Diagnostic Yield of Urgent Panendoscopy VS. Conventional Endoscopic Evaluation in Patients Presenting With Hematochezia : Randomized Controlled Trial

Gastrointestinal bleeding is a common emergency condition and an important public health issue, as it impacts hospitalization rates and mortality in the population if not properly diagnosed and treated. Currently, GI bleeding is classified into upper GI bleeding, mid GI bleeding, and lower GI bleeding, using the locations accessible by esophagogastroduodenoscopy (EGD) and colonoscopy as the dividing points between the upper, mid and lower GI tracts respectively Patients who present with hematochezia, including passing maroon or bright red blood per rectum, most commonly have lower gastrointestinal bleeding. However, patients with mid or upper gastrointestinal bleeding can also present with hematochezia if bleeding is severe. Thus, colonoscopy is often the first diagnostic test in these patients, able to identify a bleeding source in 68-79% of cases. If no bleeding site is found on colonoscopy, esophagogastroduodenoscopy is then performed, revealing a bleeding lesion in 1.3-15% of patients depending on study population. Those without an identified bleeding site on either colonoscopy or EGD are labeled as potential small bowel bleeders (PSBB). Current guidelines recommend video capsule endoscopy (VCE) in PSBB, since it can detect bleeding sites in 60-70% of these patients.

While the above diagnostic approach is widely accepted, the optimal timing for endoscopic evaluation remains controversial with conflicting study results. Several randomized controlled trials (RCTs) and observational studies have reported higher diagnostic yields and treatment rates when colonoscopy is performed within 24 hours of presentation. Particularly in diverticular bleeding, early colonoscopy enables localization and treatment to prevent rebleeding, since delayed colonoscopy may miss active bleeding once it has spontaneously stopped. However, three RCTs did not show a benefit of urgent colonoscopy. A 2020 meta-analysis also found no improvement in diagnostic yield with urgent colonoscopy in suspected lower GI bleeding. Current guidelines from the American Gastroenterological Association in 2023 also do not recommend urgent colonoscopy. Of note however, in the largest RCT by Niikura et al, the control group underwent colonoscopy at a mean of 41 hours after presentation. The small difference in timing may explain the lack of difference seen between groups.

In addition to timing of colonoscopy, timing of video capsule endoscopy (VCE) also appears to impact diagnostic yields in potential small bowel bleeders. A retrospective cohort study of 94 patients found that urgent VCE within 48 hours of admission increased the diagnosis of small bowel bleeding sources to 66%. A 2022 meta-analysis also showed that early VCE after bleeding increases lesions detection in the small bowel by 4.4-fold.

In summary, urgent colonoscopy does not appear beneficial but urgent VCE increases diagnostic yields in patients presenting with hematochezia. This poses a conflict since urgent VCE necessitates preceding urgent colonoscopy. Thus, this study aims to determine if an approach utilizing urgent colonoscopy within 24 hours followed immediately by same-day VCE in cases of normal colonoscopy can improve bleeding source detection compared to the standard sequential approach. This strategy has not been evaluated before. Additional benefits include reducing bowel preparation requirements for patients. Outcomes will be compared to a group undergoing standard sequential evaluation.