Measurement of pancreatic fat by magnetic resonance imaging: predicting the occurrence of pancreatic fistula after pancreatoduodenectomy. Ann Surg. 2010;251:932-936. [PMID: 20395858 DOI: 10.1097/sla.0b013e3181d65483]

Efficacy of the two-parts wrapping technique in reducing postoperative complications in laparoscopic pancreaticoduodenectomy

BACKGROUND

The advancement of laparoscopic technology has broadened the application of laparoscopic pancreaticoduodenectomy (LPD) for treating pancreatic head and ampullary tumors. Despite its benefits, postoperative pancreatic fistula (POPF) and postpancreatectomy hemorrhage (PPH) remain significant complications. Ligamentum teres hepatis wrapping around the gastroduodenal artery (GDA) stump show limitations in reducing POPF and PPH.

METHODS

This study retrospectively analyzed patients undergoing LPD from January 2016 to October 2023, We compared the effectiveness of the two-parts wrapping (the ligamentum teres hepatis wrapping of the gastroduodenal artery stump and the omentum flap wrapping of the pancreatojejunal anastomosis) and ligamentum teres hepatis wrapping around the gastroduodenal artery (GDA) in reducing postoperative pancreatic fistula (POPF) and postpancreatectomy hemorrhage (PPH), using propensity score matching for the analysis.

RESULTS

A total of 172 patients were analyzed, showing that the two-parts wrapping group significantly reduced the rates of overall and severe complications, POPF, and PPH compared to ligamentum teres hepatis wrapping around the GDA group. Specifically, the study found lower rates of grade B/C POPF and no instances of PPH in the two-parts wrapping group, alongside shorter postoperative hospital stays and drainage removal times. These benefits were particularly notable in patients with soft pancreatic textures and pancreatic duct diameters of < 3 mm.

CONCLUSION

The two-parts wrapping technique significantly reduce the risks of POPF and PPH in LPD, offering a promising approach for patients with soft pancreas and pancreatic duct diameter of < 3 mm.

Postoperative pancreatitis and pancreatic fistulae: a review of current evidence

OBJECTIVES

Postoperative pancreatic fistula (POPF) represents one of the most severe complications following pancreatic surgery. Despite being a leading cause of morbidity and mortality, its pathophysiology is poorly understood. In recent years, there has been growing evidence to support the role of postoperative or post-pancreatectomy acute pancreatitis (PPAP) in the development of POPF. This article reviews the contemporary literature on POPF pathophysiology, risk factors, and prevention strategies.

METHODS

A literature search was conducted using electronic databases, including Ovid Medline, EMBASE, and Cochrane Library, to retrieve relevant literature published between 2005 and 2023. A narrative review was planned from the outset.

RESULTS

A total of 104 studies fulfilled criteria for inclusion. Forty-three studies reported on technical factors predisposing to POPF, including resection and reconstruction technique and adjuncts for anastomotic reinforcement. Thirty-four studies reported on POPF pathophysiology. There is compelling evidence to suggest that PPAP plays a critical role in the development of POPF. The acinar component of the remnant pancreas should be regarded as an intrinsic risk factor; meanwhile, operative stress, remnant hypoperfusion, and inflammation represent common mechanisms for acinar cell injury.

CONCLUSIONS

The evidence base for PPAP and POPF is evolving. Future POPF prevention strategies should look beyond anastomotic reinforcement and target underlying mechanisms of PPAP development.

Serum amylase on postoperative day one is a strong predictor of pancreatic fistula after pancreaticoduodenectomy: a retrospective cohort

Background/aim

Early identification of patients at risk for developing postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) may facilitate drain management. In this context, it was aimed to examine the efficiency of the serum amylase (SA) value on postoperative day (PoD) 1 in predicting the occurrence of POPF.

Materials and methods

A total of 132 patients who underwent PD were studied. Occurrences of POPF were classified according to the International Study Group on Pancreatic Fistula classification as a biochemical leak (BL) or clinically relevant grade b/c POPF (CR-POPF). Receiver operating characteristic analysis identified a threshold value of SA on PoD 1 associated with POPF formation.

Results

Overall, 66 (50%) patients had POPF, including 51 (38.7%) with BL and 15 with CR-POPF (11.3%). The threshold value of SA associated with the development of POPF was 120 IU/L (odds ratio [OR]: 3.20; p = 0.002). In the multivariate analysis, independent POPF risk factors were SA ≥120 IU/L, soft pancreatic texture, and high-risk pathology (i.e., duodenal, biliary, ampullary, islet cell, and benign tumors); SA ≥120 IU/L outperformed soft pancreatic texture and high-risk pathology in predicting POPF, respectively (OR: 2.22; p = 0.004 vs. OR: 1.37; p = 0.012 vs. OR: 1.35; p = 0.018). In a subset analysis according to gland texture (soft vs. hard), patients with soft pancreatic texture exhibited a significantly higher incidence of POPF (63.4% vs. 34.4%) and SA ≥120 IU/L (52.1% vs. 27.9%); SA <120 IU/L had a negative predictive value of 82.5% for developing POPF in patients with hard pancreatic texture (OR: 4.28, p = 0.028).

Conclusion

A SA value ≥120 IU/L on the day after PD, which is the strongest predictor for POPF, can be used as a biomarker of the occurrence of POPF. The advantage of SA measurement is that it can contribute to identifying suitable patients for early drain removal.

Adjusting Drain Fluid Amylase for Drain Volume Does Not Improve Pancreatic Fistula Prediction

INTRODUCTION

Drain fluid amylase (DFA) levels have been used to predict clinically relevant postoperative pancreatic fistula (CR-POPF) and guide postoperative drain management. Optimal DFA cutoff thresholds vary between studies, thereby prompting investigation of an alternative assessment technique. As DFA measurements could, in theory, be distorted by variations in ascites fluid production, we hypothesized that adjusting DFA for volume corrected drain fluid amylase (vDFA) would improve CR-POPF predictive models.

METHODS

A single-institution retrospective cohort study of patients, who underwent pancreatoduodenectomies (PD) and distal pancreatectomies (DP) between 2013 and 2019, was performed. DFAs and vDFAs were measured on postoperative day (POD) 3. Clinicopathologic variables were compared between cohorts by univariable and multivariable analyses and Receiver operating characteristic (ROC) curves.

RESULTS

Patients developing a CR-POPF were more likely to be male and have elevated DFA, vDFA, and body mass index (BMI). vDFA use did not contribute to a superior CR-POPF predictive model compared to DFA-a finding consistent on subanalysis of surgery type PD versus DP. In CR-POPF predictive models, DFA, vDFA, and male sex significantly improved CR-POPF predictive models when considering both surgery subtypes, while only DFA and vDFA significantly improved models when cohorts were segregated by surgery type.

CONCLUSIONS

Postoperative DFA remains a preferred method of predicting CR-POPF as the proposed vDFA assessment technique only adds complexity without increased discriminability.

A Simple Classification of Pancreatic Duct Size and Texture Predicts Postoperative Pancreatic Fistula: A classification of the International Study Group of Pancreatic Surgery

OBJECTIVE

The aim of this study was to develop a classification system for pancreas-associated risk factors in pancreatoduodenectomy (PD).

SUMMARY BACKGROUND DATA

Postoperative pancreatic fistula (POPF) is the most relevant PD-associated complication. A simple standardized surgical reporting system based on pancreas-associated risk factors is lacking.

METHODS

A systematic literature search was conducted to identify studies investigating clinically relevant (CR) POPF (CR-POPF) and pancreas-associated risk factors after PD. A meta-analysis of CR-POPF rate for texture of the pancreas (soft vs not-soft) and main pancreatic duct (MPD) diameter was performed using the Mantel-Haenszel method. Based on the results, the International Study Group of Pancreatic Surgery (ISGPS) proposes the following classification: A, not-soft (hard) texture and MPD >3 mm; B, not-soft (hard) texture and MPD ≤3 mm; C, soft texture and MPD >3 mm; D, soft texture and MPD ≤3 mm. The classification was evaluated in a multi-institutional, international cohort.

