Hemostatic powders for gastrointestinal bleeding: a review of old, new, and emerging agents in a rapidly advancing field

A starry sky image result in a patient with active bleeding due to malignancy cause

Hemostatic powders (HP) are increasingly used to address limitations in conventional endoscopic techniques for gastrointestinal bleeding. HP is a relatively recent addition to the arsenal of hemostatic endoscopic procedures (HEPs) for gastrointestinal bleeding (GIB) due to benign and malignant lesions, which all life-threatening conditions. HP acts as a mechanical barrier and/or promotes platelet activation and coagulation cascade. Malignancy causes comprise 1-5% of all non-variceal upper gastrointestinal bleeding (NVUGIB). UI-EWD (NexPowder) is composed of oxidized dextran and succinic anhydride, which is converted to an adhesive hydrogel upon contact with moisture. The resulting hydrogel cross-links within itself and with adjacent tissue to create a mechanical barrier to promote hemostasis. As it does not require clot formation to achieve hemostasis, UI-EWD does not require active bleeding. This provides it a potential role in prophylaxis, such as post-procedure or following primary hemostasis achieved with conventional endoscopic techniques. While UI-EWD is the newest development in hemostatic powders for clinical use, initial results are promising. We report the case of a 51-year-old male with epidermoid esophageal stenosing carcinoma recently diagnosed and locally advanced. Started treatment concurrent chemotherapy and radiotherapy, being necessary a nasogastric tube for parenteral nutrition. Our patient came to the emergency unit due to hematemesis which came from a pressure ulcer with active bleeding shown in gastroscopy exploration, withdrawing the tube and spraying onto the surface of the bleeding site UI-EWD until the bleeding lesion was completely covered with the powder, doing successful hemostasis confirmed by hemostasis until 5 minutes after the endoscopic treatment. HP is highly effective in patients with NVUGIB when used either in combination with or as rescue therapy. Rapid development of hemostatic powders and growing clinical expertise has established these agents as a valuable strategy in gastrointestinal bleeding.

Hemospray® (hemostatic powder TC-325) as monotherapy for acute gastrointestinal bleeding: a multicenter prospective study

Background

Hemostatic powders are used as second-line treatment in acute gastrointestinal (GI) bleeding (AGIB). Increasing evidence supports the use of TC-325 as monotherapy in specific scenarios. This prospective, multicenter study evaluated the performance of TC-325 as monotherapy for AGIB.

Methods

Eighteen centers across Europe and USA contributed to a registry between 2016 and 2022. Adults with AGIB were eligible, unless TC-325 was part of combined hemostasis. The primary endpoint was immediate hemostasis. Secondary outcomes were rebleeding and mortality. Associations with risk factors were investigated (statistical significance at P≤0.05).

Results

One hundred ninety patients were included (age 51-81 years, male: female 2:1), with peptic ulcer (n=48), upper GI malignancy (n=79), post-endoscopic treatment hemorrhage (n=37), and lower GI lesions (n=26). The primary outcome was recorded in 96.3% (95% confidence interval [CI]: 92.6-98.5) with rebleeding in 17.4% (95%CI 11.9-24.1); 9.9% (95%CI 5.8-15.6) died within 7 days, and 21.7% (95%CI 15.6-28.9) within 30 days. Regarding peptic ulcer, immediate hemostasis was achieved in 88% (95%CI 75-95), while 26% (95%CI 13-43) rebled. Higher ASA score was associated with mortality (OR 23.5, 95%CI 1.60-345; P=0.02). Immediate hemostasis was achieved in 100% of cases with malignancy and post-intervention bleeding, with rebleeding in 17% and 3.1%, respectively. Twenty-six patients received TC-325 for lower GI bleeding, and in all but one the primary outcome was achieved.

Conclusions

TC-325 monotherapy is safe and effective, especially in malignancy or post-endoscopic intervention bleeding. In patients with peptic ulcer, it could be helpful when the primary treatment is unfeasible, as bridge to definite therapy.

