Novel classification system for walled-off necrosis: a step toward standardized nomenclature and risk-stratification framework

Application of deep learning models for accurate classification of fluid collections in acute necrotizing pancreatitis on computed tomography: a multicenter study

PURPOSE

To apply CT-based deep learning (DL) models for accurate solid debris-based classification of pancreatic fluid collections (PFC) in acute pancreatitis (AP).

MATERIAL AND METHODS

This retrospective study comprised four tertiary care hospitals. Consecutive patients with AP and PFCs who had computed tomography (CT) prior to drainage were screened. Those who had magnetic resonance imaging (MRI) or endoscopic ultrasound (EUS) within 20 days of CT were considered for inclusion. Axial CT images were utilized for model training. Images were labelled as those with≤30% solid debris and >30% solid debris based on MRI or EUS. Single center data was used for model training and validation. Data from other three centers comprised the held out external test cohort. We experimented with ResNet 50, Vision transformer (ViT), and MedViT architectures.

RESULTS

Overall, we recruited 152 patients (129 training/validation and 23 testing). There were 1334, 334 and 512 images in the training, validation, and test cohorts, respectively. In the overall training and validation cohorts, ViT and MedVit models had high diagnostic performance (sensitivity 92.4-98.7%, specificity 89.7-98.4%, and AUC 0.908-0.980). The sensitivity (85.3-98.6%), specificity (69.4-99.4%), and AUC (0.779-0.984) of all the models was high in all the subgroups in the training and validation cohorts. In the overall external test cohort, MedViT had the best diagnostic performance (sensitivity 75.2%, specificity 75.3%, and AUC 0.753). MedVit had sensitivity, specificity, and AUC of 75.2%, 74.3%, and 0.748, in walled off necrosis and 79%, 74.2%, 75.3%, and 0.767 for collections >5 cm.

CONCLUSION

DL-models have moderate diagnostic performance for solid-debris based classification of WON and collections greater than 5 cm on CT.

The role of MRCP for preventing pancreatic fluid collection recurrence after EUS-guided drainage of walled-off necrosis

BACKGROUND AND AIMS

Pancreatic fluid collections (PFCs) may recur after initial successful endoscopic drainage of walled-off necrosis (WON), most commonly due to disconnected pancreatic duct syndrome (DPDS). The primary aim of this study was to assess the role of MRCP for identifying DPDS to guide appropriate management and prevent PFC recurrence.

METHODS

Patients with WON undergoing lumen-apposing metal stent drainage of a PFC were retrospectively identified and categorized as those with MRCP versus those without MRCP before removal of transmural stents. Data on patient demographic characteristics, procedural details, cross-sectional imaging, and recurrence rates were collected through chart review.

RESULTS

A total of 121 patients with WON were identified, of whom 44 (36.4%) had an MRCP before transmural stent removal. In patients without MRCP, 13 (16.8%) of 77 had PFC recurrence versus 0 of 44 (0%; P = .003) in those with MRCP. MRCP identified DPDS in 12 (27.2%) patients, all of whom were managed with indefinite drainage with double-pigtail plastic stents without recurrence. In the group without MRCP, PFCs recurred at a median interval of 284 days (interquartile range, 182-618 days) after transmural stent removal. Among the 13 patients with PFC recurrence, 11 (85%) had undiagnosed DPDS detected on subsequent imaging, of whom 9 were subsequently managed with indefinite double-pigtail plastic stents, with no further PFC recurrence.

CONCLUSIONS

Patients with WON who underwent MRCP before transmural stent removal had a lower rate of PFC recurrence largely due to the identification of DPDS with appropriate endoscopic management.

Controversies in endoscopic ultrasonography-guided management of walled-off necrosis

Walled-off necrosis (WON) develops as local complications after acute necrotizing pancreatitis. Although less invasive interventions such as endoscopic ultrasonography (EUS)-guided drainage and endoscopic necrosectomy are selected over surgical interventions, delayed and step-up interventions are still preferred to avoid procedure-related adverse events. However, there is a controversy about the appropriate timing of drainage and subsequent necrosectomy. The advent of large-caliber lumen-apposing metal stents has also brought about potential advantages of proactive interventions, which still needs investigation in future trials. When step-up interventions of necrosectomy and additional drainage are necessary, a structured or protocoled approach for WON has been reported to improve safety and effectiveness of endoscopic and/or percutaneous treatment, but has not been standardized yet. Finally, long-term outcomes such as recurrence of WON, pancreatic endocrine, and exocrine function are increasingly investigated in association with disconnected pancreatic duct syndrome. In this review we discuss current evidence and controversy on EUS-guided management of WON.

