Post-pancreatectomy Acute Pancreatitis in Distal Pancreatectomies — a Rare Bird According to the New Definition

BACKGROUND: Post-pancreatectomy acute pancreatitis (PPAP) is a recently identified clinical condition characterized by sustained elevated serum amylase levels for at least 48 h post-operatively, consistent radiological findings, and relevant clinical features. The purpose of this study was to determine the frequency of PPAP after DP, to investigate the rate of major complications in patients with sustained or transiently elevated serum amylase activity, and to explore the usability of CT as a prerequisite for the diagnosis of PPAP. METHODS: This retrospective single-center observational study included consecutive patients 18 years or older who underwent DP at Karolinska University Hospital between 2008 and 2020. The two serum amylase levels on post-operative days (POD) 1 and 2 were correlated with post-operative major complications by logistic regression analyses. RESULTS: Of the 403 patients who underwent DP, 14% (n = 58) had sustained elevated serum amylase levels according to PPAP criteria, and 31% (n = 126) had transiently elevated serum amylase levels on either POD1 or POD2. Of the patients with sustained elevated levels, 45% (n = 26) developed major complications, but less than 2% (n = 1) showed imaging findings consistent with acute pancreatitis. Of the 126 patients who exhibited only transiently elevated serum amylase on either POD1 or POD2, 38% (n = 48) developed major complications. The frequency of PPAP was 0.25% (n = 1). CONCLUSION: These findings indicate that PPAP after DP is rare and that computed tomography has limited usability for diagnosing PPAP. The findings also suggest that transiently elevated serum amylase may be an early indicator of acute pancreatitis, especially when peaked.