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

Lipase-to-Amylase Ratio for the Prediction of Clinically Relevant Postoperative Pancreatic Fistula Following Pancreaticoduodenectomy

OBJECTIVE

Postoperative pancreatic fistula (POPF) represents a leading cause of morbidity and mortality following major pancreatic resections. This study aimed to evaluate the use of postoperative drain fluid lipase-to-amylase ratio (LAR) for the prediction of clinically relevant fistulae (CR-POPF).

METHODS

Consecutive patients undergoing pancreaticoduodenectomy between 2017 and 2021 at a tertiary centre were retrospectively reviewed. Univariable and multivariable analyses were performed to identify predictors for CR-POPF (ISGPS grade B/C). Receiver operating characteristic (ROC) curve analyses were conducted to evaluate the performance of LAR and determine optimum prediction thresholds.

RESULTS

Among 130 patients, 28 (21.5%) developed CR-POPF. Variables positively associated with CR-POPF included soft gland texture, acinar cell density, diagnosis other than PDAC or chronic pancreatitis, resection without neoadjuvant therapy, and postoperative drain fluid lipase, amylase, and LAR (all P <0.05). Multivariable regression analysis identified LAR as an independent predictor of CR-POPF ( P <0.05). ROC curve analysis showed that LAR had moderate ability to predict CR-POPF on POD1 (AUC,0.64; 95%CI,0.54-0.74) and excellent ability on POD3 (AUC,0.85; 95%CI,0.78-0.92) and POD 5 (AUC,0.86; 95%CI,0.79-0.92). Optimum thresholds were consistent over PODs 1 to 5 (ratio>2.6) and associated with 92% sensitivity and 46% to 71% specificity.

CONCLUSIONS

Postoperative drain fluid LAR represents a reliable predictor for the development of CR-POPF. With early prognostication, the postoperative care of patients at risk of developing high-grade fistulas may be optimized.

Anastomotic bleeding from invaginated pancreaticogastrostomy following pancreatoduodenectomy: incidence, risk factors, treatment and prevention

BACKGROUND

Meta-analysis of 10 randomized prospective trials demonstrated a higher risk of postoperative bleeding from pancreaticogastrostomy (PG) compared with pancreatojejunostomy following pancreatoduodenectomy (PD). This study evaluated the incidence, risk factors, and treatment of anastomotic bleeding from invaginated PG.

METHODS

We retrospectively evaluated all consecutive PDs performed between April 1, 2011 and December 31, 2022 using invaginated PG by the double purse-string technique. Multivariate analysis identified risk factors for anastomotic PG bleeding.

RESULTS

During the study, 695 consecutive patients with a median age of 66 years underwent PD; the majority was performed for ductal pancreatic adenocarcinomas. Simultaneous vascular resections were performed in 328 patients. Postoperative mortality was 4.1%. Bleeding from PG occurred in 33(4.6%) patients at a median interval of 5 days (range, 1-14) from surgery, leading to reoperation in 21(63%). PG bleeding-related mortality was 9.0%. Multivariate analyses identified a soft pancreatic texture and Wirsung duct > 3 or ≤ 3 mm (Class C and D, respectively, of the ISGPS) (odds ratio [OR]: 2.17, 95% confidence interval [95% CI]: 1.38-3.44; P = 0.0009) and wrapping of the invaginated pancreas (OR: 0.37, 95% CI: 0.17-0.84; P = 0.01) as independent risk factors for PG bleeding.

CONCLUSIONS

In a large volume setting, anastomotic bleeding from invaginated PG occurred in ~ 5% of patients and was associated with soft pancreatic parenchyma and small wirsung duct. The reduced rate of PG bleeding observed with wrapping of the invaginated pancreatic stump warrants further evaluation in a prospective randomized study.

Preoperative pancreatic radiologic characteristics predict pancreatic-specific complications before pancreaticoduodenectomy: the pancreatic acinar radiologic score

BACKGROUND

High acinar pancreatic contents are associated with a higher rate of postpancreatectomy acute pancreatitis and pancreatic fistula formation (POPF). Predicting acinar contents preoperatively might identify those at high risk of developing postoperative complications.

