Potent Hemostatic Efficacy of a Novel Recombinant Fibrin Sealant Patch (KTF-374) in Rabbit Bleeding Models

PURPOSE

Fibrin sealants are used for hemostasis during surgery. Commercially available fibrin sealants are made of materials of human or animal origin. We developed a novel recombinant fibrin sealant patch (KTF-374) that has thin and flexible properties. This study evaluated the hemostatic efficacy of KTF-374 for various patterns of bleeding in rabbits, as compared with that of the existing fibrin-coated collagen fleece (FCCF).

MATERIALS AND METHODS

Test hemostats used were KTF-374 and FCCF. Laparotomy was performed under general anesthesia in rabbits. We created wounds in the liver, caudal vena cava, and ventral aorta under anticoagulating conditions with heparin. Test hemostats were then applied to the wound site and compressed manually for 3 min. Hemostatic efficacy was evaluated with the success rate of hemostasis at 3 min.

RESULTS

In all bleeding models, the success rate of hemostasis was significantly higher with KTF-374 than FCCF. The hemostatic success rate of KTF-374 and FCCF was 100% vs. 25% (p = .007) in the partial hepatectomy model (n = 8); 100% vs. 12.5% (p = .001) in the caudal vena cava resection model (n = 8); and 100% vs. 25% (p = .004) in the ventral aortic puncture model (n = 8). The wound site could clearly be recognized through the patch after the application of KTF-374 but not FCCF.

CONCLUSIONS

These results suggest that KTF-374 possesses more potent hemostatic properties than FCCF for various patterns of bleeding. KTF-374 is a promising hemostat due to its potent efficacy and good visibility of the wound site through the patch.

Engineering a highly elastic human protein-based sealant for surgical applications

Surgical sealants have been used for sealing or reconnecting ruptured tissues but often have low adhesion, inappropriate mechanical strength, cytotoxicity concerns, and poor performance in biological environments. To address these challenges, we engineered a biocompatible and highly elastic hydrogel sealant with tunable adhesion properties by photocrosslinking the recombinant human protein tropoelastin. The subcutaneous implantation of the methacryloyl-substituted tropoelastin (MeTro) sealant in rodents demonstrated low toxicity and controlled degradation. All animals survived surgical procedures with adequate blood circulation by using MeTro in an incisional model of artery sealing in rats, and animals showed normal breathing and lung function in a model of surgically induced rat lung leakage. In vivo experiments in a porcine model demonstrated complete sealing of severely leaking lung tissue in the absence of sutures or staples, with no clinical or sonographic signs of pneumothorax during 14 days of follow-up. The engineered MeTro sealant has high potential for clinical applications because of superior adhesion and mechanical properties compared to commercially available sealants, as well as opportunity for further optimization of the degradation rate to fit desired surgical applications on different tissues.

Management of Intraoperative Difficulties During Uniportal Video-Assisted Thoracoscopic Surgery

The learning curve of the uniportal video-assisted thoracoscopic surgery (VATS) approach is linked to a larger rate of intraoperative complications, which can lead to an emergency conversion to thoracotomy. Despite technical advancements and the large number of surgical videos posted on specialized websites, live surgery events and experimental courses have significantly contributed to accelerate the learning and evolution of minimally invasive thoracic surgery. Bleeding and other complications are the most dreaded event for many VATS surgeons. This article analyzes possible major intraoperative complications during uniportal VATS and explains how to manage them effectively and safely.

Egg Albumen as a Fast and Strong Medical Adhesive Glue

Sutures penetrate tissues to close wounds. This process leads to inflammatory responses, prolongs healing time, and increases operation complexity. It becomes even worse when sutures are applied to stress-sensitive and fragile tissues. By bonding tissues via forming covalent bonds, some medical adhesives are not convenient to be used by surgeons and have side effects to the tissues. Here egg albumen adhesive (EAA) is reported with ultrahigh adhesive strength to bond various types of materials and can be easily used without any chemical and physical modifications. Compared with several commercial medical glues, EAA exhibits stronger adhesive property on porcine skin, glass, polydimethylsiloxane. The EAA also shows exceptional underwater adhesive strength. Finally, wound closure using EAA on poly(caprolactone) nanofibrous sheet and general sutures is investigated and compared in a rat wound model. EAA also does not show strong long-term inflammatory response, suggesting that EAA has potential as a medical glue, considering its abundant source, simple fabrication process, inherent nontoxicity, and low cost.