RESULTS

Of the 2917 articles identified, 108 studies were included in the analyses. Soft pancreatic texture was significantly associated with the development of CR-POPF [odds ratio (OR) 4.24, 95% confidence interval (CI) 3.67-4.89, P < 0.01) following PD. Similarly, MPD diameter ≤3 mm significantly increased CR-POPF risk compared with >3 mm diameter MPDs (OR 3.66, 95% CI 2.62-5.12, P < 0.01). The proposed 4-stage system was confirmed in an independent cohort of 5533 patients with CR-POPF rates of 3.5%, 6.2%, 16.6%, and 23.2% for type A-D, respectively ( P < 0.001).

CONCLUSION

For future pancreatic surgical outcomes studies, the ISGPS recommends reporting these risk factors according to the proposed classification system for better comparability of results.

Visual assessment of pancreatic fat deposition: useful grading system and the relation to BMI and diabetes

PURPOSE

To establish a simple and clinically useful method for the visual assessment of pancreatic fat deposition using computed tomography (CT) images, and to evaluate the relationship of the pancreatic fat deposition with body mass index (BMI) and type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

We used a four-scale grading system as the visual assessment criteria for pancreatic fat deposition using CT images. Pancreatic fat deposition was assessed for 200 patients and the results were compared with the CT attenuation-based assessment. In addition, the relationships of pancreatic fat deposition with BMI and type 2 DM were investigated.

RESULTS

The visual and CT attenuation-based assessments were considered consistent. The results of the visual assessment suggested that mild and moderate pancreatic fat deposition correlated with BMI and presence of type 2 DM while severe fat deposition did not correlate with them. No correlation between pancreatic fat deposition and HbA1c level was found.

CONCLUSION

The visual assessment criteria we used were consistent with CT attenuation-based assessment and may be useful for clinical application of pancreatic fat deposition. According to the visually assessment, mild or moderate pancreatic fat deposition correlated with BMI and the presence of type 2 DM, but severe fat deposition did not correlate with them.

Pancreatic fistula and biliary fistula after laparoscopic pancreatoduodenectomy: 500 patients at a single institution

Background

Pancreatic fistula (PF) and biliary fistula (BF) are two major leakage complications after pancreatoduodenectomy (PD). The aim of this study is to investigate the risk factors of PF and BF after laparoscopic PD (LPD).

Materials and Methods

We conducted a retrospective analysis of 500 patients who underwent LPD from 1 April 2015 to 31 March 2020. Clinical data from patients were analysed using multivariate logistic regression analysis.

Results

PF occurred in 86 (17.2%) patients. Univariate and multivariate analysis indicated that the soft texture of the pancreas (P = 0.001) was the independent risk factor for PF. BF occurred in 32 (6.4%) patients. Univariate and multivariate analysis indicated that history of cardiovascular disease (P < 0.001), surgical time (P = 0.005), pre-operative CA125 (P = 0.036) and pre-operative total bilirubin (P = 0.044) were independent risk factors for BF.

Conclusion

The texture of the pancreas was an independent risk factor for PF after LPD, which was consistent with the literatures. In addition, history of cardiovascular disease, surgical time, pre-operative CA125 and pre-operative total bilirubin were new independent risk factors for BF after LPD. Therefore, patients with high-risk factors of BF should be informed that they are at a high risk for this complication.

Impact of pancreatic fat infiltration on postoperative pancreatic fistula occurrence in patients undergoing invagination pancreaticojejunostomy

BACKGROUND

No studies to date have determined the impact of pancreatic fat infiltration on postoperative pancreatic fistula (POPF) occurrence in patients undergoing invagination pancreaticojejunostomy (IV-PJ).

METHODS

The medical records of patients with a soft pancreas who underwent pancreatoduodenectomy followed by IV-PJ were reviewed . The pancreatic fat ratio on computed tomography (CT) images (I-PFR) was determined using preoperative CT and verified by histologic examination. The relationship between the I-PFR and POPF occurrence was determined. Patients were classified into 2 groups based on I-PFR value (fatty and non-fatty pancreas). Postoperative outcomes were compared between the two groups, and specifically among patients who developed POPF.

RESULTS

Of 221 patients, POPF occurred in 67 (30.3%). I-PFR was positively correlated with histologic-calculated fat ratio (ρ = 0.517, p < 0.001). This index was shown to be an independent predictor of POPF. Based on an I-PFR cut-off value of 3.2%, 92 patients were classified in the fatty pancreas group. Subgroup analysis of the patients who developed POPF showed that incidence of abscess formation and hemorrhage tended to be higher in patients with fatty pancreas than in those with non-fatty pancreas.

CONCLUSIONS

Pancreatic fat infiltration is highly associated with POPF and possibly causes subsequent serious complications in patients undergoing IV-PJ.

The effect of duct width and pancreatic gland structure on pancreatic fistula rates in patients who underwent pancreaticoduodenectomy for pancreatic cancer

Introduction: One of the most important causes of morbidity in pancreaticoduodenectomy (PD) surgery is pancreatic anastomosis leakage. There is a possibility of pancreatic fistula even in the most experienced hands. After PD, pancreatic fistula occurs between 10% and 20% in various series. This study aims to evaluate the effects of pancreatic duct size and pancreatic tissue on the development of pancreatic fistula after PD is performed in our center. Material and Method: Pancreatic duct size was categorized as small &lt;3 mm and large &gt;3 mm. Pancreatic gland tissue was categorized as a soft, medium, and hard. These variables were calculated preoperatively with the help of computed tomography (CT), ultrasonography(USG), and Endoscopic ultrasound (EUS), and postoperative pathology results. It was accepted that the 24-hour flow rate of the drain behind the pancreatic anastomosis was more than 50 ml during 3 days after PD and/or the amylase concentration of the drain content measured at 3 different times was 3 times higher than the serum amylase concentration. Results: A total of 90 patients were included in the study, anastomotic leakage was not observed in 63 (70%) of 90 patients, and leakage was observed in 27 (30%) patients. The mean age was 71.22±10.78 years (p=0.615). There was no statistically significant difference between the ductus diameters between the two groups (p=0.240). There was no statistical difference between the groups formed according to pancreatic duct width. (p=0.059). It was observed that 60.3% of the patients in the non-leakage group had a hard appearance, and this rate was statistically significantly reduced to 29.6% in the patients with leakage (p=0.008). Conclusion: In summary, our study showed that pancreatic fistula after PD is associated with soft pancreatic parenchyma. The surgeon should consider this risk factor when performing a PD and be more careful to reduce the rate of pancreatic fistula.

Histological pancreatic findings correlate with computed tomography attenuation and predict postoperative pancreatic fistula following pancreatoduodenectomy

BACKGROUND

Although a soft pancreas is a widely-accepted reliable risk factor for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD), there is no established preoperative evaluation of pancreatic texture.

METHODS

Two hundred thirty-seven patients who underwent PD with histological pancreatic assessment were retrospectively enrolled. The degree of fibrosis and fatty infiltration was scored histologically as seven grades and five grades, respectively. Computed tomography (CT) attenuation of the pancreas was measured on preoperative unenhanced CT images. Correlations between the CT attenuation of the pancreas and the histological pancreatic findings, and the development of POPF were analyzed.

RESULTS

The fibrosis grade was significantly higher for hard pancreas than for soft pancreas (p < 0.001), whereas the fatty infiltration grade was similar between the two types (p = 0.161). CT attenuation of the pancreas was inversely correlated with both fibrosis grade (Spearman's rank correlation coefficient ([r] = -0.609, p < 0.001) and fatty infiltration grade (r = -0.382, p < 0.001). Multivariate analysis showed that body mass index ≥25 kg/m² (odds ratio [OR]: 5.64, p < 0.001) and fibrosis grade ≤2 (OR: 18.0, p < 0.001) were independent risk factors for clinically significant POPF.

CONCLUSION

Histological pancreatic texture can be evaluated with CT attenuation and might be helpful in preoperatively predicting the development of POPF after PD.

