"How I do it: utilization of high-pressure sealants in aortic reconstruction"

Underwater instant adhesion mechanism of self-assembled amphiphilic hemostatic granular hydrogel from Andrias davidianus skin secretion

The widespread use of biological tissue adhesives for tissue repair is limited by their weak adhesion in a wet environment. Herein, we report the wet adhesion mechanism of a dry granular natural bioadhesive from Andrias davidianus skin secretion (ADS). Once contacting water, ADS granules self-assemble to form a hydrophobic hydrogel strongly bonding to wet substrates in seconds. ADS showed higher shear adhesion than current commercial tissue adhesives and an impressive 72-h underwater adhesion strength of ∼47kPa on porcine skin tissue. The assembled hydrogel in water maintained a dissipation energy of ∼8 kJ/m³, comparable to the work density of muscle, exhibiting its robustness. Unlike catechol adhesion mechanism, ADS wet adhesion mechanism is attributed to water absorption by granules, and the unique equilibrium of protein hydrophobicity, hydrogen bonding, and ionic complexation. The in vivo adhesion study demonstrated its excellent wet adhesion and hemostasis performance in a rat hepatic and cardiac hemorrhage model.

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Dry granule adhesive of Andrias davidianus skin secretion build strong wet adhesion

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The granules absorb water and self-assemble to form a hydrophobic adhesive in seconds

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The adhesive showed 72-h underwater adhesion strength of ∼47kPa on porcine skin tissue

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Remarkable hemostasis effect was found on rat hepatic and cardiac hemorrhage model

Systematic review of hemostatic agents used in vascular surgery

BACKGROUND

Hemostatic agents are routinely used in vascular surgery to complement proper suture techniques and decrease the risk of perioperative bleeding. A relative lack of comparative research studies have left surgeons with the option of choosing hemostatic agents based on their personal experience. The present review has highlighted the efficacy and safety of hemostatic agents and categorized them according to their primary mechanism of action and cost.

METHODS

A systematic search strategy encompassing hemostatic agent products was deployed in the PubMed database. Single-center and multicenter, randomized, controlled trials with >10 patients were included in the present study.

RESULTS

We reviewed 12 studies on the efficacy and safety of hemostatic agents compared with manual compression or other hemostatic agents. Using the time to hemostasis as the primary end point, all studies had found hemostatic agents to be significantly more efficient than manual compression. Likewise, adhesives (high pressure sealants) and dual agents (containing biologically active and absorbable components) were found to be more efficient, but costlier, than agents with either biologically active or absorbable components only. Agents with porcine or bovine constituents were found to trigger anaphylactic reactions in rare cases. Additionally, the absence of fibrin stabilizing factor XIII in a brand of fibrin sealant was speculated to reduce the affinity of the fibrin sealant for the expanded polytetrafluoroethylene graft. The cost of agents varied greatly depending on their active ingredient.

CONCLUSIONS

Hemostatic agents appear to be highly effective at decreasing the risk of bleeding during surgical procedures. Although some hemostatic agents were demonstrated to achieve hemostasis faster than others, most are able to control bleeding within <10 minutes. Based on the limited data, the least expensive agents might suffice for limited suture lines used in routine procedures.

Evaluation of a biocompatible sealant for on-demand repair of vascular defects-a chronic study in a large animal model

OBJECTIVES

Existing surgical sealants fail to combine design requirements, such as sealing performance, on-demand activation and biocompatibility. The aim of this study was to compare the effectiveness and safety of the SETALIUM™ Vascular Sealant (SVS), a novel, on-demand activatable sealant, with the commercial sealant, BioGlue®, for the repair of vascular defects.

METHODS

In an in vivo porcine model, the use of SVS was compared with BioGlue, for sealing 2-mm defects of the carotid artery and jugular vein. Animals were followed for 7 days and 5 weeks (each time point and per experimental group, n = 4), respectively. The degree of stenosis and flow velocity was determined, and the local tissue response was evaluated.

RESULTS

In vivo incision closure succeeded in all cases, and SVS was superior in clinical usability, enabled by its on-demand activation. Unlike BioGlue, SVS use did not induce stenosis and was associated with physiological blood flow in all cases. Moreover, closure with SVS was associated with a low inflammatory reaction and no thrombus formation or intima proliferation, in contrast to BioGlue.

