Background Pulmonary arterial hypertension (PAH) is the leading cause of mortality in patients with systemic sclerosis (SSc).
Objectives To determine the cumulative survival rates and predictors of mortality in SSc- PAH
Methods Patients enrolled in a SSc longitudinal cohort between 2007 and 2015 were included. PAH was diagnosed on right heart catheterization (RHC) (mPAP >25 and PAWP <15 mmHg). Patients with pulmonary hypertension secondary to interstitial lung disease (ILD) and co-existent PAH and severe interstitial lung disease (ILD) (defined as a HRCT scan demonstrating ILD with a FVC<60%) were excluded. Summary statistics, chi-square tests and survival methods including Kaplan-Meier survival curves and cox proportional hazards regression were used to determine survival rates and identify predictors of mortality.
Results Among 132 SSc PAH, 84.9% were female, 68.9% had limited disease subtype (lcSSc), the mean age at diagnosis of PAH was 62.3 years and disease duration at PAH diagnosis was 14.1 years. Over a median follow-up of 3.7 years, 60 (45.5%) patients died with a median survival time from PAH diagnosis of 3.7 years. The standardized mortality ratio for patients with SSc-PAH compared with mortality in the general population is 5.8 (95%CI 4.3–7.8). The years of life lost overall for both males and females due to SSc-PAH was 15.22 years (95%CI 12.3–18.1). Kaplan-Meier survival curves showed a survival advantage with combination therapy and anticoagulation. In cox proportional hazards regression analysis (table1), older age at PAH diagnosis, presence of mild ILD, worse WHO functional class, higher mean pulmonary arterial pressure at PAH diagnosis and presence of digital ulcers were predictive of PAH mortality. Combination PAH therapy together with anticoagulation, provided the most significant survival advantage with a 72% reduction in mortality compared with pulmonary vasodilator therapy alone.
Conclusions Despite advanced therapy, the median survival in SSc PAH is only 4 years. In our study, the addition of anticoagulation to standard combination therapy was associated with a significant survival advantage, pointing to mechanisms involving endothelial abnormalities and small vessel thrombosis in the pathogenesis of PAH.
Disclosure of Interest None declared