PROTon Pump Inhibitors and Stent OCclusion Rate Of Lumen Apposing Metal Stents

Study Overview
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Brief Summary
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The goal of this observational retrospective cohort study in combination with an expert study is to assess the clinical relevance and management of Lumen apposing metal stent (LAMS)-occlusion and LAMS-occlusion-related complications as well as the influence of proton pump inhibitors (PPI) on LAMS-occlusion. The main questions this study aims to answer are: the individual management of LAMS-occlusion and LAMS-occlusion-related complications in the respective centers participating in the study. if there is an association between PPI-intake and LAMS-occlusion. Participants for the retrospective cohort study will be enrolled retrospectively among European centers with expertise in pancreatology. The expert survey will be distributed European-wide to centers with special expertise in pancreatology.

Detailed Description
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A common complication of acute pancreatitis is the formation of necrosis in 5-10% of all patients, which leads to an increased overall mortality of 28% for infected necroses. Currently, lumen apposing metal stents (LAMS) are widely used to address necrotic masses. LAMS-occlusion is postulated to be a considerable complication. However, the prevalence, clinical impact and management of LAMS-occlusion-related complications remains uncertain. Moreover, the German guidelines for management of acute pancreatitis do not specify whether a concomitant proton pump inhibitor (PPI)-therapy should be discontinued or not. A recent study suggested a lower rate of LAMS-occlusions, but a higher number of required endoscopic necrosectomies upon concomitant PPI-therapy. Thus, current data are conflicting. The investigators therefore aim to perform an expert survey and a retrospective cohort study to elucidate the clinical importance of LAMS-occlusion-related complications and the effect of PPI-intake on occlusion. First, a survey will be sent to European centers with special expertise in pancreatology. Here, the investigators aim to assess the number of LAMS applied annually, whether the experts consider occlusion a clinically relevant complication, and whether there are standard operating procedures for LAMS-occlusion and PPI-discontinuation. Second, the investigators will perform a retrospective multicenter cohort study to assess patient data for PPI intake, frequency of LAMS-occlusion and other complications using a RedCap database. Quality assurance and data checks of the data entered will be performed by the study coordinator after the initial data entry of the participating centers. For missing data, for which the RedCap form cannot be filled out, the online forms comprise extra fields for missing data. The data entered in the RedCap online survey will stem from paper or electronic case report forms depending which of these are used at the respective centers. Source data verification will be performed by the participating centers themselves upon data entry into the online questionnaires. A standard operating procedure will be handed out to the participating centers which will feature any information about how data should be entered. Here, the minimum number of patients which needs to be entered into the study in order to participate will be addressed. The maximum of patients who can be entered is dependent on the respective centers; in principle all patients who received a LAMS for drainage of a WON in the respective centers can be included. As the investigators perform a retrospective study, there will be no need to account for reporting of adverse events. Based on a power calculation of a preliminary in-house dataset from the University Hospital Goettingen the investigators aim to include a total number of 639 patients. For missing, unavailable, non-reported or uninterpretable data, the RedCap survey will comprise extra fields as described above. In these, the participating researcher can state that data is missing. If this information is essential for the primary or secondary endpoints of our study, the data entry can be excluded from further analyses by the data monitoring committee. For the statistical analyses of the data gathered from the expert survey the investigators will apply a Fisher/Chi2-test to assess the clinical relevance as well as the clinical management of LAMS-occlusion and LAMS-occlusion-related complications. For the retrospective cohort study, a Chi2-test will be used to address correlations between PPI-intake and LAMS-occlusion. To assess the frequency of occlusion-related-complications, risk factors for LAMS-occlusion beyond PPI-intake and differences in clinical management of LAMS-occlusion in the respective centers, logistic regression/LASSO will be applied.