Sprayable Hydrogel Sealant for Gastrointestinal Wound Shielding

Naturally occurring internal bleeding, such as in stomach ulcers, and complications following interventions, such as polyp resection post-colonoscopy, may result in delayed (5-7 days) post-operative adverse events-such as bleeding, intestinal wall perforation, and leakage. Current solutions for controlling intra- and post-procedural complications are limited in effectiveness. Hemostatic powders only provide a temporary solution due to their short-term adhesion to GI mucosal tissues (less than 48 h). In this study, a sprayable adhesive hydrogel for facile application and sustained adhesion to GI lesions is developed using clinically available endoscopes. Upon spraying, the biomaterial (based on polyethyleneimine-modified Pluronic micelles precursor and oxidized dextran) instantly gels upon contact with the tissue, forming an adhesive shield. In vitro and in vivo studies in guinea pigs, rabbits, and pig models confirm the safety and efficacy of this biomaterial in colonic and acidic stomach lesions. The authors' findings highlight that this family of hydrogels ensures prolonged tissue protection (3-7 days), facilitates wound healing, and minimizes the risk of delayed complications. Overall, this technology offers a readily adoptable approach for gastrointestinal wound management.

Use of TC-325 Hemostatic Powder as a Rescue Monotherapy for Management of Rectal Variceal Bleed

The use of the endoscopic hemostatic powder TC-325 as a rescue monotherapy or as an adjunct agent in achieving hemostasis has been studied in upper gastrointestinal variceal bleeds and nonvariceal lower gastrointestinal bleeds with promising results. In this report, we describe a case of a successful use of TC-325 as rescue monotherapy to manage rectal variceal bleeding in a patient with alcohol-related cirrhosis with no report of bleeding recurrence and no side effects within the first 7 days, 30 days, or 6 months.

Endoscopic Diagnosis, Grading, and Treatment of Bleeding Peptic Ulcer Disease

Peptic ulcer bleeding is a major cause for hospital admissions and has a significant mortality. Endoscopic interventions reduce the risk of rebleeding in high-risk patients and several options are available including injection therapies, thermal therapies, mechanical clips, hemostatic sprays, and endoscopic suturing. Proton-pump inhibitors and Helicobacter pylori treatment are important adjuncts to endoscopic therapy. Endoscopic therapy is indicated in Forrest 1a, 1b, and 2a lesions. Patients with Forrest 2b lesions may do well with proton-pump inhibitor therapy alone but can also be managed by removal of the clot and targeting endoscopic therapy to the underlying lesion.

Diagnosis and management of acute lower gastrointestinal bleeding

PURPOSE OF REVIEW

We review and summarize the most recent literature, including evidence-based guidelines, on the evaluation and management of acute lower gastrointestinal bleeding (LGIB).

RECENT FINDINGS

LGIB primarily presents in the elderly, often on the background of comorbidities, and constitutes a significant healthcare and economic burden worldwide. Therefore, acute LGIB requires rapid evaluation, informed decision-making, and evidence-based management decisions. LGIB management involves withholding and possibly reversing precipitating medications and concurrently addressing risk factors, with definitive diagnosis and therapy for the source of bleeding usually performed by endoscopic or radiological means. Recent advancements in LGIB diagnosis and management, including risk stratification tools and novel endoscopic therapeutic techniques have improved LGIB management and patient outcomes. In recent years, the various society guidelines on acute lower gastrointestinal bleeding have been revised and updated accordingly.

SUMMARY

By integrating the most recently published high-quality clinical studies and society guidelines, we provide clinicians with an up-to-date and comprehensive overview on acute LGIB diagnosis and management.

Endoscopic Management of Tumor Bleeding: Techniques and Strategies

Endoscopic management of gastrointestinal (GI) tumor-related bleeding is challenging for many reasons including high rebleeding rates, poor tissue response to endoscopic therapies, altered wound healing and underlying coagulopathy. However, endoscopic treatment may help reduce transfusion requirements, avoid surgery, and provide a temporary bridge to oncologic therapy. This article explores various endoscopic techniques in managing tumor bleeding from more traditional approaches of using thermal or mechanical therapy with injection therapy to newer topical agents.