Dual-Energy CT Iodine Concentration to Evaluate Postoperative Pancreatic Fistula after Pancreatoduodenectomy

Background Pancreatic fibrosis and fatty infiltration are associated with postoperative pancreatic fistula (POPF), but accurate preoperative assessment remains a challenge. Iodine concentration (IC) and fat fraction derived from dual-energy CT (DECT) may reflect the amount of fibrosis and steatosis, potentially enabling the preoperative prediction of POPF. Purpose To identify multiphasic DECT-derived IC and fat fraction that improve the prediction of POPF risks compared with contrast-enhanced CT attenuation values and to evaluate the underlying histopathologic changes. Materials and Methods This retrospective study included patients who underwent pancreatoduodenectomy and DECT (including pancreatic parenchymal, portal venous, and delayed phase scanning) between January 2020 and December 2020. The relationships of the quantitative DECT-derived IC and fat fraction, along with CT attenuation values from enhanced images with POPF risk, were analyzed with logistic regression analysis. The predictive performance of the IC was compared with that of the CT values. The histopathologic underpinnings of IC were evaluated with multivariable linear regression analysis. Results A total of 107 patients (median age, 65 years; interquartile range, 57-70 years; 56 men) were included. Of these, 23 (21%) had POPF. The pancreatic parenchymal-to-portal venous phase IC ratio (adjusted odds ratio [OR], 13; 95% CI: 2, 162; P < .001) was an independent predictor of POPF occurrence. The accuracy of the pancreatic parenchymal-to-portal venous phase IC ratio in predicting POPF was higher than that of the CT value ratio in the same phases (78% vs 65%, P < .001). The pancreatic parenchymal-to-portal venous phase IC ratio was independently associated with pancreatic fibrosis (β = -1.04; 95% CI: -0.44, -1.64; P = .001). Conclusion A higher pancreatic parenchymal-to-portal venous phase IC ratio was associated with less histologic fibrosis and greater risk of POPF. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Lee and Yoon in this issue.

External validation of postoperative pancreatic fistula prediction scores in pancreatoduodenectomy: a systematic review and meta-analysis

BACKGROUND

Multiple risk scores claim to predict the probability of postoperative pancreatic fistula (POPF) after pancreatoduodenectomy. It is unclear which scores have undergone external validation and are the most accurate. The aim of this study was to identify risk scores for POPF, and assess the clinical validity of these scores.

METHODS

Areas under receiving operator characteristic curve (AUROCs) were extracted from studies that performed external validation of POPF risk scores. These were pooled for each risk score, using intercept-only random-effects meta-regression models.

RESULTS

Systematic review identified 34 risk scores, of which six had been subjected to external validation, and so included in the meta-analysis, (Tokyo (N=2 validation studies), Birmingham (N=5), FRS (N=19), a-FRS (N=12), m-FRS (N=3) and ua-FRS (N=3) scores). Overall predictive accuracies were similar for all six scores, with pooled AUROCs of 0.61, 0.70, 0.71, 0.70, 0.70 and 0.72, respectively. Considerably heterogeneity was observed, with I2 statistics ranging from 52.1-88.6%.

CONCLUSION

Most risk scores lack external validation; where this was performed, risk scores were found to have limited predictive accuracy. . Consensus is needed for which score to use in clinical practice. Due to the limited predictive accuracy, future studies to derive a more accurate risk score are warranted.

Impact of Fatty Pancreas on Postoperative Pancreatic Fistulae: A Meta-Analysis

Background

Soft pancreas is widely recognized as an important risk factor for the development of postoperative pancreatic fistula (POPF). Although fatty pancreas (FP) has not been formally defined as a cause of pancreatic fistula, existing research has shown that it can increase the incidence of POPF by increasing pancreatic tenderness; therefore, it may be a potential risk factor. This study aimed to discern whether FP was associated with POPF.

Method

Two reviewers independently performed literature searches from five electronic databases. According to the established inclusion criteria, we extracted necessary data from the studies that met the criteria for further analysis. We pooled the odds ratios (ORs) from individual studies using a random-effects model to investigate the associations between POPF and the prognosis of FP.

Result

A total of 11 studies involving 2484 individuals were included. The pooled prevalence of POPF was 18% (95% CI: 12-24%). Body mass index (BMI) was associated with a significantly increased risk of POPF (OR=3.55; 95% CI: 1.83, 6.86; P=0.0002; I²=0). FP was obviously associated with the occurrence of POPF (OR=3.75; 95% CI: 1.64, 8.58; P=0.002; I²=78).

Conclusion

FP is closely associated with the development of POPF, and the early identification of these high-risk patients can help to reduce the incidence of POPF.

Systematic Review Registration

The Registration URL link is (https://www.crd.york.ac.uk/PROSPERO/). The ID is "CRD42021265141".

A modified alternative fistula risk score (a-FRS) obtained from the computed tomography enhancement pattern of the pancreatic parenchyma predicts pancreatic fistula after pancreatoduodenectomy

BACKGROUND

Alternative fistula risk score (a-FRS) is useful to predict clinically relevant postoperative pancreatic fistula (CR-POPF) after pancreatoduodenectomy (PD).

METHODS

Clinical data from 239 patients undergoing PD were collected. The CT value of the pancreatic parenchyma was measured in the nonenhanced (N), arterial (A), portal venous (P), and late (L) phases. The A/N, A/P, P/L and A/L ratios were calculated and their correlation with CR-POPF were analyzed. By replacing pancreatic texture with the best CT attenuation ratio, a modified a-FRS was developed.

RESULTS

Forty-seven patients developed CR-POPF. The A/P ratio (P < 0.001), P/L ratio (P = 0.002) and A/L ratio (P < 0.001) were significantly higher in the CR-POPF group. The A/L ratio performed best in predicting CR-POPF (AUC: 0.803) and the cut-off value is 1.36. A/L ratio >1.36 (P < 0.001), body mass index (P = 0.005) and duct diameter (P = 0.037) were independently associated with CR-POPF. By replacing soft texture with an A/L ratio >1.36, a modified a-FRS was developed and performed better than the a-FRS (AUC: 0.823 vs 0.748, P = 0.006) in predicting CR-POPF.

CONCLUSIONS

The modified a-FRS is an objective and preoperative model for predicting the occurrence of CR-POPF after PD.

Reducing the risk of postoperative pancreatic fistula in radical gastrectomy: pre-assessment with computed tomography for the diagnosis of pancreatic steatosis

PURPOSE

To determine whether pancreatic steatosis (PS) is associated with the risk of postoperative pancreatic fistula (POPF) after radical gastrectomy, and if so, to investigate whether pre-assessment by diagnostic imaging can mitigate the risk.

METHODS

The clinical records of 276 patients with cStage I gastric cancer who underwent laparoscopic gastrectomy with D1 + lymphadenectomy between 2012 and 2015 were reviewed. In the first phase up to July 2013 (n = 138), PS was classified from computed tomography (CT) findings into type S (superficial fat deposition) or type D (diffuse fatty replacement) and examined for association with POPF. In the second phase (n = 138), the preoperative CT assessment of PS was routinized. Separate samples from pancreatoduodenectomy consistent with each type were histologically examined.

RESULTS

In the first phase, the incidence of POPF was significantly higher in group S, but not in group D, compared with normal pancreas (16.3% and 9.1% vs. 3.6%, respectively; P = 0.03). The drain amylase level was lowest in group D, reflecting exocrine insufficiency. Histologically, the loose connective-tissue space between the fat infiltrating the pancreas and the peripancreatic fat containing the lymph nodes was unclear in type D but conserved in type S. In the second phase, surgery was performed with more intention on accurately tracing the dissection plane and significantly lowered incidence of POPF in Group S (16.3% to 2.1%; P = 0.047).

CONCLUSION

Peripancreatic lymphadenectomy is more challenging and likely to cause POPF in patients with PS. However, the risk may be reduced using appropriate dissection techniques based on the CT pre-assessment findings.

Clinical validation of the risk scoring systems of postoperative pancreatic fistula after laparoscopic pancreatoduodenectomy in Chinese cohorts: A single-center retrospective study

BACKGROUND

Although several prediction models for the occurrence of clinically relevant postoperative pancreatic fistula after laparoscopic pancreatoduodenectomy exist, most were established using Western cohorts. The utility of these models using a Chinese cohort has not been validated widely. The aim of the study was to validate the original Fistula Risk Score, the alternative Fistula Risk Score, and the updated alternative Fistula Risk Score for patients undergoing laparoscopic pancreatoduodenectomy in a large-scale Chinese cohort externally.

