Abstract Body (Do not enter title and authors here): Introduction: Congenital portosystemic shunt (CPSS) is a rare vascular malformation which forms shunts between the portal and systemic veins. Pulmonary arterial hypertension (PAH) in CPSS patients heightens mortality risk.
Research Questions: It remains unclear which patients’ characteristics are associated with the developing PAH in CPSS individuals. Additionally, it is not yet determined whether CPSS closure improves the prognosis of PAH in these patients.
Methods: This single-center case-control study explored the data from 31 CPSS patients at Kyushu University Hospital, Japan between 2005 and 2023. Hemodynamics and portal pressure, crucial for treatment decisions, were assessed by cardiac catheterization in all treated patients. Based on these findings, patients were divided into two groups: PAH (n = 6) and non-PAH (n = 25). The primary outcome was the clinical characteristics of PAH, including patients` background, laboratory data, and cardiac catheterization findings. The secondary outcome was the effects of CPSS closure.
Results: CPSS closure was performed in 28 of the 31 patients. There was no significant difference in age at diagnosis (median: PAH group 117 months vs. non-PAH group 18 months, p = 0.11) or prevalence of congenital heart disease (67% vs. 52%, p = 0.66) between the two groups. The prevalence of portal vein hypoplasia was 83% in the PAH group and 36% in the non-PH group. The PAH group exhibited significantly higher levels of total bilirubin (1.2 vs. 0.8 mg/dl, p = 0.02) and ALT (42 vs. 21 IU/l, p = 0.02). Before treatment, the PAH group had significantly higher median pulmonary artery pressure (39 vs. 12 mmHg, p < 0.01) and pulmonary vascular resistance (7.3 vs. 0.95 unit/m², p < 0.01) compared to the non-PAH group. However, this study showed no significant difference in cardiac index between the two groups (5.3 vs. 4.9 l/min/m², p = 0.31). In the PAH group, all cases initiated pulmonary vasodilator therapies before CPSS closure. Among them, 2 patients were able to reduce pulmonary vasodilator therapies and the other 2 patients were able to discontinue them after CPSS closure. Any patients were not deceased during this observational period.
Conclusions: The clinical features of the PAH group include portal vein hypoplasia and hepatic dysfunction. Approximately one-third of PAH was reversible in the present study. Early diagnosis followed by CPSS closure and pulmonary vasodilators may improve the prognosis of CPSS-associated PAH.