The diagnostic accuracy and safety of colonoscopy highly depends on the quality of the pre-procedural bowel preparation. A past history of poor bowel preparation is the most important risk factor of inadequate bowel cleansing at the next colonoscopy. This study aims to evaluate if an adequate level of bowel cleansing can be achieved with the Pure-Vu System in patients with previous poor bowel preparation, in a single arm international multicenter feasibility study.

Rationale: It is widely acknowledged that the efficacy and safety of colonoscopy depends on the quality of the pre-procedural bowel preparation. Despite its importance, the proportion of colonoscopies with inadequate bowel preparation still ranges from 6.8-33% across studies. A past history of poor bowel preparation is the most important risk factor of inadequate bowel cleansing at the next colonoscopy. (1, 2) Evidence to recommend a specific bowel cleansing regimen in these patients is currently lacking. (3) Mostly, patients with previous bowel preparation are advised to drink more oral purgatives, which is very difficult and unpleasant for patients and therefore often fails.

The aim of this study is to evaluate if an intra-procedural bowel cleaning device, the Pure-VuTM System (Tirat Carmel, Israel) can be used to achieve an adequate level of bowel cleansing in patients with previous poor bowel preparation.

Objective: The aim of this study is to evaluate if an adequate level of bowel cleansing can be achieved with the Pure-Vu System in patients with previous poor bowel preparation (Boston Bowel Preparation Scale [BBPS]<6).

Study design: We will perform a single arm international multicenter colonoscopy trial. Adult patients with previous poor bowel preparation (BBPS<6) will be invited to participate in our study (n= 44). All patients willing to participate will receive a limited bowel preparation (2-days of dietary restrictions + 2x 150ml picoprep) followed by intra-procedural bowel cleansing with the Pure-Vu System. The BBPS will be assessed before and after segmental washing by the endoscopist who performs the procedure and later by an independent endoscopist (photos).

Study population: Adult patients with poor bowel preparation within the last 2 years. Exclusion criteria; previous colon resection, previous colorectal cancer, colitis, lower gastrointestinal bleeding with hemodynamic instability, ASA>3, insufficiently corrected anticoagulation disorders, inability to provide informed consent.

Primary endpoint: The primary endpoint of the study will be the BBPS-score before and after intra-procedural bowel cleaning with the Pure-Vu System.

Secondary endpoints include:

• Total number of colon lesions specified by histology
• Adenoma detection rate
• Cecal intubation rates
• Procedure times (total procedure time, cecal intubation time, withdrawal time, time for all other interventions)
• Total amount of water used for washing and total amount of fluids+residual stool removed.
• Patient reported outcomes (level of discomfort during bowel preparation and during colonoscopy on a visual analog scale)
• System usability
• Endoscopists' learning curve
• Safety outcomes

Nature and extent of the burden and risk associated with participation, benefit and group relatedness: Colonoscopy is a commonly performed procedure and the overall serious adverse event (SAE) rate is low, around 2.8 per 1000 colonoscopies. The risk of adverse events (AE) with the Pure-Vu are believed to be equivalent to conventional colonoscopy, including bleeding and perforation risks (13). Participation in this study could potentially benefit colonoscopy patients because the Pure-Vu is expected to improve the quality of colonoscopy. Inadequate bowel cleansing may be prevented by the Pure-Vu System. Inadequate bowel cleansing is associated with lower adenoma detection rates (ADR), lower completion rates, longer procedure times, more complications and a higher need for repeat procedures.(4, 5) In addition, Pure-Vu reduces the reliance on patients pre-procedural bowel preparation which is often considered the most deterrent part of colonoscopy by patients.

Inclusion Criteria:

• Patients, aged between 18 and 80 years, referred and scheduled for either screening, diagnostic, or surveillance colonoscopy.
• Poor bowel preparation within the last 2 years, defined as a BBPS <6 or need for repeat colonoscopy or shortening of surveillance interval due to poor bowel preparation

Exclusion Criteria:

• Prior colon resection
• Previous colorectal cancer
• Colitis
• Lower gastrointestinal bleeding with hemodynamic instability
• Bowel obstruction
• Pregnancy or lactating
• ASA > 3
• Insufficiently corrected anticoagulation disorders
• Inability to provide informed consent

IPD will be shared upon reasonable request

Data will be shared upon reasonable request

Independent assessment of BBPS (photos).