Results from a First-in-Human Trial of a Novel Vascular Sealant

TAVAC: comprehensive review of currently available hemostatic products as adjunct to surgical hemostasis

BACKGROUND

The use of hemostatic agents by general surgeons during abdominal operations is commonplace as an adjunctive measure to minimize risks of postoperative bleeding and its downstream complications. Proper selection of products can be hampered by marginal understanding of their pharmacokinetics and pharmacodynamics. While a variety of hemostatic agents are currently available on the market, the choice of those products is often confusing for surgeons. This paper aims to summarize and compare the available hemostatic products for each clinical indication and to ultimately better guide surgeons in the selection and proper use of hemostatic agents in daily clinical practice.

METHODS

We utilized PubMed electronic database and published product information from the respective pharmaceutical companies to collect information on the characteristics of the hemostatic products.

RESULTS

All commercially available hemostatic agents in the US are described with a description of their mechanism of action, indications, contraindications, circumstances in which they are best utilized, and expected results.

CONCLUSION

Hemostatic products come with many different types and specifications. They are valuable tools to serve as an adjunct to surgical hemostasis. Proper education and knowledge of their characteristics are important for the selection of the right agent and optimal utilization.

Progress of tissue adhesives based on proteins and synthetic polymers

In recent years, polymer-based tissue adhesives (TAs) have been developed as an alternative to sutures to close and seal incisions or wounds owing to their ease of use, rapid application time, low cost, and minimal tissue damage. Although significant research is being conducted to develop new TAs with improved performances using different strategies, the applications of TAs are limited by several factors, such as weak adhesion strength and poor mechanical properties. Therefore, the next-generation advanced TAs with biomimetic and multifunctional properties should be developed. Herein, we review the requirements, adhesive performances, characteristics, adhesive mechanisms, applications, commercial products, and advantages and disadvantages of proteins- and synthetic polymer-based TAs. Furthermore, future perspectives in the field of TA-based research have been discussed.

Emerging albumin hydrogels as personalized biomaterials

Developing biomaterials-based tissue engineering scaffolds with personalized features and intrinsic biocompatibility is appealing and urgent. Through utilizing various strategies, albumin, as the most abundant protein in plasma, could be fabricated into sustainable, cost-effective, and potentially personalized hydrogels that would display enormous biological applications. To date, much of the albumin-based research is primarily engrossed in using albumin as a therapeutic molecule or a drug carrier, not much as a scaffold for tissue engineering. For this reason, we have come up with a detailed and insightful review of recent progress in albumin-based hydrogels having an emphasis on production techniques, material characteristics, and biological uses. It is envisioned that albumin-based scaffolds would be appealing and useful platforms to meet current tissue engineering needs and achieve the goal of clinical translation to benefit patients. STATEMENT OF SIGNIFICANCE: The creation of autologous material-based scaffolds is a potential method for preventing immunological reactions and obtaining the best therapeutic results. Patient-derived albumin hydrogels may consequently provide improved opportunities for personalized treatment due to their abundant supply and minimal immunogenicity. To provide a detailed and insightful summary on albumin-based hydrogels, this review includes latest comprehensive information on their preparation procedures, features, and applications in 3D printing and other biomedical applications. The challenges, along with the future potential for implementing albumin-based hydrogels in clinics, have also been addressed.

Injectable Adhesive Hydrogels for Soft tissue Reconstruction: A Materials Chemistry Perspective

Injectable bioadhesives offer several advantages over conventional staples and sutures in surgery to seal and close incisions or wounds. Despite the growing research in recent years few injectable bioadhesives are available for clinical use. This review summarizes the key chemical features that enable the development and improvements in the use of polymeric injectable hydrogels as bioadhesives or sealants, their design requirements, the gelation mechanism, synthesis routes, and the role of adhesion mechanisms and strategies in different biomedical applications. It is envisaged that developing a deep understanding of the underlying materials chemistry principles will enable researchers to effectively translate bioadhesive technologies into clinically-relevant products.

Application and outlook of topical hemostatic materials: a narrative review

Bleeding complications can cause significant morbidities and mortalities in both civilian and military conditions. The formation of stable blood clots or hemostasis is essential to prevent major blood loss and death from excessive bleeding. However, the body's self-coagulation process cannot accomplish timely hemostasis without the assistance of hemostatic agents under some conditions. In the past two decades, topical hemostatic materials and devices containing platelets, fibrin, and polysaccharides have been gradually developed and introduced to induce faster or more stable blood clot formation, updating or iterating traditional hemostatic materials. Despite the various forms and functions of topical hemostatic materials that have been developed for different clinical conditions, uncontrolled hemorrhage still causes over 30% of trauma deaths across the world. Therefore, it is important to fabricate fast, efficient, safe, and ready-to-use novel hemostatic materials. It is necessary to understand the coagulation process and the hemostatic mechanism of different materials to develop novel topical hemostatic agents, such as tissue adhesives and sealants from various natural and synthetic materials. This review discusses the structural features of topical hemostatic materials related to the stimulation of hemostasis, summarizes the commercially available products and their applications, and reviews the ongoing clinical trials and recent studies concerning the development of different hemostatic materials.

