Long-term patient survival with idiopathic/heritable pulmonary arterial hypertension treated at a single center in Japan

AIMS: Idiopathic/heritable pulmonary arterial hypertension (I/HPAH) carries a poor prognosis despite the therapeutic options available. Patient survival from Western countries has been reported, but data from Asia are scarce. MAIN METHODS: We retrospectively reviewed 56 patients with I/HPAH treated at a single referral center in Japan. Survival analyses were conducted using the Kaplan-Meier method with the log-rank test. Variables associated with survival were determined using a Cox proportional hazard model. KEY FINDINGS: There were 41 women (73%) and the mean age at the diagnosis was 32±17 years. Mean survival time from the diagnosis was 14.9±0.8 years (95% CI, 13.4-16.4 years), with 1-, 2-, 3-, 5- and 10-year survival rates of 98, 96, 96, 96 and 78%, respectively. In patients who underwent follow-up right-heart catheterization >3 months after initial catheterization, mean pulmonary arterial pressure (mPAP) was decreased significantly from 63±15 to 35±10 mm Hg with an improved cardiac index. Patients with high levels of brain natriuretic peptide (BNP) or low oxygen saturation at baseline showed worse survival. At follow-up, 98% of patients were on PAH-targeted drugs. WHO functional classes I and II, mPAP <42.5 mm Hg, cardiac index >2.5 L/min/m(2), BNP <52 pg/mL, and 6-min walk distance >347 m at follow-up were predictors of good prognosis in the univariate analysis. SIGNIFICANCE: The study revealed a long-term survival of Japanese patients with I/HPAH. Hemodynamic parameters improved significantly after treatment, which might be related to high prescription rates of PAH-targeted drugs. Multicenter studies are needed to reveal the prognostic factors for I/HPAH.