METHODS

Three clinically relevant postoperative pancreatic fistula risk models were selected for external validation with our database. Primary outcome was grade B/C postoperative pancreatic fistula (clinically relevant postoperative pancreatic fistula). Performance was measured based on sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio, and area under the curve. The original Fistula Risk Score was also compared with the alternative Fistula Risk Score and the updated alternative Fistula Risk Score.

RESULTS

Of the 400 patients who underwent laparoscopic pancreatoduodenectomy, 60 (15.00%) developed clinically relevant postoperative pancreatic fistula. For the original Fistula Risk Score, the alternative Fistula Risk Score, and the updated alternative Fistula Risk Score, the sensitivity was 65.00%, 90.00%, and 90.00%; the specificity was 43.53%, 44.12%, and 37.65%; the positive predictive value was 16.88%, 22.13%, and 20.30%; the negative predictive value was 87.57%, 96.15%, and 95.52%; positive likelihood ratio was 1.151, 1.611, and 1.443; negative likelihood ratio was 0.804, 0.227, and 0.266, respectively. The area under the curve values were 0.608 (95% confidence interval 0.573-0.649), 0.733 (95% confidence interval 0.692-0.797), and 0.720 (95% confidence interval 0.688-0.763) on the original Fistula Risk Score, the alternative Fistula Risk Score, and the updated alternative Fistula Risk Score (P < .05).

CONCLUSION

The alternative Fistula Risk Score and the updated alternative Fistula Risk Score had similarly good predictive utility. The original Fistula Risk Score performed less well. We recommended to use the alternative Fistula Risk Score and the updated alternative Fistula Risk Score to predict occurrence of clinically relevant postoperative pancreatic fistula after laparoscopic pancreatoduodenectomy when applied to a Chinese cohort.

Nonalcoholic fatty pancreas disease: An emerging clinical challenge

Nonalcoholic fatty pancreas disease (NAFPD) is an emerging disease that has gained an increasing amount of attention in recent years. It describes fat accumulation in the pancreas with insignificant alcohol consumption, but the pathogenesis is largely unknown. A wide range of terms have been used to describe the phenomenon of pancreatic fat accumulation, but NAFPD remains an under-recognized and non-independent disorder. Obesity, age, sex, race, and unhealthy lifestyle are established independent risk factors for NAFPD, which is strongly associated with metabolic syndrome, type 2 diabetes, pancreatitis, pancreatic fistula, pancreatic cancer, and nonalcoholic fatty liver disease. At present, imaging techniques are common diagnostic aids, but uniform criteria and consensus are lacking. Therapeutically, healthy diet, weight loss, and exercise are the mainstays to reduce pancreatic fat accumulation. It can be seen that there is a limited understanding of NAFPD at this stage and further exploration is needed. Previous studies have revealed that NAFPD may directly affect diagnosis and clinical decision-making. Therefore, exploring the pathophysiological mechanism and clinical associations of NAFPD is a major challenge for researchers and clinicians.

Rate of Post-Operative Pancreatic Fistula after Robotic-Assisted Pancreaticoduodenectomy with Pancreato-Jejunostomy versus Pancreato-Gastrostomy: A Retrospective Case Matched Comparative Study

BACKGROUND

Different techniques of pancreatic anastomosis have been described, with inconclusive results in terms of pancreatic fistula reduction. Studies comparing robotic pancreaticogastrostomy (PG) and pancreaticojejunostomy (PJ) are scarcely reported.

METHODS

The present study analyzes the outcomes of two case-matched groups of patients who underwent PG (n = 20) or PJ (n = 40) after pancreaticoduodenectomy. The primary aim was to compare the rate of post-operative pancreatic fistula.

RESULTS

Operative time (375 vs. 315 min, p = 0.34), estimated blood loss (270 vs. 295 mL, p = 0.44), and rate of clinically relevant post-operative pancreatic fistula (12.5% vs. 10%, p = 0.82) were similar between the two groups. PJ was associated with a higher rate of intra-abdominal collections (7.5% vs. 0%, p = 0.002), but lower post-pancreatectomy hemorrhage (2.5% vs. 10%, p = 0.003). PG was associated with a lower rate of post-operative pancreatic fistula (POPF) (33.3% vs. 50%, p = 0.003) in the high-risk group of patients.

CONCLUSIONS

The outcomes of post-operative pancreatic fistula are comparable between the two reconstruction techniques. PG may have a lower incidence of POPF in patients with high-risk of pancreatic fistula.

Risk Factors and a New Prediction Model for Pancreatic Fistula After Pancreaticoduodenectomy

Aim

In order to find the risk factors of postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) according to the latest definition and grading system of International Study Group of Pancreatic Surgery (ISGPS) (version 2016) and propose a nomogram for predicting POPF.

Methods

We conducted a retrospective analysis of 232 successive cases of PD performed at our hospital by the same operator from August 2012 to June 2020. POPF was diagnosed in accordance with the latest definition of pancreatic fistula from the ISGPS. The risk factors of POPF were analyzed by univariate and multivariate logistic regression analysis. A nomogram model to predict the risk of POPF was constructed based on significant factors.

Results

There were 18 cases of POPF, accounting for 7.8% of the total. Among them, 17 cases were classified into ISGPF grade B and 1 case was classified into ISGPF grade C. In addition, 35 cases were classified into biochemical leak. Univariate and multivariate analysis showed that hypertension, non-diabetes, no history of abdominal surgery, antecolic gastrojejunostomy and soft pancreas were independent risk factors of POPF. Based on significant factors, a nomogram is plotted to predict the risk of POPF. The C-index of this nomogram to assess prediction accuracy was 0.916 (P < 0.001) indicating good prediction performance.

Conclusion

Hypertension, non-diabetes, no history of abdominal surgery, antecolic gastrojejunostomy and soft pancreas were independent risk factors of POPF. Meanwhile, a nomogram for predicting POPF with good test performance and discriminatory capacity was constituted.

The role of acinar content at pancreatic resection margin in the development of postoperative pancreatic fistula and acute pancreatitis after pancreaticoduodenectomy

BACKGROUND

A fatty infiltration of the pancreas has been traditionally regarded as the main histological risk factor for postoperative pancreatic fistula, whereas the role of the secreting acinar compartment has been poorly investigated. The aim of this study was to evaluate the role of acinar content at pancreatic resection margin in the development of clinically relevant postoperative pancreatic fistula and clinically relevant postoperative acute pancreatitis after pancreaticoduodenectomy.

METHODS

Data from 388 consecutive patients who underwent pancreaticoduodenectomy (2018-2019) were analyzed. Pancreatic section margins were histologically assessed for acinar, fibrosis, and fat content. Acinar content was categorized using median and third quartile as cut-offs. Univariate and multivariable analysis of possible predictors of clinically relevant postoperative pancreatic fistula and clinically relevant postoperative acute pancreatitis were performed.

RESULTS

Acinar content was <60% in 166 patients (42.8%), ≥60% and ≤80% in 156 patients (40.2%), and >80% in 66 patients (17.0%). The rate of clinically relevant postoperative pancreatic fistula and clinically relevant postoperative acute pancreatitis was significantly higher in patients with acinar content >80% (39.4% and 33.3%, respectively) as well as in those with acinar content ≥60% and ≤80% (36.5% and 35.3%, respectively), compared with patients with acinar content <60% (10.2% and 5.4%, respectively) (P < .001). Acinar content was identified as an independent predictor of clinically relevant postoperative pancreatic fistula (≥60% and ≤80%, odds ratio 2.51, P = .008; >80%, odds ratio 2.93, P = .010) and clinically relevant postoperative acute pancreatitis (≥60% and ≤80%, odds ratio 9.42, P < .001; >80%, odds ratio 10.16, P < .001).

CONCLUSION

An acinar content at pancreatic resection margin ≥60% is associated to an increased risk of clinically relevant postoperative pancreatic fistula and clinically relevant postoperative acute pancreatitis. Fat content was associated neither with clinically relevant postoperative pancreatic fistula nor with clinically relevant postoperative acute pancreatitis.

Can magnetic resonance imaging radiomics of the pancreas predict postoperative pancreatic fistula?

OBJECTIVES

To evaluate whether a magnetic resonance imaging (MRI) radiomics-based machine learning classifier can predict postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) and to compare its performance to T1 signal intensity ratio (T1 SIratio).

