A preserved pancreatic exocrine function after pancreatectomy may be a crucial cause of pancreatic fistula: paradoxical results of the 13 C-trioctanoin breath test in the perioperative period

Purpose The aim of this study was to elucidate the association between pancreatic fistula (PF) and the sequential changes in the perioperative exocrine function after pancreatectomy. Methods The subjects were 96 patients who underwent a 13 C-trioctanoin breath test before and 1 month after pancreatectomy, between 2006 and 2018. We retrospectively compared the pre- and postoperative fat absorption levels between patients with PF (PF group; n = 17) and without PF (non-PF group; n = 79) using the breath test. Results The preoperative level of 13 C-trioctanoin absorption (%dose/h) was comparable between the non-PF and PF groups (36.5 vs. 36.9). In the non-PF group, 13 C-trioctanoin absorption was significantly decreased after surgery in comparison to the preoperative setting (post-operative 28.5; pre-operative 36.5; p < 0.0001), whereas these values were comparable (post-operative 36.9; pre-operative 34.5; p = 0.129) in the PF group. Moreover, postoperative absorption in the PF group was significantly better than that in the non-PF group (34.5 vs. 28.5%, p = 0.0003). The maximum drain amylase level was significantly higher in patients with a 13 C-trioctanoin absorption level (%dose/h) of ≥ 30 in comparison to patients with levels of < 30 (2502 vs. 398 U/L, p = 0.001). Conclusion PF did not exacerbate the pancreatic exocrine function in the early postoperative period, and the acceleration or preservation of the exocrine function after surgery may be an important cause of PF.