Fig. 1

Patient selection, randomization, and flow through the trial. A total of 91 patients were screened, of whom 60 were enrolled and equally randomized into six groups receiving placebo, TPN171H 2.5 mg, TPN171H 5 mg, TPN171H 10 mg, tadalafil 20 mg and tadalafil 40 mg (ten patients in each group). APVT acute pulmonary vasoreactivity testing, CHD congenital heart disease, FEV1 forced expiratory volume in 1 s; FVC forced vital capacity, mPAP mean pulmonary arterial pressure; PAH pulmonary arterial hypertension, PAWP pulmonary artery wedge pressure, PH pulmonary hypertension