Multifunctional nanoparticles as a tissue adhesive and an injectable marker for image-guided procedures

Tissue adhesives have emerged as an alternative to sutures and staples for wound closure and reconnection of injured tissues after surgery or trauma. Owing to their convenience and effectiveness, these adhesives have received growing attention particularly in minimally invasive procedures. For safe and accurate applications, tissue adhesives should be detectable via clinical imaging modalities and be highly biocompatible for intracorporeal procedures. However, few adhesives meet all these requirements. Herein, we show that biocompatible tantalum oxide/silica core/shell nanoparticles (TSNs) exhibit not only high contrast effects for real-time imaging but also strong adhesive properties. Furthermore, the biocompatible TSNs cause much less cellular toxicity and less inflammation than a clinically used, imageable tissue adhesive (that is, a mixture of cyanoacrylate and Lipiodol). Because of their multifunctional imaging and adhesive property, the TSNs are successfully applied as a hemostatic adhesive for minimally invasive procedures and as an immobilized marker for image-guided procedures.

An in vitro study of fibrin sealant as a carrier system for recombinant human bone morphogenetic protein (rhBMP)-9 for bone tissue engineering

In the craniofacial bone field, fibrin sealants are used as coagulant and adhesive tools to stabilize grafts during surgery. Despite this, their exact role in osteogenesis is poorly characterized. In the present study, we aimed to characterize the osteogenic potential of TISSEEL fibrin sealant and used its technology to incorporate growth factors within its matrix. We focused on recombinant human bone morphogenetic protein (rhBMP)-9, which has previously been characterized as one of the strongest osteogenetic inducers in the BMP family. TISSEEL displayed an excellent ability to retain rhBMP9, which was gradually released over a 10-day period. Although TISSEEL decreased bone stromal ST2 cell attachment at 8 h, it displayed normal cell proliferation at 1, 3, and 5 days when compared to tissue culture plastic. Interestingly, TISSEEL had little influence on osteoblast differentiation; however its combination with rhBMP9 significantly increased ALP activity at 7 days, Alizarin Red staining at 14 days, and mRNA levels of osteoblast differentiation markers ALP, bone sialoprotein, and osteocalcin. In summary, although fibrin sealants were shown to have little influence on osteogenesis, their combination with bone-inducing growth factors such as rhBMP9 may serve as an attractive carrier/scaffold for future bone regenerative strategies. Future animal studies are now necessary.

[Application of fibrin sealant in patients operated on for differentiated thyroid cancer. What do we improve?]

BACKGROUND

In recent years, several publications have shown that new adhesives and sealants, like Tissucol(®), applied in thyroid space reduce local complications after thyroidectomies.

STUDY AIMS

To demonstrate the effectiveness of fibrin glue Tissucol(®) in reducing the post-operative hospital stay of patients operated on for differentiated thyroid carcinoma in which total thyroidectomy with central and unilateral node neck dissection was performed (due to the debit drains decrease), with consequent cost savings.

MATERIAL AND METHODS

A prospective randomised study was conducted during the period between May 2009 and October 2013 on patients with differentiated thyroid carcinoma with cervical nodal metastases, and subjected to elective surgery. Two groups were formed: one in which Tissucol(®) was used (case group) and another where it was not used (control group). Patients were operated on by surgeons specifically dedicated to endocrine surgical pathology, using the same surgical technique in all cases.

RESULTS

A total of 60 total thyroidectomies with lymph node dissection were performed, with 30 patients in the case group, and 30 patients in control group. No statistically significant differences were observed in most of the studied variables. However, the case group had a shorter hospital stay than the control group with a statistically significant difference (p<0.05).

