Hemostatic efficacy of a novel, PEG-coated collagen pad in clinically relevant animal models

Chitosan-PEG Gels Loaded with Jatropha mollissima (Pohl) Baill. Ethanolic Extract: An Efficient and Effective Biomaterial in Hemorrhage Control

A lack of control over blood loss can have catastrophic implications, including death. Although several hemostatic medications have been employed to reduce bleeding, a vast majority of them are ineffective, expensive, or pose health risks to the patient. To overcome these constraints, chitosan-polyethylene glycol (CS-PEG) hemostatic gels loaded with ethanolic extract of Jatropha mollissima sap (EES) were prepared and their hemostatic, physicochemical, and cytotoxic properties were evaluated. The gels were produced by mixing CS with PEG (an external plasticizer) and EES. The phytochemical analysis revealed a significant concentration of total polyphenols and tannins content in the extract and catechin was identified as one of the key compounds of EES. Infrared spectroscopy analysis revealed the presence of EES in the gels, as well as the chemical interaction between CS and PEG. The gels were thermally stable between 25 and 37 °C (ambient and human body temperature range), had pseudoplastic deformation behavior (rheological properties preserved after shearing), were simple to inject (compression force 30 N), and were biocompatible. In vivo experiments showed that both CS-PEG-EES gels exhibited greater hemostatic action in preventing tail hemorrhage in Wistar rats, with decreased bleeding time and blood weight compared with unloaded CS-PEG gels (control groups) and Hemostank, a commercial product. However, the gel prepared with acetic acid was more efficient in controlling bleeding. These findings reveal that CS-PEG-EES gels can reduce hemorrhages and are a potent, simple, and safe hemostatic agent.

Current status of hemostatic agents, their mechanism of action, and future directions

The bleeding problem might seem straightforward, but it involves a plethora of complex biochemical pathways and responses. Hemorrhage control remains one of the leading causes of “preventable deaths” worldwide. The past few decades have seen a wide range of biomaterials and their derivatives targeted to serve as hemostatic agents, but none can be deemed as an ideal solution. In this review, we have highlighted the current diversity in hemostatic agents and their modalities. We have enclosed a comprehensive outlook of the proposed solutions and their clinical performance so far. In addition to these, several promising compositions are still in their infancy or developmental phases. The inclusion of novel upcoming nanocomposites has further widened the potencies of existing formulations as well.

Evaluation of the safety and effectiveness of a sealant hemostatic patch for preventing cerebrospinal fluid leaks in cranial surgery

BACKGROUND

Cerebrospinal fluid (CSF) leak remains a significant source of morbidity after neurosurgical procedures. The objective is to evaluate the effectiveness and safety of a polyethylene glycol-coated collagen patch (PCC) in different neurosurgical procedures.

METHODS

A retrospective, single-center cohort study in patients who underwent a cranial neurosurgical procedure. After collecting multiple data variables, patients were divided into two groups depending on the use of PCC as sealant on dural closure following procedures.

RESULTS

Data from 230 patients were collected (PCC, 128; control group, 102). Incidence of CSF leakage was significantly lower in the PCC group (p < .001). Complications that were significantly lower in PCC than the control group included surgical infection (p = .022), and hydrocephalus (p = .017), as well as reduced rates of reintervention (p < .001) and shorter hospital stays (p = .028). Factors associated with a higher incidence of CSF leakage included posterior fossa procedures, reinterventions, and the need for CSF drainage placement. PCC reduced the risk of suffering CSF leakage by more than 75% (p = .002) once adjusted for age, surgical approach, type of cranial opening, reintervention, CSF drainage, dural substitute, and dural defect coverage.

CONCLUSIONS

Our findings confirm PCC as an effective means of preventing CSF leakage following cranial neurosurgery with fewer associated complications.

Versatility and clinical effectiveness of a synthetic sealing hemostatic patch as alternative to parenchyma suturing in laparoscopic partial nephrectomy

BACKGROUND

Improvements in laparoscopic partial nephrectomy (LPN) in order to minimize perioperative warm ischemia time (WIT), complications, and consequently patient outcome are desirable. Veriset™ is a ready-to-use hemostatic patch of absorbable oxidized cellulose and hydrogel components that has earlier been implemented in vascular and hepatic surgery. We report our experience using this device in LPN.

