Evaluation of a predictive model for pancreatic fistula based on amylase value in drains after pancreatic resection

Early Drain Removal Versus Routine Drain Removal After Pancreaticoduodenectomy and/or Distal Pancreatectomy: A Meta-Analysis and Systematic Review

BACKGROUND

Early drain removal (EDR) has been widely accepted, but not been routinely used in patients after pancreaticoduodenectomy (PD) and distal pancreatectomy (DP). This study aimed to evaluate the safety and benefits of EDR versus routine drain removal (RDR) after PD or DP.

METHODS

A systematic search was conducted on medical search engines from January 1, 2008 to November 1, 2023, for articles that compared EDR versus RDR after PD or DP. The primary outcome was clinically relevant postoperative pancreatic fistula (CR-POPF). Further analysis of studies including patients with low-drain fluid amylase (low-DFA) on postoperative day 1 and defining EDR timing as within 3 days was also performed.

RESULTS

Four randomized controlled trials (RCTs) and eleven non-RCTs with a total of 9465 patients were included in this analysis. For the primary outcome, the EDR group had a significantly lower rate of CR-POPF (OR 0.23; p < 0.001). For the secondary outcomes, a lower incidence was observed in delayed gastric emptying (OR 0.63, p = 0.02), Clavien-Dindo III-V complications (OR 0.48, p < 0.001), postoperative hemorrhage (OR 0.55, p = 0.02), reoperation (OR 0.57, p < 0.001), readmission (OR 0.70, p = 0.003) and length of stay (MD -2.04, p < 0.001) in EDR. Consistent outcomes were observed in the subgroup analysis of low-DFA patients and definite EDR timing, except for postoperative hemorrhage in EDR.

CONCLUSION

EDR after PD or DP is beneficial and safe, reducing the incidence of CR-POPF and other postoperative complications. Further prospective studies and RCTs are required to validate this finding.

Predictive value of drain fluid amylase level on postoperative day one after pancreatic resection for predicting postoperative pancreatic fistula

Objectives

The aim of this study was to evaluate the predictive value of the first postoperative day (POD1) drain fluid amylase in predicting pancreatic fistula formation following pancreaticoduodenectomy (PD).

Material and Methods

One-hundred and eighty-five prospective patients undergoing PD between April 2014 and April 2018 were studied retrospectively. Cut-off point to predict the development of POPF was determined by median values for drain fluid amylase of 1883 U/L. Patients were classified into two groups according to POD1 drain fluid amylase values: <1883 U/L (Group 1) and ≥1883 U/L (Group 2). Differences between the groups with clinically relevant POPF and without POPF were evaluated.

Results

The incidence of POPF was 17.2%. POD1 amylase level was the strongest predictor of POPF, with levels of higher than 1883 U/L demonstrating the best accuracy (87.5%), sensitivity (78.1%), specificity (89.5%), positive predictive value (60.9%), and negative predictive value (95.1%). One-hundred and forty-four patients (77.8%) had a POD1 drain amylase level of less than 1883 U/L, and POPF developed in only seven (3.7%) cases, whereas in patients with POD1 drain amylase level of 1883 U/L or higher (n= 41), the POPF rate was 31.4% [OR: 22.24, 95% CI (7.930-62.396), p<0.001].

Conclusion

The cut-off point of POD1 drain fluid amylase level (1883 U/L) might predict the clinically relevant POPF with adequate sensitivity and specificity rates in patients undergoing pancreatic resection.

The risk of clinically-relevant pancreatic fistula after pancreaticoduodenectomy is better predicted by a postoperative trend in drain fluid amylase compared to day 1 values in isolation

BACKGROUND

Recent studies support early drain removal after pancreaticoduodenectomy in patients with a drain fluid amylase on postoperative day 1 (DFA1) level of ≤5,000. The use of DFA1 to guide drain management is increasingly common among pancreatic surgeons; however, the benefit of checking additional drain fluid amylases beyond DFA1 is less known. We sought to determine whether a change in drain fluid amylase (ΔDFA) is a more reliable predictor of clinically relevant postoperative fistula than DFA1 alone.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Plan, pancreaticoduodenectomy patients with intraoperative drain placement, known DFA1, highest recorded drain fluid amylase value on postoperative day 2 to 5 (DFA2nd), day of drain removal, and clinically relevant postoperative fistula status were reviewed. Logistic models compared the predictive performance of DFA1 alone versus DFA1 + ΔDFA.

RESULTS

A total of 2,417 patients with an overall clinically relevant postoperative fistula rate of 12.6% were analyzed. On multivariable regression, clinical predictors for clinically relevant postoperative fistula included body mass index, steroid use, operative time, and gland texture. These variables were used to develop model 1 (DFA1 alone) and model 2 (DFA1 + ΔDFA). Model 2 outperformed model 1 in predicting the risk of clinically relevant postoperative fistula. According to model 2 predictions, the risk of clinically relevant postoperative fistula increased with any rise in drain fluid amylase, regardless of whether the DFA1 was above or below 5,000 U/L. The risk of clinically relevant postoperative fistula significantly decreased with any drop in drain fluid amylase, with an odds reduction of approximately 50% corresponding with a 70% decrease in drain fluid amylase (P < .001). A risk calculator was developed using DFA1 and a secondary DFA value in conjunction with other clinical predictors for clinically relevant postoperative fistula.

CONCLUSION

Clinically relevant postoperative fistula after pancreaticoduodenectomy is more accurately predicted by DFA1 and ΔDFA versus DFA1 in isolation. We developed a novel risk calculator to provide an individualized approach to drain management after pancreaticoduodenectomy.

Hyperamylasemia grade versus drain fluid amylase: which better predicts pancreatectomy outcomes?

BACKGROUND

The clinical importance of postoperative hyperamylasemia (POHA) grade is unknown. Our objectives were to evaluate the association of POHA grade with clinically relevant postoperative pancreatic fistula (CR-POPF) and compare its prognostic utility against postoperative day 1 drain fluid amylase (DFA-1).

METHODS

Patients who underwent pancreatectomy from January 2019 through March 2020 were identified in the ACS NSQIP pancreatectomy-targeted dataset. POHA grade was assigned using post-operative serum amylase and clinical sequelae. The primary outcome was CR-POPF within 30 days. The association of POHA grade with CR-POPF was assessed using multivariable logistic regression, and c-statistics were used to compare POHA grade versus DFA-1.

RESULTS

POHA occurred in 520 patients at 98 hospitals, including 261 (50.2%) with grade A, 234 (45.0%) with grade B, and 25 (4.8%) with grade C POHA. CR-POPFs were increased among patients with grade B (66.2%, OR 9.28 [5.84-14.73]) and C (68.0%, OR 10.50 [3.77-29.26]) versus grade A POHA (19.2%). POHA-inclusive models better predicted CR-POPF than those with DFA-1 alone (p < 0.002) and models with both predictors outperformed POHA alone (p = 0.039).