Short Peptide Nanofiber Biomaterials Ameliorate Local Hemostatic Capacity of Surgical Materials and Intraoperative Hemostatic Applications in Clinics

Short designer self-assembling peptide (dSAP) biomaterials are a new addition to the hemostat group. It may provide a diverse and robust toolbox for surgeons to integrate wound microenvironment with much safer and stronger hemostatic capacity than conventional materials and hemostatic agents. Especially in noncompressible torso hemorrhage (NCTH), diffuse mucosal surface bleeding, and internal medical bleeding (IMB), with respect to the optimal hemostatic formulation, dSAP biomaterials are the ingenious nanofiber alternatives to make bioactive neural scaffold, nasal packing, large mucosal surface coverage in gastrointestinal surgery (esophagus, gastric lesion, duodenum, and lower digestive tract), epicardiac cell-delivery carrier, transparent matrix barrier, and so on. Herein, in multiple surgical specialties, dSAP-biomaterial-based nano-hemostats achieve safe, effective, and immediate hemostasis, facile wound healing, and potentially reduce the risks in delayed bleeding, rebleeding, post-operative bleeding, or related complications. The biosafety in vivo, bleeding indications, tissue-sealing quality, surgical feasibility, and local usability are addressed comprehensively and sequentially and pursued to develop useful surgical techniques with better hemostatic performance. Here, the state of the art and all-round advancements of nano-hemostatic approaches in surgery are provided. Relevant critical insights will inspire exciting investigations on peptide nanotechnology, next-generation biomaterials, and better promising prospects in clinics.

Endoscopic Resection Techniques for Duodenal and Ampullary Adenomas

Background and Aims

Duodenal polyps have a reported incidence of 0.3% to 4.6%. Sporadic, nonampullary duodenal adenomas (SNDAs) comprise less than 10% of all duodenal polyps, and ampullary adenomas are even less common. Nonetheless, the incidence continues to rise because of widespread endoscopy use. Duodenal polyps with villous features or those that are larger than 10 mm may raise concern for malignancy and require removal. We demonstrate endoscopic resection of SNDAs and ampullary adenomas using some of our preferred techniques.

Methods

The duodenum has several components that can make EMR of duodenal polyps technically challenging. Not only does the duodenum have a thin muscle layer, but it is also highly mobile and vascular, which may explain higher rates of perforation and bleeding of duodenal EMR reported in the literature compared with colon EMR. A standard adult gastroscope with a distal cap is commonly used for duodenal EMRs. Based on the location, however, side-viewing duodenoscopes or pediatric colonoscopes may be used. To prepare for EMR, a submucosal injection is performed for an adequate lift. The polyp is then resected via stiff monofilament snares and subsequently closed with hemostatic clips if feasible. The ampullectomy technique differs slightly from duodenal EMRs and carries the additional risk of pancreatitis. Submucosal injection in the ampulla may not lift well; thus, its utility is debatable. Biliary sphincterotomy should be performed, and based on endoscopist preference, the pancreatic duct (PD) guidewire can be left during resection to maintain access. After resection, a PD stent is placed to minimize pancreatitis risk.

Results

The video shows the aforementioned duodenal EMR techniques. Two clips of ampullectomy are also shown in the video.

Conclusions

A few common techniques used to perform duodenal EMR and ampullectomy are highlighted in the video. It is important to understand and manage adverse events associated with these procedures and to have established surveillance plans.

Polydopamine-Coated Polycaprolactone Electrospun Nanofiber Membrane Loaded with Thrombin for Wound Hemostasis

Hemorrhagic shock is the primary cause of death in patients with severe trauma, and the development of rapid and efficient hemostatic methods is of great significance in saving the lives of trauma patients. In this study, a polycaprolactone (PCL) nanofiber membrane was prepared by electrospinning. A PCL-PDA loading system was developed by modifying the surface of polydopamine (PDA), using inspiration from mussel adhesion protein, and the efficient and stable loading of thrombin (TB) was realized to ensure the bioactivity of TB. The new thrombin loading system overcomes the disadvantages of harsh storage conditions, poor strength, and ease of falling off, and it can use thrombin to start a rapid coagulation cascade reaction, which has the characteristics of fast hemostasis, good biocompatibility, high safety, and a wide range of hemostasis. The physicochemical properties and biocompatibility of the PCL-PDA-TB membrane were verified by scanning electron microscopy, the cell proliferation test, the cell adhesion test, and the extract cytotoxicity test. Red blood cell adhesion, platelet adhesion, dynamic coagulation time, and animal models all verified the coagulation effect of the PCL-PDA-TB membrane. Therefore, the PCL-PDA-TB membrane has great potential in wound hemostasis applications, and should be widely used in various traumatic hemostatic scenarios.

