Post Polypectomy BleedingPROCLIPNCT05169242
A Trial on Prophylactic Clipping to Prevent Post-polypectomy Bleeding After Colonoscopy in Direct Oral Anticoagulant Users
A study testing Endoclip in people with Post Polypectomy Bleeding, run by Chinese University of Hong Kong at 1 site in Hong Kong.
Trial summary
The investigators hypothesize that prophylactic clipping after colonoscopic polypectomy can reduce risk of delayed PPB among DOAC users. The investigators also hypothesize that pre-endoscopy drug level can predict the risk of hemorrhagic complications after the procedure. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Post Polypectomy Bleeding
- What is being tested?
- Endoclip
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 584 participants
- Where
- 1 siteHong Kong
- Study dates
- 15 Dec 2021to 29 Jul 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- They are active users of any DOAC
- They require elective colonoscopy for colorectal cancer screening, polyp surveillance, or investigation of symptoms such as anemia or past gastrointestinal bleeding
- Aged 18 years old or above;
- Written informed consent obtained.
Who cannot join
- Absolute contraindications to colonoscopy
- Any medical conditions precluding interruption of DOAC for procedure
- Any medical conditions requiring concomitant uninterrupted dual antiplatelet drugs (single antiplatelet drug users will not be excluded)
- Active gastrointestinal bleeding
- Clinically significant bleeding tendency (decompensated cirrhosis or severe thrombocytopenia)
- Severe renal impairment (defined as creatinine clearance < 15 ml/min)
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- Pregnancy or lactation;
- Advanced comorbid conditions (defined as American Society of Anesthesiologists grade 4 or above)
- Unable to obtain informed consent
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Double Blinded Randomized Controlled Trial on Prophylactic Clipping to Prevent Post-polypectomy Bleeding After Colonoscopy in Direct Oral Anticoagulant Users
The investigators hypothesize that prophylactic clipping after colonoscopic polypectomy can reduce risk of delayed PPB among DOAC users. The investigators also hypothesize that pre-endoscopy drug level can predict the risk of hemorrhagic complications after the procedure.
Read the detailed description
Despite the clinical benefit of colonoscopic polypectomy, post-polypectomy bleeding (PPB) occurs in up to 6.5% of patients. Current international guidelines classify polypectomy as one of the endoscopic procedures with high risk of hemorrhage.
Risk factors for PPB include advanced age, cardiovascular or renal diseases, large polyp size, pedunculated morphology, proximal location in right colon, and the use of antithrombotic medications. Among them, the use of oral anticoagulants such as warfarin and direct oral anticoagulants (DOAC) is associated with a substantially higher risk of PPB up to 13.7%.
While prophylactic clipping is often performed by endoscopists to reduce the PPB risk in clinical practice, the available evidence on its efficacy has been heterogenous and conflicting. A number of studies reported the efficacy of prophylactic clip closure after endoscopic resection to prevent PPB. On the contrary, several randomized trials did not demonstrate any significant benefit of prophylactic clipping. In recent meta-analyses, routine use of prophylactic clipping was not shown to decrease PPB risk, except in a subgroup of colonic lesion larger than 20mm and proximal to the hepatic flexure. However, the proportion of patients on oral anticoagulants was low (5.1%-26%) in the above studies, limiting the generalizability of results to this high-risk patient group. Our preliminary data involving >500 patients on oral anticoagulants showed a lower PPB risk in prophylactic clipping group among DOAC users.
Also, although the consensus is that DOAC users do not require routine drug level monitoring, studies have shown a positive correlation between plasma drug level and bleeding risks. In special circumstances, the measurement of anticoagulant effect would provide management guide, including patients with extreme body weight or renal impairment, imminent need of antidote reversal or before invasive surgical procedures. Diluted thrombin time and anti-factor Xa assays demonstrated a reasonable linear correlation with the plasma drug concentration, yet they are indirect tests. Specific DOAC drug level can be checked to provide direct measurement of anticoagulant effect. In the setting of elective invasive procedures, a pre-operative cutoff level (≦30 ng/mL) for dabigatran and rivaroxaban has been proposed. Patients undergoing interventions with high bleeding risks may benefit from drug level measurement by informing the operators to perform prophylactic measures to reduce hemorrhagic complications.
