Can the measurement of amylase in drain after distal pancreatectomy predict post-operative pancreatic fistula?

Novel Calculator to Estimate the Risk of Clinically Relevant Postoperative Pancreatic Fistula Following Distal Pancreatectomy

BACKGROUND

Drain management algorithms are based on studies that predict clinically relevant postoperative pancreatic fistula (CR-POPF) using drain fluid amylase level on POD1 (DFA1). These studies are focused on pancreaticoduodenectomy which is inherently different than distal pancreatectomy. Moreover, the change of DFA between POD1 and POD3 (ΔDFA) is underutilized despite its importance in predicting CR-POPF. We sought to generate a calculator that estimates the risk of CR-POPF following distal pancreatectomy.

METHODS

The 2014-2018 pancreas-targeted ACS-NSQIP database was used to identify patients who underwent elective distal pancreatectomy. Models to predict CR-POPF were constructed using DFA1 with/without ΔDFA. The fittest model was used to construct a calculator.

RESULTS

Out of 12,042 distal pancreatectomies, 692 patients met the study's inclusion criteria. The risk of CR-POPF was 15.9% in the included cohort versus 14.8% in the excluded one (P = 0.421). The predictors of the CR-POPF were age, operative time, DFA1, and ΔDFA. Adding ΔDFA decreased the Akaike's information criterion of the model (507.7 vs 544.7)-indicating a significantly better model fit-and improved the cross-validated area under the curve from 0.731 to 0.791. An easy-to-use calculator was created for surgeons to estimate the risk of CR-POPF based on the abovementioned variables. A sensitivity/specificity table was created at various cutoffs to direct clinical decision-making with respect to early drain removal.

CONCLUSIONS

This study highlights the importance of ΔDFA, in addition to DFA1, in predicting CR-POPF. The provided calculator will facilitate predicting CR-POPF and postoperative drain management following distal pancreatectomy.

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.

Predictive value of abdominal drain amylase for postoperative pancreatic fistula following gastric resection: A systematic review and meta-analysis

BACKGROUND

Radical dissection of lymph nodes, accompanying gastric cancer resection, can lead to collateral damage to the pancreas and development of postoperative pancreatic fistula (POPF).

METHODS

We searched the Cochrane Library, MEDLINE, Embase, and Web of Science up to April 21, 2020, to identify studies documenting the value of abdominal drain amylase level (d-AMY) on postoperative day 1 (POD1) as a predictor of POPF after gastric surgery. The quality of selected studies was assessed using the QUADAS-2 tool. The diagnostic value of d-AMY on POD1 for prediction of POPF was first assessed by calculation of pooled estimates of sensitivity, specificity, likelihood ratios (LR), and the diagnostic odds ratio (DOR). Secondly, the accuracy was further demonstrated graphically with the hierarchical summary receiver operating curve (hSROC). PROSPERO registration number: CRD42020181145.

RESULTS

DOR of nine studies (cases n = 1856) observing the occurrence of POPF after measurement of d-AMY on POD1 was 18.7 (95%CI: 10.0, 34.8), and the area under hSROC was 0.88 ± 0.02. The pooled sensitivity was 0.74 (95%CI: 0.66, 0.81) and specificity 0.84 (95%CI: 0.82, 0.86). The negative LR was at the lowest point of 0.16 (95%CI: 0.07, 0.37) at the cutoff value for d-AMY of 941 IU/L, while the positive LR ranged from 4.4 (cutoff 2119 IU/L) to 6.2 (cutoff 5000 IU/L).

CONCLUSION

d-AMY on POD1 can be used as an accurate and non-invasive predictor of POPF in the earliest stage of postoperative course following gastric cancer resection; value ≤ 941 IU/L warrants early drain removal and low probability of POPF (any grade).

Standardization of early drain removal following pancreatic resection: proposal of the "Ottawa pancreatic drain algorithm"

Background

Early drain removal after pancreatic resection is encouraged for individuals with low postoperative day 1 drain amylase levels (POD1 DA) to mitigate associated morbidity. Although various protocols for drain management have been published, there is a need to assess the implementation of a standardized protocol.