CONCLUSION

Implementation of Tissucol(®) has statistically and significantly reduced the hospital stay of patients undergoing total thyroidectomy with neck dissection, which represents a significant reduction in hospital costs. This decrease in hospital stay has no influence on the occurrence of major complications related to the intervention.

Bioinspired Nanoparticulate Medical Glues for Minimally Invasive Tissue Repair

Delivery of tissue glues through small-bore needles or trocars is critical for sealing holes, affixing medical devices, or attaching tissues together during minimally invasive surgeries. Inspired by the granule-packaged glue delivery system of sandcastle worms, a nanoparticulate formulation of a viscous hydrophobic light-activated adhesive based on poly(glycerol sebacate)-acrylate is developed. Negatively charged alginate is used to stabilize the nanoparticulate surface to significantly reduce its viscosity and to maximize injectability through small-bore needles. The nanoparticulate glues can be concentrated to ≈30 w/v% dispersions in water that remain localized following injection. With the trigger of a positively charged polymer (e.g., protamine), the nanoparticulate glues can quickly assemble into a viscous glue that exhibits rheological, mechanical, and adhesive properties resembling the native poly(glycerol sebacate)-acrylate based glues. This platform should be useful to enable the delivery of viscous glues to augment or replace sutures and staples during minimally invasive procedures.

Intraoperative bleeding control by uniportal video-assisted thoracoscopic surgery†

Owing to advances in video-assisted thoracic surgery (VATS), the majority of pulmonary resections can currently be performed by VATS in a safe manner with a low level of morbidity and mortality. The majority of the complications that occur during VATS can be minimized with correct preoperative planning of the case as well as careful pulmonary dissection. Coordination of the whole surgical team is essential when confronting an emergency such as major bleeding. This is particularly important during the VATS learning curve, where the occurrence of intraoperative complications, particularly significant bleeding, usually ends in a conversion to open surgery. However, conversion should not be considered as a failure of the VATS approach, but as a resource to maintain the patient's safety. The correct assessment of any bleeding is of paramount importance during major thoracoscopic procedures. Inadequate management of the source of bleeding may result in major vessel injury and massive bleeding. If bleeding occurs, a sponge stick should be readily available to apply pressure immediately to control the haemorrhage. It is always important to remain calm and not to panic. With the bleeding temporarily controlled, a decision must be made promptly as to whether a thoracotomy is needed or if the bleeding can be solved through the VATS approach. This will depend primarily on the surgeon's experience. The operative vision provided with high-definition cameras, specially designed or adapted instruments and the new sealants are factors that facilitate the surgeon's control. After experience has been acquired with conventional or uniportal VATS, the rate of complications diminishes and the majority of bleeding events are controlled without the need for conversion to thoracotomy.

Randomized trial of a dry-powder, fibrin sealant in vascular procedures

OBJECTIVE

Topical hemostats are important adjuncts for stopping surgical bleeding. The safety and efficacy of Fibrocaps, a dry-powder, fibrin sealant containing human plasma-derived thrombin and fibrinogen, was evaluated in patients undergoing vascular surgical procedures.

METHODS

In this single-blind trial (clinicaltrials.gov: NCT01527357), adult patients were randomized 2:1 to Fibrocaps plus gelatin sponge (Fibrocaps) vs gelatin sponge alone. Results are presented for the patient subset undergoing vascular procedures with suture hole bleeding. The primary efficacy endpoint compared time to hemostasis (TTH) over 5 minutes. Safety follow-up continued to day 29.

RESULTS

A total of 175 patients were randomized and treated (Fibrocaps, 117; gelatin sponge, 58). Patients were predominately male (69%) and underwent arterial bypass (81%), arteriovenous graft formation (9%), or carotid endarterectomy (9%). Fibrocaps significantly reduced TTH compared with gelatin sponge (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.5-3.1; median TTH, 2 minutes; 95% CI, 1.5-2.5 vs 4 minutes; 95% CI, 3.0-5.0; P < .002). Significant reductions were also observed in patients receiving concomitant antiplatelet agents alone (HR, 2.8; 95% CI, 1.0-7.4; P = .03; n = 33), anticoagulants alone (HR, 2.0; 95% CI, 1.0-4.0; P = .04; n = 43), or both antiplatelet agents and anticoagulants (Fibrocaps vs gelatin sponge, HR, 2.3; 95% CI, 1.2-4.3; P = .008; n = 65). Incidences of common adverse events (procedural pain, nausea, constipation) were generally comparable between treatment arms. Anti-thrombin antibodies developed in 2% of Fibrocaps-treated patients and no-gelatin-sponge patients.