METHODS

Sixty-two patients who underwent 3 T MRI before PD between 2008 and 2018 were retrospectively analyzed. POPF was graded and split into clinically relevant POPF (CR-POPF) vs. biochemical leak or no POPF. On T1- and T2-weighted images, 2 regions of interest were placed in the pancreatic corpus and cauda. 173 radiomics features were extracted using pyRadiomics. Additionally, the pancreas-to-muscle T1 SIratio was measured. The dataset was augmented and split into training (70 %) and test sets (30 %). A Boruta algorithm was used for feature reduction. For prediction of CR-POPF models were built using a gradient-boosted tree (GBT) and logistic regression from the radiomics features, T1 SIratio and a combination of the two. Diagnostic accuracy of the models was compared using areas under the receiver operating characteristics curve (AUCs).

RESULTS

Five most important radiomics features were identified for prediction of CR-POPF. A GBT using these features achieved an AUC of 0.82 (95 % Confidence Interval [CI]: 0.74 - 0.89) when applied on the original (non-augmented) dataset. Using T1 SIratio, a GBT model resulted in an AUC of 0.75 (CI: 0.63 - 0.84) and a logistic regression model delivered an AUC of 0.75 (CI: 0.63 - 0.84). A GBT model combining radiomics features and T1 SIratio resulted in an AUC of 0.90 (CI 0.84 - 0.95).

CONCLUSION

MRI-radiomics with routine sequences provides promising prediction of CR-POPF.

Predictive factors of postoperative pancreatic fistula after laparoscopic pancreatoduodenectomy

Background

Clinically relevant postoperative pancreatic fistula (CR-POPF) continues to be a major contributor to morbidity after pancreaticoduodenectomy (PD), but it remains unclear what risk factors can precisely predict the development of CR-POPF after laparoscopic pancreatoduodenectomy (LPD). We thus aimed to identify the risk factors for predicting CR-POPF after LPD.

Methods

A total of 388 consecutive patients who underwent LPD at our institution between July 2014 and December 2018 were identified. All data, including pre-, intra-, and postoperative risk factors associated with CR-POPF defined by the International Study Group of Pancreatic Fistula, were collected retrospectively. To evaluate the predictive performance of the risk factor models, areas under the receiver operating characteristic curve (ROC) were determined.

Results

CR-POPF was observed in 31 patients (8.0%) with significant association observed with body mass index (BMI), visceral fat area (VFA), subcutaneous fat area (SFA), total fat area (TFA), intra-abdominal fat thickness, main pancreatic duct width, soft pancreatic texture, operative time, underlying pathology, and albumin (Alb) on postoperative days (POD) 1­–3. Multivariate analyses revealed that VFA >82 cm² [odds ratio (OR) =11.088; P=0.029], main pancreatic duct width <3 mm (OR =7.701; P=0.001), soft pancreatic texture (OR =12.543; P=0.022), and operative time >320 min (OR =6.061; P<0.001) were independent risk factors for CR-POPF after LPD. Areas under the ROC curve (AUC) analysis revealed the pancreatic texture was the strongest single predictor (AUC =0.854) of CR-POPF, and pancreatic texture + pancreatic duct width was the best two-predictor model (AUC =0.904). Meanwhile, our findings indicated an association between the TFA >221 cm² (OR =8.637; P=0.001) and VFA >82 cm² (OR =7.009; P<0.001) with soft pancreatic texture.

Conclusions

Soft pancreatic texture, VFA >82 cm², main pancreatic duct width <3 mm, and operative time >320 min were independent predictive risk factors of CR-POPF for LPD.

Intraoperative amylase level of pancreatic juice as a simple predictor of pancreatic fistula after pancreaticoduodenectomy

INTRODUCTION

A soft remnant texture of the pancreas is commonly accepted as a risk factor for postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD). However, its assessment is subjective. The aim of this study was to evaluate the significance of intraoperative amylase level of the pancreatic juice as a risk factor of POPF after PD.

METHOD

This study included 75 patients who underwent PD between November 2014 and April 2020 at Jikei University Hospital. We investigated the relationship between pancreatic texture, intraoperative amylase level of pancreatic juice, results of the pathological evaluations, and the incidence of POPF.

RESULTS

Twenty-three patients (31%) developed POPF. The significant predictors of POPF were non-ductal adenocarcinoma (p < 0.01), soft pancreatic remnant (p < 0.01), high intraoperative blood loss (p < 0.01), high intraoperative amylase level of pancreatic juice (p < 0.01), and low pancreatic fibrosis (p < 0.01). Multivariate analysis revealed that the significant independent predictors of POPF were high intraoperative blood loss (p < 0.01) and high intraoperative amylase level of pancreatic juice (p = 0.02). Receiver operating characteristic (ROC) analysis showed that the cut-off value for the intraoperative amylase level of pancreatic juice was 2.17 × 10⁵ IU/L (area under the curve = 0.726, sensitivity = 95.7%, and specificity = 50.0%) CONCLUSIONS: The intraoperative amylase level of pancreatic juice is a reliable objective predictor for POPF after PD.

Retrorenal fat predicts grade C pancreatic fistula after pancreaticoduodenectomy

BACKGROUND

Pancreatic fistula after pancreaticoduodenectomy is one of the most severe complications with mortality rates as high as 45%, and the prediction of most severe form of fistula (grade C) is crucial for successful management of patients who are to undergo cephalic pancreatoduodenectomy. It has been found that the amount of abdominal fat may predict grade C postoperative pancreatic fistula. In this study, we analysed the value of retrorenal fat thickness in the prediction of grade C pancreatic fistula.

METHODS

A total of 140 patients who underwent pancreaticoduodenectomy were retrospectively analysed. Retrorenal fat thickness and intra-abdominal fat, expressed as total fat area, visceral fat area and subcutaneous fat area, were determined from computed tomography slices using the known range of attenuation values (-190 to -30). Blood loss, operating time, pancreatic texture and main pancreatic duct diameter as well as body mass index were also analysed.

RESULTS

Retrorenal fat thickness (P = 0.0004), duct diameter (P = 0.0008), subcutaneous fat area (P = 0.023) and total fat area (P = 0.014) were found to be significant predictors of grade C pancreatic fistula.

CONCLUSION

Although retrorenal fat tissue thickness may seem robust, it is a simple measure that can be used to predict the most severe grade of pancreatic fistula after pancreaticoduodenectomy.

[Predictors of external pancreatic fistulae after pancreatic resection]

Despite a significant decrease in postoperative mortality after pancreatic resections in recent years (5.2-15% after pancreatoduodenectomy and about 5% after distal pancreatectomy), incidence of postoperative complications remains high (30-50% and 22-50%, respectively). Postoperative pancreatic fistula is one of the most common and formidable complications. Currently, most authors use the classification proposed by the International Study Group for Pancreatic Fistula (biochemical failure, fistula type B and C). Prediction of the risk of postoperative fistula is still a complex and unresolved problem of modern surgical pancreatology. According to the literature, the main risk factors of postoperative pancreatic fistulae are obesity and high body mass index, concomitant cardiovascular diseases, no neoadjuvant chemo- and radiotherapy, soft pancreatic texture, narrow pancreatic duct, no fibrotic changes in parenchyma, adipose infiltration of the pancreas, advanced intraoperative blood loss, as well as center experience. Most often, magnetic resonance imaging, computed tomography, ultrasound elastography and various multivariate risk assessment systems are used to estimate the risk of pancreatic fistulae. However, a generally accepted technique does not exist. This manuscript is devoted to analysis of risk factors of postoperative pancreatic fistulae and diagnostic methods for assessment of this risk.

