What is the recommended diagnostic and management approach for pulmonary arterial hypertension secondary to systemic sclerosis?

Approach to Scleroderma-Induced Pulmonary Arterial Hypertension

Diagnostic Strategy

Begin with annual systematic screening using echocardiography in all systemic sclerosis patients, and apply the DETECT algorithm for patients with diffuse cutaneous SSc >3 years duration or limited cutaneous SSc >3 years duration to identify those requiring right heart catheterization. 1, 2

Screening Protocol

• Annual echocardiography is mandatory for all SSc patients, even without symptoms 2, 3
• Use the DETECT algorithm as your primary risk stratification tool - it combines clinical variables (FVC%, DLCO%, telangiectasias, anticentromere antibodies, NT-proBNP, uric acid, ECG findings) to identify high-risk patients requiring right heart catheterization 4, 5
• Right heart catheterization remains the gold standard for confirming PAH diagnosis - do not treat based on echocardiography alone 2

Diagnostic Criteria

The new hemodynamic definition of PAH is:

• Mean pulmonary artery pressure (mPAP) ≥20 mmHg (previously ≥25 mmHg)
• Pulmonary vascular resistance (PVR) ≥2 Wood units
• Pulmonary artery wedge pressure ≤15 mmHg 6

Critical pitfall: SSc patients can develop multiple forms of pulmonary hypertension - you must exclude Group 2 PH (left heart disease) and Group 3 PH (interstitial lung disease-associated) before diagnosing PAH, as treatment differs fundamentally 2, 5.

Treatment Approach

Initiate upfront combination therapy with an endothelin receptor antagonist (ERA) plus a phosphodiesterase-5 inhibitor (PDE5i) at the time of PAH diagnosis - this is now the standard of care based on the 2025 EULAR recommendations. 1

Initial Treatment Algorithm

For treatment-naïve patients or those on stable PDE5i/ERA monotherapy:

• Start combination ERA + PDE5i immediately at diagnosis 1
• Evidence shows 53.7% lower risk of clinical failure with upfront combination in SSc-PAH 1
• This applies whether the patient is completely treatment-naïve or already on stable doses of either drug class 1

Risk-Based Escalation Strategy

Reassess at 3-6 months using WHO functional class and ERS risk stratification:

If WHO Class I-II or ERS Low/Intermediate Risk:

• Continue current combination therapy 1
• Maintain close follow-up every 3-6 months 2

If WHO Class III-IV or ERS Intermediate-High/High Risk:

• Add selexipag (prostacyclin pathway agonist) to achieve triple therapy - this showed 44% reduction in morbidity/mortality events (HR 0.56,95% CI 0.34-0.91) in SSc-PAH patients 1
• Alternative option: Switch to riociguat (soluble guanylate cyclase stimulator) if already on dual therapy, particularly if there are tolerability issues 1
• For WHO Class IV: Consider intravenous epoprostenol for advanced disease 1

Treatment Hierarchy by Strength of Recommendation

From the 2025 EULAR guidelines 1:

• Strength A (strongest): PDE5i, ERAs (bosentan specifically mentioned)
• Strength B: Riociguat, Selexipag (prostacyclin agonists)
• Strength C: Warfarin is NOT recommended (important negative recommendation)

Key distinction: SSc-PAH responds more poorly to therapies than idiopathic PAH, making early aggressive combination therapy even more critical 7, 8.

Follow-Up Protocol

Perform structured reassessment within 3 months of diagnosis, then every 3-6 months for stable patients 2, 4:

Evaluate at each visit:

• WHO functional class
• 6-minute walk distance
• NT-proBNP or BNP levels
• Echocardiographic parameters
• Consider repeat right heart catheterization if clinical deterioration 2

Critical Pitfalls to Avoid

1. Do not delay diagnosis: SSc-PAH progresses rapidly and has worse prognosis than idiopathic PAH - the 3-year mortality approaches 50% if untreated 9

2. Do not start with monotherapy: The evidence strongly supports upfront combination therapy, not sequential escalation 1

3. Do not use PAH therapies for Group 2 or Group 3 PH: These are contraindicated in left heart disease and lung disease-associated PH 2

4. Do not forget immunomodulation: While managing PAH, continue appropriate disease-modifying therapy for the underlying SSc with rheumatology 5, 8

5. Do not manage in isolation: SSc-PAH requires multidisciplinary care involving both PH specialists and rheumatologists 2, 4

Practical Implementation

Establish a structured care pathway 4:

• Dedicated case manager or nurse coordinator
• Formal referral network between rheumatology and cardiology/pulmonology
• Protocol-driven screening implementation
• Rapid-access right heart catheterization for high-risk patients

The evidence is clear that early detection through systematic screening combined with aggressive upfront combination therapy offers the best chance of improving the historically poor outcomes in SSc-PAH 1, 4, 3.