CONCLUSIONS

Fibrocaps, a ready-to-use, dry-powder fibrin sealant, was well-tolerated and reduced TTH in patients undergoing vascular procedures, including those receiving antiplatelet agents and/or anticoagulants, demonstrating its safety and usefulness as an adjunct to hemostasis.

Binding of Anticell Adhesive Oxime-Crosslinked PEG Hydrogels to Cardiac Tissues

Postsurgical cardiac adhesions increase the number of surgeries as well as patient mortality and morbidity. A fast gelling oxime-crosslinked PEG hydrogel with tunable gelation time, degradation, and mechanical properties is presented. This material is cytocompatible and prevents cellular adhesion. Material retention on different cardiac tissues is demonstrated ex vivo over time and that functional group ratio alters material retention on different cardiac tissues.

The efficacy of a lysine-based dendritic hydrogel does not differ from those of commercially available tissue sealants and adhesives: an ex vivo study

Background

Hemostatic agents, tissue adhesives and sealants may contribute to a reduction in hemorrhage-associated morbidity and mortality. Towards this end, we have recently developed a lysine-based dendritic hydrogel (PEG-LysNH₂) that can potentially be used in the management of severe trauma and/or intraoperative bleeding. As a first step in demonstrating the potential utility of this approach, our objective was to ascertain the ability of the PEG-LysNH₂ to adhere to and seal injured tissues, as well as to maintain the seal under physiological conditions.

Methods

The efficacy of the PEG-LysNH₂ in sealing injured tissues was evaluated using an ex-vivo pressure testing system. A 2.5 mm incision was made on intact ex-vivo tissues and then sealed with the PEG-LysNH₂. Application of the PEG-LysNH₂ was followed by 1) step-wise pressure increase to a maximum of 250 mmHg and 2) fluctuating pressures, between 100–180 mmHg with a rate of 3 Hz, over a 24-hour period. The performance of the PEG-LysNH₂ was compared to those of commercially available sealants and adhesives.

Results

During gradual pressure increase, mean pressures at 30 seconds (P₃₀) ranged between 206.36 - 220.17 mmHg for the sealants, and they were greater than control and suture groups (p < 0.01 and p = 0.013, respectively). Additionally, all products held under fluctuating pressures: mean pressures ranged between 135.20 - 160.09 mmHg, and there were no differences observed between groups (p = 0.96).

Conclusions

The efficacy of the PEG-LysNH₂ was significantly superior to conventional injury repair methods (sutures) and did not differ from those of commercially available products when sealing small incisions.

Safety and usability of hemostats, sealants, and adhesives

Hemostats, sealants, and adhesives are an integral part of surgical patient care. Nurses who have knowledge about these agents can better help ensure safe, efficient surgical patient care. As a caregiver and patient advocate, the perioperative nurse must understand the most current information about these agents and be prepared to facilitate the transfer of this knowledge to all caregivers. Information about these agents, including the contraindications, warnings, and precautions associated with their use as well as their preparation and application, is provided here. Algorithms designed to clarify the best options for using hemostats, sealants, and adhesives are included as well.

Synthesis and properties of temperature-sensitive and chemically crosslinkable poly(ether-urethane) hydrogel

The PEU-MA solutions can gelate at physiological temperature, and be further crosslinked by UV light.

Mussel-inspired nanofibrous sheet for suture-less stomach incision surgery

We report a dopamine-based crosslinker-conjugated gelatin/polycaprolactone nanofibrous sheet. The nanosheet was then employed to treat stomach incisions without sutures during surgery.

