Accessory right hepatic artery

The typical origin of this vessel is the right hepatic artery in as many as 95% of patients [25], but it may also come up from the left hepatic artery (7%), common hepatic artery (3%), replaced or accessory right hepatic arteries (18%), as well as the gastroduodenal artery (1%) or superior mesenteric artery [26-29]. There is a 2%-15% incidence of double cystic artery [26, 30] (Fig. 4.12). 

VI Accessory right hepatic artery arising from superior mesenteric artery... 

VIII Replaced right hepatic artery with accessory left hepatic artery or replaced left hepatic artery with accessory right hepatic artery... 

Fig. 4.2.10. Axial MIP rendering of CT angiogram shows an accessory right hepatic artery (arrows) originating from the celiac axis (arrowhead)...

Fig. 4.2. Aberrant replaced right hepatic artery coming of the superior mesenteric artery (arrow) and aberrant accessory left hepatic artery (arrowhead) coming of the left gastric artery...

Michels classic autopsy series of200 dissections, published in 1966, defined the basic anatomic variations in hepatic arterial supply, and has served as the benchmark for all subsequent contributions in this area (Table 20.1). Variant patterns occurred in 45% of cases, and the commonest arterial variant has been shown to be an aberrant right hepatic supply, which is seen in 13%-18% of patients (Coinaud 1986). Michels motivation was to maximize the database of the surgeon performing procedures in and around the porta hepatis, so as to avoid injury to vascular and ductal structures. A modification of the Michels classification was developed to reflect the presence of vessels that were either accessory or replaced, so that Michels original ten groups could be reduced to five major types and a most rare sixth variant (Hiatt et al. 1994) (Table 20.2) (Fig. 20.3). 

In principle, SIRT is based on the general vascular accessibility of the liver and the hepatic tumor load. Therefore, detailed knowledge of the hepatic vascular anatomy and the specific tumor supply is mandatory. It is particularly necessary to identify the accessory right arteries and a potential middle hepatic artery to assess the entire supply. 

Selective left hepatic arteriogram-injection of 2 cc/ sec for 8 cc. In cases of normal anatomy, this allows for the assessment of flow to segments 2,3,4A, and 4B. Special attention should be paid to the falciform, phrenic, right or accessory gastric arteries. 

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