METHODS

A multivariable analysis was performed to identify radiological factors associated with high pancreatic acinar content at histology in patients undergoing pancreaticoduodenectomy. Clinical and radiological variables identified were used to build a composite score predicting low, moderate, and high acinar pancreatic contents.

RESULTS

Pancreatic density, wirsung caliber, and pancreatic thickness on preoperative CT-scan predicted acinar contents. These three variables predicted low, moderate, and high acinar content in 94 (26%), 122 (33.6%), and 147 (40.5%) patients, respectively. Patients with high radiological acinar scores compared with patients with intermediate-low risk scores were more frequently male (73.4% vs. 54.1%; p = 0.0003), obese (14% vs. 6%; p = 0.01), and had a statistically significant higher rate of pancreatic-specific complications (23.8% vs. 8.33%; p = 0.01), POPF (12.9% vs. 4.63%; p = 0.005) and pancreaticogastrostomy bleeding (10.8% vs. 4.17%; p = 0.01).

CONCLUSION

A simple radiological score combining pancreatic thickness, density, and wirsung caliber at CT scan preoperatively predicts patients with pancreatic parenchyma that are at higher risk of postoperative pancreatic-specific complications.

Acinar content at pancreatic resection margin is significantly associated with clinically relevant pancreatic fistula after partial pancreatoduodenectomy

BACKGROUND

This study aimed to evaluate the clinical significance of acinar content at the pancreatic resection margin after partial pancreatoduodenectomy (PD).

METHODS

A total of 228 consecutive patients undergoing PD were included for analysis. Resection margins were assessed for acinar, fibrosis, and fat contents by 2 pathologists blinded to the patients' clinical data. Univariate and multivariable analyses of possible predictors for clinically relevant postoperative pancreatic fistula (cr-POPF) were performed.

RESULTS

The median acinar, fibrosis, and fat contents were 70% (IQR, 25%-82%), 13% (IQR, 5%-40%), and 15% (IQR, 9.25%-25%), respectively. The rates of cr-POPF were significantly higher in patients with an acinar content of >70% than in patients with an acinar content of ≤70% (26.4% vs 5.5%, respectively; P < .001). In addition, the rates of postoperative hyperamylasemia (POH) were significantly higher in patients with an acinar content of ≥70% than in patients with an acinar content of ≤70% (55.2% vs 13.8%, respectively; P < .001). The median fat content did not differ between patients with and without cr-POPF (13.0% [IQR, 7.5%-20.0%] vs 15.0% [IQR, 10.0%-30.0%], respectively; P = .06). An acinar content of >70% at the pancreatic resection margin (odds ratio [OR], 4.85; 95% CI, 1.61-14.58; P = .005) and a soft pancreatic texture (OR, 2.82; 95% CI, 1.02-7.76; P = .046) were independent predictive factors of cr-POPF in the multivariable analysis.

CONCLUSION

An acinar content of ≥70% at the pancreatic resection margin was a significant predictive factor for cr-POPF after PD and was also significantly associated with POH, a precursor of cr-POPF after PD in many cases. Fatty infiltration of the pancreatic resection margin was not associated with cr-POPF.

Quantitative edge analysis of pancreatic margins in patients with head pancreatic tumors: correlations between pancreatic margins and the onset of postoperative pancreatic fistula

OBJECTIVE

To assess the correlation between pancreatic quantitative edge analysis as a surrogate of parenchymal stiffness and the incidence of postoperative pancreatic fistula (POPF), in patients undergoing pancreaticoduodenectomy (PD).

METHODS

All consecutive patients who underwent PD at our Institution between March 2018 and November 2019 with an available preoperative CT were included. Pancreatic margin score (PMS) was calculated through computer-assisted quantitative edge analysis on the margins of the pancreatic body and tail (the expected pancreatic remnant) on non-contrast scans with in-house software. Intraoperative assessment of pancreatic stiffness by manual palpation was also performed, classifying pancreatic texture into soft and non-soft. PMS values were compared between groups using an unpaired T-test and correlated with the intraoperative evaluation of stiffness and with the grading of postoperative pancreatic fistula according to the International Study Group on Pancreatic Surgery (ISGPS).