Fibrocaps for surgical hemostasis: two randomized, controlled phase II trials

BACKGROUND

Fibrocaps, a ready-to-use, dry-powder fibrin sealant containing human plasma-derived thrombin and fibrinogen, is being developed as an adjunct for surgical hemostasis.

MATERIALS AND METHODS

Safety and efficacy of Fibrocaps applied directly or by spray device, in combination with gelatin sponge, was compared with that of gelatin sponge-alone in two randomized, single-blind controlled trials: FC-002 US (United States) and FC-002 NL (the Netherlands). A total of 126 adult patients were randomized (Fibrocaps: n = 47 [FC-002 US], n = 39 [FC-002 NL]; gelatin sponge alone: n = 23 [FC-002 US], n = 17 [FC-002 NL). One bleeding site was treated during a surgical procedure (n = 125). Time to hemostasis (primary end point) was measured, with a 28-d safety follow-up. Four surgical indications included hepatic resection (n = 58), spinal procedures (n = 37), peripheral vascular procedures (n = 30), and soft tissue dissection (n = 1).

RESULTS

Mean (standard deviation) time to hemostasis was significantly shorter after Fibrocaps treatment than after gelatin sponge alone (FC-002 US: 1.9 [1.3] versus 4.8 min [3.1], P < 0.001; FC-002 NL: 2.2 [1.3] versus 4.4 min [3.1], P = 0.004). The incidence of hemostasis was greater after Fibrocaps compared with that of gelatin sponge alone within 3 min (FC-002 US: 83% versus 35%, P < 0.001; FC-002 NL: 77% versus 53%, P = 0.11), 5 min (94% versus 61%, P = 0.001; 95% versus 71%, P = 0.022), and 10 min (100% versus 78%, P = 0.003; 100% versus 82%, P = 0.025). Adverse events were consistent with surgical procedures performed and patients' underlying diseases and generally similar between treatment arms; most were mild or moderate in severity. Non-neutralizing antithrombin antibodies were detected in 5% of Fibrocaps-treated patients on day 29.

CONCLUSIONS

Fibrocaps had good safety and efficacy profiles, supporting continuing clinical development as a novel fibrin sealant.

A blood-resistant surgical glue for minimally invasive repair of vessels and heart defects

Currently, there are no clinically approved surgical glues that are nontoxic, bind strongly to tissue, and work well within wet and highly dynamic environments within the body. This is especially relevant to minimally invasive surgery that is increasingly performed to reduce postoperative complications, recovery times, and patient discomfort. We describe the engineering of a bioinspired elastic and biocompatible hydrophobic light-activated adhesive (HLAA) that achieves a strong level of adhesion to wet tissue and is not compromised by preexposure to blood. The HLAA provided an on-demand hemostatic seal, within seconds of light application, when applied to high-pressure large blood vessels and cardiac wall defects in pigs. HLAA-coated patches attached to the interventricular septum in a beating porcine heart and resisted supraphysiologic pressures by remaining attached for 24 hours, which is relevant to intracardiac interventions in humans. The HLAA could be used for many cardiovascular and surgical applications, with immediate application in repair of vascular defects and surgical hemostasis.

Fibrin Sealant: The Only Approved Hemostat, Sealant, and Adhesive-a Laboratory and Clinical Perspective

Background. Fibrin sealant became the first modern era material approved as a hemostat in the United States in 1998. It is the only agent presently approved as a hemostat, sealant, and adhesive by the Food and Drug Administration (FDA). The product is now supplied as patches in addition to the original liquid formulations. Both laboratory and clinical uses of fibrin sealant continue to grow. The new literature on this material also continues to proliferate rapidly (approximately 200 papers/year). Methods. An overview of current fibrin sealant products and their approved uses and a comprehensive PubMed based review of the recent literature (February 2012, through March 2013) on the laboratory and clinical use of fibrin sealant are provided. Product information is organized into sections based on a classification system for commercially available materials. Publications are presented in sections based on both laboratory research and clinical topics are listed in order of decreasing frequency. Results. Fibrin sealant remains useful hemostat, sealant, and adhesive. New formulations and applications continue to be developed. Conclusions. This agent remains clinically important with the recent introduction of new commercially available products. Fibrin sealant has multiple new uses that should result in further improvements in patient care.