METHODS

Patients with a solitary malignant renal mass suspicious for renal cancer underwent LPN with either the use of Veriset™ hemostatic patch (n = 40) or conventional suture technique (n = 40). Patient characteristics, operation time and WIT, postoperative course and complications were recorded retrospectively. Tumor complexity was calculated according to the R.E.N.A.L. score. Outcome was determined according to the "trifecta" criteria (negative surgical margin, WIT < 25 min, no complications within 30 days).

RESULTS

No significant differences with regard to clinical parameters and median R.E.N.A.L. score (6) were observed between both groups. Operation time (mean 127.1 min vs. 162. 8 min; p = 0.001) and WIT were both lower in the Veriset™ group (14.6 min vs. 20.6 min; p = 0.01). No differences in surgical margins (p = 0.602) and overall complication rates at 30 (p = 0.599) and 90 days (p = 0.611) postoperatively were noticed. The surgical outcome according to "trifecta" was achieved in 65% of patients using Veriset™ and in 57.5% of patients by suture closure, respectively.

CONCLUSION

The hemostatic Veriset™ patch can successfully be implemented in LPN. Handling and application appear favorable, thereby reducing operation time and WIT. The present results suggest that the device may represent an alternative to parenchyma suturing in LPN.

Hemopatch® as a Hemostatic Agent is Safe in Partial Nephrectomy: A Large, Single-Surgeon Retrospective Evaluation

Introduction

Partial nephrectomy (PN) has evolved into the surgical standard of care for localized renal lesions. Hemostatic agents (HA) support the surgeon in achieving local hemostasis during PN. We previously reported initial results with the HA Hemopatch^® in PN. We now report our experiences with Hemopatch^® in a larger and more challenging single-surgeon PN cohort.

Methods

Our study included 45 patients who underwent PN due to suspicious renal lesions between December 2013 and March 2018. All surgeries were performed by a single surgeon using the HA Hemopatch^®. Preoperative, intraoperative, and postoperative parameters were assessed.

Results

Preoperative median tumor diameter was 27 mm. Median PADUA and RENAL nephrometry scores were 7 and 6, respectively. In 13.3% of the cases an additional HA was applied. Intraoperative and postoperative bleeding occurred in 2.2% and 8.9%, respectively. Median total blood loss was 200 ml. Urgent pedicle clamping due to bleeding was necessary in 2 (4.4%) patients. The transfusion rate was 8.9%. There were no conversions.

Conclusion

We confirmed our initial results demonstrating feasibility and reliability of Hemopatch^® during PN. Notably, the cohort consists of selected patients. Prospective randomized studies are needed for comparison of different types of HA with regard to perioperative outcome.

Case Report of a Novel Technique for Repair of the Vertebral Artery During Cranial Surgery

Surgery of complex cranial base lesions carries a high risk of damage to main vessels, often resulting in life-changing or even life-threatening injuries. We describe a rapid, effective, and noninvasive application of a collagen-based hemostatic patch to repair the vertebral artery during cranial surgery. A 61-year-old male patient underwent retrosigmoid craniotomy to remove a foramen magnum meningioma that encased the vertebral artery. A linear incision was made behind the ear and standard retrosigmoid craniotomy was performed with preservation of the transverse and sigmoid sinuses. The dura was opened in a Y-shaped fashion and the cerebellum was retracted with cerebrospinal fluid being released. Removing the exposed tumor from the artery resulted in a small arterial bleed. Two pieces of an N-hydroxysuccinimide-functionalized polyethylene glycol-coated collagen patch (Hemopatch®, Baxter Healthcare Ltd.) were applied sequentially and were pressed to the bleed site for 2 min each. Hemostasis of the vertebral artery was achieved at the patient's regular blood pressure. There was no postoperative bleeding, dissection or pseudoaneurysm. The patient recovered gradually with several cranial nerve deficits. There was no brain stem stroke. Twelve months on, the patient has made an excellent recovery from surgery, is independently mobile and has minimal cranial nerve deficits. Application of the collagen-based hemostatic patch proved to be an efficient, safe, and noninvasive technique that achieved rapid hemostasis, confirming its effectiveness in complicated surgery, where risk of hemorrhage can be critical for the surgery outcome.Funding: There was no funding for this case report. Baxter Healthcare Ltd. provided funding for preparation of this manuscript and the journal's Rapid Service Fee.

