Aberrant left hepatic arteries arising from left gastric arteries and their clinical importance

Background: The Aberrant Left Hepatic Artery (ALHA) is replaced when it does not originate from the hepatic artery proper and it is the only supply to that part of the liver, while an accessory artery coexists with a normal artery. The aim of this systematic review is to evaluate the incidence of ALHAs including the one arising from the Left Gastric Artery, also named Hyrtl's artery. Methods: A literature search in PubMed, SCOPUS, WOS and Google Scholar was performed. The risk of bias was assessed by means of the AQUA tool. The main outcome was the prevalence of ALHA. Secondary outcomes were the prevalence of the accessory and replaced left hepatic arteries. A subgroup analysis was conducted by geographic region and type of evaluation. Results: This review included 57 studies, with a total of 19,284 patients. The majority of the studies involved the use of radiological techniques -especially Angio-CT-and were performed in Asia. The overall risk of bias was moderate. The overall prevalence of the ALHA was 13.52%; the overall prevalence was 8.26% for the Replaced ALHA and 5.55% for the Accessory ALHA. In the 18 studies that employed Michels' classification, Type II had the lowest prevalence (0.36%) and Type VII the highest prevalence (6.62%). Discussion: Some of the studies included did not distinguish between the ‘‘replaced’’ and ‘‘accessory’’ ALHA (34.25%). Some surgical dissection techniques proved insufficient for the localization of other hepatic arteries. These results suggest that an accurate preoperative radiological evaluation is needed to localize replaced arteries.