Replaced Hepatic Artery Variants

arteriae hepaticae variantium Michelis

Hepatic artery anatomy is highly variable (Michels classification, 10 types). Standard anatomy (type I, present in 55-75% of individuals): proper hepatic artery from the celiac trunk divides into right and left hepatic. Common variants: replaced right hepatic artery arising from the SMA (present in 11-21%); replaced left hepatic artery arising from the left gastric artery (present in 11-14%); replaced common hepatic artery from the SMA (present in 2.5%); and accessory variants alongside the replaced vessels.

Region: Abdomen

Clinical Relevance

Clinical Notes

Replaced hepatic artery variants are critical in hepatic surgery (right hepatectomy, liver transplantation), Whipple pancreaticoduodenectomy, and gastric surgery. A replaced right hepatic artery from the SMA runs in the hepatoduodenal ligament posterior to the CBD and portal vein — its inadvertent ligation during cholecystectomy or biliary surgery causes right lobe ischaemia. Pre-operative CT angiography of the celiac and SMA axes identifies hepatic artery variants before planned surgery. In liver transplantation, variant hepatic arteries require arterial reconstruction to ensure adequate graft perfusion.

Pathology

Common Injuries & Conditions

Replaced Right Hepatic Artery Injury in Cholecystectomy

A replaced right hepatic artery running posterior to the bile duct in the hepatoduodenal ligament may be mistaken for the cystic artery during cholecystectomy and ligated, causing right hepatic lobe ischaemia; pre-operative awareness of hepatic artery variants from CT angiography and careful hepatoduodenal dissection before any vessel division prevents this complication.