Natural course of asymptomatic walled off pancreatic necrosis

Plastic versus metal stents for transmural drainage of walled-off necrosis with significant solid debris: a randomized controlled trial

Background and study aims Recently, larger-caliber metal stents have been increasingly used, resulting in higher efficacy in walled-off necrosis (WON) with more solid debris. However, none of the trials have included WON with significant solid debris. The aim of this study was to compare plastic stents and metal stents for drainage of symptomatic WON with significant solid debris (≥20%). Patients and methods We conducted a single-center, open-label, noninferiority trial including 48 patients. The primary endpoint was treatment success. Secondary outcomes were technical success, total number of procedures, adverse events (AEs), duration of procedure, and treatment failure. All the outcomes were assessed at 3 weeks after drainage. Patients were followed up for 3 months to assess recurrence. Results Treatment succeeded in 21 of 24 patients (87.5%) and 20 of 24 patients (83.3%) in the metal and plastic stent groups, respectively with P =1.05 (95% confidence interval 0.81-1.39). Assuming 10% non-inferiority margin, P <0.001 for non-inferiority, suggesting that plastic stents are non-inferior to metal stents. The technical success rate was 100%. Procedure duration was significantly shorter in the metal stent group (12.95±5.3 minutes versus 29.77±6.6 minutes, P <0.001). The number of total procedures was comparable (2.8±1 vs 2.2±1, P =0.097). There were more minor AEs in plastic stent arm but no significant difference between the two groups. A single asymptomatic recurrence was observed in the metal stent arm. Conclusions Plastic stents are not inferior to metal stents for WON drainage with significant solid debris. However, larger sample-size studies are needed to make definite conclusions.

Time to think prime times for treatment of necrotizing pancreatitis: Pendulum conundrum

Pancreatic fluid collections (PFCs) typically develop as local complications of acute pancreatitis and complicate the clinical course of patients with acute pancreatitis and potentially fatal clinical outcomes. Interventions are required in cases of symptomatic walled-off necrosis (WON) (matured PFCs with necrosis) and pancreatic pseudocysts (matured PFCs without necrosis). In the management of necrotizing pancreatitis and WON, endoscopic ultrasound-guided transluminal drainage combined with on-demand endoscopic necrosectomy (i.e. the step-up approach) is increasingly used as a less invasive treatment modality compared with a surgical or percutaneous approach. Through the substantial research efforts and development of specific devices and stents (e.g. lumen-apposing metal stents), endoscopic techniques of PFC management have been standardized to some extent. However, there has been no consensus about timing of carrying out each treatment step; for instance, it is uncertain when direct endoscopic necrosectomy should be initiated and finished and when a plastic or metal stent should be removed following clinical treatment success. Despite emerging evidence for the effectiveness of noninterventional supportive treatment (e.g. antibiotics, nutritional support, irrigation of the cavity), there has been only limited data on the timing of starting and stopping the treatment. Large studies are required to optimize the timing of those treatment options and improve clinical outcomes of patients with PFCs. In this review, we summarize the current available evidence on the indications and timing of interventional and supportive treatment modalities for this patient population and discussed clinical unmet needs that should be addressed in future research.

Combined Drainage and Protocolized Necrosectomy Through a Coaxial Lumen-apposing Metal Stent for Pancreatic Walled-off Necrosis: A Prospective Multicenter Trial

OBJECTIVE

We evaluated a protocolized endoscopic necrosectomy approach with a lumen-apposing metal stent (LAMS) in patients with large symptomatic walled-off pancreatic necrosis (WON) comprising significant necrotic content, with or without infection.

SUMMARY BACKGROUND DATA

Randomized trials have shown similar efficacy of endoscopic treatment compared with surgery for infected WON.

