Hemostatic Use of Over-the-Scope Clips in Non-Variceal Upper Gastrointestinal Bleeding: A Narrative Review

James Y.W. Lau

doi:10.7704/kjhugr.2025.0072

Korean J Helicobacter Up Gastrointest Res > Volume 25(4); 2025 > Article

Lau: Hemostatic Use of Over-the-Scope Clips in Non-Variceal Upper Gastrointestinal Bleeding: A Narrative Review

Review

The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2025;25(4):342-349.

Published online: December 4, 2025

DOI: https://doi.org/10.7704/kjhugr.2025.0072

Hemostatic Use of Over-the-Scope Clips in Non-Variceal Upper Gastrointestinal Bleeding: A Narrative Review

James Y.W. Lau

Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong

Corresponding author James Y.W. Lau, MD Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Room 64009, 4/F, Clinical Science Building 32, Ngan Shing Street, Shatin, NT, Hong Kong E-mail: laujyw@surgery.cuhk.edu.hk

Received October 23, 2025; Revised November 14, 2025; Accepted November 18, 2025;

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The over-the-scope clip (OTSC) system is increasingly used for the endoscopic hemostasis of bleeding non-variceal upper gastrointestinal lesions. OTSCs provide secure, full-thickness tissue compression. The Stop the Bleeding Trial (STING-1) was a German multicenter randomized controlled trial (RCT) that compared OTSC to standard treatment (through-the-scope clips and contact thermal devices) for refractory bleeding ulcers. The rate of further bleeding was significantly reduced with the use of OTSC (19 of 33 patients [57.6%] in the standard therapy group and 5 of 33 patients [15.2%] in the OTSC group). As a first-line endoscopic treatment, OTSCs have been compared with standard treatments in five RCTs, including the STING-2 trial. OTSCs are generally superior in controlling bleeding. Therefore, we recommend the use of OTSCs for lesions with a high risk of further bleeding. These include large ulcers (2 cm in size or larger) located at the duodenal bulb and the lesser curve of the stomach, and ulcers with vessels >2 mm in size. We have also used OTSCs for Dieulafoy’s lesions, often with thick submucosal arteries. An ongoing RCT is comparing the use of OTSCs with trans-arterial embolization (TAE) for refractory bleeding. TAE is considered the most definitive, but is associated with a 30% rate of further bleeding. The results of the RCT will help define the management algorithm for such cases.

Key words: Hemostasis; Endoscopic hemostasis; Embollization; Therapeutic; Gastrointestinal hemorrhagen

INTRODUCTION

The over-the-scope clip (OTSC) system was developed in the early 2000s by Ovesco Endoscopy AG, a company based in Tübingen, Germany. The fundamental idea was to endoscopically mimic surgical suturing by performing a U-stitch suture or partial stapling using a flexible endoscope. The clips were designed to close defects or perforations in the gastrointestinal (GI) tract such as fistulas, leaks, and bleeding lesions. The OTSC is often referred to as a “bear claw” because of the shape of its teeth to grasp tissue. The clip was made of a nitinol–titanium alloy, which is a shape-memory alloy. The clip offers reliable, strong, and sustained full-thickness tissue compression and approximation. The clip was mounted in a hood on the tip of an endoscope and deployed over the target area, similar to band ligators for variceal bleeding. The original clip contained blunt round teeth. The clips were modified with spikes (T-type clips) to allow firm tissue fixation (Fig. 1).

EARLY SERIES ON THE USE OF OTSC

In 2007, Kirschniak et al. [1] first reported the use of OTSCs in 11 patients with perforations or bleeding. This study demonstrated the feasibility and effectiveness of OTSCs in controlling acute GI bleeding, including arterial bleeding. There are many series to follow. Mönkemüller et al. [2] were the first to describe the use of OTSCs in managing four patients with massive bleeding from posterior duodenal ulcers. Subsequently, a case series was conducted to confirm the hemostatic efficacy of OTSC. A retrospective study by the same group [3] evaluated the use of OTSC in 12 patients with severe GI bleeding. The study reported a 100% success rate in achieving immediate hemostasis and concluded that OTSC was particularly effective in cases where conventional methods failed, providing a reliable alternative for achieving hemostasis. We reported our initial experience with OTSCs as a rescue treatment in nine patients with peptic and malignant ulcers and reported a clinical effectiveness of 77.8% [4]. The number of cases in case series continues to increase. Gölder et al. [5] reported clinical success in 75.8% and 73.5% of the cases using OTSCs for primary and secondary hemostasis, respectively, in a series of 100 patients.

