Systematic review of congenital and acquired portal-systemic shunts in otherwise normal livers

Background: Portal-systemic shunts (PSSs) are rarely seen in healthy individuals or patients with non-cirrhotic liver disease. Theymay play an important role in hepatic metabolism as well as in the spread of gastrointestinal metastatic tumours to specific organs. Small spontaneous PSSs may be more common than generally thought. However, epidemiological data are scarce and inconclusive. This systematic review examined the prevalence of reported PSSs and the associated detection methods. Methods: Literature up to 2011 was reviewed for adult patients with proven congenital or acquired PSSs. Only PSSs in normal livers were analysed for the methods of diagnosis. Eligible studies were identified by searching relevant databases, including PubMed, Embase, MEDLINE and the Cochrane Library. The selection of eligible articles was carried out using predefined inclusion criteria (adult, non-surgical PSS) and a set of search terms that were established before the articles were identified. Results: Eighty studies were included describing 112 patients with congenital or acquired PSSs. The majority were diagnosed incidentally using Doppler ultrasound imaging and CT. Conclusion: Congenital and acquired PSSs are rare. They are usually clinically asymptomatic and discovered incidentally by radiological techniques. They may be clinically relevant owing to drug, tumour cell, metabolic and pathogen shunting.