Methods

The Ottawa pancreatic drain algorithm (OPDA), based on POD1 DA and effluent volume, was developed and implemented at our institution. A retrospective cohort analysis was conducted of all patients undergoing pancreatic resection January 1, 2016-October 30, 2017, excluding November and December 2016 (one month before and after OPDA implementation).

Results

42 patients pre-implementation and 53 patients post-implementation were included in the analysis. The median day of drain removal was significantly reduced after implementation of the OPDA (8 vs. 5 days; p = 0.01). Early drain removal appeared safe with no difference in reoperation or readmission rate after protocol implementation (p = 0.39; p = 0.76). On subgroup analysis, median length of stay was significantly shorter following OPDA implementation for patients who underwent DP and did not develop a postoperative pancreatic fistula (POPF) (6 vs 10 days, p = 0.03). Although the incidence of both surgical site infection and POPF were reduced following the intervention, neither reached statistical significance (38.1 to 28.3%, p = 0.31; and 38.1 to 28.3%, p = 0.31 respectively).

Conclusions

Implementing the OPDA was associated with earlier drain removal and decreased length of stay in patients undergoing distal pancreatectomy who did not develop POPF, without increased morbidity. Standardizing drain removal may help facilitate early drain removal after pancreatic resection at other institutions.

The Clinical Implications of Peripancreatic Fluid Collection After Distal Pancreatectomy

OBJECTIVES

Pancreatic fistula after distal pancreatectomy (DP) remains an unsolved problem, and postoperative CT imaging often demonstrates fluid collection (FC) around the pancreatic remnant. This study sought to clarify the clinical implications of FC.

METHODS

This study enrolled 146 patients who underwent DP. FC was defined as a cyst-like lesion ≥ 10 mm in diameter on CT imaging at postoperative day (POD) 7. FC size, irregularity of FC margin, and air bubbles in FC were investigated. In addition, clinical data were retrospectively collected, and useful predictive factors for postoperative pancreatic fistula (POPF) were analyzed.

RESULTS

Clinically relevant POPF was observed in 26 patients (17.8%), and FC was detected in 136 patients (94.4%). Multivariate analysis identified FC size and drain amylase levels on POD3 as significant risk factors for POPF. Cutoff values were determined by ROC analyses, and the levels of the FC size and drain amylase on POD3 were determined as 41 mm and 1026 IU/L, respectively. The sensitivity and specificity of FC diameters > 41 mm were 76.9% and 75.0%, respectively, while those of drain amylase levels > 1026 IU on POD3 were 73.1% and 75.8%, respectively.

CONCLUSIONS

While treating some FCs after DP was necessary for the management of POPF, others did not require any intervention since most of them spontaneously disappeared. FC size and drain amylase levels on POD3 were found to be significantly associated with POPF and could potentially help to determine appropriate treatment.

Utility of drain fluid amylase measurement on the first postoperative day after distal pancreatectomy

BACKGROUND

Early exclusion of a postoperative pancreatic fistula (POPF) may facilitate earlier drain removal in selected patients after distal pancreatectomy. The purpose of this study was to evaluate the role of first postoperative day drain fluid amylase (DFA1) measurement to predict POPF.

METHODS

Patients in whom DFA1 was measured after distal pancreatectomy were identified from a prospectively maintained database over a five-year period. A cut-off value of DFA1 was derived using ROC analysis, which yielded sensitivity and negative predictive value of 100% for excluding POPF.

RESULTS

DFA1 was available in 53 of 138 (38%) patients who underwent distal pancreatectomy. 19 of 53 patients (36%) developed a pancreatic fistula (Grade A - 15, Grade B - 3, Grade C - 1). Median DFA1 was significantly higher in those who developed a pancreatic fistula (5473; range 613-28,450) compared those without (802; range 57-2350). p < 0.0001. Using ROC analysis, a DFA1 less than 600 excluded pancreatic fistula with a sensitivity of 100% (AUROC of 0.91; SE = 0.04, p < 0.001).

CONCLUSION

First postoperative day drain fluid amylase measurement may have a role in excluding pancreatic fistula after distal pancreatectomy. Such patients may be suitable for earlier drain removal.

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.