Official Title
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PROTon Pump Inhibitors and Stent OCclusion Rate Of Lumen Apposing Metal Stents (PROTOCOL)

Conditions
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Acute Pancreatitis

Intervention / Treatment
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* Drug: Proton pump inhibitor
* Device: LAMS-implantation


Participation Criteria
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Eligibility Criteria
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Retrospective cohort study: Inclusion Criteria: - Patients in which a Lumen apposing metal stent (LAMS) was applied into a walled off necrosis (WON) as a complication of an acute pancreatitis (AP). Exclusion Criteria: Patients in which a LAMS was applied into a pseudocyst instead of a WON. Patients in which a LAMS was used to address a postoperative pancreatic fistula (POPF). Patients in which concomitant PPI-treatment was not assessed/not documented. Expert survey: Inclusion Criteria: - European experts (gastroenterological interventionalists) with expertise in pancreatology Exclusion Criteria: Centers which apply less than 10 LAMS per year Centers with less than two years experience with LAMS

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| PPI-group<br>Patients who received a lumen apposing metal stent (LAMS) for drainage of a walled off necroses (WON) upon acute pancreatitis (AP) and were prescribed proton pump inhibitors (PPI) concomitantly | Drug: Proton pump inhibitor<br>* Patients who received a lumen apposing metal stent (LAMS) for drainage of a walled off necrosis (WON) upon acute pancreatitis will be divided into a PPI/Non-PPI group depending on if they concomitantly were prescribed a PPI or not<br>Device: LAMS-implantation<br>* Patients who received a lumen apposing metal stent (LAMS) for drainage of a walled off necrosis (WON) upon acute pancreatitis<br>|
| Non-PPI-group<br>Patients who received a lumen apposing metal stent (LAMS) for drainage of a walled off necroses (WON) upon acute pancreatitis (AP) and were not prescribed proton pump inhibitors (PPI) concomitantly | Device: LAMS-implantation<br>* Patients who received a lumen apposing metal stent (LAMS) for drainage of a walled off necrosis (WON) upon acute pancreatitis<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retrospective Cohort Study Primary Outcome Measure: Association between frequency of LAMS-occlusion and concomitant PPI-intake | All patients who received a LAMS from the time-point since LAMS have been used at the respective centers will be included. In all patients who received LAMS, their medical records will be checked if a PPI was taken or not. Next, it will be assessed how many patients who took PPI (PPI-group) had a LAMS-occlusion in comparison with the patients who did not take a PPI (Non-PPI-group). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Expert Survey Primary Outcome Measure Number 1: Assessment of the clinical relevance of LAMS-occlusion and LAMS-occlusion-related complications | The expert will be asked if he had experiences with complications after total/partial LAMS-occlusion (yes/no). Moreover, the expert will be asked if he would consider these as frequent complications (yes/no). Next, the expert will be asked how frequent he would consider complications after total/partial LAMS-occlusion to occur (scale 0-20%). Finally, the expert will be asked which complications he had witnessed after total/partial LAMS-occlusion (progression of the pancreatic collection, infection of the WON, sepsis, other). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Expert Survey Primary Outcome Measure Number 2: Assessment of the clinical management of LAMS-occlusion in the respective participating centers | Two clinical cases will be presented. The first case will be suggestive for a total LAMS occlusion with infection/sepsis as a complication consecutive to the stent-occlusion. The second case will be suggestive for a partial LAMS occlusion with no apparent complication. For each case, the expert will be asked if he would consider this a complication (yes/no). Moreover, it will be asked if the expert would remove the LAMS (yes/no), if he would place pigtails over the ostium afterwards (yes/no) and if not what he would do otherwise (endoscopic necrosectomy, place pigtail through the LAMS, disrupted pancreatic duct evaluation via endoscopic retrograde cholangiopancreatography/magnet resonance cholangiopancreatography (ERCP/MRCP), endoscopic papillotomy, other). | Until LAMS-removal, an average of 4 weeks after implantation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retrospective Cohort Study Secondary Outcome Number 1: Determination of the frequency of LAMS-occlusion-related complications | For every case it will be assess whether ther was a LAMS-occlusion and if this led to a complication (yes/no). Moreover, the type of complication will be assessed (progress of the pancreatic collection, infection of the WON, sepsis, other/unknown). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Retrospective Cohort Study Secondary Outcome Number 2: Assessment of other risk factor for LAMS-occlusion beyond PPI-intake | For every case, other potential risk factors for LAMS-occlusion will be assessed such as the gender (female, male, diverse), the body mass index (BMI), the type of pancreatitis (acute pancreatitis, recurrent acute pancreatitis, chronic pancreatitis) and the etiology of pancreatitis (biliary, alcohol-induced, idiopathic, iatrogenic, hypercalcemia, hypertriglyceridemia, drugs, traumatic, other/unknown). Moreover, the access way of LAMS-application (transgastric, transduodenal, other/unknown), the type of LAMS used (Hot Axios, Axios, Spaxus, Hot Spaxus, Nagi, Hanaro-Stent, GEN II, other/unknown) and the lumen diameter of the LAMS (e.g. Hot Axios/Axios: 6,8,10,15,20mm, not documented/not assessed) will be assessed. | Until LAMS-removal, an average of 4 weeks after implantation | 
| Retrospective Cohort Study Secondary Outcome Number 3: Assessment of differences in the clinical management of LAMS-occlusion and LAMS-occlusion-related complications between the participating centers | For each case it will be assessed if a LAMS-occlusion occured after application (yes/no). Moreover, the type of LAMS-occlusion will be assessed (partial LAMS-occlusion, total LAMS-occlusion, unknown/not documented). Next, it will be asked how the occlusion was diagnosed (gastroscopy, endoscopic ultrasound, computer tomography, abdominal ultrasound, other). Moreover, the total number of necrosectomies will be assessed (free text). In addition it will be assessed if the LAMS was removed due to a complication (yes/no, unknown/not documented) and what was done in the following if the LAMS was removed (pigtails were placed over the ostium, another LAMS was applied, surgical procedure, percutaneous drainage, other/unknown). If the LAMS was not removed, it will be asked what else was done in the following (nothing, endoscopic necrosectomy, pigtails were placed through the LAMS, disrupted pancreatic duct evaluation via ERCP/MRCP, endoscopic papillotomy, other/unknown). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Expert Survey Secondary Outcome Number 1: To assess if a standard operating procedure (SOP) for follow-up-examinations regarding stent occlusion after LAMS-implantation exists in the respective centers. | The expert will basked if a SOP for apparative follow-up-examinations after LAMS application exists at their center (yes/no/unknown). Moreover, it will be asked how many follow up examinations are performed (1, 2, 3 or more), at which time-points (<3 days, within 1 week, 2,3,4,5-8 weeks) and how (CT, MRI, gastroscopy, endoscopic ultrasound, abdominal ultrasound) these are performed. Additionally, it will be asked when the LAMS would be removed normally (≤4weeks, 5-8 weeks, ≥9 weeks after implantation). Moreover, it will be asked which procedure is normally followed after LAMS removal (change LAMS to pigtails, just remove the LAMS, other). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Expert Survey Secondary Outcome Number 2: To assess whether the respective clinical center has a SOP regarding LAMS and concomitant PPI-intake. | The expert will be asked, if proton pump inhibitors are continued/discontinued upon LAMS-application at his/her center (should be discontinued, should be continued with the same dosage, should be continued with another dosage, currently no standard procedure). If the PPI should be continued in another dosage, it will be asked whether it should be continued in half the standard dose, standard dose, double standard dose or more than standard dose. Moreover, it will be asked if any specific PPI should be discontinued and if yes which of the following (Omeprazole, Esomeprazole, Pantoprazole, Lansoprazole, Rabeprazole). | Until LAMS-removal, an average of 4 weeks after implantation | 
| Expert Survey Secondary Outcome Number 3: To assess the experts definition of the term LAMS-occlusion in general, as well as the term partial LAMS occlusion. | The expert will be asked which of the following potential causes of LAMS occlusion he/she would include in a universal valid definition for reasons of LAMS-occlusion: tissue ingrowth, tissue overgrowth, food impaction, impaction with liquid necrotic debris, impaction with solid necrotic debris, blood clot formation, stent migration, stent kinking, stent compression, stent fracture, other. Moreover, the expert will be asked how he/she would define partial LAMS-occlusion: An occlusion which is still passable with the endoscope; An occlusion in which you can still see through the LAMS with the optics of the endoscope; An occlusion with liquid parts, other. | Until LAMS-removal, an average of 4 weeks after implantation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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acute pancreatitis, lumen apposing metal stents (LAMS), proton pump inhibitors (PPI)