Sutureless anastomoses of rabbit carotid arteries with BioGlue

The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on local tissue reaction and inflammation in rabbit carotid artery anastomosis

Objectives

In addition to the hemostatic properties of hemostatic agents, the investigation of their immunogenic properties, their local effects on application area has been the subject of many experimental studies. There are limited data on the inflammatory effects of Bovine serum albumin-glutaraldehyde and Polyethylene glycol polymer. Therefore, we investigated the effects of these agents on tissue reactions and inflammation in rabbit carotid artery anastomosis in our experimental study.

Methods

Twenty-one New Zealand male rabbits were randomly divided into three groups. The right carotid artery anastomosis was performed on the control group after transection. Hemostatic agents were applied locally to other two groups separately after transection and anastomosis. At the end of 28 days, the type of inflammation, inflammatory cell infiltration, degree of inflammation, and amount of residual adhesives were examined and compared statistically.

Results

Cell infiltrations associated with inflammation on the anastomosis site (eosinophils, epithelioid/giant cells, lymphocytes, and plasma cells) and inflammation grade in the groups of hemostatic agents were significantly lower compared to the control group ( p < .05). There was no difference between the hemostatic agents. While mild inflammation (61.9%) was dominant in the groups of hemostatic agents, moderate inflammation (85.7%) was more common in the control group. No severe inflammation was observed in any of the three groups. Residual sealant grade between hemostatic agents did not differ significantly.

Conclusions

When inflammation and tissue reactions of the 4th week were evaluated, it was determined that both hemostatic agents did not cause severe inflammation. However, comparative results at multiple time intervals are needed due to the dynamic process of inflammation.

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.

3D-Printed Sugar-Based Stents Facilitating Vascular Anastomosis

Microvascular anastomosis is a common part of many reconstructive and transplant surgical procedures. While venous anastomosis can be achieved using microvascular anastomotic coupling devices, surgical suturing is the main method for arterial anastomosis. Suture-based microanastomosis is time-consuming and challenging. Here, dissolvable sugar-based stents are fabricated as an assistive tool for facilitating surgical anastomosis. The nonbrittle sugar-based stent holds the vessels together during the procedure and are dissolved upon the restoration of the blood flow. The incorporation of sodium citrate minimizes the chance of thrombosis. The dissolution rate and the mechanical properties of the sugar-based stent can be tailored between 4 and 8 min. To enable the fabrication of stents with desirable geometries and dimensions, 3D printing is utilized to fabricate the stents. The effectiveness of the printed sugar-based stent is assessed ex vivo. The fabrication procedure is fast and can be performed in the operating room.

Experimental study of sutureless vascular anastomosis with use of glued prosthesis in rabbits

OBJECTIVE

The objective of this study is to explore the feasibility and efficacy of a new technique for sutureless vascular anastomosis, using glued prosthesis, as a sole anastomosis fixation method in rabbits.

METHODS

Ten rabbits were randomly selected to conduct the experiment. Five rabbits underwent direct anastomosis of infrarenal abdominal aorta, with glued prosthesis. In five other rabbits, reconstruction was done by sutured anastomosis. All animals were immediately examined by echo-Doppler for patency of anastomosis. The burst pressure of the glued anastomosis was measured and compared with that of a sutured artery. The animals were euthanized, and tissue samples were taken for histological examination immediately after the experiment.

RESULTS

Compared to conventional anastomoses, sutureless vascular anastomoses required shorter time of creation and significantly reduced blood loss (P<5%). There was no significant difference on the average blood flow through the anastomosis between two groups at the end of surgery. All anastomoses with glued prosthesis, examined by echo-Doppler, were patent at the anastomotic site, except one, which was stenosed immediately after surgery. In the control group, except one with stenosis, all conventional anastomoses were patent. Mean burst pressure at the anastomotic site for sutureless anastomoses was lower than in control group. Macroscopically, the BioGlue did not demonstrate any adhesion to the surrounding tissue as it was covered by the vascular prosthesis. Histological examination showed low-grade inflammatory reaction in glued anastomoses versus no inflammatory reaction at the sutured anastomoses.

CONCLUSION

This technique may provide a feasible and successful alternative in vascular surgery. However, further long-term studies are necessary to elucidate the break pressure and degree of inflammation at the anastomotic site.

The vascular connector, design of a new device for sutureless vascular anastomosis

BACKGROUND

In recent years, several methods and new techniques have been studied and proposed for establishment of sutureless vascular anastomoses, streaming use of sutureless vascular surgery in the future.

PRESENTATION OF THE HYPOTHESIS

The new vascular connector (NVC) is a hypothetical design of a vascular device, proposed for creation and maintenance of sutureless vascular anastomosis. Implication of NVC would introduce a new device and technique in establishment of sutureless vascular anastomosis in which surgical approach is minimized and so post-operation disorders. It would eliminate need for suture; shorten clampage and operation time, consequently reducing stress for both, the surgeon and the patient. It enables the creation of vascular anastomosis fast, simple, safe, reliable, with satisfactory patency and stability of anastomosis.

