A Pilot Study to Assess the Value of EUS vs EGD in Emergency Room Patients Referred for EGD

A PILOT STUDY TO ASSESS THE POTENTIAL VALUE OF ADDING ENDOSCOPIC ULTRASOUND (EUS) TO ESOPHAGO-GASTRO-DUODENOSCOPY (EGD) IN EMERGENCY ROOM PATIENTS REFERRED FOR EGD

P.I.: Anand V. Sahai MD, MSc (EPID), FRCPC

BACKGROUND Emergency room patients referred for esophago-gastro-duodenoscopy (EGD) often have many possible causes for their symptoms. These inevitably undergo further testing if EGD is inconclusive, which adds costs and inevitably prolongs emergency room length of stay (LOS).

Endoscopic ultrasound (EUS) combines EGD with high-resolution ultrasound imaging of pancreas, liver and biliary system and is the best test to diagnose bile duct stones, early chronic pancreatitis, and small [\<2cm] pancreatic cancers (all of which cannot be seen by regular ultrasound or CT scanning or MRI, yet are included in the differential diagnosis of EGD-negative abdominal pain).

EUS has traditionally been used after EGD, due to lack of availability, increased cost, and to increased risk due to larger scope diameter. However, the latest generation of EUS scopes have the same outer diameter as conventional gastroscopes, there is much wider availability of EUS in university and community hospital settings, and the cost per procedure is lower, due to increased procedural numbers and reduced maintenance costs.

In experienced hands, diagnostic EUS is now as safe and as EGD accurate as EGD for diagnosing mucosal pathology and takes approximately 1 minute longer.(1; 2) Previously published work by our group suggests that EUS may reduce resource consumption in patients with unexplained abdominal pain.(3) The investigators also showed that refractory dyspepsia with normal EGD and CT, EUS identified signs of occult chronic pancreatitis in up to 20% of cases.(4) More recently, EUS was found to identify previously undiagnosed, potential causes of unexplained abdominal pain in up to 9% of patients, or at least provides the same, if not more information and EGD and abdominal US alone.(2; 5; 6) There are no previous studies that have prospectively compared the yield of EGD and PEUS in emergency room patients. The investigators hypothesize that adding EUS to EGD ("primary EUS" [PEUS]) can safely and more efficiently diagnose or exclude significant gastro-intestinal and pancreatico-biliary pathology in emergency room patients in whom EGD has been requested. The investigators therefore propose a prospective pilot study to determine whether PEUS can reduce LOS and resource utilisation in emergency room patients referred for EGD.

AIM To perform a pilot study to determine whether PEUS reduces emergency room LOS and resource utilisation in emergency room patients referred for EGD.

METHODS

Study design This is an open-label two-arm, single center, superiority trial with 1:1 allocation ratio between EUS and standard intervention EGD.

Site

This study will be performed at the St Luc site of CHUM. Approximately 5000 EGD procedures and 3000 EUS procedures are performed at this site annually. Therefore, there should be sufficient eligible patients for efficient patient recruitment.

Research team A research team composed of the PI, one research nurse, and a biostatistician will coordinate the trial. The research assistant will be responsible for all data collection and patient recruitment (including consent). Statistical analysis will be provided by the biostatistical platform of the CR-CHUM under the supervision of Dr Martin Ladouceur.

Funding There is no external funding for this study.

Patient selection All patients referred for GI consultation in the emergency room at CHUM, site St Luc, are eligible.

Inclusion Criteria EGD requested by the consulting gastroenterologist Informed consent

Exclusion criteria Evidence of hemodynamic instability and/or ongoing active GI bleeding. Any suspicion of obstruction distal to the angle of Treitz. EGD or EUS cannot be performed before 12PM. Previous barium study, EGD, US, abdomino-pelvic CT, or abdomino-pelvic MRI within the last 6 months.

After the EGD request form is received in the GI department, the patient will be transported as usual to the endoscopy unit. Before entering an endoscopy suite, a single research assistant will present the patients the study protocol. After informed consent, each group will be randomized by sealed envelop to EGD or to PEUS. A gastroenterologist other than the one who requested EGD will perform EGD or EUS. Written EGD and PEUS reports will be presented in the standard fashion.

EGD and EUS are both available every day, before 12PM. They will be performed and interpreted by experienced operators (not fellows).

OUTCOMES

Patients in whom EGD is scheduled after GI consultation will be stratified in to 2 groups:

1. abdominal pain syndromes (defined as any pain or discomfort considered to be possibly of GI origin)
2. all other indications.

Primary outcome The primary outcome will be "time to GI diagnosis" (with T0 starting immediately after the procedure report is read and signed by the referring physician). A "GI diagnosis" is defined as diagnosis or confirmation of any condition sufficient to start treatment or to modify the existing therapeutic regimen.

Secondary outcomes

Secondary outcomes will be:

frequency of conversion to the alternate procedure (EGD to EUS, or EUS to EGD) number of subsequent imaging procedures other than endoscopy complications (defined as any event that prolongs hospital stay)

SAMPLE SIZE CALCULATIONS Given the novelty of the primary outcome of this study ("time to diagnosis, discharge, or admission"), there are no reliable data on which a sample-size estimate can be calculated. The investigators propose a pilot approach, with 40 patients per randomisation group (80 patients in total). This would be followed by an analysis to further clarify the appropriate sample size.

4.4 Expected Duration of Study Given our current patient volumes, the investigatorsshould be able to recruit 1 person per day (5 per week). This should require approximately 16 weeks (4 months) to complete this pilot project. Given that the primary endpoint is likely to occur in less than 3-4 days, the entire study duration until complete follow of the last patient would be approximately 17 weeks. To be conservative, and allow for unexpected contingencies, we propose an estimate for pilot study duration of 8 months.