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Background: Long-term survival after pancreatic surgery has increased gradually due to recent improvements in surgical techniques and experiences; therefore, postoperative evaluation of fat absorption and glucose metabolism disturbances is important. We have been reported that the non-invasive 13C-mixed triglyceride breath test (13C-MTG-T), labelled long chain triglyceride mixture can reliably diagnose pancreatic exocrine insufficiency (Surgery, 2009). In this study, we investigate fat absorptive function in patients status post pylorus preserving pancreatoduodenectomy (PPPD) with pancreaticogastrostomy (PG) reconstruction more than 12 months after the procedure.
Methods: 13C-MTG-T (200 mg 13C-MTG, 20 g fat, and breath samples over 7 hours) was performed for 52 patients undergoing PPPD with PG reconstruction and 12 healthy volunteers, forming our control group. Pancreatic exocrine insufficiency was defined as percent of cumulative 7-hour 13CO2 exhalation (% dose 13C cum 7h) < 5%, assessed by 13C-MTG-T. Sections from the surgical pancreatic cut margin were used for histological assessment. The degree of pancreatic exocrine cells was calculated as ratio of the pancreatic exocrine cells area to total area measured in the entire section. We analyze the relationship between 13C-MTG-T as a measure of pancreatic exocrine insufficiency postoperatively and the degree of pancreatic exocrine cells by histology as well as the development of diabetes mellitus (DM) as a measure of pancreatic endocrine insufficiency.
Results: % dose 13C cum 7h was significantly lower in patients with PPPD (6.8±4.8%) than in healthy controls (15.5±6.0%; P<0.01). Pancreatic exocrine insufficiency assessed by 13C-MTG-T (% dose 13C cum 7h < 5%) was observed in 20 patients (38%) in PPPD group but none in the control group. Of the 52 patients undergoing PPPD, the histological degree of pancreatic exocrine cells was significantly higher in patients with % dose 13C cum 7h >/= 5% (81.7±5.4%) than those with <5% (67.8±8.5%; P=0.01). Patients with pancreatic insufficiency (% dose 13C cum 7h <5%) significantly decreased body mass index at 12 months after PPPD comparing to those with % dose 13C cum 7h >/=5% (-10.9±8.4% vs +0.9±9%; P<010). 6 patients had been diagnosed with DM prior to undergoing the procedure, and, of the remaining 46 patients, 5 (11%) became diabetic after the procedure. Patients with DM demonstrated significantly lower % dose 13C cum 7h comparing to patients without DM (5.9±4.3% vs. 10.5±5.2%; P<0.01).
Conclusion: 13C-MTG-T as well as residual pancreatic exocrine cells represented by histological degree of pancreatic exocrine cells at cut margin, reliably show long-term fat absorptive function after PPPD. Glucose metabolism disturbance is also related to post operative fat absorption.