Review
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 7, 2016; 22(25): 5728-5741
Published online Jul 7, 2016. doi: 10.3748/wjg.v22.i25.5728
Hepatopulmonary syndrome: What we know and what we would like to know
Israel Grilo-Bensusan, Juan Manuel Pascasio-Acevedo
Israel Grilo-Bensusan, Digestive Diseases Department, HAR, Écija, APS Bajo Guadalquivir, Écija, 41400 Seville, Spain
Juan Manuel Pascasio-Acevedo, Unit for the Clinical Management of Digestive Diseases, IBIS, CIBERehd, Virgen del Rocío University Hospital, 41013 Seville, Spain
Author contributions: Grilo-Bensusan I and Pascasio-Acevedo JM wrote this paper.
Conflict-of-interest statement: The authors have no conflict of interest to report.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Israel Grilo-Bensusan, MD, PhD, Digestive Diseases Department, HAR, Écija, APS Bajo Guadalquivir, Avda, de los Emigrantes 24, Piso: 2º E, Écija, 41400 Seville, Spain. igrilob@telefonica.net
Telephone: +34-676-278900 Fax: +34-955-879090
Received: March 18, 2016
Peer-review started: March 21, 2016
First decision: May 12, 2016
Revised: May 26, 2016
Accepted: June 15, 2016
Article in press: June 15, 2016
Published online: July 7, 2016
Abstract

Hepatopulmonary syndrome (HPS) is characterized by abnormalities in blood oxygenation caused by the presence of intrapulmonary vascular dilations (IPVD) in the context of liver disease, generally at a cirrhotic stage. Knowledge about the subject is still only partial. The majority of the information about the etiopathogenesis of HPS has been obtained through experiments on animals. Reported prevalence in patients who are candidates for a liver transplantation (LT) varies between 4% and 32%, with a predominance of mild or moderate cases. Although it is generally asymptomatic it does have an impact on their quality of life and survival. The diagnosis requires taking an arterial blood gas sample of a seated patient with alveolar-arterial oxygen gradient (AaO2) ≥ 15 mm Hg, or ≥ 20 mm Hg in those over 64 years of age. The IPVD are identified through a transthoracic contrast echocardiography or a macroaggregated albumin lung perfusion scan (99mTc-MAA). There is currently no effective medical treatment. LT has been shown to reverse the syndrome and improve survival rates, even in severe cases. Therefore the policy of prioritizing LT would appear to increase survival rates. This paper takes a critical and clinical look at the current understanding of HPS, as well as the controversies surrounding it and possible future research.

Keywords: Hepatopulmonary syndrome, Liver cirrhosis, Liver transplantation, Contrast echocardiography, Macroaggregated albumin lung perfusion scan

Core tip: Hepatopulmonary syndrome is a frequent complication which influences the quality of life and ultimately the survival of patients with cirrhosis. Knowledge about the condition is still limited and this complicates clinical decision making. The most widely used methods for establishing a diagnosis are an arterial blood gas analysis and a contrast echocardiography. There is currently no effective medical treatment and other means of supporting patients have barely been evaluated. Liver transplantation has been demonstrated to reverse it and improve survival levels, although there are controversies in the policies of prioritization in terms of the waiting lists for transplantation. This review examines current knowledge about the syndrome from a practical and analytical approach.