Elevated serum bile acid concentrations may be predictive of congenital portosystemic venous shunt (CPSS) in patients with pulmonary arterial hypertension (PAH), according to a study published in the European Journal of Medical Research.

CPSS is a congenital defect in which the portal blood partially or completely bypasses the liver via a portosystemic shunt; patients with this rare condition have their portal blood drain directly into the inferior vena cava. This congenital defect has been identified as a possible, if uncommon, cause of PAH. 

“The clinical manifestations of CPSS-associated PAH are not specific, thus making it difficult to distinguish from PAH caused by other pathogenetic factors based on clinical presentations alone,” the authors of the study wrote. 

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They hence performed a retrospective analysis of the clinical data of patients with CPSS who were admitted to the Pulmonary Hypertension Center at Wuhan Asia Heart Hospital in China between May 2018 and July 2021. The research team identified 6 patients who were diagnosed with CPSS; 5 of them were also diagnosed with PAH, via right heart catheterization. 

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The researchers reported that all 6 patients had a notably high cardiac output. As for the 5 patients who were diagnosed with both CPSS and PAH, the authors of the study identified varying levels of liver dysfunction, including a deranged liver profile. Significantly, serum bile acid concentrations were found to be raised. These signs of liver dysfunction are likely driven by liver congestion and reduced function. 

Among the 5 patients with both CPSS and PAH, 2 underwent transcatheter closure to block the portosystemic shunt, which successfully returned their pulmonary arterial pressure to normal, 2 were managed conservatively with pulmonary vasodilators, and 1 was lost to follow-up. 

Reflecting on their findings, the authors of the study wrote that many patients with PAH who also have CPSS do not have special clinical manifestations; therefore, this congenital defect is often missed. Routine investigations are not performed due to their invasive nature. Nonetheless, detecting an elevation in serum bile acids is a potentially cheap and easy way to determine the risk of CPSS among patients with PAH. 

“When PAH patients present a remarkable increase in bile acid level, it should be [an] alert to the existence of CPSS,” the authors of the study concluded.


Li Y, Deng X, Zhou H, Zheng X, Zhang G, Xiong Q. Bile acid predicts congenital portosystemic venous shunt in patients with pulmonary arterial hypertensionEur J Med Res. 2023;28(1):74. doi:10.1186/s40001-023-01039-0