Hemostatic strategies for traumatic and surgical bleeding

Wide interest in new hemostatic approaches has stemmed from unmet needs in the hospital and on the battlefield. Many current commercial hemostatic agents fail to fulfill the design requirements of safety, efficacy, cost, and storage. Academic focus has led to the improvement of existing strategies as well as new developments. This review will identify and discuss the three major classes of hemostatic approaches: biologically derived materials, synthetically derived materials, and intravenously administered hemostatic agents. The general class is first discussed, then specific approaches discussed in detail, including the hemostatic mechanisms and the advancement of the method. As hemostatic strategies evolve and synthetic-biologic interactions are more fully understood, current clinical methodologies will be replaced.

The economic burden of complications occurring in major surgical procedures: a systematic review

OBJECTIVES

On the basis of a systematic review, we aimed to establish the cost and drivers of cost and/or resource use of intra- and perioperative complications occurring as a result of selected major surgical procedures, as well as to understand the relationship between costs and severity of complication and, consequently, the economic burden they represent. We also assessed the clinical and economic methodologies used to derive costs and resource use across the studies with a view to providing guidance on reporting standards for these studies.

METHODS

We searched EMBASE, MEDLINE and Econlit (from 2002 to 2012) for study publications including resource use/cost data relating to surgical complications.

RESULTS

We identified 38 relevant studies on pancreatic (n = 14), urologic (n = 4), gynaecological (n = 6), thoracic (n = 13) and hepatic surgery (n = 1). All studies showed that complications lead to higher resource use and hospital costs compared with surgical procedures without complications. Costs depend on type of complication and complication severity, and are driven primarily by prolonged hospitalisation. There was considerable heterogeneity between studies with regard to patient populations, outcomes and procedures, as well as a lack of consistency and transparency of reporting of costs/resource use. Complication severity grading systems were used infrequently.

CONCLUSIONS

The overall conclusions of included studies are consistent: complications represent an important economic burden for health care providers. We conclude that more accurate and consistent data collection is required to serve as input for good-quality economic analyses, which in turn can inform hospital decisions on cost-efficient allocation of their limited resources.

Comparison of hemostatic agents used in vascular surgery

INTRODUCTION

Over the past 15 years, a wide range of agents have been developed for use in surgical procedures to achieve hemostasis. These agents can be divided into three broad categories: hemostats, sealants and adhesives. They vary widely related to their mechanism of action, composition, ease of application, adherence to wet or dry tissue, immunogenicity and cost.

AREAS COVERED

This article focuses on the agents used in vascular surgery to achieve hemostasis; agents involved in clinical trials are also covered.

EXPERT OPINION

When surgeons achieve rapid hemostasis, potential benefits include better visualization of the surgical area, shorter operative times, decreased requirement for transfusions, better management of an anticoagulated patient, decreased wound healing time and overall improvement in patient recovery time. The need for safe and efficacious hemostatic agents that can provide a range of benefits is clearly a significant surgical issue.

Microbial production and chemical transformation of poly-γ-glutamate

Poly-γ-glutamate (PGA), a novel polyamide material with industrial applications, possesses a nylon-like backbone, is structurally similar to polyacrylic acid, is biodegradable and is safe for human consumption. PGA is frequently found in the mucilage of natto, a Japanese traditional fermented food. To date, three different types of PGA, namely a homo polymer of D-glutamate (D-PGA), a homo polymer of L-glutamate (L-PGA), and a random copolymer consisting of D- and L-glutamate (DL-PGA), are known. This review will detail the occurrence and physiology of PGA. The proposed reaction mechanism of PGA synthesis including its localization and the structure of the involved enzyme, PGA synthetase, are described. The occurrence of multiple carboxyl residues in PGA likely plays a role in its relative unsuitability for the development of bio-nylon plastics and thus, establishment of an efficient PGA-reforming strategy is of great importance. Aside from the potential applications of PGA proposed to date, a new technique for chemical transformation of PGA is also discussed. Finally, some techniques for PGA and its derivatives in advanced material technology are presented.