Objective To explore the effects of intravenous treprostinil in different doses on the hemodynamics and postoperative outcomes after high-risk total cavo-pulmonary connection (TCPC). MethodsFrom 2018 to 2021, among 189 patients who underwent TCPC in the Department of Pediatric Cardiac Surgery of Fuwai Hospital, 26 high-risk patients who received the intravenous treprostinil therapy were retrospectively analyzed. There were 12 males and 14 females, with an age of 4 (3, 6) years and a weight of 17.6±6.2 kg. The patients were divided into two groups: a high-dose group [15 patients, maintaining dose>10 ng/(kg·min)] and a low-dose group [11 patients, maintaining dose≤10 ng/(kg·min)]. The hemodynamics before treprostinil using and during the first 24 hours after reaching the maintaining dose of treprostinil, and postoperative outcomes of the two groups were investigated. ResultsThe incidence of heterotaxia was higher in the high-dose group (66.7% vs. 18.2%, P=0.021). During the observation period, the mean pulmonary artery pressure decreased from 11.9±3.6 mm Hg to 11.0±3.3 mm Hg in the low-dose group (P=0.013), and from 12.9±4.7 mm Hg to 10.2±3.4 mm Hg in the high-dose group (P=0.001). The decreasing effect in the high-dose group was better than that in the low-dose group (P=0.010). There was no statistical difference in the postoperative outcomes between the two groups (P>0.05). In terms of side effects, patients needed temporarily increased dosage of vasoactive drugs to maintain stable blood pressure during 6-12 h after treprostinil therapy in the high-dose group. ConclusionIn patients after high-risk TCPC, intravenous high-dose treprostinil has a better therapeutic effect on reducing pulmonary artery pressure. However, it should be noted that increased dosage of vasoactive agents may be required to maintain blood pressure stability in patients with high-dose treprostinil.