DESIGN

We conducted a regulatory, prospective, multicenter single-arm clinical trial examining the efficacy and safety of endoscopic ultrasound -guided LAMS with protocolized necrosectomy to treat symptomatic WON ≥6 cm in diameter with >30% solid necrosis. After LAMS placement, protocolized WON assessment was conducted and endoscopic necrosectomy was performed for insufficient WON size reduction and persistent symptoms. Patients with radiographic WON resolution to ≤ 3 cm and/or 60-day LAMS indwell had LAMS removal, then 6-month follow-up. Primary endpoints were probability of radiographic resolution by 60 days and procedure-related serious adverse events.

RESULTS

Forty consecutive patients were enrolled September 2018 to March 2020, of whom 27 (67.5%) were inpatients and 19 (47.5%) had clinical evidence of infection at their index procedure. Mean WON size was 15.0 ± 5.6 cm with mean 53.2% ± 16.7% solid necrosis. Radiographic WON resolution was seen in 97.5% (95% CI, 86.8%, 99.9%) by 60 days, without recurrence in 34 patients with 6-month follow-up data. Mean time to radiographic WON resolution was 34.1 ± 16.8 days. Serious adverse events occurred in 3 patients (7.5%), including sepsis, vancomycin-resistant enterococcal bacteremia and shock, and upper gastrointestinal bleeding. There were no procedure-related deaths.

CONCLUSIONS

Endoscopic ultrasound-guided drainage with protocolized endoscopic necrosectomy to treat large symptomatic or infected walled-off necrotic pancreatic collections was highly effective and safe. Clinicaltrials.-gov no: NCT03525808.

Natural History of Asymptomatic Walled-off Necrosis in Patients With Acute Pancreatitis

Background and objectives Studies on the natural history of asymptomatic walled-off necrosis (WON) in acute pancreatitis (AP) are scarce. We conducted a prospective observational study to look for the incidence of infection in WON. Material and methods In this study, we included 30 consecutive AP patients with asymptomatic WON. Their baseline clinical, laboratory, and radiological parameters were recorded and followed up for three months. Mann Whitney U test and unpaired t-tests were used for quantitative data and chi-square and Fisher's exact tests were used for qualitative data analysis. A p-value <0.05 was considered significant. Receiver operating characteristic curve (ROC) analysis was done to identify the appropriate cutoffs for the significant variables. Results Of the 30 patients enrolled, 25 (83.3%) were males. Alcohol was the most common etiology. Eight patients (26.6%) developed an infection on follow-up. All were managed by drainage either percutaneously (n=4, 50%) or endoscopically (n=3, 37.5%). One patient required both. No patient required surgery and there was no mortality. Median baseline C-reactive protein (CRP) was higher in infection group 76 (IQR=34.8) mg/L vs asymptomatic group, 9.5 mg/dl (IQR=13.6), p<0.001. IL-6 and tumor necrosis factor (TNF)-alpha was also higher in the infection group. The size of the largest collection (157.50±33.59 mm vs 81.95±26.22 mm, P<0.001) and CT severity index (CTSI) (9.50±0.93 vs 7.82±1.37, p<0.01) were also higher in infection group as compared to the asymptomatic group. ROC curve analysis of baseline CRP (cutoff 49.5mg/dl), size of WON (cutoff 127mm) and CTSI (cutoff of 9) showed AUROC (area under ROC) of 1, 0.97, and 0.81 respectively for the future development of infection in WON. Conclusion Around one-fourth of asymptomatic WON patients developed an infection during three-months follow-up. Most patients with infected WON can be managed conservatively.

Controversies in EUS-guided treatment of walled-off necrosis

This review gives an overview of different techniques in the treatment of post-acute complications of acute pancreatitis. The endoscopic treatment of those complications is currently standard of care. EUS opened up the broad implementation of internal drainage methods to make them safe and effective. Due to different endoscopic approaches worldwide, controversies have arisen that are pointed out in this paper. The main focus was placed on weighing up evidence to find the optimal approach. However, if no evidence can be provided, the authors, experienced in the field, give their personal advice.