Practical approach to acute pancreatitis: from diagnosis to the management of complications

The purpose of this review is to provide a practical guide for the clinical care of patients with acute pancreatitis (AP) from the management of the early phases of disease to the treatment of local complications. AP is one of the most frequent causes of gastroenterological admission in emergency departments. It is characterized by a dynamic and unpredictable course and in its most severe forms, is associated with organ dysfunction and/or local complications, requiring intensive care with significant morbidity and mortality. Initial therapy includes adequate fluid resuscitation, nutrition, analgesia, and when necessary critical care support. In recent years, the development of minimally invasive tailored treatments for local complications, such as endoscopic drainage, has improved patients' acceptance and outcomes. Despite this, the management of AP remains a challenge for clinicians. The present review was conducted by the authors, who formulated specific questions addressing the most critical and current aspects of the clinical course of AP with the aim of providing key messages.

Does the site, size, and number of necrotic collections affect the outcome of necrotizing pancreatitis? - a prospective analysis

PURPOSE

In patients with acute necrotizing pancreatitis (ANP), the site, size, and the number of acute necrotic collections (ANC) may determine the outcome of patients. The current study aimed to correlate the nature of ANC with the adverse outcomes in ANP patients.

METHODS

This was a single-center, prospective study (August 2019-August 2022) recruiting patients with ANP, correlating the site, size, and number of ANC with the length of hospital stay, intensive care unit (ICU) stays, development of organ failure and infection, need for intervention, and mortality.

RESULTS

A total of 114 patients (mean age: 37.3 ± 13.4 years, 85.1% males) with ANP were included in the study. The number and maximum diameter of collections significantly correlated with the length of the hospital and ICU stay and the need for intervention. Taking a cut-off size of 8 cm, the sensitivity and specificity for predicting the need for intervention were 82.7% and 74.2%, respectively. ANCs located in the perinephric, paracolic, subhepatic, and epigastric regions had a significant correlation with two or more adverse outcomes. Additional points were added to the modified CT severity index (mCTSI) based on the present study's findings. The new score had significantly higher AUROC than mCTSI for predicting infection, need for intervention, ICU stay > 1 week, and mortality.

CONCLUSION

The site, size, and number of EPNs have a significant correlation with adverse clinical outcomes in patients with ANP. The inclusion of these parameters, along with present scoring systems, will help further improve the prognostication of patients.

Effect of the Step-Jump Approach in Infected Pancreatic Necrosis: A Propensity Score-Matched Study

Purpose

The effects of the step-jump approach on the survival and prognosis of infected pancreatic necrosis (IPN) patients have not yet been determined.

Patients and Methods

Between November 2018 and June 2023, 188 patients were included in this study. There were 144 patients in the step-up group (the SU group) and 44 in the step-jump group (the SJ group). In the SU group, patients successfully treated with percutaneous catheter drainage (PCD) alone were classified into the SU-1 group (n=101), while those requiring additional surgery after PCD were categorized into the SU-2 group (n=43). In the SJ group, patients who underwent minimally invasive necrosectomy (MIN) without PCD were assigned to the SJ-1 group (n=34), whereas those who initially underwent PCD followed by immediate open surgery were placed in the SJ-2 group (n=10). Propensity score matching (PSM) was used to mitigate bias.

Results

After PSM, a total of 34 pairs were successfully matched. A comparison of the SU group with the SJ-1 group (upfront MIN without PCD) revealed similar mortality rates (P=0.239); however, the incidences of multiple drug-resistant organisms (MDROs) (P=0.029) and surgical complications (P<0.001) were significantly lower in the SJ-1 group. After comparing the SU-2 and SJ-2 groups (patients who underwent direct open necrosectomy without MIN after PCD failure), the incidences of surgical complications and MDRO in the SJ-2 group were significantly lower (P<0.05).

Conclusion

Compared with the step-up approach, the step-jump approach is safer and more effective and can significantly reduce the incidence of MDRO and surgical complications.