CONCLUSION

POHA grade represents a measure of post-pancreatectomy outcomes that predicts CR-POPF and outperforms DFA-1 but must be aligned with new international definitions.

Early detection of anastomotic leakage after pancreatoduodenectomy with microdialysis catheters: an observational Study

BACKGROUND

Microdialysis catheters can detect focal inflammation and ischemia, and thereby have a potential for early detection of anastomotic leakages after pancreatoduodenectomy. The aim was to investigate whether microdialysis catheters placed near the pancreaticojejunostomy can detect leakage earlier than the current standard of care.

METHODS

Thirty-five patients with a median age 69 years were included. Two microdialysis catheters were placed at the end of surgery; one at the pancreaticojejunostomy, and one at the hepaticojejunostomy. Concentrations of glucose, lactate, pyruvate, and glycerol were analyzed hourly in the microdialysate during the first 24 h, and every 2-4 h thereafter.

RESULTS

Seven patients with postoperative pancreatic fistulae (POPF) had significantly higher glycerol levels (P < 0.01) in the microdialysate already in the first postoperative samples. Glycerol concentrations >400 μmol/L during the first 12 postoperative hours detected patients with POPF with a sensitivity of 100% and a specificity of 93% (P < 0.001). After 24 h, lactate and lactate-to-pyruvate ratio were significantly higher (P < 0.05) and glucose was significantly lower (P < 0.05) in patients with POPF.

CONCLUSION

High levels of glycerol in microdialysate was an early detector of POPF. The subsequent inflammation was detected as increase in lactate and lactate-to-pyruvate ratio and a decrease in glucose (NCT03627559).

OUP accepted manuscript

Background

Recent studies have suggested postoperative acute pancreatitis (POAP) as a serious complication after pancreaticoduodenectomy (PD) and have speculated on its possible role in the pathogenesis of postoperative pancreatic fistula (POPF). This study aimed to assess the impact of POAP on post-PD outcomes and fistula risk score (FRS) performance in predicting POAP.

Methods

All PDs at Helsinki University Hospital between 2013 and 2020 were analysed. POAP was defined as a plasma amylase activity greater than the normal upper limit on postoperative day (POD) 1 and stratified as clinically relevant (CR)-POAP once C-reactive protein (CRP) reached or exceeded 180 mg/l, and non-CR-POAP once CRP was less than 180 mg/l on POD 2. The Comprehensive Complication Index (CCI) was used to assess total postoperative morbidity. Different FRSs were assessed using receiver operating characteristic curves.

Results

Of the 508 patients included, POAP occurred in 202 (39.8 per cent) patients, of whom 91 (17.9 per cent) had CR-POAP. The incidence of CR-POPF was 12.6 per cent (64 patients). Patients with non-CR-POAP had a similar morbidity to patients with no POAP (median CCI score 24.2 versus 22.6; P = 0.142), while CCI score was significantly higher (37.2) in patients with CR-POAP (P < 0.001). CR-POAP was associated with increased rates of CR-POPF, delayed gastric emptying, haemorrhage, and bile leak, while non-CR-POAP was associated only with CR-POPF. Ninety-day mortality was 1.6 per cent, 0.9 per cent, and 3.3 per cent in patients with no-POAP, non-CR-POAP, and CR-POAP, respectively. Updated alternative FRS showed the best performance in predicting CR-POAP (area under the curve 0.834).

Conclusion

CR-POAP was associated with a higher CCI score, suggesting CR-POAP as a distinct entity from non-CR-POAP. FRSs can be used to assess the risk of CR-POAP.

The value of drain fluid amylase as a predictor of postoperative pancreatic fistula after pancreaticogastrostomy

BACKGROUND

Drain fluid amylase is commonly used as a predictor of pancreatic fistula after pancreaticoduodenectomy (PD). This study aimed to determine the ideal cut-off value of drain fluid amylase on postoperative day 1 (DFA1) for predicting pancreatic fistula after pancreaticogastrostomy (PG).

METHODS

Prospective data of 272 consecutive patients undergoing PG between 2010 and 2020 was collected and analysed to determine the postoperative pancreatic fistula (POPF) risk factors.

RESULTS

The incidence of POPF was 143 cases (52.6%). The median DFA1 in patients with POPF was significantly higher than that of patients with NO-POPF (5483 versus 311, P < 0.001). DFA1 correlated with POPF in the area under the curve (AUC) of 0.84 (P < 0.001). When DFA1 was 2300 U/L, Youden index was the highest, with a sensitivity of 72.7% and a specificity of 82.9%. Logistic regression analysis showed that DFA1 ≥ 2300 U/L was an independent predictor of POPF (P < 0.001; OR: 12.855; 95% CI: 7.019-23.544). The AUC of DFA1 and clinically relevant postoperative pancreatic fistula (CR-POPF) was 0.674 (P < 0.001).

CONCLUSION

DFA1 ≥ 2300 U/L can be used as an independent predictor of POPF after PG. DFA1 ≥ 3000 U/L can predict the occurrence of CR-POPF, when DFA1 ≥ 3000 U/L, the patients should be observed closely active for complications.

Comprehensive Diagnostic Nomogram for Predicting Clinically Relevant Postoperative Pancreatic Fistula After Pancreatoduodenectomy

BACKGROUND

Clinically relevant postoperative pancreatic fistula (CR-POPF) remains a severe and challenging complication of pancreaticoduodenectomy (PD). This study aimed to establish a novel postoperative nomogram-based diagnostic model for the early detection of CR-POPF in patients subjected to PD.

METHODS

Consecutive patients who underwent PD in Zhongshan Hospital, Fudan University from December 2018 to October 2020 were retrospectively enrolled. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for CR-POPF. Then, a novel predictive nomogram was established accordingly.

RESULTS

Among the consecutive 176 patients who underwent PD, 37 (21.1%) patients developed CR-POPF. Through univariate and multivariate analyses, the drain amylase (P = 0.002), serum creatinine (P = 0.009), and serum C reactive protein (P = 0.045) at postoperative day 1 (POD1) as well as the neutrophil count (P = 0.025) and temperature (P = 0.025) at POD3 were identified as independent risk factors for CR-POPF. Based on this, a novel predictive nomogram containing these factors was constructed to predict the probability of CR-POPF after PD. The formulated nomogram showed better performance to detect CR-POPF after PD with a sensitivity of 0.784, specificity of 0.770, positive predictive value of 0.475, and negative predictive value of 0.930 when compared to other predictors. In addition, the predictive value of the nomogram was assessed by a concordance index of 0.814 (95% CI, 0.736-0.892), which was significantly higher than indicators alone. This was further validated and depicted by decision curve analysis and clinical impact curve.