Predictive Factors Associated with Complications after Laparoscopic Distal Pancreatectomy

Although laparoscopic distal pancreatectomy (LDP) has become more popular, the postoperative complication rate remains high. We sought to identify the risk factors for post-LDP complications. We examined 1227 patients who underwent LDP between March 2005 and December 2015 at a single large-volume center. We used logistic regression for the analysis. The overall (13.2%) and major (3.3%) complication rates were determined. Postoperative pancreatic fistula was the most frequent complication, and 58 patients (4.7%) had clinically significant (grade B) pancreatic fistulas. No 90-day mortality was recorded. Long operative time (≥200 min), large estimated blood loss (≥320 mL), LDP performed by an inexperienced surgeon (<50 cases), and concomitant splenectomy were identified as risk factors for overall complications using a logistic regression model. For major complications, male sex (p = 0.020), long operative time (p = 0.005), and LDP performed by an inexperienced surgeon (p = 0.026) were significant predictive factors. Using logistic regression analysis, surgery-related factors, including long operative time and LDP performed by an inexperienced surgeon, were correlated with overall and major complications of LDP. As LDP is a technically challenging procedure, surgery-related variables emerged as the main risk factors for postoperative complications. Appropriate patient selection and sufficient surgeon experience may be essential to reduce the complications of LDP.

The novel early predictive marker presepsin for postoperative pancreatic fistula: A pilot study

Postoperative pancreatic fistula (PF) is a major and serious complication that occurs after pancreaticoduodenectomy (PD). The aim of the current study was to evaluate the use of a novel biomarker, presepsin, for predicting clinically relevant postoperative pancreatic fistula (CR-POPF) after PD. A prospective pilot study was conducted using 30 consecutive patients who underwent PD. Risk factors and candidates for predictive biomarkers for CR-POPF were statistically analyzed. CR-POPF (grade B and C; determined according to the guidelines of the International Study Group of Pancreatic Fistula) occurred in 15 patients (50%). Univariate analysis revealed that certain underlying conditions, including non-pancreatic cancer, smaller pancreatic ducts and soft pancreas texture were significantly associated with CR-POPF (P=0.005, P=0.004 and P=0.014, respectively). Furthermore, on day 1 post surgery (POD1), white blood cell count (P=0.040), levels of serum amylase (P=0.002) and serum presepsin (P=0.012), and the concentration of presepsin in drainage fluid (P<0.001) were significantly increased in CR-POPF compared with non-CR-POPF cases. Receiver operating characteristic curve analyses revealed that, on POD1, serum amylase and the concentration of presepsin in drainage fluid had an area under the curve value exceeding 0.8. A multivariate logistic regression analysis revealed that a higher concentration of presepsin in the drainage fluid was an independent predictive marker for CR-POPF (odds ratio, 14.503; 95% confidence interval, 1.750-120.229; P=0.013). To the best of our knowledge, the present study demonstrated for the first time that presepsin concentration in drainage fluid is a useful marker of CR-POPF after PD.

Pancreas-visceral fat CT value ratio and serrated pancreatic contour are strong predictors of postoperative pancreatic fistula after pancreaticojejunostomy

BACKGROUND

Our aim is to elucidate the true preoperative risk factors for postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD), making it possible to select POPF high-risk patients preoperatively regardless of intraoperative pancreatic consistency judged by the surgeon's hand.

METHODS

Among the 298 patients who underwent PD with pancreaticojejunostomy from 2007 to 2016, 262 patients had preoperative CT configurations that could be precisely evaluated. Risk factor analyses were conducted using various perioperative factors, including preoperative CT findings, such as CT values of the pancreas, pancreas-visceral fat CT value ratio and pancreatic outer contour. Pancreatic outer contour was further divided into smooth- (smooth interlobular) and serrated-type contours (feathery, irregular interlobular) by preoperative CT.

RESULTS

In terms of the incidence of POPF, among the 262 patients, POPF grade B/C was found in 27 (10.3%): grade B in 23 (8.8%) and grade C in 4 (1.5%). According to multivariate analysis, a high pancreas-visceral fat CT value ratio (p = 0.002), serrated-type contour (p = 0.02) and no history of chemoradiotherapy (p = 0.019) were identified as independent risk factors for POPF grade B/C. Even in patients with soft pancreas, the incidence of POPF grade B/C was 0% (0/57) in patients with a pancreas-visceral fat CT value ratio of less than - 0.4 and smooth-type contour, whereas the incidence was markedly high (45.0%, 9/20) in patients with a pancreas-visceral fat CT value ratio of - 0.4 or greater and serrated-type contour, indicating that patients with soft pancreas should be categorized into POPF high-risk and low-risk groups according to preoperative CT scan results.

CONCLUSIONS

The pancreas-visceral fat CT value ratio and serrated-type pancreas are useful markers to preoperatively identify true POPF high-risk groups in patients undergoing PD, regardless of the pancreatic texture judged intraoperatively.

Pancreatic Fat and Body Composition Measurements by Computed Tomography are Associated with Pancreatic Fistula After Pancreatectomy

OBJECTIVES

Postoperative pancreatic fistula (POPF) is the most threatening complication after pancreatectomy. This study aimed to directly assess pancreatic fatty infiltration with preoperative computed tomography (CT) imaging and to investigate whether a preoperative analysis of patient variables, including CT characteristics and clinical factors, can predict POPF.

METHODS

We enrolled 150 consecutive patients who underwent curative pancreatectomy. Radiographic factors, including pancreatic fat volume, were measured using preoperative CT imaging and the predictive factors were explored using univariate and multivariate analyses.

RESULTS

POPF developed in 30 patients (20.0%). The ratio of pancreatic fat (RPF) ≥ 4.83% was associated with a risk of POPF, high body mass index (BMI), and obese body habitus. Patients with POPF were significantly more likely to have high BMI (≥ 25 kg/m²), obese body habitus, and an RPF ≥ 4.83% than patients without POPF. In the multivariate analysis, visceral fat area/skeletal muscle index (VFA/SMI) ≥ 1.94 (odds ratio [OR] 4.28, 95% confidence interval [CI] 1.43-12.9, p = 0.0095) was the sole independent predictive factor for POPF. For patients with a soft pancreas, VFA/SMI ≥ 1.94 (OR 5.67, 95% CI 2.05-15.7, p = 0.0008) was again the sole independent predictive factor for POPF.

CONCLUSION

Preoperative CT images can examine pancreatic fatty infiltration, and patients who had POPF were significantly associated with a high RPF. Among several parameters, VFA/SMI was the only independent predictive factor for clinically relevant POPF. Preoperative evaluation of these body composition variables and the pancreatic configuration could be useful for predicting POPF.

A Novel Way of Preventing Postoperative Pancreatic Fistula by Directly Injecting Profibrogenic Materials into the Pancreatic Parenchyma

This paper aims to validate if intrapancreatic injection of penicillin G can enhance hardness and suture holding capacity (SHC) of the pancreas through prompting the fibrosis process. Soft pancreatic texture is constantly mentioned as one of the most contributory predictors of postoperative pancreatic fistula (POPF). Soft pancreas has poor SHC and higher incidence of parenchymal tearing, frequently leading to POPF. From a library of 114 antibiotic compounds, we identified that penicillin G substantially enhanced pancreatic hardness and SHC in experimental mice. Specifically, we injected penicillin G directly into the pancreas. On determined dates, we measured the pancreatic hardness and SHC, respectively, and performed molecular and histological examinations for estimation of the degree of fibrosis. The intrapancreatic injection of penicillin G activated human pancreatic stellate cells (HPSCs) to produce various fibrotic materials such as transforming growth factor-β1 (TGF-β1) and metalloproteinases-2. The pancreatic hardness and SHC were increased to the maximum at the second day after injection and then it gradually subsided demonstrating its reversibility. Pretreatment of mice with SB431542, an inhibitor of the TGF-β1 receptor, before injecting penicillin G intrapancreatically, significantly abrogated the increase of both pancreatic hardness and SHC caused by penicillin G. This suggested that penicillin G promotes pancreatic fibrosis through the TGF-β1 signaling pathway. Intrapancreatic injection of penicillin G promotes pancreatic hardness and SHC by enhancing pancreatic fibrosis. We thus think that penicillin G could be utilized to prevent and minimize POPF, after validating its actual effectiveness and safety by further studies.

Measurement of Pancreatic Fat Fraction by CT Histogram Analysis to Predict Pancreatic Fistula after Pancreaticoduodenectomy

Objective

To evaluate the effectiveness of computed tomography (CT) Hounsfield unit histogram analysis (HUHA) in postoperative pancreatic fistula (PF) prediction.