The significance of collagen dressings in wound management: a review

Clinical experience and research has improved our understanding of wound healing which, in turn, has enabled health professionals to aid wound healing and manufacturers to develop modern wound dressings. The significant role of collagen in wound healing has led to the development of numerous products on the basis of this biological material. The main focus of this review is to provide a critical appraisal of publications about collagen and acellular collagen dressings with a fleece-like or spongy structure. It is intended for clinicians and researchers, and aims to keep them up-to-date in the complex field of interactive, collagen-based wound dressings, including their manufacture, combination possibilities, mechanisms of action, performance in the promotion of wound healing and indications. Despite the small number of clinical studies, the importance of acellular collagen dressings with a fleece- or sponge-like structure is likely to increase in the future. As there is no ideal wound dressing, the knowledge attained is meant to support health professionals in selecting the right product, and pave the way for new applications and clinical studies.

Rice Starch–Based Sponge for Use as Topical Hemostatic Agent

The topical hemostatic agents in surgery are biomaterials that very important for surgeons to stop bleeding in the complicated areas. Currently available hemostatic agents are often expensive, ineffective or raise safety concerns. Synthetic rice starch-based sponge was an inexpensive and promising alternative. In this study, we synthesized and characterized a new hemostatic agent from rice starch and investigated their use as a hemostatic material. The rice starch-based sponge having interconnected pore were synthesized via blending of the rice starch and additive of carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and glycerol in hot water, freezing and drying by vacuum sublimation with enlarged porosity and rapid swelling behavior. Characteristics of the final products were then investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS). In vivo studies using 4 rabbits with liver injury showed rice starch-based sponge blood aggregate formation as well as bulk blood coagulation inhibition. The biocompatibility tests showed that this sponge is safe and effective after follow-up for at least 6 months of animal and clinical trial.

Next Generation Hemostatic Materials Based on NHS-Ester Functionalized Poly(2-oxazoline)s

In order to prevent hemorrhage during surgical procedures, a wide range of hemostatic agents have been developed. However, their efficacy is variable; hemostatic devices that use bioactive components to accelerate coagulation are dependent on natural sources, which limits reproducibility. Hybrid devices in which chain-end reactive poly(ethylene glycol) is employed as active component sometimes suffer from irregular cross-linking and dissolution of the polar PEG when blood flow is substantial. Herein, we describe a synthetic, nonbioactive hemostatic product by coating N-hydroxysuccinimide ester (NHS)-functional poly(2-oxazoline)s (POx-NHS) onto gelatin patches, which acts by formation of covalent cross-links between polymer, host blood proteins, gelatin and tissue to seal the wound site and prevent hemorrhage during surgery. We studied different process parameters (including polymer, carrier, and coating technique) in direct comparison with clinical products (Hemopatch and Tachosil) to obtain deeper understanding of this class of hemostatic products. In this work, we successfully prove the hemostatic efficacy of POx-NHS as polymer powders and coated patches both in vitro and in vivo against Hemopatch and Tachosil, demonstrating that POx-NHS are excellent candidate polymers for the development of next generation hemostatic patches.

Improved bleeding scores using Gelfoam(®) Powder with incremental concentrations of bovine thrombin in a swine liver lesion model