RESULTS

Patient population included 200 patients (mean age 64.6 years), 146 without onset of POPF (73%, non-POPF group), and 54 with POPF (27%, POPF group). A significant difference in PMS values was observed between POPF and non-POPF (respectively 1.88 ± 0.05 vs 0.69 ± 0.01; p < 0.0001). PMS values of pancreatic parenchymas intraoperatively considered "soft" were significantly higher than those evaluated as "non-soft" (1.21 ± 0.04 vs 0.73 ± 0.02; p < 0.0001). A significant correlation between PMS values and POPF grade was observed (r = 0.8316), even in subgroups of patients with soft (r = 0.8016) and non-soft (r = 0.7602) pancreas (all p < 0.0001).

CONCLUSIONS

Quantitative edge analysis with dedicated software may stratify patients with different pancreatic stiffness, thus potentially improving preoperative risk assessment and strategies for POPF mitigation.

CLINICAL RELEVANCE STATEMENT

This study proposes quantitative pancreas edge analysis as a predictor for postoperative pancreatic fistula. The test has high accuracy and correlation with fistula grade according to the International Study Group on Pancreatic Surgery.

KEY POINTS

• Prediction of postoperative pancreatic fistula (POPF) onset risk after pancreaticoduodenectomy is based only on intraoperative evaluation. • Quantitative edge analysis may preoperatively identify patients with higher risk of POPF. • Quantification of pancreatic stiffness through the analysis of pancreatic margins could be done on preoperative CT.

Risk Factors of Postoperative Acute Pancreatitis and Its Impact on the Postoperative Course after Pancreaticoduodenectomy-10 Years of Single-Center Experience

BACKGROUND

Clinically relevant acute postoperative pancreatitis (CR-PPAP) after pancreaticoduodenectomy (PD) is a complication that may lead to the development of local and systemic consequences. The study aimed to identify risk factors for CR-PPAP and assess the impact of CR-PPAP on the postoperative course after PD.

METHODS

The study retrospectively analyzed data from 428 consecutive patients who underwent PD at a single center between January 2013 and December 2022. The presence of increased amylase activity in plasma, above the upper limit of normal 48 h after surgery, was checked. CR-PPAP was diagnosed when accompanied by disturbing radiological features and/or symptoms requiring treatment. We investigated the relationship between the occurrence of CR-PPAP and the development of postoperative complications after PD, and possible predictors of CR-PPAP.

RESULTS

The postoperative follow-up period was 90 days. Of the 428 patients, 18.2% (n = 78) had CR-PPAP. It was associated with increased rates of CR-POPF, delayed gastric emptying, occurrence of intra-abdominal collections, postoperative hemorrhage, peritonitis, and septic shock. Patients who developed CR-PPAP were more often reoperated (37.17% vs. 6.9%, p < 0.0001)) and had increased postoperative mortality (14.1% vs. 5.74%, p < 0.0001). Soft pancreatic parenchyma, intraoperative blood loss, small diameter of the pancreatic duct, and diagnosis of adenocarcinoma papillae Vateri were independent risk factors for CR-PPAP and showed the best performance in predicting CR-PPAP.

CONCLUSIONS

CR-PPAP is associated with an increased incidence of postoperative complications after PD, worse treatment outcomes, and an increased risk of reoperation and mortality. Pancreatic consistency, intraoperative blood loss, width of the duct of Wirsung, and histopathological diagnosis can be used to assess the risk of CR-PPAP. Amylase activity 48 h after surgery > 161 U/L is highly specific in the diagnosis of CR-PPAP.

Either High or Low Risk: The Acinar Score at the Resection Margin Dichotomizes the Risk Spectrum of Pancreas-specific Complications After Pancreatoduodenectomy

BACKGROUND

Pancreatic acinar content (Ac) has been associated with pancreas-specific complications after pancreatoduodenectomy. The aim of this study was to improve the prediction ability of intraoperative risk stratification by integrating the pancreatic acinar score.