In this randomized controlled trial, we aim to evaluate the efficacy of prophylactic clipping in preventing PPB in colonoscopy among DOAC users. We also wish to investigate the correlation of pre-endoscopy DOAC drug level and the risk of hemorrhagic complications after the procedure.
- Conditions
- Post Polypectomy Bleeding
- Being tested
- Endoclip
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EndoclipProcedure or surgery
In the intervention arm, one or more endoclips will be used to completely close the mucosal defect after polypectomy. Prophylactic clipping will be applied to all post-polypectomy sites. The total number of endoclips used will be recorded.
| Study group | Role | What they receive |
|---|---|---|
| Intervention group | Experimental | In the intervention arm, one or more endoclips will be used to completely close the mucosal defect after polypectomy. Prophylactic clipping will be applied to all post-polypectomy sites. The total number of endoclips used will be recorded. Receives: Procedure: Endoclip |
| Control group | No intervention | In the control arm, no endoclip will be applied to all post-polypectomy sites, with the exceptions of uncontrolled immediate PPB or pre-treatment in very large pedunculated polyps as specified above. The subjects with endoclips applied due to safety reasons will be included in the subsequent intention-to-treat analysis, but not the per-protocol analysis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Clinically significant delayed post-polypectomy bleeding
The primary endpoint is clinically significant delayed post-polypectomy bleeding.
Measured: 2 years
Secondary outcomes (1)
Overall delayed post-polypectomy bleeding rate and cardio-thrombotic event rate
Secondary endpoints are overall delayed post-polypectomy bleeding rate, cardio-thrombotic event rate within 30 days after procedure and pre-endoscopy DOAC drug levels. Overall delayed post-polypectomy bleeding is defined as occurrence of any gastrointestinal bleeding within 30 days after index colonoscopy (including those not fulfilling the criteria of primary endpoint). Cardio-thrombotic events are defined according to the Antithrombotic Trialists' criteria (non-fatal myocardial infarction, non-fatal stroke, or death from cardiovascular cause). [44] The baseline and trough DOAC drug levels measured before colonoscopy would also be analyzed and correlated with clinical bleeding or thrombotic events.
Measured: 2 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Dec 2021
- Study start15 Dec 2021
- Primary completion15 Jan 2025
- Study completion29 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Post Polypectomy BleedingStudies of the same condition, open and under way.
- More trials run by Chinese University of Hong KongThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 584 participants (actual)
Sponsor and investigators
- Lead sponsor
- Chinese University of Hong Kong
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Louis Ho Shing Lau, Chinese University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05169242
- Sponsor's protocol ID
- 2021.381
- Acronym
- PROCLIP
- Status last verified
- Sep 2026
- First submitted
- 9 Sep 2021
- Last updated
- 24 Sep 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Double Blinded Randomized Controlled Trial on Prophylactic Clipping to Prevent Post-polypectomy Bleeding After Colonoscopy in Direct Oral Anticoagulant Users
- ClinicalTrials.gov ID
- NCT05169242
- Acronym / sponsor ID
- PROCLIP / 2021.381
- Conditions
- Post Polypectomy Bleeding
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 584 participants (actual)
- Lead sponsor
- Chinese University of Hong KongUniversity, hospital or other
- Study start
- 15 Dec 2021 (actual)
- Primary completion
- 15 Jan 2025 (actual)
- Study completion
- 29 Jul 2025 (actual)
- First posted
- 23 Dec 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The investigators hypothesize that prophylactic clipping after colonoscopic polypectomy can reduce risk of delayed PPB among DOAC users. The investigators also hypothesize that pre-endoscopy drug level can predict the risk of hemorrhagic complications after the procedure.
Detailed description
Despite the clinical benefit of colonoscopic polypectomy, post-polypectomy bleeding (PPB) occurs in up to 6.5% of patients. Current international guidelines classify polypectomy as one of the endoscopic procedures with high risk of hemorrhage.
Risk factors for PPB include advanced age, cardiovascular or renal diseases, large polyp size, pedunculated morphology, proximal location in right colon, and the use of antithrombotic medications. Among them, the use of oral anticoagulants such as warfarin and direct oral anticoagulants (DOAC) is associated with a substantially higher risk of PPB up to 13.7%.