Novel through-the-scope suture closure of colonic EMR defects (with video)

BACKGROUND AND AIMS

Large colon polyps removed by EMR can be complicated by delayed bleeding. Prophylactic defect clip closure can reduce post-EMR bleeding. Larger defects can be challenging to close using through-the-scope clips (TTSCs), and proximal defects are difficult to reach using over-the-scope techniques. A novel, through-the-scope suturing (TTSS) device allows direct closure of mucosal defects without scope withdrawal. The goal of this study was to evaluate the rate of delayed bleeding after the closure of large colon polyp EMR sites with TTSS.

METHODS

A multicenter retrospective cohort study was performed involving 13 centers. All defect closure by TTSS after EMR of colon polyps ≥2 cm from January 2021 to February 2022 were included. The primary outcome was rate of delayed bleeding.

RESULTS

A total of 94 patients (52% female; mean age, 65 years) underwent EMR of predominantly right-sided (n = 62 [66%]) colon polyps (median size, 35 mm; interquartile range, 30-40 mm) followed by defect closure with TTSS during the study period. All defects were successfully closed with TTSS alone (n = 62 [66%]) or with TTSS and TTSCs (n = 32 [34%]), using a median of 1 (interquartile range, 1-1) TTSS system. Delayed bleeding occurred in 3 patients (3.2%), with 2 requiring repeated endoscopic evaluation/treatment (moderate).

CONCLUSION

TTSS alone or with TTSCs was effective in achieving complete closure of all post-EMR defects, despite a large lesion size. After TTSS closure with or without adjunctive devices, delayed bleeding was seen in 3.2% of cases. Further prospective studies are needed to validate these findings before wider adoption of TTSS for large polypectomy closure.

Hemostatic powder for acute upper gastrointestinal bleeding: Recent research advances

Acute upper gastrointestinal bleeding (AUGIB) is a clinically common emergency condition. The common causes of AUGIB are peptic ulcer and esophagogastric variceal bleeding. Despite continuous improvements in endoscopic hemostasis techniques, endoscopic treatment is still unsuccessful in 5%-15% of patients. Hemostatic powder, a new drug for endoscopic hemostasis that is sprayed on the bleeding site with the assistance of an air pump, can absorb water to promote clotting substance aggregation and then adhere over the lesion, forming a mechanical barrier and then achieving hemostasis. It is convenient to spray hemostatic powder under endoscopy, where precise positioning is not warranted. The immediate hemostasis rate of hemostatic powder is often high, and it can be used as a remedy after the failure of conventional hemostasis. However, until now, there have been no recommendations in China regarding the use of hemostatic powder for the treatment of AUGIB. This article summarizes the mechanism, clinical applicability, and side effects of five major types of hemostatic powder by reviewing the existing evidence, with an aim to strengthen endoscopists' understanding of this drug.

Hemostatic Powders in Non-Variceal Upper Gastrointestinal Bleeding: The Open Questions

Hemostatic powder (HP) is a relatively recent addition to the arsenal of hemostatic endoscopic procedures (HEPs) for gastrointestinal bleeding (GIB) due to benign and malignant lesions. Five types of HP are currently available: TC-325 (Hemospray™), EndoClot™, Ankaferd Blood Stopper^®, and, more recently, UI-EWD (Nexpowder^TM) and CEGP-003 (CGBio™). HP acts as a mechanical barrier and/or promotes platelet activation and coagulation cascade. HP may be used in combination with or as rescue therapy in case of failure of conventional HEPs (CHEPs) and also as monotherapy in large, poorly accessible lesions with multiple bleeding sources. Although the literature on HP is abundant, randomized controlled trials are scant, and some questions remain open. While HP is highly effective in inducing immediate hemostasis in GIB, the rates of rebleeding reported in different studies are very variable, and conditions affecting the stability of hemostasis have not yet been fully elucidated. It is not established whether HP as monotherapy is appropriate in severe GIB, such as spurting peptic ulcers, or should be used only as rescue or adjunctive therapy. Finally, as it can be sprayed on large areas, HP could become the gold standard in malignancy-related GIB, which is often nonresponsive or not amenable to treatment with CHEPs as a result of multiple bleeding points and friable surfaces. This is a narrative review that provides an overview of currently available data and the open questions regarding the use of HP in the management of non-variceal upper GIB due to benign and malignant diseases.