Postoperative acute necrotizing pancreatitis of the pancreatic remnant (POANP): a new definition of severe pancreatitis following pancreaticoduodenectomy

Extracellular volume fraction derived from dual-energy CT: a potential predictor for acute pancreatitis after pancreatoduodenectomy

OBJECTIVES

To investigate the value of extracellular volume (ECV) fraction and fat fraction (FF) derived from dual- energy CT (DECT) for predicting postpancreatectomy acute pancreatitis (PPAP) after pancreatoduodenectomy (PD).

METHODS

This retrospective study included patients who underwent DECT and PD between April 2022 and September 2022. PPAP was determined according to the International Study Group for Pancreatic Surgery (ISGPS) definition. Iodine concentration (IC) and FF of the pancreatic parenchyma were measured on preoperative DECT. The ECV fraction was calculated from iodine map images of the equilibrium phase. The independent predictors for PPAP were assessed by univariate and multivariable logistic regression analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

Sixty-nine patients were retrospectively enrolled (median age, 60 years; interquartile range, 55-70 years; 47 men). Of these, nine patients (13.0%) developed PPAP. These patients had lower portal venous phase IC, equilibrium phase IC, FF, and ECV fraction, and higher pancreatic parenchymal-to-portal venous phase IC ratio and pancreatic parenchymal-to-equilibrium phase IC ratio, compared with patients without PPAP. After multivariable analysis, ECV fraction was independently associated with PPAP (odd ratio [OR], 0.87; 95% confidence interval [CI]: 0.79, 0.96; p < 0.001), with an area under the curve (AUC) of 0.839 (sensitivity 100.0%, specificity 58.3%).

CONCLUSIONS

A lower ECV fraction is independently associated with the occurrence of PPAP after PD. ECV fraction may serve as a potential predictor for PPAP after PD.

CLINICAL RELEVANCE STATEMENT

DECT-derived ECV fraction of pancreatic parenchyma is a promising biomarker for surgeons to preoperatively identify patients with higher risk for postpancreatectomy acute pancreatitis after PD and offer selective perioperative management.

KEY POINTS

PPAP is a complication of pancreatic surgery, early identification of higher-risk patients allows for risk mitigation. Lower DECT-derived ECV fraction was independently associated with the occurrence of PPAP after PD. DECT aids in preoperative PAPP risk stratification, allowing for appropriate treatment to minimize complications.

Gradient inflammation in the pancreatic stump after pancreaticoduodenectomy: Two case reports and review of literature

BACKGROUND

Postoperative pancreatic fistula (POPF) contributes significantly to morbidity and mortality after pancreaticoduodenectomy (PD). However, the underlying mechanisms remain unclear. This study explored this pathology in the pancreatic stumps and elucidated the mechanisms of POPF following PD.

CASE SUMMARY

Pathological analysis and 16S rRNA gene sequencing were performed on specimens obtained from two patients who underwent complete pancreatectomy for grade C POPF after PD. Gradient inflammation is present in the pancreatic stump. The apoptosis was lower than that in the normal pancreas. Moreover, neutrophil-dominated inflammatory cells are concentrated in the ductal system. Notably, neutrophils migrated through the ductal wall in acinar duct metaplasia-formed ducts. Additionally, evidence indicates that gut microbes migrate from the digestive tract. Gradient inflammation occurs in pancreatic stumps after PD.

CONCLUSION

The mechanisms underlying POPF include high biochemical activity in the pancreas, mechanical injury, and digestive reflux. To prevent POPF and address pancreatic inflammation and reflux, breaking the link with anastomotic dehiscence is practical.

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.

Completion Pancreatectomy After Pancreatoduodenectomy: Who Needs It?

OBJECTIVE

The objective of this study was to identify the indications for and report the outcomes of completion pancreatectomy (CPLP) in the postoperative course after pancreatoduodenectomy (PD).

BACKGROUND

CPLP may be considered or even inevitable for damage control after PD.

METHODS

A prospectively maintained database of all patients undergoing PD between 2001 and 2019 was searched for patients who underwent CPLP in the postoperative course after PD. Baseline characteristics, perioperative details, and outcomes of CPLP patients were analyzed and specific indications for CPLP were identified.

