Yes, systemic sclerosis (scleroderma) is a well-established cause of pulmonary arterial hypertension (PAH).
Scleroderma is one of the most common causes of PAH among connective tissue diseases, with a prevalence of approximately 7-12% in systemic sclerosis patients based on right heart catheterization, and represents the second most common cause of PAH after idiopathic PAH in registry data 1, 2.
Epidemiology and Risk
The association between systemic sclerosis and PAH is particularly strong:
- Prevalence ranges from 7-12% when confirmed by right heart catheterization 3, 2
- Limited systemic sclerosis (CREST syndrome) carries the highest risk, with PAH being the cause of death in up to 50% of patients who die from scleroderma-related complications 4
- Echocardiographic screening suggests even higher prevalence (up to 27%), though this includes false positives 3
Pathophysiology
The pulmonary vasculopathy in SSc-PAH is histologically indistinguishable from idiopathic PAH, characterized by progressive thickening and obliteration of pulmonary vessels 2, 5. However, there is more frequent involvement of pulmonary veins in SSc-PAH compared to other forms 2.
Clinical Implications and Prognosis
SSc-PAH carries a worse prognosis than idiopathic PAH, with poorer response to conventional therapies 6, 7, 5. In one study, patients with scleroderma-associated PAH had only 40% two-year survival compared to better outcomes in idiopathic PAH 6. Even with epoprostenol therapy, SSc-PAH patients demonstrate worse outcomes (hazard ratio for death 2.32) 6.
Screening Recommendations
All symptomatic patients with scleroderma should undergo echocardiographic screening for PAH detection (Class I, Level B recommendation) 8, 1, 2. The guidelines also suggest that screening may be considered even in asymptomatic patients with scleroderma spectrum disease (Class IIb, Level C) 8, 1.
Annual echocardiographic screening is recommended for systemic sclerosis patients, with right heart catheterization if echocardiogram demonstrates evidence of PAH 3, 9. The DETECT algorithm has been developed specifically to improve early detection in SSc patients with diffusion capacity <60% 9.
Diagnostic Confirmation
Right heart catheterization is mandatory in all cases of suspected PAH associated with connective tissue disease, particularly if specific drug therapy is being considered (Class I, Level C) 8, 1, 2. Echocardiography alone is insufficient for diagnosis, as it cannot distinguish precapillary from postcapillary PH or accurately assess pulmonary vascular resistance.
Treatment Approach
The same treatment algorithm used for idiopathic PAH is recommended for SSc-PAH (Class I, Level A) 8, 1, 2. However, recent guidelines advocate for upfront combination therapy with endothelin receptor antagonists and phosphodiesterase-5 inhibitors at diagnosis 10, 11. For patients with WHO functional class III/IV or intermediate/high risk, escalation to triple therapy including selexipag or switching to riociguat should be promptly considered 10.
Important Caveats
- SSc patients can develop multiple forms of pulmonary hypertension beyond PAH, including PH from left heart disease, interstitial lung disease, or pulmonary veno-occlusive disease 12, 13
- Distinguishing isolated PAH from PH associated with significant interstitial lung disease is critical, as treatment approaches differ
- Follow-up within 3 months of PAH diagnosis is critical given the rapid progression in SSc-PAH 11