**11. Pancreatitis**

Acute pancreatitis is relatively uncommon (incidence 1-3%) following cardiopulmonary by‐ pass [15]. Clinically apparent pancreatitis usually occurs slightly later following cardiac sur‐ gery than other gastrointestinal complications, such as bleeding or mesenteric ischemia. Patients typically complain of upper abdominal and left upper quadrant pain, nausea, vom‐ iting, and/or abdominal distension. Laboratory values including elevated amylase and li‐ pase are usually present. However, due to high incidence of hyperamylasemia in cardiac surgery patients (>33%) [15], clinical correlation is required before definitive diagnosis of pancreatitis is made.

The severity of pancreatitis ranges from subclinical (i.e., noted only on laboratory values) to severe hemorrhagic, necrotic pancreatitis (seen in <0.5% of patients) (Figure 4) [60]. In one study, nearly 20% of patients who underwent cardiac surgery were found to have evidence of pancreatitis on autopsy [61]. Although the mechanism explaining the development of pancreatitis after cardiac surgery has not been discovered, it has been hypothesized that low flow state, tissue ischemia, gallstone disease, micro-embolization, and history of pre-existing pancreatic disease all contribute to post-CTS acute pancreatitis.

**Figure 4.** Abdominal CT of a patient who developed acute upper abdominal pain following aortic valve replacement surgery. Representative images of severe necrotizing pancreatitis are shown. Non-operative management resulted in resolution of pancreatitis approximately 2 weeks after the diagnosis was made.
