Clinical aspects and controversies of spontaneous portosystemic shunts in cirrhotic patients

Spontaneous portosystemic shunts (SPSSs) are common among patients with liver cirrhosis. These vascular structures are collateral veins that directly connect the portal vein system with the systemic circulation. The prevalence increases as cirrhosis worsens. Published studies exist investigating the possible association between presence and extension of SPSSs and clinical manifestation of liver cirrhosis, however some issues continue to be debated. Recent research on this topic has extended knowledge and brought out interesting new aspects. The aim of this review is to provide a comprehensive and updated revision of the role of SPSSs in liver cirrhosis, from pathophysiology to clinical and therapeutic considerations, specifically addressing the most controversial and emerging findings. On this purpose PubMed and Medline were used as data sources and an extensive review of the literature, including the most recent and relevant published studies, was performed. The presence of SPSSs, especially if multiple and/or large, is associated with an increased risk of developing several complications of liver cirrhosis. Patients with higher MELD have larger SPSSs with negative impact on survival. Regarding hepatocellular carcinoma, there is evidence suggesting a potential tumorigenic effect associated with SPSSs, but further investigations on humans are needed. In the context of liver transplantation, the negative effect of SPSSs on graft function and patients' survival is a matter of debate, with no consensus on their surgical management. Currently, several interventional treatments have been proposed for SPSSs that have demonstrated excellent outcomes in selected populations.