WONDER-02: plastic stent vs. lumen-apposing metal stent for endoscopic ultrasound-guided drainage of pancreatic pseudocysts-study protocol for a multicentre randomised non-inferiority trial

BACKGROUND

Endoscopic ultrasound (EUS)-guided transluminal drainage has become a first-line treatment modality for symptomatic pancreatic pseudocysts. Despite the increasing popularity of lumen-apposing metal stents (LAMSs), plastic stents may resolve non-necrotic fluid collections effectively with lower costs and no LAMS-specific adverse events. To date, there has been a paucity of data on the appropriate stent type in this setting. This trial aims to assess the non-inferiority of plastic stents to a LAMS for the initial EUS-guided drainage of pseudocysts.

METHODS

The WONDER-02 trial is a multicentre, open-label, non-inferiority, randomised controlled trial, which will enrol pancreatic pseudocyst patients requiring EUS-guided treatment in 26 centres in Japan. This trial plans to enrol 80 patients who will be randomised at a 1:1 ratio to receive either plastic stents or a LAMS (40 patients per arm). In the plastic stent group, EUS-guided drainage will be performed using two 7-Fr double pigtail stents. In the LAMS group, the treatment will be performed in the same way except for LAMS use. The step-up treatment will be performed via endoscopic and/or percutaneous procedures at the trial investigator's discretion. The primary endpoint is clinical success, which is defined as a decrease in a pseudocyst size to ≤ 2 cm and an improvement in inflammatory indicators (i.e. body temperature, white blood cell count, and serum C-reactive protein). Secondary endpoints include technical success, adverse events including mortality, pseudocyst recurrence, and medical costs.

DISCUSSION

The WONDER-02 trial will investigate the efficacy and safety of plastic stents compared to a LAMS in EUS-guided treatment of symptomatic pancreatic pseudocysts with a particular focus on the non-inferior efficacy of plastic stents. The findings will help establish a new treatment algorithm for this population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06133023 registered on 9 November 2023. UMIN000052647 registered on 30 October 2023. jRCT1032230444 registered on 7 November 2023.

Infected pancreatic necrosis-Current trends in management

Acute necrotizing pancreatitis is a common gastrointestinal disease requiring hospitalization and multiple interventions resulting in higher morbidity and mortality. Development of infection in such necrotic tissue is one of the sentinel events in natural history of necrotizing pancreatitis. Infected necrosis develops in around 1/3rd of patients with necrotizing pancreatitis resulting in higher mortality. So, timely diagnosis of infected necrosis using clinical, laboratory and radiological parameters is of utmost importance. Though initial conservative management with antibiotics and organ support system is effective in some patients, a majority of patients still requires drainage of the collection by various modalities. Mode of drainage of infected pancreatic necrosis depends on various factors such as the clinical status of the patient, location and characteristics of collection and availability of the expertise and includes endoscopic, percutaneous and minimally invasive or open surgical approaches. Endoscopic drainage has proved to be a game changer in the management of infected pancreatic necrosis in the last decade with rapid evolution in procedure techniques, development of novel metal stent and dedicated necrosectomy devices for better clinical outcome. Despite widespread adoption of endoscopic transluminal drainage of pancreatic necrosis with excellent clinical outcomes, peripheral collections are still not amenable for endoscopic drainage and in such scenario, the role of percutaneous catheter drainage or minimally invasive surgical necrosectomy cannot be understated. In a nutshell, the management of patients with infected pancreatic necrosis involves a multi-disciplinary team including a gastroenterologist, an intensivist, an interventional radiologist and a surgeon for optimum clinical outcomes.

Risk factors for adverse outcomes at various phases of endoscopic ultrasound-guided treatment of pancreatic fluid collections: Data from a multi-institutional consortium

OBJECTIVES

No comprehensive study has examined short- and long-term adverse outcomes of endoscopic ultrasound (EUS)-guided treatment of pancreatic fluid collections (PFCs) including walled-off necrosis (WON) and pseudocysts.

METHODS

In a multi-institutional cohort of 357 patients receiving EUS-guided treatment of PFCs (228 with WON and 129 with pseudocysts), we examined PFC type-specific risk factors for procedure-related adverse events (AEs), clinical failure, and recurrence. Odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were computed using the logistic and Cox regression models, respectively, adjusting for potential confounders.