RESULTS

A total of 3953 consecutive patients underwent PD during the observation period. CPLP was performed in 120 patients (3%) after a median of 10 days following PD. The main indications for CPLP included postpancreatectomy acute necrotizing pancreatitis [n=47 (39%)] and postoperative pancreatic fistula complicated by hemorrhage [n=41 (34%)] or associated with uncontrollable leakage of the pancreatoenteric anastomosis [n=23 (19%)]. The overall 90-day mortality rate of all 3953 patients was 3.5% and 37% for patients undergoing CPLP.

CONCLUSIONS

Our finding that only very few patients (3%) need CPLP suggests that conservative, interventional, and organ-preserving surgical measures are the mainstay of complication management after PD. Postpancreatectomy acute necrotizing pancreatitis, uncontrollable postoperative pancreatic fistula, and fistula-associated hemorrhage are highly dangerous and represent the main indications for CPLP after PD.

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.

Early and Sustained Elevation in Serum Pancreatic Amylase Activity: A Novel Predictor of Morbidity After Pancreatic Surgery

OBJECTIVE

To characterize early postoperative serum pancreatic amylase (spAMY) trends after pancreatic resections.

SUMMARY BACKGROUND DATA

A postoperative spAMY elevation is a common finding but uncertainties remain about its meaning and prognostic implications.

METHODS

Analysis of patients who consecutively underwent pancreatectomy from 2016 to 2019. spAMY activity was assessed from postoperative day (POD) 0 to 3. Different patterns of spAMY have been identified based on the spAMY standard range (10-52 U/l).

RESULTS

Three patterns were identified: (#1) spAMY values always < the lower limit of normal/within the reference range /a single increase in spAMY > upper limit of normal at any POD; (#2) Sustained increase in spAMY activity on POD 0 + 1; (#3) Sustained increase in spAMY activity including POD 1 + 2. Shifting through spAMY patterns was associated with increase morbidity (21% in #1 to 68% in #3 at POD 7; log rank < 0.001). Almost all severe complications (at least Clavien-Dindo ≥3) occurred in patients with pattern #3 (15% vs 3% vs 5% in #1 and #2 at POD 7, P = 0.006), without difference considering >3-times or >the spAMY normal limit ( P = 0.85). POPF (9% in #1 vs 48% in #3, P < 0.001) progressively increased across patterns. Pre-operative diabetes (OR 0.19), neoadjuvant therapy (OR 0.22), pancreatic texture (OR 8.8), duct size (OR 0.78), and final histology (OR 2.2) were independent predictors of pattern #3.

CONCLUSIONS

A sustained increase in spAMY activity including POD 1 + 2 (#3) represents an early postoperative predictor of overall and severe early morbidity. An early and dynamic evaluation of spAMY could crucially impact the subsequent clinical course with relevant prognostic implications.

Surgical management of severe pancreatic fistula after pancreatoduodenectomy: a comparison of early versus late rescue pancreatectomy

Background

Rescue pancreatectomy for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD) is associated with high mortality. However, in-depth literature is scarce and hard to interpret. This study aimed to evaluate the indications, timing and perioperative outcomes of rescue pancreatectomy for severe POPF after PD.

Methods

Retrospective single-centre study from all consecutive patients (2008–2020) with POPF-C after PD (ISGPS 2016 definition). Major morbidity and mortality during hospitalization or within 90 days after index surgery were evaluated. Time from index surgery to rescue pancreatectomy was dichotomized in early and late (≤ 11 versus > 11 days).

Results

From 1076 PDs performed, POPF-B/C occurred in 190 patients (17.7%) of whom 53 patients (4.9%) with POPF-C were included. Mortality after early rescue pancreatectomy did not differ significantly compared to late rescue pancreatectomy (13.6% versus 35.3%; p = 0.142). Timing of a rescue pancreatectomy did not change significantly during the study period: 11 (IQR, 8–14) (2008–2012) versus 14 (IQR, 7–33) (2013–2016) versus 8 days (IQR, 6–11) (2017–2020) (p = 0.140). Over time, the mortality in patients with POPF grade C decreased from 43.5% in 2008–2012 to 31.6% in 2013–2016 up to 0% in 2017–2020 (p = 0.014). However, mortality rates after rescue pancreatectomy did not differ significantly: 31.3% (2008–2012) versus 28.6% (2013–2016) versus 0% (2017–2020) (p = 0.104).

Conclusions

Rescue pancreatectomy for severe POPF is associated with high mortality, but an earlier timing might favourably influence the mortality. Hypothetically, this could be of value for pre-existent vulnerable patients. These findings must be carefully interpreted considering the sample sizes and differences among subgroups by patient selection.

