What is the appropriate workup for a patient with suspected pulmonary hypertension?

Workup for Pulmonary Hypertension

Begin with transthoracic echocardiography as the first-line screening test to estimate pulmonary artery pressure and assess right ventricular function, followed by right heart catheterization to confirm the diagnosis and guide therapy. 1

Initial Non-Invasive Evaluation

Echocardiography (Essential First Step)

• Perform Doppler echocardiography immediately in all patients with suspected PH to evaluate right ventricular systolic pressure, right atrial enlargement, right ventricular enlargement, pericardial effusion, and left-sided abnormalities 1
• Use contrast echocardiography to detect intracardiac shunting 1
• Assess for left ventricular systolic/diastolic dysfunction, chamber enlargement, and valvular disease to identify Group 2 PH (left heart disease) 1

Basic Screening Tests

• ECG: Screen for cardiac anatomic abnormalities and arrhythmias, though it lacks sensitivity as a standalone screening tool 1
• Chest radiography: Detect features supportive of PH and identify underlying lung diseases 1
• Complete blood count, comprehensive metabolic panel, thyroid function tests, HIV serology, and connective tissue disease screening (ANA, anti-Scl-70, anti-centromere antibodies) in all patients with unexplained PAH 1, 2
• BNP or NT-proBNP levels: Provides prognostic information and helps assess disease severity 2

Distinguishing PH Subtypes

Ventilation-Perfusion Scan (Critical for CTEPH Exclusion)

• Perform V/Q scanning in all patients with PAH to rule out chronic thromboembolic pulmonary hypertension (CTEPH) - a normal scan effectively excludes CTEPH 1
• Do not rely on CT pulmonary angiography alone to exclude CTEPH, as it may miss the diagnosis 1
• If V/Q scan shows multiple segmental perfusion defects, proceed to pulmonary angiography for definitive CTEPH diagnosis and operability assessment 1

Pulmonary Function Testing

• Perform spirometry, lung volumes, and DLCO measurement to evaluate for underlying lung disease (Group 3 PH) 1, 2
• Obtain arterial blood gas analysis to assess oxygenation 1, 2
• Consider nocturnal oximetry if sleep-disordered breathing is suspected 1

High-Resolution Chest CT

• Obtain high-resolution CT in all patients to evaluate parenchymal lung disease, identify pulmonary veno-occlusive disease features, and assess for chronic thromboembolic disease 1, 2

Definitive Diagnosis

Right Heart Catheterization (Mandatory)

• Right heart catheterization is required in all patients with suspected PH to confirm the diagnosis, establish specific hemodynamic classification, determine severity, and guide therapy 1
• Measure mean pulmonary artery pressure (mPAP >20 mmHg defines PH), pulmonary artery wedge pressure (PAWP), cardiac output, and calculate pulmonary vascular resistance 1, 3
• Distinguish pre-capillary PH (PAWP ≤15 mmHg, PVR >2 WU) from post-capillary PH (PAWP >15 mmHg) 3

Acute Vasoreactivity Testing

• Perform acute vasoreactivity testing during catheterization in patients with idiopathic PAH using short-acting agents (IV epoprostenol, adenosine, or inhaled nitric oxide) 1
• A positive response (fall in mean PAP ≥10 mmHg to ≤40 mmHg with increased or unchanged cardiac output) identifies candidates for calcium channel blocker therapy 1
• Testing should be performed by physicians experienced in pulmonary vascular disease management 1

Additional Specialized Testing

Abdominal Ultrasound

• Perform abdominal ultrasound to screen for portal hypertension in patients with unexplained PAH 1

Genetic Testing

• Offer genetic testing and counseling to relatives of patients with familial/heritable PAH 1
• Advise patients with idiopathic PAH about genetic testing availability for their relatives 1

Functional Assessment

• Perform 6-minute walk test with Borg dyspnea score to establish baseline exercise capacity and provide prognostic information 1, 2
• Consider cardiopulmonary exercise testing for additional functional assessment 1

Critical Pitfalls to Avoid

• Never use calcium channel blockers empirically without documented acute vasoreactivity, as this can be harmful 1
• Do not perform lung biopsy routinely due to high risk; reserve only for cases where tissue diagnosis is essential 1
• Do not delay referral to a PH expert center once diagnosis is suspected - early specialist involvement improves outcomes 1, 4, 5
• Ensure V/Q scanning is performed before relying on CT alone to exclude CTEPH, as CT has insufficient sensitivity 1

Referral Timing

Refer immediately to a pulmonary hypertension specialist center when echocardiography suggests high probability of PH, when right ventricular dysfunction is present, or when initial workup confirms PH without clear left heart or lung disease etiology 1, 4, 5