CONCLUSION

This study established a diagnostic nomogram of postoperative objective parameters that can predict the development of CR-POPF after PD with a good discriminative ability and predictive accuracy.

Postoperative day 1 combination of serum C-reactive protein and drain amylase values predicts risks of clinically relevant pancreatic fistula. The "90-1000" score

BACKGROUND

Several scoring systems predict risks of clinically relevant postoperative pancreatic fistula after pancreatectomy, but none have emerged as the gold standard. This study aimed to evaluate the accuracy of postoperative day 1 drain amylase and serum C-reactive protein levels in predicting clinically relevant postoperative pancreatic fistula compared with intraoperative pancreatic characteristics.

METHODS

Patients who underwent pancreatectomy between 2017 and 2019 were included prospectively. Cutoff values were determined using receiver operating characteristic curves, and a score combining postoperative day 1 drain amylase and serum C-reactive protein was tested in a multivariate logistic regression model to evaluate clinically relevant postoperative pancreatic fistula risk.

RESULTS

A total of 274 pancreatic resections (182 pancreaticoduodenectomies and 92 distal pancreatectomies) were included. The pancreatic gland texture was "soft" in 47.8% (n = 131), and 55.8% (n = 153) had a small size main pancreatic duct (≤3 mm). Clinically relevant postoperative pancreatic fistula occurred in 58 patients (21.2%). Drain amylase ≥1,000 UI/L and serum C-reactive protein ≥90 mg/L were identified as the optimal cutoffs to predict clinically relevant postoperative pancreatic fistula. On multivariate analysis these cutoffs were independent predictors of clinically relevant postoperative pancreatic fistula after both pancreaticoduodenectomies (drain amylase: P < .001, serum C-reactive protein: P = .006) and distal pancreatectomies (drain amylase: P = .009, serum C-reactive protein: P = .001). The postoperative day 1 "90-1000" model, a 2-value score relying on these cutoffs, significantly (P < .001) outperformed intraoperative pancreatic parenchymal characteristics in predicting clinically relevant postoperative pancreatic fistula after both pancreaticoduodenectomies and distal pancreatectomies. A postoperative day 1 "90-1000" score = 0 had a negative predictive value of 97% and 94%, respectively, after pancreaticoduodenectomy and distal pancreatectomies.

CONCLUSION

A combined score relying on postoperative day 1 values of drain amylase and serum C-reactive protein levels was accurate in predicting risks of clinically relevant postoperative pancreatic fistula after pancreatectomy.

Redefining the Role of Drain Amylase Value for a Risk-Based Drain Management after Pancreaticoduodenectomy: Early Drain Removal Still Is Beneficial

BACKGROUND

The application of postoperative pancreatic fistula (POPF) risk stratification and mitigation strategies requires an update of the protocol for an early drain removal after pancreaticoduodenectomy (PD). The aim of the study is to highlight the unreliability of a single drain fluid amylase (DFA) cutoff-based protocol in the setting of a risk-based drain management.

METHODS

The role of postoperative day one (POD1) DFA in predicting POPF was explored in the setting of both selective drain placement and early drain removal protocols. Receiver operating characteristics (ROC) curves were used to assess the POPF diagnostic performance in terms of negative predictive value (NPV) of several POD1 DFA cutoffs in different clinical scenarios according to POPF risk and mitigation strategies.

RESULTS

The areas under the curve (AUCs) for POD1-DFA were 0.815 for intermediate risk and pancreaticojejunostomy (PJ) (best cutoff 1000 IU/L, NPV 92.9%), 0.712 for intermediate risk and PJ with external stent (best cutoff 1000 IU/L, NPV 88.8%), and 0.574 for high risk and external stent (best cutoff 250 IU/L, NPV 93.7%). Independent predictors of POPF were body mass index, pancreatic texture, and early drain removal, whereas POD1 DFA was not.

CONCLUSION

In the era of risk stratification and mitigation strategies, selective early drain removal still is associated with a reduced rate of POPF. However, a single protocol based on POD1-DFA is not suitable for all clinical scenarios after PD.

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.

Clinical relevant pancreatic fistula after pancreatoduodenectomy: when negative amylase levels tell the truth

Drain Amylase level are routinely determined to diagnose pancreatic fistula after Pancreatocoduodenectomy. Consensus is lacking regarding the cut-off value of amylase to diagnosis clinically relevant postoperative pancreatic fistulae (POPF). The present study proposes a model based on Amylase Value in the Drain (AVD) measured in the first three postoperative days to predict a POPF. Amylase cut-offs were selected from a previous published systematic review and the accuracy were validated in a multicentre database from 12 centres in 2 countries. The present study defined POPF the 2016 ISGPS criteria (3 times the upper limit of normal serum amylase). A learning machine method was used to correlate AVD with the diagnosis of POPF. Overall, 454 (27%) of 1638 patients developed POPF. Machine learning excluded a clinically relevant postoperative pancreatic fistulae with an AUC of 0.962 (95% CI 0.940-0.984) in the first five postoperative days. An AVD at a cut-off of 270 U/L in 2 days in the first three postoperative days excluded a POPF with an AUC of 0.869 (CI 0.81-0.90, p < 0.0001). A single AVD in the first three postoperative days may not exclude POPF after pancreatoduodenectomy. The levels should be monitored until day 3 and have two negative values before removing the drain. In the group with a positive level, the drain should be kept in and AVD monitored until postoperative day five.

What should we trust to define, predict and assess pancreatic fistula after pancreatectomy?

OBJECTIVE

The ISGPF postoperative pancreatic fistula (POPF) definition using amylase drain concentration is widely used. However, the interest of lipase drain concentration, daily drain output and absolute enzyme daily production (concentration x daily drain volume) have been poorly investigated.

MATERIAL AND METHODS

These predictive on postoperative day (POD) 1, 3, 5 and 7 were analyzed in a development cohort, and subsequently tested in an independent validation cohort.

RESULTS

Of the 227 patients of the development cohort, 17% developed a biochemical fistula and 34% a POPF (Grade B/C). Strong correlation was found between amylase/lipase drain concentration at all postoperative days (ρ = 0.90; p = 0.001). Amylase and lipase were both significantly higher in patients with a POPF (p < 0.001) presenting an equivalent under the ROC curve area (0.85 vs 0.84; p = 0.466). Combining POD1 and POD3 threefold enzyme cut-off value increased significantly POPF prediction sensibility (97.4% vs 77.8%) and NPV (97.1% vs 86.3%). These results were also confirmed in the validation cohort of 554 patients. Finally, absolute enzyme daily production and daily drain output were significantly higher in patients with a POPF (p < 0.001) but did not add clinical value when compared to drain enzyme concentration.

