Background Pulmonary arterial hypertension (PAH) is a severe pulmonary complication in systemic lupus erythematosus (SLE) and may progress to deterioration of right heart dysfunction, while the long-term outcomes of PAH patients with SLE (SLE-PAH) are rarely reported.

Objectives This study aimed to describe the long-term outcomes and predictors of mortality in SLE-PAH patients in a single-center, right heart catheterization (RHC)-confirmed SLE-PAH cohort.

Methods A prospective observational cohort of SLE-PAH patients was established and followed from November 2006 to May 2014, in our rheumatology center. All eligible participants fulfilled the 1997 or 2009 ACR revised classification criteria of SLE and was diagnosed with PAH by RHC and ruling out interstitial lung disease and chronic pulmonary thromboembolism. Clinical characteristics, laboratory parameters, SLE disease activity measurements were recorded as well as long-term outcomes including PAH-related death, and treat-to-target. Survival analysis was performed using the Kaplan-Meier method with comparisons performed by log-rank test. Multivariate Cox proportional hazards models were performed to identify independent predictors of different outcomes.

Results A total of 104 RHC-confirmed SLE-PAH patients were enrolled. The duration of SLE and PAH at enrollment were (6.99±6.30) years and (1.77±2.07) years, respectively. RHC revealed mean pulmonary arterial pressure was (46.9±11.4) mmHg, cardiac index (CI) (2.7±0.8) L/(min·m²). Forty-eight (46.2%) patients were in WHO functional class I/II. All patients received glucocorticoids and immunosuppressants including cyclophosphamide, cyclosporine, azathioprine, mycophenolate mofetil or methotrexate. 64.4% of them were treated with PAH-targeted medications. All of the patients were followed up for a median of 18.6months (range 1.8-90.7 months), during which 14 (13.5%) patients died, and 51 (49.0%) patients got treat-to-target achievement. The overall survival rates as 1 and 3 years were 93.0%, 78.0%, respectively. Multivariate Cox analysis showed that right atrial pressure elevation (>5 mmHg) was the only independent risk factor of PAH-related death (HR 7.767, P =0.017). Hypocomplementemia (HR 4.692, P =0.007), Early diagnosed PAH by RHC (<6 months) (HR 4.859, P =0.007), and CI ≥2.5 L/min/m² ((HR 4.290, P =0.013) were independent predictive factors for treat-to-target achievement.

Conclusions This study described the long-term outcome in a cohort of patients with SLE-PAH followed with comprehensive evaluation by both rheumatologists and cardiologists. The survival rates were estimated higher than previously reported cohorts. Increased RAP at the time of PAH diagnosis portended a poor prognosis in these patients. Those PAH patients with increased SLE activity score, reserved heart function and who received prompt diagnostic procedure at early stage of PAH were more responsive to PAH treatment.

Acknowledgements This study was supported by the Chinese National Key Technology R&D Program, Ministry of Science and Technology (2008BAI59B02,2011BAI11B15), the Chinese National High Technology Research and Development Program, Ministry of Science and Technology (2012AA02A513), the Research Special Fund for Public Welfare Industry of Health, Minstry of Health (201202004)

Disclosure of Interest None declared