METHODS

A training and validation cohort underwent pancreatoduodenectomy with a subsequent histologic assessment of pancreatic section margins for Ac, fibrosis (Fc), and fat. Intraoperative risk stratification (pancreatic texture, duct diameter) and pancreas-specific complications (postoperative hyperamylasemia [POH], postpancreatectomy acute pancreatitis [PPAP], pancreatic fistula [POPF]) were classified according to ISGPS definitions.

RESULTS

In the validation cohort (n= 373), the association of pancreas-specific complications with higher Ac and lower Fc was replicated (all P <0.001). In the entire cohort (n= 761), the ISGPS classification allocated 275 (36%) patients into intermediate-risk classes B (POH 32%/PPAP 3%/POPF 17%) and C (POH 36%/PPAP 9%/POPF 33%). Using the acinar score (Ac ≥60% and/or Fc ≤10%), intermediate-risk patients could be dichotomized into a low-risk (POH 5%/PPAP 1%/POPF 6%) and a high-risk (POH 51%/PPAP 9%/POPF 38%) group (all P <0.001). The acinar score AUC for POPF prediction was 0.70 in the ISGPS intermediate-risk classes. Overall, 239 (31%) patients were relocated into the high-risk group from lower ISGPS risk classes using the acinar score.

CONCLUSIONS

The risk of pancreas-specific complications appears to be dichotomous-either high or low-according to the acinar score, a tool to better target the application of mitigation strategies in cases of intermediate macroscopic features.

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.

Incidence and risk factors of postoperative acute pancreatitis after pancreaticoduodenectomy: a systematic review and meta-analysis

Background

Postoperative acute pancreatitis (POAP) is a specific complication after pancreatectomy. The acute inflammatory response of the residual pancreas may affect the healing of pancreatoenteric anastomoses, leading to postoperative pancreatic fistulas (POPFs), abdominal infections, and even progressive systemic reactions, conditions that negatively affect patients' prognoses and can cause death. However, to the best of our knowledge, no systematic reviews or meta-analytic studies have assessed the incidence and risk factors of POAP after pancreaticoduodenectomy (PD).

Method

We searched PubMed, Web of Science, Embase, and Cochrane Library databases for relevant literature describing the outcomes of POAP after PD until November 25, 2022, and we used the Newcastle-Ottawa Scale to assess the quality of the studies. Next, we pooled the incidence of POAP and the odds ratios (ORs) and 95% confidence intervals (CIs) of the risk factors using a random-effect meta-analysis. I² tests were used to assess heterogeneity between the studies.

Results

We analyzed data from 7,164 patients after PD from 23 articles that met the inclusion criteria for this study. The subgroup results of the meta-analysis by different POAP diagnostic criteria showed that the incidences of POAP were 15% (95% CI, 5-38) in the International Study Group for Pancreatic Surgery group, 51% (95% CI, 42-60) in the Connor group, 7% (95% CI, 2-24) in the Atlanta group, and 5% (95% CI, 2-14) in the unclear group. Being a woman [OR (1.37, 95% CI, 1.06-1.77)] or having a soft pancreatic texture [OR (2.56, 95% CI, 1.70-3.86)] were risk factors of POAP after PD.

Conclusion

The results showed that POAP was common after PD, and its incidence varied widely according to different definitions. Large-scale reports are still needed, and surgeons should remain aware of this complication.

Systematic Review Registration

identifier: CRD42022375124.

Prediction of postoperative pancreatic fistula and pancreatitis after pancreatoduodenectomy or distal pancreatectomy: A review

BACKGROUND AND OBJECTIVE

Postoperative pancreatic fistula (POPF) is the leading cause of morbidity and early mortality in patients undergoing pancreatic resection. In addition, recent studies have identified postoperative acute pancreatitis (POAP) as an independent contributor to morbidity. Most perioperative mitigation strategies experimented for POPF have been shown to be in vain with no consensus on the best perioperative management. Clinical prediction models have been developed with the hope of identifying high POPF risk patients with the leading idea of finding subpopulations possibly benefiting from pre-existing or novel mitigation strategies. The aim of this review was to map out the existing prediction modeling studies to better understand the current stage of POPF prediction modeling, and the methodology behind them.

METHODS

A narrative review of the existing POPF prediction model studies was performed. Studies published before September 2022 were included.