Clinical significance of postpancreatectomy acute pancreatitis defined by the International Study Group for Pancreatic Surgery

Aim

The International Study Group for Pancreatic Surgery (ISGPS) developed a structured definition of postpancreatectomy acute pancreatitis (PPAP) in 2021. This study aimed to evaluate the clinical significance of PPAP as defined by the ISGPS criteria.

Methods

We evaluated the medical records and postoperative computed tomography (CT) findings of 247 patients who underwent pancreaticoduodenectomy. Postoperative hyperamylasemia (POH) was defined as an elevation in serum amylase levels over the upper baseline limit (≥133 U/L) on postoperative days 1 and 3. PPAP was defined as acute pancreatitis satisfying the following three requirements: POH, clinically relevant deterioration, and radiologic features consistent with acute pancreatitis.

Results

Postoperative hyperamylasemia and PPAP were prevalent in 9.7% (24/247) and 3.6% (9/247) of the patients, respectively. PPAP grade B occurred in eight patients, seven of whom experienced Clavien-Dindo grade IIIA complications, including postoperative pancreatic fistula (POPF) and extended periods of postoperative hospitalization. PPAP grade C occurred in one patient, who died from the exacerbation of underlying interstitial pneumonia following the POPF occurrence. Acute pancreatitis determined by CT was observed in 15.3% (38/247) of the patients who underwent pancreaticoduodenectomy and was strongly associated with severe morbidity (P < .0001) and longer postoperative hospitalization (P < .0001). POH preceded acute pancreatitis on CT in only 23.7% (9/38) of those cases, resulting in a low incidence rate of PPAP.

Conclusion

Post-pancreatectomy acute pancreatitis is a major postoperative complication of pancreatic resection; however, based on the current ISGPS criteria, its prevalence is low. Defining PPAP promotes universal evaluation and understanding of this new concept.

Pancreatic Apoplexy: Fulminant Necrotizing Pancreatitis Leading to Completion Pancreatectomy Within 3 Days After Partial Pancreaticoduodenectomy

OBJECTIVES

Patient characteristics with postoperative acute necrotizing pancreatitis and completion pancreatectomy (CP) after pancreaticoduodenectomy (PD) remain unclear.

METHODS

Data from all patients who underwent a PD with need for CP (January 2011-December 2019) at a German University Hospital were analyzed regarding the indications and timing of CP, laboratory and histopathological findings, and overall outcome.

RESULTS

Six hundred twelve patients underwent PD, 33 (5.4%) of them needed a CP. Indications were grade C pancreatic fistula with or without biliary leak (46% and 12%), biliary leak (6%), and hemorrhage due to pancreatic fistula (36%). Eight patients (24%) underwent CP within 3 days after PD. These fulminant courses ("pancreatic apoplexy") were accompanied by significantly higher levels of lactate dehydrogenase, C-reactive protein, serum amylase, serum lipase, drain amylase, and drain lipase compared with patients with CP after the third day. Pancreatic apoplexy was histologically associated with higher rates of pancreatic necrosis (P = 0.044) and hemorrhage (P = 0.001). A trend toward higher mortality was observed (75% vs 36%, P = 0.058).

CONCLUSIONS

Pancreatic apoplexy, defined as fulminant necrotizing pancreatitis after PD leading to CP within 3 days, is associated with characteristic laboratory and histopathological findings and a trend to higher mortality.

Risk Factors and Clinical Impacts of Post-Pancreatectomy Acute Pancreatitis After Pancreaticoduodenectomy: A Single-Center Retrospective Analysis of 298 Patients Based on the ISGPS Definition and Grading System

Background

The definition and grading system of post-pancreatectomy acute pancreatitis (PPAP) has recently been proposed by ISGPS. This study aimed to put this definition and classification into practice and investigate the potential risk factors and clinical impacts of PPAP.

Methods

Demographic and perioperative data of consecutive patients who underwent pancreaticoduodenectomy (PD) from January 2019 to July 2021 were collected and analyzed retrospectively. The diagnostic criteria of PPAP published by ISGPS, consisting of biochemical, radiologic, and clinical parameters, were adopted. The risk factors were analyzed by univariate and multivariate analyses.