THE STOP THE BLEEDING STING-1 TRIAL

The Stop the Bleeding (STING) trial was the only randomized controlled trial (RCT) [6] that compared endoscopic treatment with OTSCs to standard treatments (through-the-scope [TTS] clips or thermal devices). This multicenter study was conducted in Germany. Patients with recurrent or refractory bleeding from peptic ulcers or Dieulafoy lesions were randomized. Further bleeds within 30 days of treatment occurred in 15.2% of 33 patients treated with OTSCs compared to 57.6% of 33 patients treated with standard therapies (odds ratio: 0.2; 95% confidence interval: 0.06–0.63). This study provided definitive evidence that OTSCs are a superior option for managing refractory non-variceal upper gastrointestinal bleeding (NVUGIB) compared with conventional methods.

THE PRIMARY USE OF OTSC

Five RCTs [7-11] compared OTSCs as the first-line treatment with standard endoscopic hemostasis for NVUGIB (Table 1).

Jensen et al. [7] published the first RCT with 53 patients (25 OTSC, 28 standard). Only one patient in the OTSC group had an unusually high rate of rebleeding with standard treatment (28.6%). Stop-the-Bleeding Trial 2 (STING-2) [10] was a German multicenter study that assessed the first-line use of OTSCs. Initial control with OTSCs was universal in all 48 randomly assigned patients. Persistent bleeding was observed in six of the 52 patients treated using standard methods. Recurrent bleeding was observed in four (8.3%) and eight (15.4%) patients in the OTSC and standard groups, respectively. A study from the Asia-Pacific region [8] enrolled only ulcers 15 mm in size or larger. One hundred patients were included in the study. On intention-to-treat analysis, 30-day rebleeding occurred in 5 of 50 (10%) patients in the OTSC group vs. 9 of 50 (18%) in the standard treatment group. The authors concluded that the routine use of OTSC as a first-line treatment was not associated with a significant decrease in rebleeding. In this RCT, the rate of unsuccessful OTSC placement was high (8%). The rate of further bleeding after successful OTSC was significantly lower (4.35% vs. 18.75%, p=0.03). This suggests a learning curve for the endoscopic use of OTSCs.

Here, we report a multicenter RCT [9] conducted in Hong Kong and China. In intention-to-treat analysis, the 30-day probabilities of further bleeding in the OTSC and standard treatment groups were 3.2% (3/93) and 14.6% (14/97), respectively. In our trial, we excluded approximately 10 eligible patients. These included patients with post-bulbar stenosis and lesions near the esophagogastric junction (Cameron lesions) with luminal obstruction after OTSC application. Furthermore, OTSCs could not be positioned successfully in 5% of the randomized patients. In the OTSC group, we reported a complication of pyloric obstruction caused by a pseudo-polyp from OTSC treatment of a prepyloric ulcer. There was also a case of perforation due to a bulbar ulcer after OTSC. Gas insufflation during endoscopy may have opened previously sealed ulcers.

Last year, Soriani et al. [11] reported another RCT that compared OTSCs to scope clips in 112 of 251 screened patients; the successful initial hemostasis rates were 98.4% (60/61) in the OTSC group and 78.4% (40/51) in the TTS clip group (p=0.001). One patient and two patients bled again within 30 days. The overall clinical success rates were 96.7% (59/61) with the OTSCs and 74.5% (38/51) with the TTS clips (p=0.001).

There are some limitations to these trials. The most important issue is the option to cross over to another treatment if the assigned treatment fails. It is difficult to define failure in the initial control of bleeding using standard thermal devices or TTS clips. The low threshold for switching favors the results of the OTSCs. The exclusion of some cases indicated that the endoscopists were selecting their cases for OTSC application.

Overall, OTSCs appear to be superior to standard treatments for controlling bleeding from NVUGIB. OTSCs appear to offer the greatest benefit in lesions considered to be at a high risk of failure with standard treatments. There is also a learning curve in the use of OTSCs. We must carefully select cases that are anatomically suitable for use with OTSCs.

COMPLICATIONS

OTSCs are generally considered safe for managing GI bleeding. Clip-related complications include misplacement and mal-deployment. The clip may not be deployed correctly, leading to failure to achieve hemostasis. Further endoscopic treatment of vessels underneath an OTSC may be difficult. The clip may detach prematurely, particularly if the tissue is friable or fibrotic, thereby provoking bleeding. Many endoscopists are concerned about local tissue ischemia or necrosis caused by excessive compression. However, this complication has not been reported. The clip was designed such that there were gaps between the teeth to avoid tissue strangulation. Here, we present a case of pyloric obstruction. Rarely, patients may experience discomfort at the site of clip placement, especially in sensitive areas, such as the esophagus or duodenum. The clips were cut using a bipolar direct-current grasping device (remOVE system; Ovesco) [12]. The long-term complications associated with OTSC are not fully understood. In theory, granulation tissue can form around a clip.