While prophylactic clipping is often performed by endoscopists to reduce the PPB risk in clinical practice, the available evidence on its efficacy has been heterogenous and conflicting. A number of studies reported the efficacy of prophylactic clip closure after endoscopic resection to prevent PPB. On the contrary, several randomized trials did not demonstrate any significant benefit of prophylactic clipping. In recent meta-analyses, routine use of prophylactic clipping was not shown to decrease PPB risk, except in a subgroup of colonic lesion larger than 20mm and proximal to the hepatic flexure. However, the proportion of patients on oral anticoagulants was low (5.1%-26%) in the above studies, limiting the generalizability of results to this high-risk patient group. Our preliminary data involving >500 patients on oral anticoagulants showed a lower PPB risk in prophylactic clipping group among DOAC users.
Also, although the consensus is that DOAC users do not require routine drug level monitoring, studies have shown a positive correlation between plasma drug level and bleeding risks. In special circumstances, the measurement of anticoagulant effect would provide management guide, including patients with extreme body weight or renal impairment, imminent need of antidote reversal or before invasive surgical procedures. Diluted thrombin time and anti-factor Xa assays demonstrated a reasonable linear correlation with the plasma drug concentration, yet they are indirect tests. Specific DOAC drug level can be checked to provide direct measurement of anticoagulant effect. In the setting of elective invasive procedures, a pre-operative cutoff level (≦30 ng/mL) for dabigatran and rivaroxaban has been proposed. Patients undergoing interventions with high bleeding risks may benefit from drug level measurement by informing the operators to perform prophylactic measures to reduce hemorrhagic complications.
In this randomized controlled trial, we aim to evaluate the efficacy of prophylactic clipping in preventing PPB in colonoscopy among DOAC users. We also wish to investigate the correlation of pre-endoscopy DOAC drug level and the risk of hemorrhagic complications after the procedure.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Intervention group | Experimental | Procedure: EndoclipIn the intervention arm, one or more endoclips will be used to completely close the mucosal defect after polypectomy. Prophylactic clipping will be applied to all post-polypectomy sites. The total number of endoclips used will be recorded. |
| Control group | No intervention | –In the control arm, no endoclip will be applied to all post-polypectomy sites, with the exceptions of uncontrolled immediate PPB or pre-treatment in very large pedunculated polyps as specified above. The subjects with endoclips applied due to safety reasons will be included in the subsequent intention-to-treat analysis, but not the per-protocol analysis. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- They are active users of any DOAC
- They require elective colonoscopy for colorectal cancer screening, polyp surveillance, or investigation of symptoms such as anemia or past gastrointestinal bleeding
- Aged 18 years old or above;
- Written informed consent obtained.
Key exclusion criteria (9 listed)
- Absolute contraindications to colonoscopy
- Any medical conditions precluding interruption of DOAC for procedure
- Any medical conditions requiring concomitant uninterrupted dual antiplatelet drugs (single antiplatelet drug users will not be excluded)
- Active gastrointestinal bleeding
- Clinically significant bleeding tendency (decompensated cirrhosis or severe thrombocytopenia)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| EndoclipIn the intervention arm, one or more endoclips will be used to completely close the mucosal defect after polypectomy. Prophylactic clipping will be applied to all post-polypectomy sites. The total number of endoclips used will be recorded. | Procedure or surgery | Intervention group |
Primary outcome
Clinically significant delayed post-polypectomy bleeding
Time frame: 2 years
The primary endpoint is clinically significant delayed post-polypectomy bleeding.
1 secondary outcome
Overall delayed post-polypectomy bleeding rate and cardio-thrombotic event rate
Time frame: 2 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Sep 2026.
- Individual participant dataSharing planned: No
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Myocardial Infarction (MI), Cardiovascular Events
Not yet recruitingPhase 4
Prevention of Delayed Post-polypectomy Bleeding by Endoscopic Sucralfate Spray in High-risk Patients: A Randomized Controlled Trial
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Endoclip in people with Post Polypectomy Bleeding, run by Chinese University of Hong Kong at 1 site in Hong Kong.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Clinically significant delayed post-polypectomy bleeding (time frame: 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Sep 2026.