RESULTS

Adverse events were observed predominantly in WON, and risk factors were WON extension to the pelvis (OR 2.49; 95% CI 1.00-6.19) and endoscopic necrosectomy (OR 5.15; 95% CI 1.61-16.5). Risk factors for clinical failure in WON treatment included higher Charlson Comorbidity Index (OR for ≥3 vs. ≤2, 2.58; 95% CI 1.05-6.35), extension to the pelvis (OR 3.63; 95% CI 1.57-8.43), nonuse of a lumen-apposing metal stent (OR 2.88; 95% CI 1.10-7.54), and percutaneous drainage (OR 3.73; 95% CI 1.27-10.9). Patients with pseudocysts extending to the paracolic gutter and the need for more than two endoscopic/percutaneous procedures had ORs for clinical failure of 5.28 (95% CI 1.10-25.3) and 5.52 (95% CI 1.61-18.9), respectively. Pseudocysts requiring the multigateway approach were associated with a high risk of recurrence (HR 4.00; 95% CI 1.11-11.6).

CONCLUSION

The adverse outcomes at various phases of EUS-guided PFC treatment may be predictable based on clinical parameters. Further research is warranted to optimize treatment strategies for high-risk patients.

Prediction of Admission to Intensive Care Unit and 1-Year Mortality After Acute Pancreatitis With Walled-Off Pancreatic Necrosis: A Retrospective, Single-Center Cohort Study

BACKGROUND AND AIMS

Pancreatic walled-off necrosis (WON) carries significant mortality and morbidity risks, often necessitating intensive care unit (ICU) admission. This retrospective study aimed to evaluate whether routine biochemical parameters at the time of the index endoscopic procedure could predict ICU admission and 1-year mortality following endoscopic treatment of WON.

MATERIALS AND METHODS

We retrospectively identified 201 consecutive patients who underwent endoscopic drainage for WON between January 1, 2010, and December 31, 2020. Associations between routine biochemical blood tests and outcomes were assessed using logistic regression models.

RESULTS

Within 1 year of the index endoscopy, 31 patients (15.4%) died, and 40 (19.9%) were admitted to the ICU due to sepsis. Preoperative electrolyte disturbances were more prevalent among ICU-admitted patients and nonsurvivors. Hyperkalemia, hypoalbuminemia, and elevated urea were significant predictors of 1-year mortality, while hypernatremia, elevated serum creatinine, and hypoalbuminemia predicted ICU admission. Predictive models exhibited good discriminative ability, with an AUC of 0.84 (95% CI,0,75-0.93) for 1-year mortality and 0.86 (95%CI, 0.79-0.92) for ICU admission.

CONCLUSIONS

Preoperative imbalances in routine blood tests effectively predict adverse outcomes in endoscopically treated WON patients.

Endoscopic Ultrasound-Guided Drainage of Pancreatic Fluid Collections: Not All Queries Are Already Solved

Pancreatic fluid collections (PFCs) are well-known complications of acute pancreatitis. The overinfection of these collections leads to a worsening of the prognosis with an increase in the morbidity and mortality rate. The primary strategy for managing infected pancreatic necrosis (IPN) or symptomatic PFCs is a minimally invasive step-up approach, with endosonography-guided (EUS-guided) transmural drainage and debridement as the preferred and less invasive method. Different stents are available to drain PFCs: self-expandable metal stents (SEMSs), double pigtail stents (DPPSs), or lumen-apposing metal stents (LAMSs). In particular, LAMSs are useful when direct endoscopic necrosectomy is needed, as they allow easy access to the necrotic cavity; however, the rate of adverse events is not negligible, and to date, the superiority over DPPSs is still debated. Moreover, the timing for necrosectomy, the drainage technique, and the concurrent medical management are still debated. In this review, we focus attention on indications, timing, techniques, complications, and particularly on aspects that remain under debate concerning the EUS-guided drainage of PFCs.

Indications, Techniques and Future Perspectives of Walled-off Necrosis Management

Necrotizing pancreatitis is a complex clinical condition burdened with significant morbidity and mortality. In recent years, the huge progress of interventional endoscopic ultrasound (EUS) has allowed a shift in the management of pancreatic necrotic collections from surgical/percutaneous approaches to mini-invasive endoscopic internal drainage and debridement procedures. The development of lumen-apposing metal stents (LAMSs), devices specifically dedicated to transmural EUS interventions, further prompted the diffusion of such techniques. Several studies have reported excellent outcomes of endoscopic interventions, in terms of technical success, clinical efficacy and safety compared to surgical interventions, and thus endoscopic drainage of walled-off necrosis (WON) has become a fundamental tool for the management of such conditions. Despite these advancements, some critical unresolved issues remain. Endoscopic therapeutic approaches to WON are still heterogeneous among different centers and experts. A standardized protocol on indication, timing and technique of endoscopic necrosectomy is still lacking, and experts often adopt a strategy based on personal experience more than robust data from well-conducted studies. In this review, we will summarize the available evidence on endoscopic management of WON and will discuss some unanswered questions in this rapidly evolving field.

