Knowledge of the cystic artery and its variations is essential to perform safe cholecystectomies. The cystic artery originates from the right hepatic artery, passing posterior to the common hepatic duct, anterior to the cystic duct, and branching into two branches at the neck of the gallbladder. However, variations in position, size, and relationship with adjacent structures are common.

This article presents a literature review regarding cystic artery variations and their frequency during cholecystectomies.

The articles selected for this review were chosen from the PubMed and SciELO databases. The standardized descriptors used were anatomic variation and cholecystectomy. These were chosen using the "Medical Subject Headings" and combined with the Boolean operator AND and the non-standard descriptor cystic artery.

It was found in 54.5% of the studies that the anatomical pattern of the cystic artery was the most frequent type. A different origin from the standard was cited in 63.6% of the articles. Double irrigation of the gallbladder was found in 59.1%. In 36.4%, the cystic artery was anterior to the common hepatic duct or the cystic duct. Cystic arteries outside Calot's triangle were found in 36.4%. Short cystic arteries were found in 13.6%. The absence or non-identification of the artery was reported in 9.1%.

Variations of the cystic artery are common and are frequently reported. One aspect of a safe cholecystectomy is anatomical knowledge and its possible variations. Thus, surgeons must be familiar with this point in order to reduce vascular and biliary injuries.

The anatomical structure of the pancreaticoduodenal region is complex and closely related to the surrounding vessels. A variant of the hepatic artery, which is not a rare finding during pancreatic surgery, is prone to intraoperative injury. Inadvertent injury to the hepatic artery may affect liver perfusion, resulting in necrosis, liver abscess, and even liver failure. The preoperative identification of hepatic artery variations, detailed planning of the surgical approach, careful intraoperative dissection, and proper management of the damaged artery are important for preventing hepatic hypoperfusion. Nevertheless, despite the potential risks, planned artery resection has become acceptable in carefully selected patients. Arterial reconstruction is sometimes essential to prevent postoperative ischemic complications and can be performed using various methods. The complexity of procedures such as pancreatectomy with en bloc celiac axis resection may be mitigated by the presence of an aberrant right hepatic artery or a common hepatic artery originating from the superior mesenteric artery. Here, we comprehensively reviewed the anatomical basis of hepatic artery variation, its incidence, and its effect on the surgical and oncological outcomes after pancreatic resection. In addition, we provide recommendations for the prevention and management of hepatic artery injury and liver hypoperfusion. Overall, the hepatic artery variant may not worsen surgical and oncological outcomes if it is accurately identified pre-operatively and appropriately managed intraoperatively.

To analyze the origin and anatomic course of the hepatic arteries by using digital subtraction angiography (DSA) and multidetector CT in a large study sample.

This retrospective study included 5625 patients who underwent liver CT and chemoembolization between January 2005 and December 2018 (mean age, 60 years ± 11 [range, 11-99 years]; 4464 males). The CT and DSA images were reviewed to evaluate the visceral arterial anatomy for variations in the celiac axis and hepatic arteries. Aberrant right hepatic arteries (aRHAs) and aberrant left hepatic arteries (aLHAs) were defined on the basis of their origin and anatomic course. Statistical analyses were performed to evaluate the association between aRHAs and aLHAs and the association between variations in the hepatic artery and celiac axis.

Right hepatic arteries were categorized as being aRHAs (if originating from the proximal to middle common hepatic artery, gastroduodenal artery, superior mesenteric artery [SMA], celiac axis, aorta, splenic artery, or left gastric artery [LGA]) or as being aLHAs (if arising from the LGA, celiac axis, aorta, or SMA). The prevalence of aRHAs (15.63%; 879 of 5625) and the prevalence aLHAs (16.32%; 918 of 5625) were similar. Patients with an aRHA were more likely to have an aLHA than those without an aRHA (29.01% vs 13.97%; P < .001), and patients with an aLHA were more likely to have an aRHA than those without an aLHA (27.78% vs 13.26%; P < .001). There was no association between the hepatic arterial variations and celiac axis variations. A hypothetical anatomic model summarizing the observed variations was created.

A comprehensive list of hepatic arterial variations and a three-dimensional hypothetical model for the observed variations were described.Keywords: CT, Angiography, Liver, Anatomy, Arteries© RSNA, 2021 Supplemental material is available for this article. See also commentary by Sutphin and Kalva in this issue.

BACKGROUND The liver is a frequent site of surgical resection for both benign and malignant lesions. Advanced knowledge of the hepatic arterial system and its variants is crucial to avoid incidental injuries during a resection procedure. Many variants have been previously described in the literature, yet extremely rare cases continue to be encountered in clinical practice. Documentation of these variants can thus allow for proper preoperative procedural planning when considering interventions involving the liver. Our aim is to present one such unique and extremely rare anomaly. CASE REPORT During routine cadaveric dissection of a 78-year-old man who had died of acute myeloid leukemia, a rare anatomic variant of the hepatic vasculature was revealed: a replaced right hepatic artery (rRHA) coming directly from the celiac trunk, a middle hepatic artery (MHA) continuing from the common hepatic artery (CHA), and a replaced left hepatic artery (rLHA) branching from the left gastric artery (LGA). To the best of our knowledge, this anomaly has only been described once before in the literature. CONCLUSIONS We report a rare anatomical variant of the hepatic vasculature. The significance of this variant must be considered during preoperative planning and the intra-arterial infusion of targeted drugs. This case further emphasizes the importance of proper medical imaging and documentation to ensure the best course of treatment for each patient. Given that this variant has only so far been identified in 2 post-mortem subjects, further work should include attempts at characterizing its physiologic effects in a living patient.

Each hepatic artery is functionally essential for providing blood supply to the liver, and so are variant arteries. Variant arteries, including the accessory right hepatic artery (ARHA) and replaced right hepatic artery (RRHA) are commonly described in the literature. However, they usually occur independently. Here, we report an extremely rare case that involved both an ARHA and an RRHA arising from the gastroduodenal artery (GDA) and superior mesenteric artery (SMA), respectively. To date, this situation has never been reported in the literature.They were preoperatively identified during magnetic resonance imaging (MRI) examination in a 69-year-old male patient with hepatocellular carcinoma. And they were further verified by following conventional angiography for transcatheter arterial chemoembolization (TACE) for the patient. In addition, the patient's tumor was primarily supplied by these 2 variant arteries. After the successful TACE procedure, the patient had a well postoperative recovery.

By analyzing this case and performing a systematic review of the literature, the important clinical implications of the ARHA and RRHA will be investigated and discussed. Main lessons learned from this case thorough understanding of the normal anatomy of the hepatic artery and its anatomic variation is crucial for surgeons and interventional radiologists; preoperative computed tomography, MRI, and intraoperative angiography play an important role in detecting the variant hepatic artery; identifying these anomalous hepatic arteries before operation can effectively avoid unintentional injury during surgery, such as massive hemorrhage or hepatic infarction.