TESTING THE HYPOTHESIS

Efficacy of NVC needs to be evaluated in further studies, in order to be confirmed for clinical use. The effectiveness of NVC should be verified firstly in vitro and in vivo tests; and by animal experiments. The likelihood of its negative influence in thrombogenicity should be well evaluated.

IMPLICATIONS OF THE HYPOTHESIS

Implication of the new vascular connector (NVC) would be of interest to both patients and the surgeon due to the following main achievements: 1) enables the creation of vascular anastomosis fast and simple, 2) significant shortening of clampage time of blood vessels and operation time-this assumption would be followed by reduced risk of operative and post-operative complications and length of hospital stay or admission to Intensive care unit, 3) safe and reliable, 4) compatible with any blood vessel and standard vascular graft, 5) using the NVC we will reduce in minimum need for replaced blood volume, 6) reduces the cost of treatment. It is anticipated that the NVC would provide shorter operation time and least operative and post-operative complications in creation of sutureless vascular anastomosis.

Isocyanate-functional adhesives for biomedical applications. Biocompatibility and feasibility study for vascular closure applications

Biodegradable isocyanate-functional adhesives based on poly(ethylene glycol)-adipic acid esters were synthesized, characterized, and evaluated in vitro and in vivo. Two types of formulations, P2TT and P2MT, were developed by functionalization with 2,4-tolylene diisocyanate (TDI) or 4,4'-methylene-bis(phenyl isocyanate) (MDI), respectively, and branching with 1,1,1-trimethylolpropane (TMP). The biocompatibility of the synthesized adhesive formulations was evaluated as per ISO 10993. Cytotoxicity, systemic toxicity, pyrogenicity, genotoxicity (reverse mutation of Salmonella typhimurium and Escherichia coli), hemolysis, intracutaneous reactivity, and delayed-type hypersensitivity were evaluated. All formulations met the requirements of the conducted standard tests. The biological behavior and ability of the adhesive formulations to close an arteriotomy and withstand arterial pressure following partial approximation with a single suture were evaluated in a rat abdominal aorta model. Animals were evaluated at 1, 2, 3, and 4 weeks after surgery. Macroscopic and histopathologic evaluation of explanted arteries suggested that the P2TT formulation had better in vivo performance than the P2MT formulation. Additionally, the P2TT formulation resulted in less tissue reaction than P2MT formulation. To our knowledge, this is the first study demonstrating the potential of this new class of isocyanate-functional degradable adhesives for vascular applications.

Stent-and-glue sutureless vascular anastomosis

Vascular anastomosis is commonly done by hand-sewn methods which not only are slow in pace, but also need experiences in surgeons' hands. As the old techniques are replaced by the new ones all the time, it is sensed that a new sutureless approach should be welcomed in the field of vascular anastomosis. Although lots of efforts have been done, such previous recommended techniques are associated with adverse consequences and here is where the need for new methods is still sensed. In this manuscript, we bring all the benefits from other methods together and conclude a novel one for end-to-end vascular anastomosis which uses biological glue as connecting material and also an absorbable stent to keep vessel patency while using balloon catheter and tacking suture.

Experimental simplification of the excimer laser-assisted nonocclusive anastomosis (ELANA) technique

BACKGROUND

The excimer laser-assisted nonocclusive anastomosis (ELANA) technique facilitates the construction of an end-to-side anastomosis between a donor vessel and a recipient artery without the need to temporarily occlude the recipient artery.

OBJECTIVE

To test whether the surgically difficult ELANA technique can be simplified.

METHODS

In 42 rabbits, with the aorta as the recipient artery and human saphenous veins as donor grafts, we made 30 conventional ELANAs with 8 microsutures, 90 ELANAs with 4 microsutures (ELANA-4s), 40 ELANAs with 2 microsutures (ELANA-2s), and 90 sutureless ELANAs (SELANAs). SELANA involved a new ring design with 2 pins. ELANA-4, ELANA-2, and SELANA were each combined with 3 different sealants (Bioglue, Tachoseal, and Tisseel) and compared regarding application time, complications, and burst pressure.

RESULTS

The conventional ELANA was constructed in a mean of 14.8 +/- 2.6 minutes. All experimental anastomoses were constructed significantly faster; the ELANA-4 in a mean of 10.9 +/- 1.3 minutes, the ELANA-2 in a mean of 5.4 +/- 1.7 minutes, and the SELANA in a mean of 2.5 +/- 1.8 minutes. All ELANA and ELANA-4 anastomoses were sufficiently strong with a burst pressure > 200 mm Hg, except for 1 insufficiently sealed ELANA-4 anastomosis. ELANA-2 was sufficiently strong only with Bioglue, showing a burst pressure > 280 mm Hg. SELANA was sufficiently strong with Bioglue or TachoSil, showing a burst pressure > 260 mm Hg.

CONCLUSION

The ELANA technique can be simplified by reducing or even abandoning microsutures. Of the experimental anastomoses tested, we consider the SELANA technique combined with TachoSil of most potential benefit. Long-term survival studies will be performed in animals before we consider using any of these new techniques in patients.