The Argentina Brief Colonoscopy Difficulty Score (ABCD)

Colonoscopy is the most performed digestive endoscopy procedure worldwide. It is indicated for colorectal cancer screening, pre-existence surveillance, diagnostic approach in symptomatic patients, and therapeutic purposes. Bowel preparation is the most crucial quality criterion that guarantees appropriate colonic mucosa assessment. Other colonoscopy quality criteria included a colonoscope withdrawal time above 6 to 10 minutes and colonoscopy completion by caecal intubation.

Besides bowel preparation, some situations limit caecal intubation: stenosis, diverticulitis, or haemodynamic instability. In the absence of one of those situations or similar, caecal intubation must be the goal to be achieved by every endoscopist. However, it sometimes represents a significant effort for the endoscopist. It can require additional techniques such as manual abdominal compression, postural changes, colonoscopy restart, and another endoscopist's new attempt. Also, this increases caecal intubation time by over 10 minutes, more anaesthesia and post-colonoscopy abdominal pain, with a higher risk of unnoticed lesions.

To the best of our knowledge, there is no standard definition for colonoscopy technical difficulty in terms of caecal intubation or any tool that grades it based on previously mentioned additional techniques. For the moment, developed tools such as the Difficult Colonoscopy Score (DCS) to consider patients' pre-colonoscopy factors such as age, body mass index (BMI), sleep quality, and endoscopist experience. Other tools are based on a qualitative appreciation of the technical difficulty.

A tool that documents those endpoints constitutes an additional objective quality criterion for colonic mucosa assessment, with critical change management during intra-colonoscopy and post-colonoscopy. Noticed a technically difficult colonoscopy deserves a more prolonged withdrawal time, more photo documentation, a more cautious discharge, more detailed patient instructions, and a personalised follow-up directed to adverse events warnings. A patient with a previous technically difficult colonoscopy will be planned for an earlier next colonoscopy, with a risk assessment independently on the age, pre-colonoscopy consulting with detailing of more potential adverse events, planned in a particular time and with a different anaesthesia planning, and even performed by a more experienced endoscopist or in a referral centre.

This study pursues to describe the frequency of additional techniques for caecal intubation in a large sample of Argentinians in different centres who undergo colonoscopy for attending purposes, to develop a novel score for assessing colonoscopy technical difficulty.

Inclusion criteria

• Patients with colonoscopy indication due to colorectal cancer screening, pre-existence surveillance, or diagnostic approach in symptomatic patients.
• Patients with colonoscopy indication due to therapeutic purposes, but with the intention of caecal intubation.

Exclusion criteria

• Patients with a previous colonoscopy performed by the attending centre in the last three months.
• Patients with a Boston Bowel Preparation Score (BBPS) ≤1 in at least one colon segment (ascending, transverse, descending).
• Patients with any situations which does not allow caecal intubation: colorectal stenosis, diverticulitis, the indication of proctosigmoidoscopy for assessing ulcerative colitis, or intraprocedural haemodynamic instability, among others.
• Patients with any contraindication for an invasive procedure: uncontrolled coagulopathy, kidney/liver failure or any comorbidity with an important impact on cardiac risk assessment or physical status: New York Heart Association (NYHA) risk III/IV, or American Society Association (ASA) risk III-V, respectively.