Preoperative Risk Stratification of Postoperative Pancreatic Fistula: Training and External Validation of a Risk-tree Predictive Model for Pancreatoduodenectomy

Abstract

Purpose: Existing postoperative pancreatic fistula (POPF) risk scores rely on intraoperative parameters, limiting their value in the preoperative setting. We sought to build and externally validate a preoperative predictive model to stratify the risk of developing POPF before pancreatoduodenectomy (PD). Methods: A regression risk-tree model for preoperative POPF risk stratification was developed in the Verona University Hospital training cohort using preoperative variables and then tested prospectively in a validation cohort of patients who underwent PD at San Raffaele Hospital of Milan. Results: In the study period 566 (training cohort) and 456 (validation cohort) patients underwent PD. In the multivariate analysis BMI, radiographic main pancreatic duct (MPD) diameter and ASA score ≥3 were independently associated with POPF. The regression tree analysis allocated patients into three preoperative risk groups with an 8%, 21% and 32% risk of POPF (all P< 0.01) based on MPD diameter (≥ or < 5 mm) and BMI (≥ or < 25). The three groups were labeled low, intermediate, and high risk and consisted of 206 (37%), 188 (33%) and 172 (30%) patients, respectively. The risk-tree was applied to validation cohort, successfully reproducing three risk groups with significantly different POPF risks (all P<0.01). Conclusions: In candidates for PD, the risk of POPF can be quickly and accurately determined in the preoperative setting based on the BMI and MPD diameter at radiology. Preoperative risk stratification could potentially guide clinical decision-making, improve patient counseling, and allow the establishment of personalized preoperative protocols.