Endoscopic step up: When and how

The management of (peri)pancreatic collections has undergone a paradigm shift from open surgical drainage to minimally invasive endoscopic, percutaneous, or surgical interventions. Minimally invasive interventions are associated with less morbidity and mortality compared to open necrosectomy. The (peri)pancreatic collections are currently treated with a “step-up approach” of an initial drainage procedure followed, if necessary, by a more invasive debridement. The step-up approach for management of (peri)pancreatic collections is mainly of two types, namely, surgical and endoscopic. Surgical step up includes initial image-guided percutaneous catheter drainage followed, if necessary, by minimally invasive video-assisted retroperitoneal debridement. Endoscopic step-up approach includes endoscopic transluminal drainage followed, if necessary by direct endoscopic necrosectomy. The development of endoscopic ultrasound and lumen apposing metal stents (LAMSs) has revolutionized the endoscopic management of (peri)pancreatic collections. Compared to surgical step-up approach, endoscopic step-up treatment approach has been reported to be associated with less new-onset organ failure, pancreatic fistula, enterocutaneous fistula, or perforation of visceral organ and shorter hospital/intensive care unit stay. This review will mainly focus on indications, techniques, timing, and recent advances related to endoscopic step-up approach in management of symptomatic(peri)pancreatic collections.

Indian College of Radiology and Imaging Consensus Guidelines on Interventions in Pancreatitis

Acute pancreatitis (AP) is one of the common gastrointestinal conditions presenting as medical emergency. Clinically, the severity of AP ranges from mild to severe. Mild AP has a favorable outcome. Patients with moderately severe and severe AP, on the other hand, require hospitalization and considerable utilization of health care resources. These patients require a multidisciplinary management. Pancreatic fluid collections (PFCs) and arterial bleeding are the most important local complications of pancreatitis. PFCs may require drainage when infected or symptomatic. PFCs are drained endoscopically or percutaneously, based on the timing and the location of collection. Both the techniques are complementary, and many patients may undergo dual modality treatment. Percutaneous catheter drainage (PCD) remains the most extensively utilized method for drainage in patients with AP and necrotic PFCs. Besides being effective as a standalone treatment in a significant proportion of these patients, PCD also provides an access for percutaneous endoscopic necrosectomy and minimally invasive necrosectomy. Endovascular embolization is the mainstay of management of arterial complications in patients with AP and chronic pancreatitis. The purpose of the present guideline is to provide evidence-based recommendations for the percutaneous management of complications of pancreatitis.

Endotherapy in Pancreatic Diseases

Interventional endoscopy is now considered an effective minimally invasive treatment modality for the management of pancreatic diseases. It is important for the clinician to know the indications and contraindications as well as the timing of various endoscopic interventions. This will help in its safe and effective use and consequently decrease morbidity and mortality from various pancreatic diseases. This review will provide a broad overview of the indications, techniques, and outcomes of pancreatic endotherapy.

A Case Series of Late Gastrointestinal Fistulization in 16 Patients with Walled-Off Necrosis

BACKGROUND

Gastrointestinal fistulization (GIF) is a rare and potentially fatal complication of acute necrotizing pancreatitis (ANP). There is paucity of data on clinical course and outcome of GIF in walled of necrosis (WON).

OBJECTIVE

To evaluate frequency, clinical as well as imaging findings and outcome of spontaneous symptomatic GIF in patients with WON.

METHODS

Retrospective analysis of database of patients with asymptomatic WON on regular follow-up over last six years to identify patients with symptomatic GIF.

RESULTS

Out of 138 patients with asymptomatic WON seen during the study period, 16 (11.5%) patients (all males; mean age 41.7 ± 9.9 years) developed symptomatic GIF. The mean size of WON in patients who developed GIF was 9.5 ± 2.4 cm, and fistulization occurred after 65.1 ± 17.8 days of the onset of ANP. The site of fistulization was stomach, duodenum, jejunum, colon, and esophagus in seven (43.7%), five (31.2%), one (6.2%), two (12.5%), and one (6.2%) patients, respectively. GIF resulted in spontaneous resolution in two patients (stomach 1 and esophagus 1). The remaining patients with gastric (six patients) and duodenal (five patients) fistulization were successfully treated endoscopically by placing multiple plastic stents in the necrotic cavity after balloon dilatation of the fistulous tract. Patients with colonic fistulization required surgery. None of the patients succumbed to the illness.