CONCLUSION

Lipase is as effective as amylase drain concentration to define POPF. Absolute enzyme daily production or daily drain output do not help to better predict clinically significant POPF occurrence and severity. Lipase and amylase should mainly be used for their negative predictive value to predict the absence of clinically significant POPF and could allow early drain removal and hospital discharge.

The Role of Hyponatraemia Before Surgery in Patients With Radical Resected Pancreatic Cancer

Objectives:

Hyponatraemia represents a negative prognostic factor in patients with cancer. The aim of this study was to assess, for the first time, the role of hyponatraemia in patients undergoing radical surgery for pancreatic ductal adenocarcinoma.

Methods:

A total of 89 patients with stage I-III pancreatic ductal adenocarcinoma underwent radical surgery between November 2012 and October 2014. Relapse-free survival (RFS) and disease-specific survival (DSS) were estimated using Kaplan-Meier method. A Cox regression model was carried out for univariate and multivariate analyses. Fisher exact test was used to estimate correlation between variables.

Results:

In total, 12 patients (14%) presented with hyponatraemia at diagnosis. The median DSS was 20 months in patients with hyponatraemia and not reached in patients with eunatraemia (P < .1073), while a statistical significant difference was observed in terms of median RFS (10 months vs 17 months, respectively; P = .0233). Considering clinical features (hyponatraemia, smoke and alcoholic habit, diabetes, pain, and jaundice), patients with 4 or more of these factors had a worse prognosis (mDSS: 30 months vs not reached; hazard ratio [HR]: 0.40, 95% confidence interval [CI] = 0.16-0.80; P = .0120).

Conclusions:

The presence of hyponatraemia and its prompt correction at the diagnosis time should be considered for the correct management of patients with pancreatic carcinoma.

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.

C-reactive protein and drain amylase accurately predict clinically relevant pancreatic fistula after partial pancreaticoduodenectomy

BACKROUND

C-reactive protein (CRP) and procalcitonin (PCT) have shown to be reliable predictors of inflammatory complications and anastomotic leak after colorectal surgery. Their predictive value after partial pancreaticoduodenectomy (PD) remains unclear.

MATERIALS AND METHODS

All consecutive pancreaticoduodenectomies (2009-2018) at our hospital were included. Drain amylase was evaluated on postoperative day (POD) 1, serum CRP and PCT were evaluated on POD 1-3. Receiver-operating characteristics curves were performed and significant cut-off values were tested using logistic regression.

RESULTS

Among 188 patients who underwent partial PD, clinically relevant pancreatic fistulas (POPF) occurred in 30 (16%) patients, including 20 (10.6%) with Grade B and 10 (5.3%) patients with Grade C. Postoperative complications (Clavien-Dindo ≥ III) were reported in 46 (24.5%) patients, including Grade IIIa in 16 (8.5%), IIIb in 18 (9.6%), IVa in 3 (1.6%), IVb in 2 (1.1%) and V in 7 (3.7%) patients. Drain amylase on POD 1 showed the largest area under the curve (0.872, p < 0.001), followed by CRP (0.803, p < 0.001) and PCT on POD 3 (0.651, p < 0.011). Drain amylase on POD 1 > 303 U/l (OR 0.045, 95% CI 0.010-0.195, p < 0.001), CRP > 203 mg/l (OR 0.098, 95% CI 0.041-0.235, p < 0.001) and PCT > 0.85 μg/l (OR 0.393, 95%CI 0.178-0.869, p = 0.02) were significant predictors of relevant POPF in the univariate analysis. CRP > 203 mg/l (OR 0.098, 95% CI 0.024-0.403, p = 0.001) and drain amylase > 303 U/l (OR 0.064, 95% CI 0.007-0.554, p = 0.01) remained independent predictors in the multivariable analysis. The combination of drain amylase on POD 1 and CRP on POD 3 had a sensitivity and specificity of 87.4% and 90.9% to predict relevant POPF.

CONCLUSION

Drain amylase on POD 1 and CRP on POD 3 can accurately predict clinically relevant POPF after partial pancreaticoduodenectomy. The accuracy of PCT on POD 3 is limited.

Identification of an Optimal Cut-off for Drain Fluid Amylase on Postoperative Day 1 for Predicting Clinically Relevant Fistula After Distal Pancreatectomy: A Multi-institutional Analysis and External Validation

OBJECTIVE

The aim of this study was to investigate the relationship between drain fluid amylase value on the first postoperative day (DFA1) and clinically relevant fistula (CR-POPF) after distal pancreatectomy (DP), and to identify the cut-off of DFA1 that optimizes CR-POPF prediction.

BACKGROUND

DFA1 is a well-recognized predictor of CR-POPF after pancreatoduodenectomy, but its role in DP is largely unexplored.

METHODS

DFA1 levels were correlated with CR-POPF in 2 independent multi-institutional sets of DP patients: developmental (n = 338; years 2012 to 2017) and validation cohort (n = 166; years 2006 to 2016). Cut-off choice was based on Youden index calculation, and its ability to predict CR-POPF occurrence was tested in a multivariable regression model adjusted for clinical, demographic, operative, and pathological variables.

RESULTS

In the developmental set, median DFA1 was 1745 U/L and the CR-POPF rate was 21.9%. DFA1 correlated with CR-POPF with an area under the curve of 0.737 (P < 0.001). A DFA1 of 2000 U/L had the highest Youden index, with 74.3% sensitivity and 62.1% specificity. Patients in the validation cohort displayed different demographic and operative characteristics, lower values of DFA1 (784.5 U/L, P < 0.001), and reduced CR-POPF rate (10.2%, P < 0.001). However, a DFA1 of 2000 U/L had the highest Youden index in this cohort as well, with 64.7% sensitivity and 75.8% specificity. At multivariable analysis, DFA1 ≥2000 U/L was the only factor significantly associated with CR-POPF in both cohorts.

CONCLUSION

A DFA1 of 2000 U/L optimizes CR-POPF prediction after DP. These results provide the substrate to define best practices and improve outcomes for patients receiving DP.

Early postoperative drain fluid amylase in risk-stratified patients promotes tailored post-pancreatectomy drain management and potential for accelerated discharge

BACKGROUND

First postoperative day drain fluid amylase (DFA1) <5000 U/L is commonly used for early drain removal. We manage patients with risk-stratified pancreatectomy care pathways determined preoperatively by risk for postoperative pancreatic fistula. We hypothesized that preoperative risk stratification would yield unique DFA1/DFA3 cutoffs for safe early drain removal.

