Impact of the ratio of fecal short-chain fatty acids to lactic acid concentration on postoperative infectious complications after pancreaticoduodenectomy.

BACKGROUND

We previously reported that the balance of short-chain fatty acids and lactic acid in feces affects postoperative infectious complications after major hepatectomy. However, the effect remains unclear in pancreaticoduodenectomy.

METHODS

Preoperative fecal samples were collected from 210 patients who underwent pancreaticoduodenectomy at 2 institutions between January 2019 and June 2021. Organic acid concentrations were measured per 1 g of feces by high-performance liquid chromatography; the ratio, defined as the sum of acetic, propionic, and butyric acid divided by lactic acid, was calculated. The correlation between the acetic, propionic, and butyric acid divided by lactic acid ratio and postoperative infectious complications was determined using univariate and multivariate analyses.

RESULTS

Sixty-one patients (29%) had postoperative infectious complications, represented by intra-abdominal abscess, cholangitis, and surgical-site infection. Fecal lactic acid levels ranged from 0.13 to 36.98, with a median of 0.69; the median level was 1.10 μmol/g in the postoperative infectious complications group and 0.36 μmol/g in the nonpostoperative infectious complications group (P < .001). The acetic, propionic, and butyric acid divided by lactic acid ratio ranged from 1.65 to 1,753.4, with a median of 105.8; the median ratio was 59.1 in the postoperative infectious complications group and 198.6 in the nonpostoperative infectious complications group (P = .002). Multivariate analysis revealed that a low acetic, propionic, and butyric acid divided by lactic acid ratio (<75) in the preoperative feces was an independent risk factor for postoperative infectious complications, with an odds ratio of 3.5 and a 95% confidence interval of 1.8-7.0 (P < .001). Preoperative biliary drainage was significantly associated with a low acetic, propionic, and butyric acid divided by lactic acid ratio.

CONCLUSION

The preoperative fecal organic acid profile determined using the acetic, propionic, and butyric acid divided by lactic acid ratio clinically impacted the incidence of postoperative infectious complications in patients who underwent pancreaticoduodenectomy.