Materials and Methods

Fifty-four patients (33 males and 21 females; mean age, 65.6 years; age range, 37–89 years) who had undergone preoperative CT and pancreaticoduodenectomy were included in this retrospective study. Two radiologists measured mean CT Hounsfield unit (CTHU) values by drawing regions of interest (ROIs) at the level of the pancreaticojejunostomy site on preoperative pre-contrast images. The HUHA values were arbitrarily divided into three categories, comprising HUHA-A ≤ 0 HU, 0 HU < HUHA-B < 30 HU, and HUHA-C ≥ 30 HU. Each HUHA value within the ROI was calculated as a percentage of the entire area using commercial 3-dimensional analysis software. Pancreas texture was evaluated as soft or hard by manual palpation.

Results

Fifteen patients (27.8%) had clinically relevant PFs. The PF group had significantly higher HUHA-A (p < 0.01) and significantly lower mean CTHU (p < 0.01) values than those of the non-PF group. The HUHA-A value had a moderately strong correlation with PF occurrence (r = 0.60, p < 0.01), whereas the mean CTHU had a weak negative correlation with PF occurrence (r = −0.27, p < 0.01). The HUHA-A and mean CTHU areas under the curve (AUCs) for predicting PF occurrence were 0.86 and 0.65, respectively, with significant difference (p < 0.01). The HUHA-A and mean CTHU AUCs for predicting pancreatic softness were 0.86 and 0.64, respectively, with significant difference (p < 0.01).

Conclusion

The HUHA-A values on preoperative pre-contrast CT images demonstrate a strong correlation with PF occurrence.

External validation of alternative fistula risk score (a-FRS) for predicting pancreatic fistula after pancreatoduodenectomy

BACKGROUND

The utility of the proposed alternative fistula risk score (a-FRS) for predicting risk of clinically relevant postoperative pancreatic fistula (CR-POPF) after pancreaticoduodenectomy (PD) has not been validated widely.

METHODS

This retrospective analysis included data of patients undergoing open and laparoscopic PD during March 2012-May 2018 in our institution. The predictive abilities of a-FRS and original-FRS were compared. Risk factors for CR-POPF were also evaluated by multivariate regression analysis.

RESULTS

Of the 370 patients, 80 (21.62%) developed CR-POPF. The incidences of CR-POPF in patients classified as low risk, intermediate risk, and high risk by a-FRS were 5.88%, 24.38%, and 57.69%, respectively (R2 = 0.97). The incidences of CR-POPF in patients classified as negligible risk, low risk, intermediate risk, and high-risk by original-FRS were 0%, 8.62%, 21.51%, and 52.50%, respectively (R2 = 0.92). The area under the ROC curve (AUC) was 0.74 for a-FRS vs. 0.70 for original-FRS. The a-FRS performed better than original-FRS for prediction of CR-POPF in open PD patients (AUC: 0.74 vs. 0.69) and was comparable with original- FRS in laparoscopic PD patients (AUC: 0.70 vs. 0.72).

CONCLUSIONS

The a-FRS appears to be an accurate and convenient tool for predicting occurrence of CR-POPF after PD.

The potential of machine learning to predict postoperative pancreatic fistula based on preoperative, non-contrast-enhanced CT: A proof-of-principle study

BACKGROUND

Postoperative pancreatic fistula remains an unsolved challenge after pancreatoduodenectomy. Important in this regard is the presence of a soft pancreatic texture which is a major risk factor. Advances in machine learning and texture analysis of medical images allow identification of features of parenchyma that are invisible to the human eye. The aim of this study was to investigate the potential of machine learning to predict postoperative pancreatic fistula based on preoperative, non-contrast-enhanced computed tomography.

METHODS

We screened a prospectively assessed database including all patients undergoing pancreatoduodenectomy at a tertiary center from 2008 until 2018 for patients based on the occurrence of postoperative pancreatic fistula. In total, 110 patients were included, consisting of 55 patients who developed a postoperative pancreatic fistula and 55 without postoperative pancreatic fistula. For machine learning-based texture analysis preoperative, non-contrast-enhanced computed tomography axial images were used. Machine learning results were tested using 10-fold cross validation. Previously validated clinical fistula risk scores (original and alternative fistula risk scores) served as reference tests.

RESULTS

Both the original and the alternative fistula risk scores showed good discrimination between patients without and with postoperative pancreatic fistula (area under the curve 0.76 and 0.72, respectively). Machine learning-based texture analysis showed potential to detect histologic fibrosis (area under the curve 0.84, sensitivity 75%; specificity 92%), histologic lipomatosis (area under the curve 0.82, sensitivity 78%; specificity 89%), and intraoperative pancreatic hardness (area under the curve 0.70, sensitivity 78%; specificity 74%). The features of the machine learning-based texture analysis were most accurate in predicting the occurrence of postoperative pancreatic fistula (area under the curve 0.95, sensitivity of 96%; specificity 98%) after pancreatoduodenectomy.

CONCLUSION

This proof-of-principle study suggests the ability of machine learning in recognizing important features of pancreatic texture associated with an increased risk of postoperative pancreatic fistula based on preoperative computed tomography.

Non-alcoholic fatty pancreas disease - practices for clinicians

Obesity is a growing health burden worldwide, increasing the risk for several diseases featuring the metabolic syndrome - type 2 diabetes mellitus, dyslipidemia, non-alcoholic fatty liver disease and cardiovascular diseases. With the increasing epidemic of obesity, a new pathologic condition has emerged as a component of the metabolic syndrome - that of non-alcoholic fatty pancreas disease (NAFPD). Similar to non-alcoholic fatty liver disease (NAFLD), NAFPD comprises a wide spectrum of disease - from deposition of fat in the pancreas - fatty pancreas, to pancreatic inflammation and possibly pancreatic fibrosis. In contrast with NAFLD, diagnostic evaluation of NAFPD is less standardized, consisting mostly in imaging methods. Also the natural evolution of NAFPD and its association with pancreatic cancer is much less studied. Not least, the clinical consequences of NAFPD remain largely presumptions and knowledge about its metabolic impact is limited. This review will cover epidemiology, pathogenesis, diagnostic evaluation tools and treatment options for NAFPD, with focus on practices for clinicians.

Hepatic and pancreatic fat as imaging biomarkers of metabolic syndrome

OBJECTIVE

To objectively evaluate hepatic and pancreatic involvement in metabolic syndrome through magnetic resonance imaging (MRI) biomarkers.

MATERIAL AND METHODS

From an initial retrospective sample of 407 patients diagnosed with metabolic syndrome studied by MRI in a single center during a 2-year period, 154 were excluded because of a lack of clinical and/or laboratory data, pancreatic abnormalities, or inadequate quality of MRI studies. To measure hepatic and pancreatic fat, we used chemical shift imaging (in-phase and out-of-phase), measuring the fat fraction (%) in regions of interest in the pancreas and liver. Associations between the fat fraction and selected clinical and laboratory variables were assessed with beta regression models.

RESULTS

In the end, 253 patients were included. The hepatic fat fraction was 4.9% and the pancreatic fat fraction was 7.9%. We found no significant associations between the hepatic fat fraction and any of the clinical or laboratory variables. However, the pancreatic fat fraction was positively associated with age (OR=1.025, p<0.001) and baseline glucose (OR=1.005, p<0.001). Patients with diabetes had higher values of pancreatic fat fraction (OR=2.64, p=0.038). Pancreatic fat fraction and hepatic fat fraction were positively associated (OR=69.44, p<0.001).

CONCLUSIONS

Pancreatic steatosis can be considered a marker of metabolic syndrome and diabetes. Quantitative MRI enables the diagnosis and grading of fatty pancreas through simple chemical shift techniques.

A score model based on pancreatic steatosis and fibrosis and pancreatic duct diameter to predict postoperative pancreatic fistula after Pancreatoduodenectomy

PURPOSES

To establish a scoring model for the risk of postoperative pancreatic fistula (POPF) following pancreatoduodenectomy (PD).

METHODS

PD Patients from 7 institutions in 2 independent sets: developmental (n = 457) and validation cohort (n = 152) were retrospectively enrolled and analyzed. Pancreatic Fibrosis (PF) and Pancreatic Steatosis (PS) were assessed by pathological examination of the pancreatic stump.