CONCLUSION

Symptomatic GIF of WON usually occurs within the first three months of onset of ANP. It commonly occurs in either stomach or duodenum and can be successfully managed endoscopically.

Paediatric acute pancreatitis: Clinical profile and natural history of collections

BACKGROUND & AIMS

Acute Pancreatitis (AP) tends to have a benign course in children. However there is a paucity of information with respect to severity of AP in children, the categorization of collections viz., walled off necrosis (WON)& pseudocyst and their natural history & outcomes.

METHODS

A retrospective medical record review of 187 children with pancreatitis diagnosed and managed at our centre was performed.

RESULTS

101 children (59% boys, Median age 9yrs) had AP of which 37.6%, 60.4% and 2% had mild, moderately severe and severe AP. 61.4%(62) had PFC at diagnosis; 34%(21) acute pancreatic fluid collections (APFC) and 66%(41) acute necrotic collections (ANC). 52.3%(11of21) of APFC evolved into pseudocysts & 68.2%(28of41) of ANC into WON's. Drainage was required in 31%(12of39) of persisting collections, more frequently in children with traumatic AP. Percutaneous catheter drainage (PCD) was done in 6 children and endoscopic ultrasound (EUS) guided cystogastrostomy with placement of plastic or self expanding metal stents (SEMS) in 6 children.

CONCLUSIONS

Moderately severe AP is common in hospitalized children with AP with PFC developing in 61.4%, majority being APFC. 48% of APFC and 32% of ANC will resolve and the rest evolve into pseudocyst or WON. Spontaneous resolution is more likely in children with non -traumatic AP having pseudocysts rather than WON's.

Efficacy and safety of plastic versus lumen-apposing metal stents for transmural drainage of walled-off necrosis: a retrospective single-center study

Background

Lumen-apposing metal stents (LAMS) were considered a breakthrough in the endoscopic management of walled-off necrosis (WON), as their larger drainage diameter was expected to provide effective drainage of necrotic material. However, various studies and meta-analyses that have compared plastic and metal stents for the treatment of WON have shown conflicting results. We retrospectively compared the efficacy and safety of endoscopic transmural drainage between multiple plastic stents and LAMS.

Methods

Endoscopic data were retrospectively retrieved for patients who had undergone endoscopic ultrasound (EUS)-guided drainage/debridement of WON. Patients were divided into 2 groups according to whether multiple plastic stents or LAMS were deployed during initial drainage. The resolution and complication rates were compared between the 2 groups.

Results

One hundred sixty-six patients (83% male, mean age 37.5 years) with symptomatic WON were treated with EUS-guided drainage using either multiple plastic stents (n=138) or LAMS (n=28). Patients in the LAMS group had significantly larger WON and a significantly higher proportion of solid content. WON resolution rates did not differ between plastic stents and LAMS (98.5% vs. 96.4% respectively, P=0.42). However, the time taken to resolution was significantly shorter in the LAMS group than in the plastic stents group (26.7 vs. 29.8 days, P=0.03). There was no significant difference between the groups in either mortality or complication rates.

Conclusions

The technical success, rates of WON resolution and complications were similar in patients treated with multiple plastic stents and LAMS. However, LAMS were associated with a significantly shorter time to resolution.

CT imaging, classification, and complications of acute pancreatitis

Acute pancreatitis is an increasingly common condition and can result in significant morbidity and mortality. Contrast enhanced computed tomography (CECT) is the primary initial imaging modality in the characterization of acute pancreatitis. In this article, we provide sample CECT technical acquisition parameters for pancreatic imaging. We also review the classification systems for acute pancreatitis and give examples of common and uncommon complications of acute pancreatitis.