CONCLUSIONS

SVS demonstrated effective and rapid sealing of 2-mm vascular defects, with favourable biocompatibility compared to BioGlue. Thus, SVS seems to be an effective and safe vascular sealant.

Article Commentary: Hemostats, Sealants, and Adhesives: A Practical Guide for the Surgeon

Hemostats, sealants, and adhesives are useful adjuncts to modern surgical procedures. To maximize their benefit, a surgeon needs to understand the safety, efficacy, usability, and cost of these agents. To be truly added to a surgeon's own toolbox, the operator must also have knowledge of when and how to best use these materials. This commentary is designed to succinctly facilitate this understanding and knowledge. A nomenclature and classification system based on group, category, and class has been created to help with this process and is provided here. By using this system, materials consisting of similar design and for common indications can be compared. For example, in this system, the three functional groups are hemostats, sealants, and adhesives. The hemostats may be divided into four categories: mechanical, active, flowable, and fibrin sealant. These hemostat categories are further subdivided into generic classes based on the composition of the approved materials. Similarly, categories and classes are provided for sealants and adhesives. In this commentary, the salient points with respect to the characteristics of these agents are presented. A discussion of when these agents can be used in specific indications and how they may be applied to achieve the best results is also provided.

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.

Does BioGlue contribute to anastomotic pseudoaneurysm after thoracic aortic surgery?

BACKGROUND

Although bovine serum albumin-glutaraldehyde glue (BioGlue®) has been successfully used as a hemostatic adjunct in aortic surgical procedures, there are reports that it may lead to anastomotic pseudoaneurysm formation. We seek to examine if the use of BioGlue is associated with a high incidence of anastomotic pseudoaneurysm formation following surgical repair of thoracic aortic disease.

METHODS

We reviewed the medical records and follow-up computed tomography (CT) scans of patients from 2001 to 2015 in whom BioGlue was used during surgical repair of thoracic aortic disease to detect postoperative anastomotic pseudoaneurysm formation.

RESULTS

A total of 233 patients with BioGlue use were identified. Mean age was 63.5±14.0 years (median 66; range 14-88; 25-75%, IQR 54-74 years) and 149 were male (63.9%). Surgical indication was thoracic aortic aneurysm in 169 (72.5%) patients, aortic dissection in 49 (21.0%), intramural hematoma in 9 (3.9%), penetrating aortic ulcer in 3 (1.3%) and other in 3 (1.3%). Emergency/urgent surgery was performed in 68 cases (29.2%). Operative mortality was 7.3% (17/233). Re-exploration for bleeding and neurologic deficits occurred in 24 (10.3%) and 21 (9.0%) patients respectively. All operative survivors were followed (100%, 216/216) and CT follow-up was available in 81.9% (177/216) for a mean duration of 2.4 years (median 0.6; 25-75% IQR 0.2-3.6 years). Anastomotic pseudoaneurysm was detected in 1 patient (0.6%) at 3 years postoperatively. This was an elderly female with extremely frail tissues who underwent a reoperative ascending and arch replacement for dissection.

CONCLUSIONS

The use of BioGlue in thoracic aortic surgery was not associated with excess incidence of anastomotic pseudoaneurysm formation following surgical repair of thoracic aortic disease. Its use need not be discouraged on this basis.

Meta-analysis of the use of surgical sealants for suture-hole bleeding in arterial anastomoses

BACKGROUND

Suture-hole bleeding in arterial anastomoses prolongs operating time and increases blood loss, particularly with the use of prosthetic grafts. Surgical sealants (such as fibrin) may be used as haemostatic adjuncts in vascular surgery. This is a systematic review and meta-analysis of published studies that investigated the utility of surgical sealants in arterial-to-prosthetic graft anastomoses.

METHODS

A systematic review was undertaken of papers published until January 2015 on Embase, MEDLINE, PubMed, PubMed Central and Cochrane databases that analysed the use of surgical sealants as haemostatic adjuncts after arterial anastomoses. RCTs were included, with study endpoints of time to haemostasis or haemostasis at 5 min. Secondary outcomes included treatment failure, mean difference in estimated blood loss and duration of surgery. Sensitivity and subgroup analyses were performed, as well as funnel plot analysis for publication bias.