RESULTS

Stepwise univariate and multivariate analysis indicated that pancreatic duct diameter ≤ 3 mm, increased PS and decreased PF were independent risk factors for POPF and Clinically Relevant Postoperative Pancreatic Fistula (CR-POPF). Based on the relative weight and odds ratio of each factor in the POPF, a simplified scoring model was developed. And patients were stratified into high-risk group (22~28 points), medium-risk group (15~21 points) and low-risk group (8~14 points). The receiver operating characteristic curve demonstrated that the Area under the curve for the predictive model was 0.868 and 0.887 in the model design group and the external validation group.

CONCLUSIONS

This study establishes a simplified scoring model based on accurately and quantitatively measuring the PS, PF and pancreatic duct diameter. The scoring model accurately predicted the risk of POPF.

Density and enhancement of the pancreatic tail on computer tomography predicts acinar score and pancreatic fistula after pancreatoduodenectomy

BACKGROUND

Acinar score calculated at the pancreatic resection margin is associated with postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD). The present study evaluates the association between (i) computed tomography (CT) density of the pancreas and the acinar score of the pancreatic resection margin, and (ii) CT density of the pancreas and POPF after PD.

METHODS

Consecutive patients who underwent PD were included for analysis. CT densities of the pancreatic head, neck, body and tail were measured in non-contrast (NC), arterial (ART) and portal venous (PV) phases. Histologic slides of the pancreatic resection margin were scored for acinar cell density.

RESULTS

Ninety patients were included for analysis. Non-contrast density of the pancreatic tail was a good predictor of POPF (AUROC 0.704, p = 0.036), and a cut-off value of >40 Hounsfield units predicted POPF with 70.0% sensitivity and 73.4% specificity. The ratio of densities between PV and NC phases in the pancreatic tail was also a good predictor of POPF (AUROC 0.712, p = 0.030), and a cut-off value of <2.29 predicted POPF with 70.9% sensitivity and 80% specificity.

CONCLUSION

Non-contrast CT density of the pancreatic tail correlates with acinar cell density of the pancreatic resection margin and predicts the development of POPF after PD.

Assessment of acute obstructive pancreatitis by magnetic resonance imaging: Predicting the occurrence of pancreatic fistula following pancreatoduodenectomy

The aim of the present study was to assess the effect of preoperative acute obstructive pancreatitis on the risk of the occurrence of pancreatic fistula (PF) following pancreaticoduodenectomy. A total of 22 patients who developed postoperative PF were carefully matched with 22 control patients without PF according to demographic data, pancreatic pathology, presenting symptoms and other surgery-associated parameters. These parameters were compared between these two groups. The mean pancreatic apparent diffusion coefficient (ADC) values in the fistula group were 1.14±0.31×10^-3 mm²/s, which was significantly decreased compared with the non-fistula group (1.48±0.44×10^-3 mm²/s) (P=0.005). The pancreas-muscle signal intensity (SI) ratio on fat-suppressed T1 weighted image (rT1) in the fistula group was 1.71±0.25, which was significantly increased compared with the non-fistula group (1.25±0.29) (P<0.001). The pancreas-muscle SI ratios on fat-suppressed T2 weighted image (T2WI) in the fistula group and the non-fistula group were 0.72±0.08 and 0.62±0.07, respectively (P=0.79). There was no significant difference in pancreas-muscle SI ratio on fat-suppressed T2-weighted image (rT2) value between these two groups. Based on the receiver operating characteristic curve, the optimal cut-off value of ADC as a criterion for prediction of pancreatic fistula was 1.29×10^-3 mm²/s, which yielded a sensitivity of 77.3% and a specificity of 63.6%. In conclusion, the severity of acute obstructive pancreatitis was negatively associated with ADC values and pancreas-muscle SI ratio on rT1 images, which may be useful for predicting the occurrence of PF preoperatively.

Systematic review and meta-analysis of postoperative pancreatic fistula rates using the updated 2016 International Study Group Pancreatic Fistula definition in patients undergoing pancreatic resection with soft and hard pancreatic texture

BACKGROUND

In 2016, the International Study Group of Pancreatic Fistula (ISGPS) proposed an updated definition for postoperative pancreatic fistula (POPF). Pancreas texture (PT) is an established risk factor of POPF. The definition of soft vs. hard texture, however, remains elusive.

METHODS

A systematic search was performed to identify PT definitions and a meta-analysis linking POPF to PT using the updated ISGPS definition.

RESULTS

122 studies including 22 376 patients were identified. Definition criteria for PT varied among studies and most classified PT in hard and soft based on intraoperative subjective assessment. The total POPF rate (pooled grades B and C) after pancreatoduodenectomy was 14.5% (n = 10 395) and 15.5% (n = 3767) after distal pancreatectomy. In pancreatoduodenectomy, POPF rate was higher in soft compared to hard pancreas (RR, 4.4, 3.3 to 6.1; p < 0.001; n = 6393), where PT grouped as soft and hard. No data were available for intermediate PT.

CONCLUSION

The reported POPF rates may be used in planning future prospective studies. A widely accepted definition of PT is lacking and a correlation with the risk of POPF is based on subjective evaluation, which is still acceptable. Classification of PT into 2-groups is more reasonable than classification into 3-groups.

Evaluation of Pancreatic Fibrosis With Acoustic Radiation Force Impulse Imaging and Automated Quantification of Pancreatic Tissue Components

OBJECTIVES

The aim of this study was to determine whether computer-assisted digital analysis and acoustic radiation force impulse (ARFI) imaging were useful for assessing pancreatic fibrosis, and if ARFI imaging predicted postoperative pancreatic fistula (POPF).

METHODS

Seventy-eight patients scheduled to undergo pancreatic resection were enrolled. Shear wave velocity (SWV) at the pancreatic neck was measured preoperatively using ARFI imaging. Pancreatic tissue components on a whole slide image were quantified using an automatic image processing software. The relationship between SWV, fibrotic tissue content, and POPF incidence and clinical severity was analyzed.

RESULTS

The median collagen fiber, fatty tissue, and acinar cell contents were 11.6%, 8.5%, and 61.3%, respectively. Unlike fatty tissue, collagen fiber content and acinar cells were correlated with SWV (ρ = 0.440, P < 0.001 and ρ = -0.428, P < 0.001, respectively). Although collagen fiber content and SWV were associated with the overall incidence of POPF (P = 0.004 and 0.001, respectively), collagen fiber content and SWV had no statistical correlation with clinically relevant POPF (P = 0.268 and 0.052, respectively).

CONCLUSIONS

We objectively quantified the pancreatic tissue components using an automatic image processing software. Shear wave velocity was significantly related to collagen fiber content and suggests that ARFI imaging can be useful for evaluating pancreatic fibrosis.

Development of MR quantified pancreatic fat deposition as a cancer risk biomarker

BACKGROUND

Excess body adiposity is associated with increased risk of pancreatic cancer, and in animal models excess intra-pancreatic fat is a driver of pancreatic carcinogenesis. Within a programme to evaluate pancreatic fat and PC risk in humans, we assessed whether MR-quantified pancreatic fat fraction (PFF) was 'fit for purpose' as an imaging biomarker.

METHODS

We determined PFF using MR spectroscopy (MRS) and MR chemical shift imaging (CS-MR), in two groups. In Group I, we determined accuracy of MR-derived PFF with histological digital fat quantification in 12 patients undergoing pancreatic resection. In a second study, we assessed reproducibility in 15 volunteers (Group IIa), and extended to 43 volunteers (Group IIa & IIb) to relate PFF with MR-derived hepatic fat fraction (HFF), body mass index (BMI), and waist circumference (WC) using linear regression models. We assessed intra- and inter-observer, and between imaging modality levels of agreement using Bland-Altman plots.

RESULTS

In Group I patients, we found strong levels of agreement between MRS and CS-MR derived PFF and digitally quantified fat on histology (rho: 0.781 and 0.672 respectively). In Group IIa, there was poor reproducibility in initial assessments. We refined our protocols to account for 3D dimensionality of the pancreas, and found substantially improved intra-observer agreements. In Group II, HFF and WC were significantly correlated with PFF (p values < 0.05).

INTERPRETATION

Both CS-MR and MRS (after accounting for pancreatic 3D dimensionality) were 'fit for purpose' to determine PFF and might add information on cancer prediction independent from measures of general body adiposity.