Pseudoaneurysms

Approximately 50% of gastroduodenal and 30% of pancreaticoduodenal artery aneurysms are related to pancreatitis (Figures 1 and 2). Pseudoaneurysms of these arteries are most often a consequence of pancreatitis. Mechanisms of aneurysmal formation in this setting include acute or subacute vascular disruption by activated pancreatic enzymes and later chronic pseudocyst erosion into an adjacent artery. Traumatic aneurysms, especially as a result of iatrogenic injury associated with hepatobiliary and pancreatic operations, are uncommon, but when they do occur they most often involve the gastroduodenal artery. Septic emboli are a rare cause of pseudoaneurysms affecting these peripancreatic arteries.

Treatment

Most clinicians favor early treatment of these aneurysms once they have been recognized. Endovascular or open operative interventions are proposed for all but the highest-risk patients with gastroduodenal and pancreaticoduodenal arterial pseudoaneurysms and have been undertaken in nearly two thirds of reported cases.

In critically ill patients who are unstable, endovascular occlusion of the bleeding pseudoaneurysm may be a lifesaving measure that can be followed by a later definitive procedure if needed. Transcatheter embolization has been reported to initially control bleeding aneurysms in 75% of those in whom it was attempted. This means of management is most likely to be successful in treating pseudoaneurysms unassociated with pancreatic cyst erosions into the involved artery.

Open surgical treatment is most often pursued in cases where endovascular interventions have failed and in patients with large pancreatitis-related pseudoaneurysms associated with pseudocysts. This is especially appropriate when the pancreatic pathology is associated with gastric or biliary tract obstruction and in instances of an infected pseudocyst. In addition, open operations are also favored in cases of intractable pain. In these cases the surgical procedure most often includes arterial ligation from within the aneurysmal sac rather than extra-aneurysmal arterial ligation. Extensive dissection about the pancreas in this setting is hazardous.

Among patients with pseudocyst-related aneurysms, some form of cyst drainage may be warranted. Drainage of cysts can be internal without evidence of infection or external in the case of an infected cyst or frank abscess. Rebleeding and other complications are not uncommon in pseudocyst-related aneurysms subjected to simple ligation procedures, with or without a drainage procedure. This is particularly true with infected pseudocysts. Concurrent or later pancreatic resection is often required to address the underlying pancreatic disease and, depending on the pseudoaneurysm’s location, may necessitate a distal pancreatectomy or pancreaticoduodenectomy.