Results

A total of 298 patients were enrolled in this study, and the total incidence of PPAP was 52.4% (150 patients). Stratified by clinical impacts of PPAP, the incidences of grades B and C PPAP were 48.9% and 3.5%, respectively. PPAP after PD was significantly associated with pancreatic fistula and other unfavorable complications. Soft pancreatic texture (OR 3.0) and CRP ≥ 180 mg/L (OR 3.6) were the independent predictors of PPAP, AUC 0.613. Stratified by the grade of PPAP, soft pancreatic texture (OR 2.7) and CRP ≥ 180 mg/L (OR 3.4) were the independent predictors of grade B PPAP, and soft pancreatic texture (OR 19.3), operation duration >360 min (OR 13.8), and the pancreatic anastomosis by using conventional duct to mucosa methods (OR 10.4) were the independent predictors of grade C PPAP. PPAP complicated with pancreatic fistula significantly increased the severe complications and mortality compared to only PPAP occurrence.

Conclusion

PPAP was not an uncommon complication after PD and was associated with unfavorable clinical outcomes, especially since it was complicated with pancreatic fistula. Soft pancreatic texture and CRP ≥ 180 mg/L were the independent predictors of PPAP. Higher-volume multicenter and prospective studies are strongly needed.

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.

Double purse-string telescoped pancreaticogastrostomy is not superior in preventing pancreatic fistula development in high-risk anastomosis: a 6-year single-center case-control study

PURPOSE

The double purse-string telescoped pancreaticogastrostomy (PG) technique has been suggested as an alternative approach to reduce the risk of postoperative pancreatic fistula (POPF). Its efficacity in high-risk situations has not yet been explored. This study compared the incidence of clinically relevant POPF (CR-POPF) between patients with high-risk anastomosis undergoing PG and those undergoing pancreaticojejunostomy (PJ).

METHODS

From 2013 to 2019, 198 consecutive patients with high-risk anastomosis, an updated alternative fistula risk score > 20%, and who underwent pancreatoduodenectomy with the PJ (165) or PG (33) technique were included. Optimal mitigation strategy (external stenting/octreotide omission) was applied for all patients. The primary endpoint was the incidence of CR-POPF.

RESULTS

The mean ua-FRS was 33%. CR-POPF (grade B/C) was found in 42 patients (21%) and postoperative hemorrhage in 30 (15%); the mortality rate was 4%. CR-POPF rates were comparable between the PJ (19%) and PG (33%) groups (P = 0.062). The PG group had a higher rate of POPF grade C (24% vs. 10%; P = 0.036), longer operative time (P = 0.019), and a higher transfusion rate (P < 0.001), even after a matching process on ua-FRS. In the multivariate analysis, the type of anastomosis (P = 0.88), body mass index (P = 0.47), or main pancreatic duct diameter (P = 0.7) did not influence CR-POPF occurrence.

CONCLUSIONS

For patients with high-risk anastomosis, the double purse-string telescoped PG technique was not superior to the PJ technique for preventing CR-POPF.

Postoperative acute pancreatitis is a serious but rare complication after distal pancreatectomy

BACKGROUND

The clinical relevance of hyperamylasemia after distal pancreatectomy (DP) remains unclear and no internationally accepted definition of postoperative acute pancreatitis (POAP) exists. The aim of this study was to characterize POAP after DP and to assess the role of serum amylase (SA) in POAP.

METHODS

Outcomes of 641 patients who had undergone DP between 2015 and 2019 were analyzed. Postoperative SA was determined in all patients. POAP was defined based on contrast-enhanced computed tomography (CT) or intraoperative findings during relaparotomy.

RESULTS

An elevation of SA on postoperative day 1 (hyperamylasemia^POD1) was found in 398 patients (62.1%). Twelve patients (1.87%) were identified with POAP. Ten patients demonstrated radiologic criteria for POAP and in two patients POAP was diagnosed during relaparotomy. Outcome of POAP patients was worse than that of patients with hyperamylasemia^POD1 alone and that with normal SA^POD1 without POAP evidence (postoperative pancreatic fistula 50% vs 30.6% vs 18.5%; length of hospital stay 26 days vs 12 vs 11, respectively). The overall 90-day mortality of all 641 patients was 0.6%.

CONCLUSION

POAP is a serious but rare complication after DP. Hyperamylasemia^POD1 is of prognostic relevance after DP, but it seems not sufficient as a single parameter to diagnose POAP.

Characterization of postoperative acute pancreatitis (POAP) after distal pancreatectomy

BACKGROUND

Postoperative acute pancreatitis has recently been reported as a specific complication after pancreatoduodenectomy. The aim of this study was to characterize postoperative acute pancreatitis after distal pancreatectomy.