INDICATIONS FOR THE USE OF OTSC

The European Society of Gastrointestinal Endoscopy (ESGE) [13] recommends OTSC as a rescue therapy. The American Society for Gastrointestinal Endoscopy (ASGE) [14] in addition suggests the use of OTSC as an option for difficult-totreat bleeding, particularly in high-risk patients or lesions.

OTSCs are mostly used as a rescue therapy when conventional endoscopic methods (e.g., TTS clips, thermal therapy, or injection therapy) fail to achieve hemostasis. The clinical scenarios included failed initial hemostasis, persistent bleeding despite standard endoscopic treatment, and recurrent bleeding after initial hemostasis.

We have also used OTSC as the primary treatment for lesions associated with a significant risk of recurrent bleeding or failure of conventional hemostatic methods. The Mayo group [15] defined high-risk lesions as those situated in the area of a major artery and larger than 2 mm in diameter and/or a deep penetrating, excavated, fibrotic ulcer with high-risk stigmata in which perforation could not be ruled out. We agree with these indications. Large posterior bulbar and the lesser curvature ulcers can erode into the gastroduodenal and left gastric artery complexes, respectively. We also used OTSCs to treat Dieulafoy lesions (Fig. 2). They typically appear near the cardia in the high-lesser curve. Bleeding originates from the thick submucosal arteries that erode through the mucosa, causing severe bleeding.

OTSC may also be preferred in patients with clinical factors that increase the risk of rebleeding or complications. A mechanical hemostatic device, such as an OTSC, is preferred in patients with coagulopathy, such as those on anticoagulants or with clotting disorders. We also considered the use of OTSC in patients who presented with severe bleeding and unstable hemodynamics, particularly those with significant comorbid illnesses that increase the risk of poor outcomes.

TECHNICAL TIPS IN THE APPLICATION OF OTSC

In the upper GI tract, we generally use a standard GIF scope with a waterjet function for the OTSC. The GIF scope is more maneuverable. Irrigation is crucial for clearing clots and accurately placing an OTSC over the vessel. We generally use 11T, which is a traumatic type with sharp teeth. The teeth grip and hold firmly to prevent slippage from the pulsatile vessels. A retrospective comparative study [16] suggested that outcomes following the use of OTSCs with blunt teeth were better. With a short cap, we would obtain an en-face view of the bleeding lesion and avoid tangential application of the OTSC. In emergencies, we suggest assembling the system on the back table with a second scope. Before reinserting the endoscope, we ensure that the cap has been firmly pushed into its end. We use gentle suction to draw the tissue and bleeding point into the cap, and ask our assistant to turn the cogwheel, releasing the clip while maintaining my cap position on the lesion. If the lesion is located in a difficult position (e.g., angular notch or low lesser curvature with the scope in retroflexion) or if the tissue is hard and fibrotic, we recommend the use of an anchor device. We punctured the ulcer next to the vessel and pushed the OTSC into position (Fig. 3).

CURRENT RESEARCH

The current standard of care for patients with refractory bleeding from peptic ulcers and other non-variceal causes has not yet been clearly defined. European guidelines recommend the use of either surgery or angiographic embolization [17]. In a meta-analysis [18], retrospective comparative studies between surgery and trans-arterial embolization (TAE) reported a high rate of further bleeding. The pooled rate of further bleeding after TAE was 51/178 (32%) compared to 26/241 (14.9%) after surgery. The high rate of further bleeding can be attributed to the rich vascular supply of peptic ulcers, especially those in the bulbar duodenum. Bulbar ulcers receive a dual arterial supply from the celiac and superior mesenteric artery systems. The anterior and posterior pancreaticoduodenal arcades are formed by branches from the gastroduodenal artery (GDA), superior and the inferior pancreaticoduodenal arteries. There are considerable anatomical variations. Often, we see “backdoor” bleeding from collaterals after GDA coiling.

OTSCs have emerged as an alternative to TAE and are often considered the most definitive. An ongoing RCT is comparing OTSC with TAE to test the hypothesis that OTSC may be better than TAE in controlling refractory bleeding (Clinical trial registry: NCT04902248). In clinical practice, OTSCs are used because of their immediate availability before TAE. These two treatments are likely to complement one another under challenging conditions (Fig. 4).

