Variant hepatic arterial anatomy

Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the coeliac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60% of the population. 

In general, the common hepatic artery may arise from the abdominal aorta or superior mesenteric artery (SMA) and all or part of the right and left hepatic arteries may arise from (be replaced to) other vessels.  

The two most common variants are:

• right hepatic artery replaced to the SMA
• left hepatic artery replaced to the left gastric artery

Another common finding, though not considered a variant by many authors, is trifurcation of the common hepatic artery into right hepatic artery, left hepatic artery and gastroduodenal artery (GDA). With this branching pattern there is no proper hepatic artery.

Variant anatomy

Common hepatic artery

• from aorta: 2%
• from SMA: 2%
• trifurcation into RHA, LHA and GDA: ~6% (range 4-8%)

Right hepatic artery (RHA)

• from coeliac artery: ~2.5% (range 1-4%)
• from SMA: ~12.5% (range 9-15%)
• accessory RHA from SMA: ~4% (range 1-7%)

Left hepatic artery (LHA)

• from left gastric artery (LGA): ~7.5% (range 4-11%) 
• accessory LHA from LGA: ~7.5% (range 4-11%)

Right and left hepatic arteries

• RHA from SMA and LHA from LGA: ~1% (range 0.5-2%)
• accessory RHA and LHA: 1%

Classification

A classification method was described by Michel et al in 1955 ⁶

• I: standard anatomy ~60% (range 55-61%)
• II: replaced LHA ~7.5% (range 3-10%)
• III: replaced RHA ~10% (range 8-11 %)
• IV: replaced RHA and LHA  ~1%
• V: accessory LHA from LGA ~10% (range 8-11%)
• VI: accessory RHA from SMA ~5% (range 1.5-7%)
• VII: accessory RHA and LHA ~1%
• VIII: accessory RHA and LHA and replaced LHA or RHA ~2.5%
• IX: CHA replaced to SMA ~3% (range 2-4.5%)
• X: CHA replaced to LGA ~0.5%
• unclassified
  • CHA separate origin from aorta ~2%
  • double hepatic artery ~4%
  • PHA replaced to SMA; GDA origin from aorta <0.5%

See also

• variant hepatic venous anatomy