Common Hepatic Artery: Anatomy, Function, and Variations

The common hepatic artery is one of three main branches of the celiac trunk, the short vessel that springs from the front of the aorta just below the diaphragm. It travels a few centimeters to the right before dividing into the proper hepatic artery, which heads toward the liver, and the gastroduodenal artery, which supplies the stomach and duodenum. Despite its relatively short length, the common hepatic artery is a landmark that surgeons, radiologists, and transplant teams rely on constantly, and its anatomy varies from person to person far more than most people would expect.

Where It Sits and What It Feeds

The celiac trunk typically gives off three branches: the left gastric artery, the splenic artery, and the common hepatic artery. Of these, the common hepatic artery runs to the right along the upper border of the pancreas, passing behind the first part of the duodenum before reaching the hepatoduodenal ligament, the strip of tissue that carries the major structures entering the liver. At that point it divides. The proper hepatic artery continues upward toward the liver, splitting into right and left branches to supply each lobe. The gastroduodenal artery dips downward behind the duodenum, giving off branches that feed the pancreas, stomach, and the first part of the small intestine.

This branching point is a surgical crossroads. Surgeons performing a Whipple procedure for pancreatic cancer, for instance, work in the exact territory where the common hepatic artery sits. Accidentally damaging it can cut off arterial flow to the liver. Computed tomography angiography is now considered essential for mapping the vessel before hepatobiliary or pancreatic operations, precisely because the anatomy is so variable.¹

Dual Blood Supply and the Buffer Response

The liver is unusual among solid organs: it receives blood from two separate sources. Roughly three-quarters of its incoming blood arrives through the portal vein, carrying nutrient-rich but oxygen-poor blood from the intestines. The remaining quarter comes through the hepatic artery, delivering oxygen-rich blood from the aorta. These two streams merge inside the liver’s sinusoids, the tiny channels where hepatocytes do their work.²

Because the liver depends on two inflows, it has a built-in safety mechanism called the hepatic arterial buffer response. When portal vein flow drops for any reason, the hepatic artery automatically dilates to compensate. The mechanism relies on adenosine, a signaling molecule that is produced at a steady rate near the arterial resistance vessels. Under normal conditions, the flow of portal blood washes adenosine away and keeps arterial tone relatively high. If portal flow falls, adenosine accumulates, the arterial wall relaxes, and more arterial blood gets through.³ The reverse does not work as neatly: a drop in hepatic artery flow does not trigger the portal vein to open wider. That asymmetry is part of why hepatic artery injuries and occlusions can be so dangerous.

Why Variations Are the Rule, Not the Exception

If you picture an anatomy textbook showing the common hepatic artery arising neatly from the celiac trunk, keep in mind that this “normal” pattern exists in only about half to two-thirds of people. Depending on the study, anywhere from 45% to 75% of individuals have some form of hepatic arterial variation.⁴ One CT angiography study found hepatic artery variants in 48% of its patients.⁵

The most widely used framework for classifying these variations comes from the anatomist Nicholas Michels, who dissected 200 cadavers and described ten types. In the “normal” type (Michels type I), everything arises from the celiac trunk as the textbook describes. In type II, the left hepatic artery comes off the left gastric artery instead. In type III, the right hepatic artery comes off the superior mesenteric artery. Other types combine these replacements or add accessory vessels. In rarer patterns, the entire hepatic trunk can arise from the superior mesenteric artery alone, or the common hepatic artery can branch from the left gastric artery.⁶

How Embryonic Development Explains the Variation

The reason so many people deviate from the textbook pattern traces back to fetal development. During embryogenesis, the liver is supplied by three separate arteries. The embryonic left hepatic artery comes off the left gastric artery to supply what will become segment II. The embryonic middle hepatic artery, which will eventually become the adult common hepatic artery system, supplies segments III, IV, V, and VIII. The embryonic right hepatic artery branches from the superior mesenteric artery and feeds segments VI and VII.⁷

Normally, the embryonic left and right hepatic arteries regress, and the middle hepatic artery system takes over the full blood supply. When one of those primitive vessels fails to regress, it persists as a “replaced” or “accessory” artery in the adult. The celiac trunk itself forms from a series of embryonic vitelline arteries that link the dorsal and ventral aortae. As certain connecting segments disappear and others persist, the celiac trunk and superior mesenteric artery become two separate vessels. Slight variations in which segments disappear produce the full range of adult hepatic artery patterns.⁸