Current concepts for the diagnosis of acute pancreatitis by multiparametric magnetic resonance imaging

Acute pancreatitis is classically characterized by acute chemical inflammation of the pancreatic gland itself, peripancreatic tissues, and even remote organs. The newly revised Atlanta Classification 2012 redefined the patterns of pancreatic necrosis and local complications in acute pancreatitis. The Atlanta Classification's novelty was in emphasizing that extrapancreatic fat necrosis, which leads to walled-off necrosis, is associated with poor prognosis. Conversely, the free fluid liquid was considered to be less related to complications. The Atlanta's classification's main weakness is that it is mainly computed tomography (CT) based, as contrast-enhanced CT is the predominant imaging technique used for evaluating a wide range of pathological processes of acute pancreatitis. However, some local complications are difficult to distinguish accurately on CT. Recent advances, including significantly better soft-tissue contrast, favor multiparametric magnetic resonance imaging (mpMRI) for a more comprehensive assessment of acute pancreatitis pathology, particularly for small necrotic/fat debris within a collection. In addition, the MRI severity index (MRSI), which combines Balthazar's grade points and points of the extent of pancreatic necrosis, has been proven to be crucial for the initial evaluation, staging, and prognosis of acute pancreatitis. Other innovations, such as the recognition of important MRI features in acute pancreatitis and the utilization of newer, more effective terminology for imaging reporting assistance in the differentiation of the common local complications following this disease, have improved the treatment for acute pancreatitis. In this paper, with reference to the 2012 revised Atlanta classification, we review the strengths and limitations of MRI for identifying acute pancreatitis, the MRI findings of a spectrum of pathological entities, and the important local complications secondary to acute pancreatitis.

Complications of endoscopic ultrasound-guided transmural drainage of pancreatic fluid collections and their management

The development of endoscopic ultrasound (EUS)-guided drainage techniques and lumen-apposing metal stents (LAMS) has markedly reduced the complication rate of endoscopic transmural drainage of pancreatic collections and made these procedures safer and more effective. Despite its improved safety profile, various types of complications, some even life-threatening, can occur after EUS-guided drainage of pancreatic fluid collections. Stent maldeployment/migration, bleeding, gastrointestinal perforation, and air embolism are important complications of EUS-guided drainage of pancreatic collections. Delayed complications weeks after the procedure, such as bleeding and buried LAMS due to the presence of prolonged indwelling transmural stents, have also been described. Careful patient selection, with proper assessment of the size, solid necrotic content and location of the collection, as well as an in-depth understanding of various risk factors that predict complications, are important for a safer and more effective endoscopic transmural drainage. For a better clinical outcome, it is important for the endoscopist to know about various complications of EUS-guided drainage of pancreatic collections, as well as their appropriate management strategies.

An overview of walled-off pancreatic necrosis for clinicians

Walled of pancreatic necrosis (WOPN) is a new term coined for encapsulated fluid collection developing after acute necrotising pancreatitis (ANP). It is a heterogeneous collection containing varying amount of liquid as well as solid necrotic material. The literature on its natural history as well as appropriate management is gradually expanding thereby improving treatment outcomes of this enigmatic disease. Areas covered: This review discusses currently available literature on etiology, frequency, natural history, and imaging features WOPN. Also, updated treatment options including endoscopic, radiological and surgical drainage are discussed. Expert opinion: WOPN is alocal complication of ANP occurring in the delayed phase of ANP and may be asymptomatic (50%) or present with pain, fever, jaundice, or gastric outlet obstruction. Natural courses of asymptomatic WOPN have been infrequently studied, and it appears that the majority remain asymptomatic and resolve spontaneously. Magnetic resonance imaging and endoscopic ultrasound are the best imaging modalities to evaluate solid necrotic debris. Symptomatic WOPN usually needs immediate drainage, this can be done endoscopically, radiologically, or surgically. Current evidence suggests that endoscopic transluminal drainage is the preferred drainage technique as it is effective and associated with lower mortality, risk of organ failure, adverse effects, and length of hospital stay.