blood gases help evaluate for underlying lung disease. 1

Definitive Diagnosis: Right Heart Catheterization

Right heart catheterization is essential for accurate diagnosis and must be performed before initiating PAH-specific therapy. 4, 5 It is required to: 6, 7

• Confirm PH (mean PAP ≥25 mmHg at rest, or >20 mmHg by newer definitions) 6, 7
• Differentiate pre-capillary PH (PAWP ≤15 mmHg, PVR >3 Wood units) from post-capillary PH (PAWP >15 mmHg) 6, 7
• Assess vasoreactivity for treatment selection 5

Acute vasoreactivity testing during catheterization determines appropriate therapy, defined as: 5

• Decrease in mean PAP of ≥10 mmHg
• Final mean PAP ≤40 mmHg
• Normal or high cardiac output 5

Initial Management Strategy

Immediate Actions Based on Severity

For symptomatic patients with confirmed PH: 1

• Assess WHO Functional Class (I-IV) to guide prognosis and treatment intensity 1, 2
• Perform 6-minute walk test (distance >500m = better prognosis; <300m = worse prognosis) 1
• Measure BNP/NT-proBNP levels (normal/near-normal = better prognosis; very elevated = worse prognosis) 1

Referral Pathway

Urgent referral to a designated PH center is required if: 3

• Patient is syncopal
• Rapidly progressing symptoms
• Signs of heart failure
• Suspected pulmonary arterial hypertension or CTEPH 3

All patients with confirmed PAH or CTEPH must be referred to a specialist center. 4

Treatment Approach by PH Group

The treatment strategy differs fundamentally based on PH classification:

Group 1 (Pulmonary Arterial Hypertension): Targeted PAH therapies including phosphodiesterase-5 inhibitors, endothelin receptor antagonists, prostacyclin analogues, and soluble guanylate cyclase stimulators are indicated. 6, 4

Group 2 (Left Heart Disease): Management focuses on treating the underlying cardiac condition; PAH-specific vasodilators are contraindicated. 3, 4

Group 3 (Lung Disease/Hypoxia): Aggressive management of the underlying lung disease is the cornerstone; routine use of PAH-specific vasodilators is discouraged except in highly selected cases. 8 Supplemental oxygen to maintain SpO₂ >90% is essential. 8

Group 4 (CTEPH): Surgical pulmonary endarterectomy is the treatment of choice for eligible patients. 6, 4

Supportive Care Measures

Long-term oxygen therapy is indicated when arterial oxygen pressure is consistently <60 mmHg (8 kPa) or to maintain SpO₂ >90%. 8, 6

Diuretics should be used for signs of right ventricular failure or fluid overload. 8

Vaccination against influenza and pneumococcal disease is advised. 8

Follow-Up Monitoring

Reassessment every 3-6 months should include: 1

• WHO Functional Class
• 6-minute walk test
• BNP/NT-proBNP levels
• Echocardiography
• Right heart catheterization at baseline, with therapy changes, or clinical worsening 1

Critical Pitfalls to Avoid

Do not rely on ECG or chest X-ray alone - normal results do not exclude severe PH. 1

Do not use PAH-specific vasodilators in Group 2 or Group 3 PH without specialist consultation, as they are contraindicated in left heart disease and can worsen ventilation-perfusion mismatch in lung disease. 8, 3

Do not delay V/Q scanning - it is mandatory to exclude CTEPH, which requires surgical rather than medical management. 1, 4

Open or thoracoscopic lung biopsy is not recommended in patients with PAH (Class III recommendation). 1