A systematic review and meta-analysis: prevalence and clinical implications of anatomical variants of the hepatic portal vein

The hepatic portal vein is the main vascular route responsible for collecting blood from the liver, spleen, pancreas, stomach, gallbladder, and intestines. Its key function is to metabolize the components acquired from the blood. The objective of this study was to analyze the characteristics of HPV variants and understand the possible clinical considerations that arise with them. The databases Medline, Scopus, Web of Science, Google Scholar, Cumulative Index to Nursing and Allied Health Literature and Latin American and Caribbean Literature in Health Sciences were researched until January 2024. Tree authors independently performed the search, study selection and data extraction. Methodological quality was evaluated with an assurance tool for anatomical studies. Pooled prevalence was estimated using a random effects model. A total of 31 studies met the established selection criteria. In this study, 21 articles were included for the meta-analysis with a total of 51,244 subjects. Of these 21 articles, the topics studied came mainly from Europe and Asia, with three (n = 554; 1.08%) and 11 articles (n = 50,090; 97.75%) respectively, also having six articles from North America (n = 442; 0.86%) and one from Africa (n = 158; 0.31%), discarding the articles from Oceania and South America. For the HPV trifurcation variant, it was 8% (CI = 7-10%). Apropos the right posterior portal vein variant, as the primary tributary from the main HPV, it was 7% (CI = 4-11%). About the right anterior portal vein variant originating from the left portal vein, it was 4% (CI = 1-6%). Finally, the prevalence of the isolated variants was 2% (CI = 1-3%). The knowledge of HPV and its anatomical variants is of utmost importance for both medical professionals and anatomists, as it is one of the vessels that collects blood from many important viscera found in the abdominal cavity, any structural alteration could be crucial in diagnosis and surgical procedures.