METHODS

We analyzed the outcomes retrospectively of 368 patients who underwent distal pancreatectomies during the period January 2016 to December 2019. Postoperative acute pancreatitis was defined as an increase of serum amylase activity greater than our laboratory normal upper limit on postoperative days 0 to 2. We assessed the incidence of postoperative acute pancreatitis after distal pancreatectomy and examined possible predictors of postoperative acute pancreatitis and relationships of postoperative acute pancreatitis with postoperative pancreatic fistula.

RESULTS

The rates of postoperative acute pancreatitis and postoperative pancreatic fistula after distal pancreatectomy were 67.9% and 28.8%, respectively. Patients who developed postoperative acute pancreatitis experienced an increased rate of severe morbidity (18.4 vs 9.3%; P = .030). Neoadjuvant therapy (odds ratio 0.28, 0.09-0.85; P = .025), age ≥ 65 y (odds ratio 0.34, 0.13-0.85; P = .020), duct size (odds ratio 0.02, 0.002-0.47; P = .013), pancreatic thickness (odds ratio 3.4, 1.29-8.9; P = .013), resection at the body-tail level (odds ratio 4.3, 1.15-23.19; P = .041), and neuroendocrine histology (odds ratio 1.14, 1.06-3.90; P = .013) were independent predictors of postoperative acute pancreatitis. Furthermore, postoperative acute pancreatitis was an independent predictor of postoperative pancreatic fistula (odds ratio 5.8, 2.27-15.20; P < .001). Postoperative pancreatic fistula occurred in 37% of patients who developed postoperative acute pancreatitis. Patients developing postoperative acute pancreatitis alone demonstrated a statistically significantly increased rate of biochemical leakage and bacterial contamination in the peripancreatic drainage fluid.

CONCLUSION

Postoperative acute pancreatitis is a frequent event after distal pancreatectomy and, despite its close association with postoperative pancreatic fistula, evidently represents a separate phenomenon. A universally accepted definition of postoperative acute pancreatitis that applies to all types of pancreatic resections is needed, because it may identify patients at greater risk for additional morbidity immediately after pancreatic resections.

Postoperative hyperamylasemia (POH) and acute pancreatitis after pancreatoduodenectomy (POAP): State of the art and systematic review

BACKGROUND

Postoperative hyperamylasemia is a frequent finding after pancreatoduodenectomy, but its incidence and clinical implications have not yet been analyzed systematically. The aim of this review is to reappraise the concept of postoperative hyperamylasemia with postoperative acute pancreatitis, including its definition, interpretation, and correlation.

METHODS

Online databases were used to search all available relevant literature published through June 2019. The following search terms were used: "pancreaticoduodenectomy," "amylase," and "pancreatitis." Surgical series reporting data on postoperative hyperamylasemia or postoperative acute pancreatitis were selected and screened.

RESULTS

Among 379 screened studies, 39 papers were included and comprised data from a total of 9,220 patients. Postoperative hyperamylasemia was rarely defined in most of these series, and serum amylase values were measured at different cutoff levels and reported on different postoperative days. The actual levels of serum amylase activity and the representative cutoff levels required to reach a diagnosis of postoperative acute pancreatitis were markedly greater on the first postoperative days and tended to decrease over time. Most studies analyzing postoperative hyperamylasemia focused on its correlation with postoperative pancreatic fistula and other postoperative morbidities. The incidence of postoperative acute pancreatitis varied markedly between studies, with its definition completely lacking in 40% of the analyzed papers. A soft pancreatic parenchyma, a small pancreatic duct, and pathology differing from cancer or chronic pancreatitis were all predisposing factors to the development of postoperative hyperamylasemia.

CONCLUSION

Postoperative hyperamylasemia has been proposed as the biochemical expression of pancreatic parenchymal injury related to localized ischemia and inflammation of the pancreatic stump. Such phenomena, analogous to those associated with acute pancreatitis, could perhaps be renamed as postoperative acute pancreatitis from a clinical standpoint. Patients with postoperative acute pancreatitis experienced an increased rate of all postoperative complications, particularly postoperative pancreatic fistula. Taken together, the discrepancies among previous studies of postoperative hyperamylasemia and postoperative acute pancreatitis outlined in the present review may provide a basis for stronger evidence necessary for the development of universally accepted definitions for postoperative hyperamylasemia and postoperative acute pancreatitis.