Imaging Before Surgery

Because so many people carry a variant pattern, preoperative imaging is now standard before any major hepatobiliary or pancreatic operation. CT angiography gives surgeons a three-dimensional roadmap showing exactly where the common hepatic artery originates, how long it is, and whether additional or replacement vessels cross the operative field. This is especially critical before pancreaticoduodenectomy (the Whipple procedure), hepatic resection, or living-donor liver transplant, where even a short stretch of unexpected artery can mean the difference between a clean dissection and a catastrophic bleed.⁹

Doppler ultrasound is used differently. Rather than mapping anatomy before surgery, it monitors blood flow after surgery, particularly after liver transplantation. In the early post-transplant period, an absent or very low-velocity signal in the common hepatic artery, or a resistive index below about 0.50, is a warning sign for hepatic artery thrombosis.¹⁰ In non-surgical settings, the hepatic artery resistive index can also be tracked over time to assess liver fibrosis and steatohepatitis, though the clinical utility of that measure is still being refined.¹¹

Hepatic Artery Thrombosis After Liver Transplant

The most feared complication involving the hepatic artery in transplant medicine is hepatic artery thrombosis, where a clot blocks flow through the reconstructed vessel. Because the transplanted liver’s bile ducts depend almost entirely on arterial blood for their oxygen supply (the portal vein feeds the hepatocytes, but the bile duct walls rely on tiny arterial branches), losing arterial inflow often leads to bile duct necrosis, abscess formation, and graft failure. Early hepatic artery thrombosis without successful re-opening of the vessel has traditionally been considered almost uniformly fatal, especially when it occurs within the first few days.¹²

That conventional wisdom, however, has exceptions. A small case series described three living-donor liver transplant recipients who developed early hepatic artery thrombosis and in whom surgical and endovascular attempts at re-opening the artery both failed. Against expectations, all three survived with functioning grafts at follow-ups ranging from four to thirty-two months, managed with aggressive nonsurgical support rather than emergency retransplantation.¹³ Three patients is far too few to change clinical protocols, but the cases illustrate that the liver’s collateral circulation and the portal vein’s contribution can occasionally keep a graft alive even when the artery is lost.

Collateral Pathways When the Artery Is Blocked

The liver has an impressive ability to recruit alternative blood routes when the main hepatic artery is occluded, whether from thrombosis, embolization, surgical ligation, or catheter-related injury. These collateral arteries develop in two broad categories. Intrahepatic collaterals form within the portal triads and the subcapsular region between the liver lobes. Extrahepatic collaterals develop in the ligaments suspending the liver and through structures closely attached to its surface.¹⁴

In a study of patients with hepatic artery occlusion, the most common source of extrahepatic collateral supply was the superior mesenteric artery, seen in about 73% of cases, followed by the gastroduodenal artery and the left gastric artery.¹⁵ These pathways matter enormously for interventional radiologists treating liver tumors, because if the main hepatic artery is blocked, chemotherapy or embolization particles need to be delivered through whichever collateral has taken over the tumor’s supply.

Cancer Treatments That Rely on the Hepatic Artery

The dual blood supply of the liver creates a useful therapeutic window for treating liver tumors. Most liver cancers, particularly hepatocellular carcinoma and colorectal liver metastases, draw the vast majority of their blood from the hepatic artery rather than the portal vein. Healthy liver tissue, by contrast, leans heavily on portal venous blood. That difference allows clinicians to deliver cytotoxic drugs or embolic particles directly through the hepatic artery to attack tumors while relatively sparing the surrounding parenchyma.

Transarterial chemoembolization (TACE) involves threading a catheter into the hepatic artery, injecting chemotherapy drugs mixed with embolic material, and physically blocking the tumor’s arterial supply. Hepatic artery infusion chemotherapy (HAIC) takes a different approach, delivering sustained chemotherapy directly into the artery without necessarily blocking it. A prospective study comparing HAIC using a modified FOLFOX regimen against conventional TACE in patients with massive, unresectable hepatocellular carcinoma found differences worth noting.¹⁶ Another comparative study reported significantly better objective response rates and disease control rates in patients receiving high-dose hepatic artery infusion compared to TACE for advanced hepatocellular carcinoma.¹⁷

Both techniques demand precise knowledge of the hepatic artery anatomy. A replaced right hepatic artery coming off the superior mesenteric artery, for example, means an entirely different catheter approach is needed to reach the right lobe. Missing such a variant can leave part of the tumor untreated.