Topical hemostatic agents are used intra-operatively to prevent uncontrolled bleeding. Gelfoam(®) Powder contains a hemostatic agent prepared from purified pork skin gelatin, the efficacy of which is increased when combined with thrombin. However, the effect of increasing concentrations of thrombin on resultant hemostasis is not known. This study sought to evaluate the ability of various concentrations of thrombin in combination with Gelfoam Powder to control bleeding using a swine liver lesion model. Ten pigs underwent a midline laparotomy. Circular lesions were created in the left medial, right medial, and left lateral lobes; six lesions per lobe. Gelfoam Powder was hydrated with Thrombin-JMI(®) diluted to 250, 375, and 770 IU/mL. Each concentration was applied to two lesion sites per lobe. Bleeding scores were measured at 3, 6, 9, and 12 min using a 6-point system; comparison of bleeding scores was performed using ANOVA with the post hoc Tukey test. The bleeding scores with thrombin concentrations at 770 IU/mL were significantly lower than at 250 and 375 IU/mL at all four time points. The percentage of biopsies with a clinically acceptable bleeding score rose from 37.9, 46.6, and 71.2 % at 3 min to 55.2, 69.0, and 88.1 % at 12 min in the 250, 375, and 770 IU/mL thrombin groups, respectively. The study showed that the hemostatic response to thrombin was dose-related: using higher concentrations of thrombin with Gelfoam Powder yielded improved hemostasis, as determined by lower bleeding scores.

Functional improvement of hemostatic dressing by addition of recombinant batroxobin

Although a number of natural materials have been used as hemostatic agents, many substances do not act quickly enough. Here, we created a novel dressings using collagen and chitosan with recombinant batroxobin (r-Bat) to promote faster and more effective hemostasis. We hypothesized that r-Bat would promote synergetic blood coagulation because it contains a blood coagulation active site different than those of collagen and chitosan. Our results suggest that each substances can maintain hemostatic properties while in the mixed dressings and that our novel hemostatic dressings promotes potent control of bleeding, as demonstrated by a whole blood assay and rat hemorrhage model. In a rat femoral artery model, the scaffold with a high r-Bat concentration more rapidly controlled excessive bleeding. This novel dressings has enormous possible for rapidly controlling bleeding and it improves upon the effect of collagen and chitosan used alone. Our novel r-Bat dressings is a possible candidate for improving preoperative care and displays promising properties as an absorbable agent in hemostasis.

STATEMENT OF SIGNIFICANCE

Despite the excellent hemostatic properties of collagen and chitosan pads, they reported to brittle behavior and lack sufficient hemostatic effect within relevant time. Therefore, we created a novel pad using collagen and chitosan with recombinant batroxobin (r-Bat). r-Bat acts as a thrombin-like enzyme in the coagulation cascade. Specifically, r-Bat, in contrast to thrombin, only splits fibrinopeptide A off and does not influence other hemostatic factors or cells, which makes it clinically useful as a stable hemostatic agent. Also the materials in the pad have synergetic effect because they have different hemostatic mechanisms in the coagulation cascade. This report propose the novel hemostatic pad isreasonable that a great potential for excessive bleeding injury and improve effects of natural substance hemostatic pad.

Hemopatch Application for Ventricular Wall Laceration in Redo Cardiac Surgical Procedures

As survival among patients with complex congenital heart disease continues to improve, long-term survivors frequently require redo surgical procedures, with potentially escalating technical difficulty and bleeding risk. This report describes our experience with a new hemostatic pad, Hemopatch (Baxter Deutschland GmbH, Unterschleissheim, Germany) in redo cardiac surgery.

Control of bleeding in surgical procedures: critical appraisal of HEMOPATCH (Sealing Hemostat)

The need for advanced hemostatic agents increases with the complexity of surgical procedures and use of anticoagulation and antiplatelet treatments. HEMOPATCH (Sealing Hemostat) is a novel, advanced hemostatic pad that is composed of a synthetic, protein-reactive monomer and a collagen backing. The active side is covered with a protein-reactive monomer: N-hydroxysuccinimide functionalized polyethylene glycol (NHS-PEG). NHS-PEG rapidly affixes the collagen pad to tissue to promote and maintain hemostasis. The combined action of the NHS-PEG and collagen is demonstrated to have benefit relative to other hemostatic agents in surgery and preclinical surgical models. This paper reviews the published investigations and case reports of the hemostatic efficacy of HEMOPATCH, wherein HEMOPATCH is demonstrated to be an effective, easy-to-use hemostatic agent in open and minimally invasive surgery of patients with thrombin- or platelet-induced coagulopathies.

Insights into the interactions between porcine collagen and a Zr–Al–Ti metal complex

Porcine acelluar dermal matrix (pADM), known as pure collagen with a three dimensional structure, was used to explore the interactions between porcine collagen and a metal complex in this study.