Biliary-intestinal anastomosis leads to alterations in intestinal flora and its flora metabolites and increases the risk of long-term postoperative complications: a case-control study

Baicheng Li Zhao Chen ^* Shili Ning ^* Guangzhi Wang Yuzhuo Chen Hou Xingdong Bowei Lu ^*

• Second Affiliated Hospital of Dalian Medical University, Dalian, China

Pancreaticoduodenectomy (PD) involves resecting multiple organs and reconstructing the digestive tract, including pancreatico-enteric, bilioenteric, and gastroenteric anastomoses. Previous studies have shown a high incidence of long-term complications after PD, impacting patient prognosis and survival. The mechanisms remain unclear, but biliary-intestinal anastomosis may alter bile flow and affect gut microbiota and its metabolites. Given the link between biliary tract infections and gut microbiota changes, we hypothesize that post-PD alterations in intestinal flora and metabolites could contribute to long-term complications.This study included 17 patients who underwent PD (Group T) and 20 matched controls (Group N). Group T was further divided into complication and non-complication subgroups. Fecal samples were collected for 16S rRNA gene sequencing to analyze microbial composition and metabolites. Results showed: 1. No significant differences in alpha diversity indices between groups. 2. Group T had higher levels of Escherichia-Shigella, Veillonella, and Enterobacter, and lower levels of Blautia and Bifidobacterium compared to Group N. 3. Escherichia-Shigella correlated negatively with Blautia, positively with Veillonella and Enterobacter. Blautia and Bifidobacterium correlated positively with each other. 4. The complication subgroup had significantly higher Escherichia-Shigella levels. 5. Metabolomic analysis revealed increased L-palmitoylcarnitine, arachidic acid, and PG 13:0_15:0 in Group T, while 3-isopropylmalic acid decreased. 6. KEGG pathway analysis identified nine metabolic pathways associated with these shifts. Conclusion: 1. Biliary-intestinal anastomosis during PD alters intestinal flora. 2. Increased Escherichia-Shigella abundance may promote long-term complications. 3. Post-PD biliary-intestinal anastomosis affects metabolite profiles. 4. Altered intestinal flora and metabolites may contribute to long-term complications via specific metabolic pathways.