METHODS

Patients with DFA1/DFA3 values after pancreaticoduodenectomy or distal pancreatectomy were identified. Patients were risk stratified as "low-risk pancreaticoduodenectomy," "high-risk pancreaticoduodenectomy," or "distal pancreatectomy." Receiver operator characteristic analyses yielded clinically relevant sensitivity thresholds for International Study Group on Pancreatic Surgery grade B/C postoperative pancreatic fistulas.

RESULTS

From October 2016 to April 2018, 174 patients were preoperatively stratified as low-risk pancreaticoduodenectomy (n = 78, 45%), high-risk pancreaticoduodenectomy (n = 51, 29%), and distal pancreatectomy (n = 45, 26%). B/C postoperative pancreatic fistulas developed in 3% (n = 2) of low-risk pancreaticoduodenectomies, 37% (n = 19) of high-risk pancreaticoduodenectomies, and 24% (n = 11) of distal pancreatectomies (low- vs high-risk pancreaticoduodenectomy P < .001, low-risk pancreaticoduodenectomy versus distal pancreatectomy P = .004, high-risk pancreaticoduodenectomy versus distal pancreatectomy P = .25). B/C postoperative pancreatic fistulas occurred in 16% (n = 21) pancreaticoduodenectomy patients (high- + low-risk pancreaticoduodenectomy), and B/C postoperative pancreatic fistulas were excluded in pancreaticoduodenectomy with 100% sensitivity if DFA1 ≤ 136 or DFA3 ≤ 93. DFA1 < 5000 excluded B/C postoperative pancreatic fistulas with only 57% sensitivity after pancreaticoduodenectomy. Exclusion of B/C postoperative pancreatic fistulas occurred with 100% sensitivity if DFA1 ≤ 661 or DFA3 ≤ 141 in low-risk pancreaticoduodenectomy patients, DFA1 ≤ 136 or DFA3 ≤ 93 in high-risk pancreaticoduodenectomy patients, and DFA1 < 49 or DFA3 < 26 in distal pancreatectomy patients.

CONCLUSION

Preoperative risk stratification results in unique DFA1/DFA3 thresholds to exclude B/C postoperative pancreatic fistulas, thus allowing for safe drain removal and potential for accelerated discharge. Rather than applying generic DFA cutoffs based on national databases, we propose institution-specific DFA1 and DFA3 values tailored to 3 replicable postoperative pancreatic fistula-risk pathways.

Predictive value of drain pancreatic amylase concentration for postoperative pancreatic fistula on postoperative day 1 after pancreatic resection: An updated meta-analysis

BACKGROUND

Postoperative pancreatic fistula (POPF) is a potentially fatal complication following pancreaticoduodenectomy. Early prediction and exclusion of POPF may be highly advantageous to enhance patient outcomes, and accelerate recovery. In this meta-analysis, we sought to assess the prediction of drain pancreatic amylase concentration on postoperative day 1 (DPA1) for POPF.

METHODS

By searching online databases up to April 2018, all researches mentioned DPA1 for detecting POPF were analyzed. STATA 12.0 was used to analyze pooled predictive parameters.

RESULTS

Seventeen studies were finally analyzed including 4676 patients in total. The pooled sensitivity and specificity of DPA1 were respectively 0.85 (95% CI: 0.71, 0.93), 0.80 (95% CI: 0.74, 0.85) to predict overall POPF, and 0.70 (95% CI: 0.53, 0.82), 0.88 (95% CI: 0.86, 0.90) to predict CR-POPF. If pretest probability was 50%, corresponding post-test (+) were respectively 81%, 86% for overall POPF and CR-POPF when DPA1 was above cutoffs, while the post-test (-) were respectively 16%, 26% when DPA1 was under cutoffs. In subgroup analysis, sensitivities of cutoff >5000 group, 1000< cutoff <5000 group, and cutoff <1000 group were respectively 0.65 (0.43-0.82), 0.82 (0.71-0.89), 0.87 (0.78-0.92); and specificities were respectively 0.88 (0.83-0.92), 0.83 (0.77-0.88), 0.71 (0.62-0.79). Positive LR was 5.5 (3.4-8.8), 4.8 (3.4-6.7), and 3.0 (2.3-4.0) respectively. Negative LR was 0.40 (0.22-0.72), 0.22 (0.13-0.37), and 0.19 (0.11-0.32) respectively.

CONCLUSION

DPA1, which has good sensitivity and specificity, is useful for predicting overall POPF and CR-POPF, according to the present studies. Meanwhile, it should be cautious to apply because there is a wide range in cutoffs between different studies.

The Combination of Pancreas Texture and Postoperative Serum Amylase in Predicting Pancreatic Fistula Risk

Postoperative pancreatic fistula (PF) remains one of the most significant complications after pancreaticoduodenectomy (PD). Recently, studies have suggested that post-PD serum hyper-amylasemia (HA) may be a risk factor. In this study, we evaluate the relationship of pancreas texture and post-operative serum amylase levels in determining PF risk. This retrospective cohort study evaluated all patients who underwent PD at Thomas Jefferson University from 2009 to 2014. The highest postoperative serum amylase level from postoperative day (POD) 0 to POD 5 was obtained. Chi-square analyses and odds ratio (OR) evaluated the relationship between pancreas texture, serum amylase level, and the development of PF. Data from 524 consecutive patients were analyzed. Serum amylase threshold value of 165 IU/L yielded greatest accuracy from the receiver operating characteristic curve analysis (Sensitivity, 0.70; specificity, 0.72). Grade B or C PF were more common among HA patients (20 vs 3%; P < 0.001). HA was associated with increased rates of PD-associated complications. On multivariable analysis, early postoperative serum HA was more predictive of PF risk (OR, 4.87; P < 0.001) than either pancreatic duct size ≤3 mm (OR, 2.97; P = 0.01) or pancreas texture (OR,1.87; P = 0.05). Conclusion: The presence of HA on POD 0 or POD 1 is more predictive than soft pancreas texture or small pancreas duct size alone.

Sequential drain amylase to guide drain removal following pancreatectomy

BACKGROUND

Although used as criterion for early drain removal, postoperative day (POD) 1 drain fluid amylase (DFA) ≤ 5000 U/L has low negative predictive value for clinically relevant postoperative pancreatic fistula (CR-POPF). It was hypothesized that POD3 DFA ≤ 350 could provide further information to guide early drain removal.

