Pulmonary Artery Pressure as a Treatment Target to Improve the Prognosis of Idiopathic Pulmonary Arterial Hypertension　― Insight From a Cohort From Two Japanese Pulmonary Hypertension Centers ―

Background: The prognosis of pulmonary arterial hypertension (PAH) has been improving since the introduction of epoprostenol (EPO). The 3-year survival of naïve idiopathic PAH (IPAH) and hereditary PAH (HPAH) was 96% in a recent prospective Japanese registry. This increase in survival in Japan may have been due to the reduction of pulmonary artery pressure (PAP) by a rapid and sufficient dosage of EPO. The aim of this retrospective study was therefore to analyze whether decreasing the PAP contributes to improving PAH prognosis. Methods and Results: Sixty-four patients with IPAH/HPAH followed up at Keio and Kyorin University Hospitals between 1999 and 2011 were enrolled and divided into 2 groups: surviving or non-surviving. Of 14 variables, EPO use, most improved mean PAP (mPAP), brain natriuretic peptide level, cardiac output, 6-min walk distance, and sex were significantly different between the 2 groups. The former 3 variables were significantly related to death on multiple regression analysis. mPAP had the highest odds ratio of 1.44 and the largest area under the receiver operating characteristic curve. The value of mPAP with the optimal combination of sensitivity and specificity was 42 mmHg. Conclusions: The best treatment target for the prognosis of IPAH/HPAH may be the reduction of mPAP; a similar large-scale study is anticipated.