Multidetector CT findings differ between surgical grades of pancreatic fistula after pancreaticoduodenectomy

Validation of a CT-based model for early prediction of post pancreatectomy haemorrhage risk

BACKGROUND

Identification of early predictors of postoperative pancreatic fistula (POPF) related postpancreatectomy hemorrhage (PPH) on contrast-enhanced computed tomography (CT) may help tailoring management after pancreaticoduodenectomy (PD) although no model has been validated so far.

METHODS

A bicentric analysis of consecutive PD performed between 2017 and 2022 was performed. A recently reported CT-based score (CTS) was externally validated. Sensitivity refinements were proposed through a modified-CTS which was internally (development cohort, n=182) and externally validated (validation cohort, n=62). Bootstrap corrected Areas under the curve (AUCs), Sensitivity (Se) and Positive Predictive Value (PVV) were used to evaluate and compare the two scores.

RESULTS

A total of 244 patients (55.1% women; median age: 68 years [IQR: 58.0-75.0], clinically relevant (cr)-POPF: 25.4%, cr-PPH: 13.9%) were included. CTS accurately predicted a cr-PPH with an AUC of 0.83 (1000-boostrap 95% CI: 0.76-0.89). The modified-CTS, made available online (https://stylianostzedakis.shinyapps.io/pph_risk_calculator/), included CTS with 2 supplementary variables selected from a multivariable backward-stepwise regression: Perianastomotic air bubbles, posterosuperior pancreaticojejunal (PJ) anastomosis collection, posterior PJ defect, PJ collection in contact with hepatic or gastroduodenal artery stump and arterial wall irregularities. When compared with the CTS, although modified-CTS AUC [95%CI] were similar in the validation cohort (0.81 [0.62-0.95] vs. 0.87 [0.56-0.96], DeLong p=0.7), Se and PPV for early PPH detection were significantly higher (0.82 [0.75-0.92] vs. 0.71 [0.35-0.75] and 0.95 [0.83-0.99] vs. 0.33 [0.12-0.62], McNemar's p = 0.03).

CONCLUSIONS

With a robust prediction model, early CT-scan after PD seems a valid tool for early identification of high-risk cr-PPH patients.

Cross-sectional imaging after pancreatic surgery: The dialogue between the radiologist and the surgeon

Pancreatic surgery is nowadays considered one of the most complex surgical approaches and not unscathed from complications. After the surgical procedure, cross-sectional imaging is considered the non-invasive reference standard to detect early and late compilations, and consequently to address patients to the best management possible. Contras-enhanced computed tomography (CECT) should be considered the most important and useful imaging technique to evaluate the surgical site. Thanks to its speed, contrast, and spatial resolution, it can help reach the final diagnosis with high accuracy. On the other hand, magnetic resonance imaging (MRI) should be considered as a second-line imaging approach, especially for the evaluation of biliary findings and late complications. In both cases, the radiologist should be aware of protocols and what to look at, to create a robust dialogue with the surgeon and outline a fitted treatment for each patient.

Differentiation Between Abscesses and Unnecessary Intervention Fluid After Pancreas Surgery Using Dual-Energy Computed Tomography

INTRODUCTION

This study aimed to evaluate the potential of dual-energy computed tomography (CT) to distinguish postoperative ascites, pancreatic fistula, and abscesses.

MATERIALS AND METHOD

Patients who underwent biliary and pancreatic surgery performed at our institution between June 2021 and February 2022 were included in the study. Postoperative body fluid samples were collected through a drain or percutaneous drainage. These samples were set in a phantom, and imaging data were obtained using dual-energy CT. Image analysis was performed to obtain CT values at each energy in virtual monoenergetic images (VMIs), effective atomic number, iodine map, and virtual non-contrast (VNC) images. VMIs were calculated from 80 and 140 kVp tube data at 10 kV each from 40-140 kV. Additionally, the effective atomic number, iodine map, and VNC images were reconstructed from the material decomposition process using water and iodine as the base material pair.

RESULTS

In this study, 25 patients (eight with abscess and 17 with ascites) were included. No significant association was observed between the presence or absence of abscess and malignancy or surgical procedure. The intervention was performed in six of the eight patients with abscesses. In contrast, five of the 17 patients with postoperative ascites required intervention. A significant relationship was observed between the intervention and the presence of an abscess. Significant differences in C-reactive protein values and the incidence of fever were observed between the groups. Only VNC showed a significant difference between the groups.

CONCLUSIONS

VNC using dual-energy CT could differentiate abscesses from postoperative fluid.