CONCLUSION

The OTSC system is considered to be a game-changer in endoscopic hemostasis, offering durable and full-thickness compression, high success rates, and low rebleeding risk. Although technically demanding, its benefits in high-risk NVUGIB are well-supported by evidence from the literature. OTSCs are particularly suited for the treatment of high-risk lesions with erosion into major arterial complexes. An algorithm for the use of OTSC for acute NVUGIB is presented in Fig. 5.

Notes

Availability of Data and Material

Data sharing not applicable to this article as no datasets were generated or analyzed during the study.

Conflicts of Interest

The author has no financial conflicts of interest.

Funding Statement

None

Acknowledgements

None

Fig. 1.

A T-type over-the-scope clip in a transparent hood and the anchor device.

Fig. 2.

Endoscopic application to a bleeding Dieulafoy’s lesion near the cardia of the stomach. A and B: A bleeding Dieulafoy’s lesion located at the lesser curvature of the stomach. C: An OTSC was used, incorporating multiple through-the-scope clips. D: An OTSC was deployed leading to hemostasis. OTSC, over-the-scope clip.

Fig. 3.

Endoscopic use of the OTSC in an angular notch ulcer with a large visible vessel. A: An angular incisural ulcer with a large visible vessel. B: An anchor device was used to puncture the base of the ulcer, and the ulcer was gently pulled into the cap. C: An OTSC was deployed with the anchor in situ. D: The anchor device was retracted leaving the OTSC compressing the vessel. OTSC, over-the-scope clip.

Fig. 4.

Endoscopic treatment of a pseudoaneurysm of the pancreaticoduodenal artery after transarterial embolization. A: A pulsatile artery supplying a bulbar ulcer. B: A transparent cap with an OTSC was pushed onto the bleeding vessel. C: An OTSC was deployed over the vessel. The pulsation disappeared after OTSC use. D: Angiography reveals a pseudoaneurysm of the superior pancreaticoduodenal artery. The patient underwent embolization of the gastroduodenal artery and developed recurrent bleeding from the retrograde filling of the aneurysm via collaterals of the inferior pancreaticoduodenal artery. OTSC, over-the-scope clip.

Fig. 5.

Indications for use of OTSCs in acute non-variceal upper gastrointestinal bleeding. OTSC, over-the-scope clip.

Table 1.

Randomized controlled trials that compared endoscopic use of OTSCs to standard treatment in patients with bleeding peptic ulcers or Dieulafoy’s lesions

Study	Participant	Primary endpoint	Failed initial control OTSC vs. standard	Recurrent bleeding OTSC vs. standard	Further bleeds OTSC vs. standard	Risk ratio in further bleeds, OR (95% CI)
Jensen et al., [7] 2021	53	Clinically significant continued or recurrent bleeds within 30 days	-	1/25 (4) vs. 8/28 (26.8)	1/25 (4) vs. 8/28 (26.8)	0.10 (0.01 to 0.91)
Meier et al., [10] 2022	100	Clinical success defined as successful endoscopic hemostasis without evidence of recurrent bleeds within 30 days	0/48 (0) vs. 6/52 (11.5)	4/48 (8.3) vs. 8/52 (15.4)	6/48 (12.5) vs. 14/52 (26.9)	0.54 (0.17 to 1.69)
Chan et al., [8] 2023^*	100	Clinical rebleeding within 30 days	4/50 (8) vs. 2/50 (4)	5/50 (10) vs. 9/50 (18)	5/50 (10) vs. 9/50 (18)	0.56 (0.20 to 1.52)
Lau et al., [9] 2023	190	30-day probability of further bleeds	1/93 (1.1) vs. 6/97 (6.2)	2/93 (2.2) vs. 8/97 (8.8)	3/93 (3.2) vs. 14/97 (14.6)	0.22 (0.07 to 0.75)
Soriani et al., [11] 2024	112	The rate of 30-day rebleeding after successful initial hemostasis	1/61 (1.6) vs. 11/51 (21.6)	1/61 (1.8) vs. 2/51 (3.9)	2/61 (3.3) vs. 13/51 (25.4)	0.096 (0.02 to 0.40)

Values are presented as n/n (%) unless otherwise indicated.

^* The study included only ulcers 15 mm or larger in size.

OTSC, over-the-scope clip; OR, odds ratio; CI, confidence interval.

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