RESULTS

A total of 2513 citations were reviewed; 19 RCTs comprising 1560 patients were ultimately included in the analysis. The majority of studies compared fibrin sealant with control haemostatic measures. Pooled analysis suggested that surgical sealants reduced the time to haemostasis (mean difference 243·26 (95 per cent c.i. 183·99 to 302·53) s; P < 0·001), improved haemostasis at 5 min (odds ratio 4·50, 95 per cent c.i. 2·59 to 7·81; P < 0·001), and were associated with less treatment failure, blood loss and shorter duration of surgery.

CONCLUSION

Surgical sealants appear to reduce suture-hole bleeding significantly in vascular prosthetic graft anastomoses compared with standard haemostatic measures.

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.

Intraoperative surgical sealant application during cardiac defect repair

Bleeding can occur as a sequela to cardiac surgery. Surgical products-such as conventional sutures and clips, and somewhat less conventional sealants-have been developed to prevent this event. Among these, CoSeal is a sealant used at our institution; here we report the cases of 2 patients in whom CoSeal was used successfully as either a supplement or an alternative to suture repair. This sealant was found to be useful in attaining hemostasis both in high-pressure ventricular repair and in the rupture of a friable coronary sinus adjacent to vital structures (in this instance, a left circumflex coronary artery).

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.

Assessment of the effect on blood loss and transfusion requirements when adding a polyethylene glycol sealant to the anastomotic closure of aortic procedures: a case-control analysis of 102 patients undergoing Bentall procedures

Background

The use of CoSeal®, a polyethylene glycol sealant, in cardiac and vascular surgery for prevention of anastomotic bleeding has been subject to prior investigations. We analysed our perioperative data to determine the clinical benefit of using polyethylene glycol sealant to inhibit suture line bleeding in aortic surgery.

Methods

From January 2004 to June 2006, 124 patients underwent aortic surgical procedures such as full root replacements, reconstruction and/or replacement of ascending aorta and aortic arch procedures. A Bentall procedure was employed in 102 of these patients. In 48 of these, a polyethylene glycol sealant was added to the anastomotic closure of the aortic procedure (sealant group) and the other 54 patients did not have this additive treatment to the suture line (control group).

Results

There were no significant between-group differences in the demographic characteristics of the patients undergoing Bentall procedures. Mean EuroSCORES (European System for Cardiac Operative Risk Evaluation) were 13.7 ± 7.7 (sealant group) and 14.4 ± 6.2 (control group), p = NS. The polyethylene glycol sealant group had reduced intraoperative and postoperative transfusion requirements (red blood cells: 761 ± 863 versus 1248 ± 1206 ml, p = 0.02; fresh frozen plasma: 413 ± 532 versus 779 ± 834 ml, p = 0.009); and less postoperative drainage loss (985 ± 972 versus 1709 ± 1302 ml, p = 0.002). A trend towards a lower rate of rethoracotomy was observed in the sealant group (1/48 versus 6/54, p = 0.07) and there was significantly less time spent in the intensive care unit or hospital (both p = 0.03). Based on hypothesis-generating calculations, the resulting economic benefit conferred by shorter intensive care unit and hospital stays, reduced transfusion requirements and a potentially lower rethoracotomy rate is estimated at €1,943 per patient in this data analysis.

Conclusions

The use of this polymeric surgical sealant demonstrated improved intraoperative and postoperative management of anastomotic bleeding in Bentall procedures, leading to reduced postoperative drainage loss, less transfusion requirements, and a trend towards a lower rate of rethoracotomy. Hypothesis-generating calculations indicate that the use of this sealant translates to cost savings. Further studies are warranted to investigate the clinical and economic benefits of CoSeal in a prospective manner.

BioGlue in 2011: what is its role in cardiac surgery?

BioGlue surgical adhesive was developed as an adjunct for achieving hemostasis during cardiovascular surgery, and it was approved for use in the United States by the Food and Drug Administration in 2001. When applied to cardiovascular tissues, the glutaraldehyde and bovine serum albumin that comprise BioGlue produce strong crosslinking that bonds tissues and seals defects. These features have made BioGlue particularly well suited for preventing bleeding from fragile cardiovascular anastomoses such as those inherent in the repair of acute aortic dissection. Over the 10-year period since its approval, several studies and clinical reports have illuminated the relative risks and benefits of using BioGlue during cardiovascular operations. Understanding these merits and limitations of BioGlue is essential to ensuring its safe and effective use.