RESULTS

While the number of POPF prediction models for pancreatoduodenectomy has increased, none of the currently existing models stand out from the crowd. For distal pancreatectomy, two unique POPF prediction models exist, but due to their freshness, no further external validation or adoption in clinics or research has been reported. There seems to be a lack of adherence to correct methodology or reporting guidelines in most of the studies, which has rendered external validity-if assessed-low. Few of the most recent studies have demonstrated preoperative assessment of pancreatic aspects from computed tomography (CT) scans to provide relatively strong predictors of POPF.

CONCLUSIONS

Main goal for the future would be to reach a consensus on the most important POPF predictors and prediction model. At their current state, few models have demonstrated adequate transportability and generalizability to be up to the task. Better understanding of POPF pathophysiology and the possible driving force of acute inflammation and POAP might be required before such a prediction model can be accessed.

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 Impact of CT-Assessed Liver Steatosis on Postoperative Complications After Pancreaticoduodenectomy for Cancer

INTRODUCTION

Liver steatosis (LS) has been increasingly described in preoperative imaging of patients undergoing pancreaticoduodenectomy (PD). The aim of this study was to assess the impact of preoperative LS on complications after PD and identify possible contributors to LS development in this specific cohort.

METHODS

Pancreatic head adenocarcinoma (PDAC) patients scheduled for PD, with preoperative CT-imaging available were included in the study. LS was defined as mean liver density lower than 45 Hounsfield units. Patients showing preoperative LS were matched for patient age, gender, BMI, ASA score, neoadjuvant treatment, and vascular and multivisceral resections, based on propensity scores in a 1:2 ratio to patients with no LS. The primary outcome was postoperative complication severity at 90 days as measured by the comprehensive complication index (CCI) RESULTS: Overall, 247 patients were included in the study. Forty-three (17%) patients presented with LS at preoperative CT-scan. After matching, the LS group included 37 patients, whereas the non-LS group had 74 patients. LS patients had a higher mean (SD) CCI, 29.7 (24.5) versus 19.5 (22.5), p = 0.035, and a longer length of hospital stay, median [IQR] 12 [8-26] versus 8 [7-13] days, p = 0.006 compared with non-LS patients. On multivariate analysis, variables independently associated with CCI were: LS (16% increase, p = 0.048), male sex (19% increase, p = 0.030), ASA score ≥ 3 (26% increase, p = 0.002), fistula risk score (FRS) (28% increase for each point of FRS, p = 0.001) and vascular resection (20% increase, p = 0.019).

CONCLUSION

Preliminary evidence suggests that preoperative LS assessed by CT-scan influences complication severity in patients undergoing PD for PDAC.

Postpancreatectomy Acute Pancreatitis (PPAP): Definition and Grading From the International Study Group for Pancreatic Surgery (ISGPS)

OBJECTIVE

The ISGPS aimed to develop a universally accepted definition for PPAP for standardized reporting and outcome comparison.

BACKGROUND

PPAP is an increasingly recognized complication after partial pancreatic resections, but its incidence and clinical impact, and even its existence are variable because an internationally accepted consensus definition and grading system are lacking.

METHODS

The ISGPS developed a consensus definition and grading of PPAP with its members after an evidence review and after a series of discussions and multiple revisions from April 2020 to May 2021.

RESULTS

We defined PPAP as an acute inflammatory condition of the pancreatic remnant beginning within the first 3 postoperative days after a partial pancreatic resection. The diagnosis requires (1) a sustained postoperative serum hyperamylasemia (POH) greater than the institutional upper limit of normal for at least the first 48 hours postoperatively, (2) associated with clinically relevant features, and (3) radiologic alterations consistent with PPAP. Three different PPAP grades were defined based on the clinical impact: (1) grade postoperative hyperamylasemia, biochemical changes only; (2) grade B, mild or moderate complications; and (3) grade C, severe life-threatening complications.

DISCUSSIONS

The present definition and grading scale of PPAP, based on biochemical, radiologic, and clinical criteria, are instrumental for a better understanding of PPAP and the spectrum of postoperative complications related to this emerging entity. The current terminology will serve as a reference point for standard assessment and lend itself to developing specific treatments and prevention strategies.