Amylase value in drains after pancreatic resection as predictive factor of postoperative pancreatic fistula: results of a prospective study in 137 patients

Abstract

Background: The correlation of the amylase value in drains (AVD) with the development of pancreatic fistula (PF) is still unclear.

Aim: The purpose of this study was to identify within the first postoperative day (POD1) the predictive role of different risks factors, including AVD, in the development of PF.

Patients and methods: We prospectively investigated 137 patients who underwent major pancreatic resections. PF was defined and graded in accordance with the International Study Group on PF.

Results: We considered 101 pancreaticoduodenectomies and 36 distal resections. The overall incidence of PF (A, B, and C grades) was 19.7% and it was 14.8% after pancreaticoduodenectomy and 33.3% after distal resection. All PF occurred in "soft" remnant pancreas. The PF developed in patients with a POD1 median AVD of 10,000 U/L, whereas patients without PF had a median AVD of 1222 U/L (P < 0.001). We established a cut-off of 5000 U/L POD1 AVD for univariate and multivariate analysis. The area under the receiver operating characteristic (ROC) curve was 0.922 (P < 0.001). The predicting risk factors selected in the univariate setting were "soft" pancreas (P = 0.005; odds ratio [OR]: 1.54; 95% CI: 1.32-1.79) and AVD (P < 0.001; OR: 5.66; 95% CI: 3.6-8.7; positive predictive value 59%; negative predictive value 98%), whereas in multivariate analysis the predicting risk factor was the POD1 AVD (P < 0.001; OR: 68.4; 95% CI: 14.8-315). Only 2 PFs were detected with AVD <5000 U/L and both were in pancreatogastric anastomosis (P = 0.053).

Conclusions: AVD in POD1 > or =5000 U/L is the only significant predictive factor of PF development.

Figures

FIGURE 1. Median values of amylase in drains during postoperative recovery. Vertical bars show 25th and 75th percentiles.

FIGURE 2. ROC curve based on amylase levels in drains on POD1 (area under the curve 0.922; P < 0.001; 95% CI: 0.878–0.966).

FIGURE 3. Median postoperative liquid output in drains. Vertical bars show 25th and 75th percentiles.