Right hepatic artery aneurysm is uncommon. The incidence of all visceral artery aneurysms is thought to be 1%, with hepatic artery aneurysm forming approximately 20% of this group.1–3
A recent review of experience with visceral artery aneurysms in 1 centre over 25 years yielded 55 cases, of which 7 were common hepatic and none were right hepatic.4
Estimates of incidence are difficult to ascertain on review of the literature, as due to the infrequency of the occurrence each series reporting on visceral artery aneurysms contained different types of aneurysm, including splenic, mesenteric, common hepatic and left hepatic. In addition they can be subdivided into true or false and intrahepatic or extrahepatic, and the pathogenesis is not well known. Various different aetiologies have also been described. Atherosclerosis is thought to be a secondary event1
and the causes reported in the literature include trauma, which is often iatrogenic following surgical or percutaneous hepatobiliary procedures, congenital disorders, immunosuppression and neoplasia, inflammatory disorders such as pancreatitis and infection.5–9
A further problem with the estimation of incidence is that many hepatic artery aneurysms are asymptomatic and incidence may appear to be increasing due to the increased frequency of CT scanning, particularly following blunt abdominal trauma.9
Mycotic aneurysms were more common previously, often secondary to infective endocarditis,10
however, with changing patterns of disease and the increase in surgical procedures, particularly laparoscopic cholecystectomy and percutaneous liver biopsy, iatrogenic injury to the artery is now the most common cause and in many series mycotic aneurysms are rare.11 12
Infections cited in the literature include embolic phenomenon from infective endocarditis, which is now mainly seen among intravenous drug taking populations, severe systemic sepsis and amoebic infections.13
In addition immunosuppression has been reported as a cause for mycotic aneurysms in conjunction with liver transplantation or treatment for other malignancies or disorders such as Crohn's disease.14–16
This case is particularly interesting as it occurred in a case of presumed acalculous cholecystitis that was not severe as it necessitated only a short admission and no intervention other than antibiotic treatment at that time.
This case also highlights some of the diagnostic difficulty that can occur with hepatopancreatobiliary lesions. The differential diagnosis of the mass abutting the common bile duct in an 85-year-old man with cachexia is carcinoma of the head of the pancreas, particularly as neoplasia is a better known cause of right hepatic artery false aneurysm than acalculous cholecystitis. No biopsies were possible due to anatomical position and those taken at ERCP were normal. This could have caused management and decision-making difficulties in the case of massive haemobilia with resulting instability.
On review of the literature, although embolisation of the aneurysmal artery is now well recognised as preferred management of these lesions, it is worth noting that our patient is one of the oldest on record to undergo this procedure.1 2 5 9 16
As stated above, a stent graft to maintain patency of the vessel while excluding the aneurysm was not possible. Embolising the artery causes a degree of right hepatic lobe ischaemia, which we believe was the cause of our patient's persistently deranged, albeit improved LFTs (bilirubin 99, ALP 271). Despite this degree of physiological insult and his general frailty the patient did well clinically and put on some weight.
In summary, this case is a worthy addition to the literature as it highlights that a supposedly benign case of acalculous cholecystitis can cause right hepatic artery false aneurysm, and this responds well to treatment with embolisation in an older patient.
- Acalculous cholecystitis may be associated with right hepatic artery pseudoaneurysm.
- Visceral pseudoaneurysms may cause what appear to be mild inflammatory conditions.
- Coil embolisation of the right hepatic artery pseudoaneurysm is an effective and feasible treatment in older patients.