Arterial Resection in Pancreatic Surgery

In pancreatic cancer, tumors sometimes grow into or around the common hepatic artery. When that happens, surgeons face a choice: declare the tumor unresectable, or proceed with a combined pancreatectomy and arterial resection. A series examining this approach found that among ten patients who underwent combined pancreatectomy and arterial resection, an R0 (negative margin) resection was achieved in 85% of cases. Median operative time was about seven and a half hours, and no perioperative deaths occurred. At roughly 21 months of follow-up, 62% of the resected patients were alive without disease.¹⁸

The most common procedure in that context is the modified Appleby operation, which involves removing the celiac trunk and part of the common hepatic artery along with the distal pancreas and spleen. The liver survives because arterial flow is maintained through collateral pathways, typically retrograde flow through the gastroduodenal artery from the superior mesenteric artery. This operation is only feasible when preoperative imaging confirms that those collaterals are robust enough to keep the liver perfused.

Aneurysms of the Hepatic Artery

Hepatic artery aneurysms are uncommon but clinically significant, accounting for a substantial share of all visceral artery aneurysms. They can be “true” aneurysms, involving all three layers of the arterial wall ballooning outward, or pseudoaneurysms, where only a contained leak of blood is held in place by surrounding tissue. Pseudoaneurysms tend to form after trauma, surgery, or infection. In a series of 22 patients with hepatic artery aneurysms, there were 16 true aneurysms and 7 pseudoaneurysms. Treatment depended on location: surgery was preferred for extrahepatic lesions, while catheter-based embolization was used for intrahepatic aneurysms. Early mortality in that series was about 9%, and the complication rate was roughly 23%.¹⁹

Not all hepatic artery aneurysms require immediate intervention. Small, stable aneurysms, particularly those found incidentally on imaging, may be managed with serial imaging and watchful waiting.²⁰ For pseudoaneurysms of the common hepatic artery that do need treatment but where open surgery carries high risk, stent-grafts offer another option. A stent-graft bridges the weak spot from inside the vessel, excluding the pseudoaneurysm from blood flow while preserving arterial supply to the liver.²¹

Injury During Gallbladder Surgery

Laparoscopic cholecystectomy is one of the most commonly performed operations in the world, and the common hepatic artery and its right branch sit in uncomfortably close proximity to the cystic duct and cystic artery that the surgeon must clip and divide. When a bile duct injury occurs during cholecystectomy, there is a disturbingly high chance that the hepatic artery has been damaged too. In a study of 55 patients referred for postcholecystectomy bile duct strictures, vascular injuries were present in 47% of cases, most commonly disruption of the right hepatic artery or a replaced right hepatic artery.²²

Combined bile duct and hepatic artery injuries carry a much worse prognosis than bile duct injuries alone. Patients with both types of damage developed biliary complications after reconstructive surgery at a rate of about 55%, compared with roughly 11% in patients whose arteries were intact.²³ The reason goes back to bile duct biology: the bile ducts depend on a network of tiny arterial branches, the peribiliary plexus, for their oxygen supply. Cut off that blood flow by injuring the hepatic artery and the repaired bile duct is left trying to heal in ischemic tissue, which predictably fails at higher rates.

Hemodynamic Research and Computational Modeling

Advances in computational fluid dynamics are opening new windows into how blood actually moves through the hepatic arterial tree. Researchers have used patient-specific vessel models to simulate wall shear stress, pressure gradients, and flow distribution ratios across hepatic artery branches. One application involves biliary atresia in children, where changes in hepatic artery hemodynamics may signal early fibrosis before it becomes obvious on conventional imaging.²⁴ Another line of work uses one-dimensional flow modeling to study how hepatic artery wall shear stress differs in patients with single-ventricle heart defects who have undergone the Fontan procedure, a population at high risk for liver disease due to chronically elevated venous pressures.²⁵

These models are still primarily research tools rather than bedside decision-makers, but they represent a shift in how clinicians think about the hepatic artery. Instead of treating it as a static tube with a fixed diameter, the emerging view is of a dynamic conduit whose flow patterns influence disease progression in ways that imaging alone cannot fully capture.