Cholangiography Using Carbon Dioxide Versus Iodinated Contrast in ERCP

Study Overview
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Brief Summary
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Carbon dioxide (CO2) gas is widely used for luminal insufflation during endoscopic retrograde cholangiopancreatography (ERCP) of the biliary tract. While frequently observed during routine ERCP, there are few data on the topic of air or CO2 cholangiography. Our primary aim is to compare radiographic cholangiograms in patients with biliary tract disease (from stones or strictures) during ERCP obtained by using carbon dioxide as the contrast medium vs. conventional iodinated contrast.

Detailed Description
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It has been recommended that endoscopic retrograde cholangiopancreatography (ERCP) be performed using carbon dioxide (CO2) instead of room air as the infused air or gas for luminal insufflation for reasons of improved patient comfort and in case of procedural adverse events (as CO2 is more quickly absorbed by the body and as it can be exhaled via the lungs). Air cholangiograms are often incidentally visible on fluoroscopy (radiographically) during ERCP prior to injection of iodinated contrast into the biliary tree. Despite the information from an air cholangiogram being readily available in many instances, biliary endoscopists and radiologists who read the fluoroscopic images taken during ERCP do not usually comment or interpret the air or CO2 cholangiograms. Consequently, very little data is available on the topic of air or CO2 cholangiography. As a contrast medium for cholangiography, CO2 might be safer than iodinated contrast, which is the standard contrast medium used during ERCP, as iodinated contrast cannot be easily absorbed by the body and as it can be trapped proximal to obstructing biliary stones or strictures and lead to biliary tract infection. This is a prospective cohort study that will enroll patients undergoing ERCP for suspected choledocholithiasis and/or biliary stricture(s). If they did not participate in this study, these patients would still require an ERCP with CO2 used as the endoscopically insufflated air medium. Enrolled patients will undergo an initial cholangiogram with CO2 (injected into the bile ducts) utilizing both conventional fluoroscopy and digital subtraction fluoroscopic imaging, followed by conventional cholangiography using iodinated contrast (injected into the bile ducts). Digital subtraction fluoroscopic imaging is a commercially available setting on certain fluoroscopy units that optimizes resolution with air or CO2 used as a contrast medium. Findings on CO2 cholangiography will be compared to those obtained from pre-procedural abdominal imaging along with the cholangiogram done using iodinated contrast at the time of the ERCP procedures.

Official Title
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CO2 Cholangiography as an Alternative to Iodinated Contrast in Endoscopic Retrograde Cholangiopancreatography

Conditions
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Choledocholithiasis, Bile Duct Diseases, Bile Duct Carcinoma

Intervention / Treatment
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* Other: Air contrast cholangiography using carbon dioxide gas


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients 18 years of age or older Patients with choledocholithiasis, benign biliary strictures, malignant biliary strictures Biliary pathology suggested or confirmed by imaging with abdominal ultrasonography, CT scan, MRI/MRCP scan, or endoscopic ultrasonography (EUS) Exclusion Criteria: Pregnancy (self reported) Presence of cholangitis before ERCP Prior history of surgery on the stomach or duodenum that precludes conventional ERCP or prior biliary tree surgery (not including cholecystectomy) Failure to selectively cannulate the bile duct Life expectancy less than 30 days Prisoners Patients unable to give consent

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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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Single arm<br>All patients will undergo endoscopic retrograde cholangiopancreatography (ERCP) that is indicated for suspected or confirmed choledocholithiasis or biliary strictures. Air contrast cholangiography using carbon dioxide gas will be performed with standard fluoroscopy and digital subtraction fluoroscopic image capture followed by routine cholangiography using iodinated contrast and standard fluoroscopy. Carbon dioxide (CO2) is routinely used in ERCP procedures and would flow into the biliary tree of patients at the time of ERCP, irrespective of this study's interventions. Digital subtraction image capture is a commercially available setting on certain fluoroscopy units that optimizes resolution with air or CO2 used as a contrast medium. | Other: Air contrast cholangiography using carbon dioxide gas<br>* Carbon dioxide (CO2) will be injected into the biliary tree (which is already exposed to CO2 during routine ERCP) and images will be obtained by using fluoroscopy and digital subtraction imaging (a specific setting on certain fluoroscopy tables).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Technical success of CO2 cholangiography vs. iodinated contrast | For choledocholithiasis: correct identification of the number and location of stones. For biliary strictures: correct identification of number and location of strictures. | Intraprocedural/immediate (during ERCP) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Technical success of digital subtraction fluoroscopy vs. traditional fluoroscopy (while using CO2 as the contrast medium) | For choledocholithiasis: correct identification of the number and location of stones. For biliary strictures: correct identification of number and location of strictures. | Intraprocedural/immediate (during ERCP) | 
| Radiation usage/exposure of CO2 cholangiography using conventional fluoroscopy or digital subtraction fluoroscopy vs. iodinated contrast | Fluoroscopy/radiation usage/exposure will be measured for each imaging modality and then compared | Intraprocedural/immediate (during ERCP) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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choledocholithiasis, ERCP, cholangiography, biliary stricture, bile ducts, carbon dioxide