Prevention and Treatment of Grade C Postoperative Pancreatic Fistula

Postoperative pancreatic fistula (POPF) is a troublesome complication after pancreatic surgeries, and grade C POPF is the most serious situation among pancreatic fistulas. At present, the incidence of grade C POPF varies from less than 1% to greater than 9%, with an extremely high postoperative mortality rate of 25.7%. The patients with grade C POPF finally undergo surgery with a poor prognosis after various failed conservative treatments. Although various surgical and perioperative attempts have been made to reduce the incidence of grade C POPF, the rates of this costly complication have not been significantly diminished. Hearteningly, several related studies have found that intra-abdominal infection from intestinal flora could promote the development of grade C POPF, which would help physicians to better prevent this complication. In this review, we briefly introduced the definition and relevant risk factors for grade C POPF. Moreover, this review discusses the two main pathways, direct intestinal juice spillover and bacterial translocation, by which intestinal microbes enter the abdominal cavity. Based on the abovementioned theory, we summarize the operation techniques and perioperative management of grade C POPF and discuss novel methods and surgical treatments to reverse this dilemma.

C-reactive protein identifies patients at risk of postpancreatectomy hemorrhage

Background

Postpancreatectomy hemorrhage grade C (PPH C) is a dreaded complication after pancreaticoduodenectomy (PD) with high mortality rate. Concurrent risk factors for PPH C have been difficult to recognize. Connection between postoperative pancreatic fistulas (POPF) and PPH C is well known, but POPF is often unknown prior to the PPH. The aim of this retrospective study was to define potential predictive factors for PPH C.

Methods

Retrospectively, 517 patients who underwent PD between 2003 and 2018 were included in the study. Twenty-three patients with PPH C were identified, and a matched control group of 92 patients was randomly selected. Preoperative data (body mass index, cardiovascular disease, history of abdominal surgery, biliary stent, C-reactive protein (CRP), ASA-score), perioperative data (bleeding, pancreatic anastomosis, operation time), and postoperative data (CRP, drain amylase, POPF, biliary fistula) were analyzed as potential predictors of PPH C.

Results

High postoperative CRP (median 140 mg/L on day 5 or 6) correlated with the development of PPH C (p < 0.05). Postoperative drain amylase levels were not clinically relevant for occurrence of PPH C. Grade C POPF or biliary leak was observed in the majority of the PPH C patients, but the leaking anastomoses were not detected before the bleeding started.

Discussion

High postoperative CRP levels are related to an increased risk of PPH C.

Before sentinel bleeding: early prediction of postpancreatectomy hemorrhage (PPH) with a CT-based scoring system

OBJECTIVES

Clinically significant pancreatic fistula (POPF) has been established as a well-known risk factor for late and severe postpancreatectomy hemorrhage after pancreaticoduodenectomy (PD) (postpancreatectomy pancreatic fistula-associated hemorrhage [PPFH]). Our aim was to assess whether contrast-enhanced CT scan after PD is an effective tool for early prediction of PPFH.

METHODS

From a prospectively acquired database, all consecutive patients who underwent PD between January 2013 and May 2019 were identified; within this database, all patients who were evaluated, for clinical suspicion of POPF, with at least one contrast-enhanced CT scan examination, were enrolled in this retrospective study. The selected CT findings included perianastomotic fluid collections and air bubbles; pancreaticojejunostomy (PJ) was analyzed in terms of dehiscence and defect.

RESULTS

One hundred seventy-eight out of 953 PD patients (18.7%) suffered from clinically significant POPF; after exclusions, 166 patients were enrolled. Among this subset, 33 patients (19.9%) had at least one PPFH episode. In multivariable analysis, PPFH was associated with postoperative CT evidence of fluid collections (p = 0.046), air bubbles (p = 0.046), and posterior PJ defect (p < 0.001). Based on these findings, a practical 4-point prediction score was developed (AUC: 0.904, Se: 76%, Sp: 93.8%): patients with a score ≥ 3 demonstrated a significantly higher risk of PPFH development (OR = 45.6, 95% CI: 13.0-159.3).

CONCLUSIONS

Postoperative CT scan permits early stratification of PPFH risk, thus providing an actual aid for patients' management.

KEY POINTS

• Postpancreatectomy hemorrhage (PPH) is a dramatic, clinically unpredictable occurrence. • After pancreaticoduodenectomy (PD), early identification of posterior pancreaticojejunostomy defect, perianastomotic air bubbles, and retroperitoneal fluid collections enables effective PPH risk stratification by means of a practical CT-based 4-point scoring system. • CT scan after PD allows a paradigm shift in the management PPH, from a conventional "wait and see" approach, to a more proactive one that relies on early anticipation and timely prevention.