Endoscopic ultrasound-guided drainage of early pancreatic necrotic collection: Single-center retrospective study

BACKGROUND

Endoscopic ultrasound (EUS)-guided drainage is the standard of care for drainage of pancreatic necrosis. Though initially it was mainly used for drainage of only walled-off necrosis, recently, a few studies have also shown its safety in the management of acute necrotic collections. We did a retrospective study to evaluate the safety and efficacy of EUS-guided drainage in the early phase of pancreatitis as compared to interventions in the late phase.

METHODS

We retrieved baseline disease-related, procedure-related and outcome-related details of patients who underwent EUS-guided drainage of pancreatic necrosis. Patients were divided into early (≤ 28 days from onset of pancreatitis) or delayed (> 28 days) drainage groups. Both groups were compared for disease-related characteristics and outcomes.

RESULTS

Total 101 patients were included in the study. The mean age of included patients was 35.54 ± 13.58 years and 75 were male. Thirty-five patients (34.7%) underwent early drainage. In the early group, a majority of patients underwent intervention due to infected collection (88.6% vs. 18.2%; p < 0.001). More patients in the early group had < 30% wall formation (28.6% vs. 0%; p < 0.001) and > 30% solid debris within the collection (42.9% vs. 15.2%; p = 0.005). Patients in the early group were also more likely to require endoscopic necrosectomy (57.1% vs. 27.3%; p = 0.003) and additional percutaneous drainage (31.4% vs. 12.1%; p = 0.018). Overall, three patients in the early group and one patient in the delayed group had procedure-related complications. Four patients in the early group and one patient in the delayed group succumbed to illness (p = 0.029).

CONCLUSION

Though delayed interventions remain standard of care in the management of acute pancreatitis, some patients may require early intervention due to infected collection with deteriorating clinical status. Early EUS-guided interventions in such carefully selected patients have in similar clinical outcomes and complication rates compared to delayed intervention. However, such patients are more likely to require additional endoscopic or percutaneous interventions.

WONDER-01: immediate necrosectomy vs. drainage-oriented step-up approach after endoscopic ultrasound-guided drainage of walled-off necrosis-study protocol for a multicentre randomised controlled trial

BACKGROUND

With the increasing popularity of endoscopic ultrasound (EUS)-guided transmural interventions, walled-off necrosis (WON) of the pancreas is increasingly managed via non-surgical endoscopic interventions. However, there has been an ongoing debate over the appropriate treatment strategy following the initial EUS-guided drainage. Direct endoscopic necrosectomy (DEN) removes intracavity necrotic tissue, potentially facilitating early resolution of the WON, but may associate with a high rate of adverse events. Given the increasing safety of DEN, we hypothesised that immediate DEN following EUS-guided drainage of WON might shorten the time to WON resolution compared to the drainage-oriented step-up approach.

METHODS

The WONDER-01 trial is a multicentre, open-label, superiority, randomised controlled trial, which will enrol WON patients aged ≥ 18 years requiring EUS-guided treatment in 23 centres in Japan. This trial plans to enrol 70 patients who will be randomised at a 1:1 ratio to receive either the immediate DEN or drainage-oriented step-up approach (35 patients per arm). In the immediate DEN group, DEN will be initiated during (or within 72 h of) the EUS-guided drainage session. In the step-up approach group, drainage-based step-up treatment with on-demand DEN will be considered after 72-96 h observation. The primary endpoint is time to clinical success, which is defined as a decrease in a WON size to ≤ 3 cm and an improvement of inflammatory markers (i.e. body temperature, white blood cell count, and C-reactive protein). Secondary endpoints include technical success, adverse events including mortality, and recurrence of the WON.

DISCUSSION

The WONDER-01 trial will investigate the efficacy and safety of immediate DEN compared to the step-up approach for WON patients receiving EUS-guided treatment. The findings will help us to establish new treatment standards for patients with symptomatic WON.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05451901, registered on 11 July 2022. UMIN000048310, registered on 7 July 2022. jRCT1032220055, registered on 1 May 2022.