METHODS

Data from a pancreas surgery consortium database for pancreatoduodenectomy and distal pancreatectomy patients were analyzed retrospectively. Those patients without drains or POD 1 and 3 DFA data were excluded. Patients with POD1 DFA ≤ 5000 were divided into groups based on POD3 DFA: Group A (≤350) and Group B (>350). Operative characteristics and 60-day outcomes were compared using chi-square test.

RESULTS

Among 687 patients in the database, all data were available for 380. Fifty-five (14.5%) had a POD1 DFA > 5000. Among 325 with POD1 DFA ≤ 5000, 254 (78.2%) were in Group A and 71 (21.8%) in Group B. Complications (35 (49.3%) vs 87 (34.4%); p = 0.021) and CR-POPF (13 (18.3%) vs 10 (3.9%); p < 0.001) were more frequent in Group B.

CONCLUSIONS

In patients with POD1 DFA ≤ 5000, POD3 DFA ≤ 350 may be a practical test to guide safe early drain removal. Further prospective testing may be useful.

What are the predictors that can help identify safe removal of drains following pancreatectomy?

BACKGROUND

The management of a drain after Pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) remains a controversial issue. Our aim in this study was to identify a safe time for drain removal.

STUDY DESIGN

This is a retrospective study, of a prospective database, of patients who underwent a PD or DP at two tertiary care institutions.

RESULTS

A total of 180 patients underwent PD and DP during the observation period. Seventeen patients developed fistulas (9.4%), with 70.6% (n = 12) developing in soft pancreatic remnants vs. 29.4% (n = 5) in firm pancreatic remnants. Patients with amylase levels greater than 173 U/L on a postoperative day three were 11.46 times more likely to form a fistula compared to those with an amylase level at or below 173 U/L (p < .001).

CONCLUSION

Fistula formation is associated with pancreas texture, duct size, and drain amylase following PD or DP. Patients with firm pancreatic texture and large ducts are less likely to develop fistulas than those with soft pancreatic texture and small ducts.

Multicenter, Prospective Trial of Selective Drain Management for Pancreatoduodenectomy Using Risk Stratification

OBJECTIVE

This multicenter study sought to prospectively evaluate a drain management protocol for pancreatoduodenectomy (PD).

BACKGROUND

Recent evidence suggests value for both selective drain placement and early drain removal for PD. Both strategies have been associated with reduced rates of clinically relevant pancreatic fistula (CR-POPF)-the most common and morbid complication after PD.

METHODS

The protocol was applied to 260 consecutive PDs performed at two institutions over 17 months. Risk for ISGPF CR-POPF was determined intraoperatively using the Fistula Risk Score (FRS); drains were omitted in negligible/low risk patients and drain fluid amylase (DFA) was measured on postoperative day 1 (POD 1) for moderate/high risk patients. Drains were removed early (POD 3) in patients with POD 1 DFA ≤5,000 U/L, whereas patients with POD 1 DFA >5,000 U/L were managed by clinical discretion. Outcomes were compared with a historical cohort (N = 557; 2011-2014).

RESULTS

Fistula risk did not differ between cohorts (median FRS: 4 vs 4; P = 0.933). No CR-POPFs developed in the 70 (26.9%) negligible/low risk patients. Overall CR-POPF rates were significantly lower after protocol implementation (11.2 vs 20.6%, P = 0.001). The protocol cohort also demonstrated lower rates of severe complication, any complication, reoperation, and percutaneous drainage (all P < 0.05). These patients also experienced reduced hospital stay (median: 8 days vs 9 days, P = 0.001). There were no differences between cohorts in the frequency of bile or chyle leaks.

CONCLUSIONS

Drains can be safely omitted for one-quarter of PDs. Drain amylase analysis identifies which moderate/high risk patients benefit from early drain removal. This data-driven, risk-stratified approach significantly decreases the occurrence of clinically relevant pancreatic fistula.

Bottleneck in secretion of α-amylase in Bacillus subtilis

Amylase plays an important role in biotechnology industries, and Gram-positive bacterium Bacillus subtilis is a major host to produce heterogeneous α-amylases. However, the secretion stress limits the high yield of α-amylase in B. subtilis although huge efforts have been made to address this secretion bottleneck. In this question-oriented review, every effort is made to answer the following questions, which look simple but are long-standing, through reviewing of literature: (1) Does α-amylase need a specific and dedicated chaperone? (2) What signal sequence does CsaA recognize? (3) Does CsaA require ATP for its operation? (4) Does an unfolded α-amylase is less soluble than a folded one? (5) Does α-amylase aggregate before transporting through Sec secretion system? (6) Is α-amylase sufficient stable to prevent itself from misfolding? (7) Does α-amylase need more disulfide bonds to be stabilized? (8) Which secretion system does PrsA pass through? (9) Is PrsA ATP-dependent? (10) Is PrsA reused after folding of α-amylase? (11) What is the fate of PrsA? (12) Is trigger factor (TF) ATP-dependent? The literature review suggests that not only the most of those questions are still open to answers but also it is necessary to calculate ATP budget in order to better understand how B. subtilis uses its energy for production and secretion.

Early Postoperative Prediction of Clinically Relevant Pancreatic Fistula after Pancreaticoduodenectomy: usefulness of C-reactive Protein

BACKGROUND

An early recognition of clinically relevant pancreatic fistula (PF) after pancreaticoduodenectomy (PD) is essential.

METHODS

All consecutive patients who underwent PD in two institutions were included (2013-2015). In all patients amylase value in drains (AVD) was evaluated in postoperative day 1 (POD1). White-blood cell count (WBC), serum pancreatic amylase (SPA) and C-reactive protein (CRP) were routinely evaluated in POD1, POD2, and POD3. Receiver operator characteristic (ROC) curves were performed. Significant diagnostic cut-offs were tested in a multivariate model.

RESULTS

Overall, 463 patients underwent PD. Postoperative morbidity and mortality were 58% and 4%, respectively. Sixty-four patients (14%) had a clinically relevant PF (grade B or C). ROC curve analyses revealed that AVD on POD1 had the greatest area under the curve value (0.881, P < 0.0001) followed by CRP on POD3 (0.796, P < 0.0001). Multivariable analysis identified male gender (OR 2.29 95%CI: 1.12-4.70, P = 0.023), AVD on POD1>500 U/l (OR 21.72, 95%CI: 7.41-63.67, P < 0.0001), CRP on POD2 > 150 mg/l (OR 3.480, 95%CI: 1.21-9.99, P = 0.021), and CRP on POD3 > 185 mg/l (OR 6.738, 95%CI: 1.91-23.78, P = 0.003) as independent predictors of clinically relevant PF.

CONCLUSION

The combination of CRP and AVD was effective in the early prediction of clinically relevant POPF after PD.

