＜Editors' Choice＞ Differential effects of combination therapy on the components of the risk stratification table in patients with idiopathic or heritable pulmonary arterial hypertension in a Japanese population.

Risk stratification by ESC/ERS guideline is recommended to estimate the vital prognosis and select the treatment strategy in patients with idiopathic or heritable pulmonary arterial hypertension (IPAH/HPAH). However, we are not confident whether we can achieve low-risk status in the risk table at the follow-up shortly after combination therapy. Therefore, we aimed to verify the effects of combination therapy in IPAH/HPAH on each category of the risk table at diagnosis and at the first follow-up. We retrospectively analyzed 10 consecutive patients with IPAH/HPAH with no previous treatment history diagnosed at Nagoya University Hospital between October 2014 and January 2019. Four categories including symptoms, exercise tolerance, BNP levels and hemodynamics were validated both at baseline and at the first follow-up of right heart catheterization. Score of 1, 2 and 3 were assigned to the low risk, intermediate risk and high risk, respectively. In each category the highest score was adopted. The scores at diagnosis were compared with those at the first follow-up. The result shows that all patients were female, median age was 32 years old, and were treated with initial combination therapy. The median total risk score also was improved from 2.6 to 1.4 (p<0.01). However, the score in exercise tolerance was not improved (3 to 2.5 p=0.16). In conclusion, at the first follow up shortly after the initial combination therapy of IPAH/HPAH, the mean total risk score was significantly improved, however, even patients in the low-risk status may not achieve improvement in exercise tolerance.