**12. Acute cholecystitis**

abdominal approaches using temporary abdominal coverage with negative pressure wound

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

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

**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

therapy have been described in such situations [27].

pancreatic disease all contribute to post-CTS acute pancreatitis.

resolution of pancreatitis approximately 2 weeks after the diagnosis was made.

**11. Pancreatitis**

362 Principles and Practice of Cardiothoracic Surgery

pancreatitis is made.

Acute cholecystitis is another commonly seen gastrointestinal complication following CTS (Figure 5). In one study, incidence of acute cholecystitis was approximately 8% among all postoperative gastrointestinal complications [5]. Many cases of acute cholecystitis associated with CTS are termed "acalculous cholecystitis" and are secondary to biliary stasis as a result of multiple factors such as lack of enteral feeding and gallbladder wall ischemia secondary to a "low flow" state. Mortality rates associated with acalculous cholecystitis are significant (>50%) which may reflect the overall poor general health status of patients at risk for this complication [62, 63]. Typical symptoms include right upper quadrant pain and tenderness on examination. However, diagnosis is often delayed secondary to the presence of mechani‐ cal ventilation and sedation in significant proportion of patients with acalculous cholecysti‐ tis. Patients with acute cholecystitis, diagnosed most often on right upper quadrant ultrasound or cholescintigraphy scan, require surgical intervention or percutaneous chole‐ cystostomy tube placement for treatment of cholecystitis. For poor surgical candidates, per‐ cutaneous cholecystostomy can serve as "bridging" therapy that facilitates the patient's recovery until he or she is ready to undergo cholecystectomy [64].

**Figure 5.** Elderly male patient developed cerebral infarction 2 days after undergoing aortic valve replacement. His re‐ covery was further complicated by acute cholecystitis, as demonstrated by right upper quadrant ultrasound showing distended gallbladder with wall thickening, sludge and pericholecystic fluid (left). His operative risk for cholecystecto‐ my was prohibitive at that time, prompting the placement of percutaneous cholecystostomy (right). Following good functional recovery and hospital discharge, the percutaneous drain was removed and the patient underwent elective laparoscopic cholecystectomy.