Amylase in drain fluid for the diagnosis of pancreatic leak in post-pancreatic resection

BACKGROUND

The treatment of people with clinically significant postoperative pancreatic leaks is different from those without clinically significant pancreatic leaks. It is important to know the diagnostic accuracy of drain fluid amylase as a triage test for the detection of clinically significant pancreatic leaks, so that an informed decision can be made as to whether the patient with a suspected pancreatic leak needs further investigations and treatment. There is currently no systematic review of the diagnostic test accuracy of drain fluid amylase for the diagnosis of clinically relevant pancreatic leak.

OBJECTIVES

To determine the diagnostic accuracy of amylase in drain fluid at 48 hours or more for the diagnosis of pancreatic leak in people who had undergone pancreatic resection.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index Expanded, and the National Institute for Health Research Health Technology Assessment (NIHR HTA) websites up to 20 February 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase.

SELECTION CRITERIA

We included all studies that evaluated the diagnostic test accuracy of amylase in the drain fluid at 48 hours or more for the diagnosis of pancreatic leak in people who had undergone pancreatic resection excluding total pancreatectomy. We planned to exclude case-control studies because these studies are prone to bias, but did not find any. At least two authors independently searched and screened the references produced by the search to identify relevant studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included studies. The included studies reported drain fluid amylase on different postoperative days and measured at different cut-off levels, so it was not possible to perform a meta-analysis using the bivariate model as planned. We have reported the sensitivity, specificity, post-test probability of a positive and negative drain fluid amylase along with 95% confidence interval (CI) on each of the different postoperative days and measured at different cut-off levels.

MAIN RESULTS

A total of five studies including 868 participants met the inclusion criteria for this review. The five studies included in this review reported the value of drain fluid amylase at different thresholds and different postoperative days. The sensitivities and specificities were variable; the sensitivities ranged between 0.72 and 1.00 while the specificities ranged between 0.73 and 0.99 for different thresholds on different postoperative days. At the median prevalence (pre-test probability) of 15.9%, the post-test probabilities for pancreatic leak ranged between 35.9% and 95.4% for a positive drain fluid amylase test and ranged between 0% and 5.5% for a negative drain fluid amylase test.None of the studies used the reference standard of confirmation by surgery or by a combination of surgery and clinical follow-up, but used the International Study Group on Pancreatic Fistula (ISGPF) grade B and C as the reference standard. The overall methodological quality was unclear or high in all the studies.

AUTHORS' CONCLUSIONS

Because of the paucity of data and methodological deficiencies in the studies, we are uncertain whether drain fluid amylase should be used as a method for testing for pancreatic leak in an unselected population after pancreatic resection; and we judge that the optimal cut-off of drain fluid amylase for making the diagnosis of pancreatic leak is also not clear. Further well-designed diagnostic test accuracy studies with pre-specified index test threshold of drain fluid amylase (at three times more on postoperative day 5 or another suitable pre-specified threshold), appropriate follow-up (for at least six to eight weeks to ensure that there are no pancreatic leaks), and clearly defined reference standards (of surgical, clinical, and radiological confirmation of pancreatic leak) are important to reliably determine the diagnostic accuracy of drain fluid amylase in the diagnosis of pancreatic leak.

Risk factors and preventive strategies for post-operative pancreatic fistula after pancreatic surgery: a comprehensive review

BACKGROUND

Pancreas surgery has developed into a fairly safe procedure in terms of mortality, but is still hampered by considerable morbidity. Among the most frequent and dreaded complications are the development of a post-operative pancreatic fistula (POPF). The prediction and prevention of POPF remains an area of debate with several questions yet to be firmly addressed with solid answers.

METHODS

A systematic review of systematic reviews/meta-analyses and randomized trials in the English literature (PubMed/MEDLINE, Cochrane library, EMBASE) covering January 2005 to December 2015 on risk factors and preventive strategies for POPF.

RESULTS

A total of 49 systematic reviews and meta-analyses over the past decade discussed patient, surgeon, pancreatic disease and intraoperative related factors of POPF. Non-modifiable factors (age, BMI, comorbidity) and pathology (histotype, gland texture, duct size) that indicates surgery are associated with POPF risk. Consideration of anastomotic technique and use of somatostatin-analogs may slightly modify the risk of fistula. Sealant products appear to have no effect. Perioperative bleeding and transfusion enhance risk, but is modifiable by focus on technique and training. Drains may not prevent fistulae, but may help in early detection. Early drain-amylase may aid in detection. Predictive scores lack uniform validation, but may have a role in patient information if reliable pre-operative risk factors can be obtained.

CONCLUSIONS

Development of POPF occurs through several demonstrated risk factors. Anastomotic technique and use of somatostatin-analogs may slightly decrease risk. Drains may aid in early detection of leaks, but do not prevent POPF.

Förster Resonance Energy Transfer-Based Self-Assembled Nanoprobe for Rapid and Sensitive Detection of Postoperative Pancreatic Fistula

Postoperative pancreatic fistula (POPF) is the most serious and challenging complication following gastroenterological surgery. Activated pancreatic juice leaking from the organ remnant contains proteases that attack the surrounding tissue, potentially leading to severe inflammation, tissue necrosis, and fistula formation. However, it is difficult to observe pancreatic leakage during surgery and to evaluate the protease activity of leaked fluid at the patient's bedside. This report describes a protein nanocage-based protease ratiometric sensor comprising a pancreatic protease-sensitive small heat-shock protein (HSP) 16.5, which is a naturally occurring protein in Methanococcus jannaschii that forms a spherical structure by self-assembly of 24 subunits, and a chemically conjugated donor-acceptor dye pair for Förster resonance energy transfer (FRET). The HSP-FRET probe was constructed by subunit exchange of each dye-labeled engineered HSP, resulting in a spherical nanocage of approximately 10 nm in diameter, which exhibited very high stability against degradation in blood plasma and no remarkable toxicity in mice. The efficiency of FRET was found to depend on both the dye orientation and the acceptor/donor ratio. Pancreatic proteases, including trypsin, α-chymotrypsin, and elastase, were quantitatively analyzed by fluorescence recovery with high specificity using the HSP-FRET nanoprobe. Furthermore, the HSP-FRET nanoprobe was sufficiently sensitive to detect POPF in the pancreatic juice of patients using only the naked eye within 10 min. Thus, this novel nanoprobe is proposed as an effective and convenient tool for the detection of POPF and the visualization of activated pancreatic juice during gastroenterological surgery.