Polymeric Tissue Adhesives

Polymeric tissue adhesives provide versatile materials for wound management and are widely used in a variety of medical settings ranging from minor to life-threatening tissue injuries. Compared to the traditional methods of wound closure (i.e., suturing and stapling), they are relatively easy to use, enable rapid application, and introduce minimal tissue damage. Furthermore, they can act as hemostats to control bleeding and provide a tissue-healing environment at the wound site. Despite their numerous current applications, tissue adhesives still face several limitations and unresolved challenges (e.g., weak adhesion strength and poor mechanical properties) that limit their use, leaving ample room for future improvements. Successful development of next-generation adhesives will likely require a holistic understanding of the chemical and physical properties of the tissue-adhesive interface, fundamental mechanisms of tissue adhesion, and requirements for specific clinical applications. In this review, we discuss a set of rational guidelines for design of adhesives, recent progress in the field along with examples of commercially available adhesives and those under development, tissue-specific considerations, and finally potential functions for future adhesives. Advances in tissue adhesives will open new avenues for wound care and potentially provide potent therapeutics for various medical applications.

Surgical applications of intracorporal tissue adhesive agents: current evidence and future development

Introduction: Traditional mechanical closure techniques pose many challenges including the risk of infection, tissue reaction, and injury to both patients and clinicians. There is an urgent need to develop tissue adhesive agents to reform closure technique. This review examined a variety of tissue adhesive agents available in the market in an attempt to gain a better understanding of intracorporal tissue adhesive agents as medical devices.Areas covered: Fundamental principles and clinical determinants of the tissue adhesives were summarized. The available tissue adhesives for intracorporal use and their relevant clinical evidence were then presented. Lastly, the perspective of future development for intracorporal tissue adhesive were discussed. Clinical evidence shows current agents are efficacious as adjunctive measures to mechanical closure and these agents have been trialed outside of clinical indications with varied results.Expert opinion: Despite some advancements in the development of tissue adhesives, there is still a demand to develop novel technologies in order to address unmet clinical needs, including low tensile strength in wet conditions, non-controllable polimerization and sub-optimal biocompatibility. Research trends focus on producing novel adhesive agents to remit these challenges. Examples include the development of biomimetic adhesives, externally activated adhesives, and multiple crosslinking strategies. Economic feasibility and biosafety are limiting factors for clinical implementation.

Experimental study of femoral vein reconstruction with sugarcane biopolymer tubular graft

OBJECTIVE

to evaluate, through Doppler flowmetry, venography, histology and clinical evolution, the use of sugarcane biopolymer (BP) tubular grafts in the reconstruction of femoral veins in dogs.

METHODS

we submitted eight adult dogs to femoral vein reconstruction, on the left with BP tubular graft and on the right with autologous vein. In the postoperative period, the animals underwent clinical evaluation and femoral vein Doppler flowmetry. After 360 days, we reoperated the dogs and submitted them to femoral vein phlebography with iodinated contrast. We removed the segments of the femoral veins containing the grafts and sent them for histopathological evaluation.

RESULTS

the dogs did not present hemorrhage, hematoma, surgical wound infection or operated limb edema. One animal had superficial venous dilatation in the left inguinal region. Phlebography performed 360 days after the first surgery showed that three (37.5%) BP grafts and seven (87.5%) grafts from the control group (C) were patent. In the histopathological evaluation, we found an inflammatory reaction, with neutrophils and lymphocytes on the external surface of both groups. In the intimal layer of the grafts and in the outer layer in the two groups, we observed fibrosis.

CONCLUSION

based on the results obtained with the experimental model used, BP presents potential to be used as a tubular graft for venous revascularization. However, new research must be performed to confirm its efficacy in the revascularization of medium and large diameter veins, which could allow its use in clinical practice.

Real-world Bleeding Outcomes and Costs Following Vascular Graft Anastomosis Using PROLENE Sutures with HEMO-SEAL Technology in Patients Undergoing Abdominal Aortic Aneurysm Repair

Background: Suture hole bleeding is a common complication of vascular graft anastomosis that has potential to prolong vascular procedures, increase costs, and compromise patient outcomes. Objectives: Compare real-world bleeding-related outcomes and costs following vascular anastomosis using PROLENE sutures with HEMO-SEAL technology (HEMO-SEAL sutures) compared with standard PROLENE sutures in patients receiving abdominal aortic aneurysm (AAA) repair in the United States. Methods: AAA repair procedures using hemostats and either HEMO-SEAL sutures or standard PROLENE sutures were identified from 2009 to 2013 using the Premier Healthcare Database. The primary outcome was the number and cost of hemostat units. Secondary outcomes were number and cost of sutures, bleeding complications, and transfusions. Results: A total of 5082 discharges for AAA repairs using hemostats and HEMO-SEAL sutures or standard PROLENE sutures were identified. HEMO-SEAL sutures were used in 79 (1.6%) discharges, standard PROLENE sutures were used in 4946 (97.3%); both sutures (excluded from the analysis) were used in 57 (1.1%). Discharge demographics were similar across suture groups, with the exception of disease severity; the HEMO-SEAL suture group had a higher proportion of minor discharges and a lower proportion of extreme discharges compared with the standard PROLENE suture group. Mean number of hemostat units used per discharge (2.34 vs 3.30; median = 2.0 in both groups; p=0.026) and median hemostat costs per discharge ($111 vs $186; p<0.01) were significantly lower in the HEMO-SEAL suture group compared with the standard PROLENE suture group. Fewer sutures per discharge (p<0.0001), lower mean costs of sutures per discharge, higher median costs of sutures per discharge (p=0.0045), and fewer transfusions (0.0019) were also seen in the HEMO-SEAL suture group compared with the standard PROLENE suture group. No statistically significant difference in bleeding complications was observed between suture groups. Conclusion: The results indicate that real-world use of HEMO-SEAL sutures may be associated with reduced hemostat usage and costs, and reduced bleeding that requires additional hemostats and/or transfusions.