Systematic Review and Meta-Analysis of Pancreatic Amylase Value on Postoperative Day 1 After Pancreatic Resection to Predict Postoperative Pancreatic Fistula

Early detection of postoperative pancreatic fistula (POPF) may help to improve the outcome following pancreatic surgery, and exclusion of POPF may allow early drain removal which can accelerate recovery. The aim of this study was to evaluate the diagnostic accuracy of drain/plasma pancreatic amylase values on postoperative day 1 (DPA1/PPA1) in POPF by means of a systemic review and meta-analysis.Online journal databases and a manual search up to March 2015 were used. Studies clearly documenting DPA1 or PPA1 in predicting overall POPF (Grade 0 vs A+B+C) or clinically relevant POPF (Grade 0+A vs B+C) following pancreatic surgery were selected. Pooled predictive parameters were performed using STATA 12.0.Fifteen studies were finally identified with a total of 4331 patients. The pooled sensitivity and specificity of DPA1 were 0.92 (95% confidence interval (CI) 0.81-0.96) and 0.77 (95% CI 0.64-0.86) for predicting overall POPF and 0.79 (95% CI 0.61-0.90) and 0.83 (95% CI 0.74-0.89) for predicting clinically relevant POPF. The pooled sensitivity and specificity of PPA1 were 0.74 (95% CI 0.63-0.82) and 0.62 (95% CI 0.55-0.70) for overall POPF. After the DPA1 at/over cutoff values for overall POPF or clinically relevant POPF, corresponding post-test probability (Post-test (+)) (if pretest probability was 50%) was 80% and 82% respectively, while, if values were below the cutoff values, the post-test probability (Post-test (-)) was 10% and 20% respectively. Post-test (+) and Post-test (-) of PPA1 for overall POPF were 66% and 30% respectively. In subgroup analysis, the summary sensitivities of cutoff <1000 group and cutoff >1000 group were 0.96 (0.92-0.98) and 0.85 (0.64-0.95), respectively; the summary specificities were 0.59 (0.44-0.72) and 0.86 (0.80-0.91) respectively. Positive LR were 2.3 (1.7-3.3) and 6.2 (3.7-10.2) respectively. Negative LR were 0.06 (0.03-0.14) and 0.18 (0.07-0.47) respectively.DPA1 is a useful predictive test for overall POPF and clinically relevant POPF which has good sensitivity and specificity based on the current studies. Meanwhile, it should be cautiously applied to clinical practice because cutoffs had a wide range between studies.

Meta-analysis of drain amylase content on postoperative day 1 as a predictor of pancreatic fistula following pancreatic resection

Background

Drain amylase content in the days immediately after major pancreatic resection has been investigated previously as a predictor of postoperative pancreatic fistula (POPF). Its accuracy, however, has not been determined conclusively. The purpose of this study was to evaluate the accuracy of drain amylase content on the first day after major pancreatic resection in predicting the occurrence of POPF.

Methods

A literature search of the MEDLINE, Embase and Scopus® databases to 13 May 2015 was performed to identify studies evaluating the accuracy of drain amylase values on day 1 after surgery in predicting the occurrence of POPF. The area under the hierarchical summary receiver operating characteristic (ROC) curve (AUChSROC) was calculated as an index of accuracy, and pooled estimates of accuracy indices (sensitivity and specificity) were calculated at different cut-off levels. Subgroup and meta-regression analyses were performed to test the robustness of the results.

Results

Thirteen studies involving 4416 patients were included. The AUChSROC was 0·89 (95 per cent c.i. 0·86 to 0·92) for clinically significant POPF and 0·88 (0·85 to 0·90) for POPF of any grade. Pooled estimates of sensitivity and specificity were calculated for the different cut-offs: 90–100 units/l (0·96 and 0·54 respectively), 350 units/l (0·91 and 0·84) and 5000 units/l (0·59 and 0·91). Accuracy was independent of the type of operation, type of anastomosis performed and octreotide administration.

Conclusion

Evaluation of drain amylase content on the first day after surgery is highly accurate in predicting POPF following major pancreatic resection. It may allow early drain removal and institution of an enhanced recovery pathway.

Analysis on evolutionary relationship of amylases from archaea, bacteria and eukaryota

Amylase is one of the earliest characterized enzymes and has many applications in clinical and industrial settings. In biotechnological industries, the amylase activity is enhanced through modifying amylase structure and through cloning and expressing targeted amylases in different species. It is important to understand how engineered amylases can survive from generation to generation. This study used phylogenetic and statistical approaches to explore general patterns of amylases evolution, including 3118 α-amylases and 280 β-amylases from archaea, eukaryota and bacteria with fully documented taxonomic lineage. First, the phylogenetic tree was created to analyze the evolution of amylases with focus on individual amylases used in biofuel industry. Second, the average pairwise p-distance was computed for each kingdom, phylum, class, order, family and genus, and its diversity implies multi-time and multi-clan evolution. Finally, the variance was further partitioned into inter-clan variance and intra-clan variance for each taxonomic group, and they represent horizontal and vertical gene transfer. Theoretically, the results show a full picture on the evolution of amylases in manners of vertical and horizontal gene transfer, and multi-time and multi-clan evolution as well. Practically, this study provides the information on the surviving chance of desired amylase in a given taxonomic group, which may potentially enhance the successful rate of cloning and expression of amylase gene in different species.

Postoperative drain amylase predicts pancreatic fistula in pancreatic surgery: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

This study to evaluate the utility of drain fluid amylase as a predictor of PF in patients undergoing pancreatic surgery based on the International Study Group of Pancreatic Fistula definitions of pancreatic fistula.

METHODS

A comprehensive search was carried out using Pubmed (Medline), Embase, Web of science and Cochrane database for clinical trials, which studied DFA as a diagnostic marker for pancreatic fistula after pancreatic surgery. Sensitivity, specificity and the diagnostic odds ratios with 95% confidence interval were calculated for each study. Summary receiver-operating curves were conducted and the area under the curve was evaluated.

RESULTS

A total of 10 studies were included. The pooled sensitivity and specificity of drain fluid amylase Day 1 for the diagnosis of postoperative pancreatic fistula were 81% and 87%, respectively (area under the curve was 0.897, diagnostic odds ratios was 16.83 and 95%CI was 12.66-22.36), the pooled sensitivity and specificity of drain fluid amylase Day 3 for the diagnosis of postoperative pancreatic fistula were 56% and 79%, respectively (area under the curve was 0.668, diagnostic odds ratios was 3.26 and 95%CI was 1.83-5.82) CONCLUSIONS: The drain fluid amylase Day 1, instead of drain fluid amylase Day 3, may be a useful criterion for the early identification of postoperative pancreatic fistula, and a value of drain fluid amylase Day 1 over than 1300 U/L was a risk factor of pancreatic fistula. And the diagnostic accuracy and the proposed cut-off levels of drain fluid amylase Day 1 in predicting the postoperative pancreatic fistula will have to be validated by multicenter prospective studies.