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

Light-Activated Vascular Anastomosis

Background. There have been few advances in technique since vascular anastomosis was performed with silk suture on a curved needle in 1902. This technique results in disruption of the endothelium with exposed intraluminal suture, both of which may lead to thrombocyte aggregation, intimal hyperplasia, and vascular stenosis. A variety of alternative techniques have been explored, with limited success. Photochemical tissue bonding (PTB) is a light-activated methodology of rapidly cross-linking tissue interfaces at the molecular level. Herein, we describe a new technique for anastomosis of venous interposition graft in an ovine model of femoral artery bypass utilizing PTB. Methods. Polypay specific pathogen free sheep (n = 5; 40-45 kg) underwent femoral artery bypass utilizing saphenous vein. The femoral artery was transected and reversed saphenous vein was implanted as an interposition graft. The proximal anastomosis was created as a vein-over-artery cuff utilizing PTB, and the distal anastomosis was created with standard interrupted 8-0 polypropylene suture. Four weeks post-index operation, femoral angiogram was performed to evaluate patency, tortuosity, and luminal diameter. All bypass grafts were harvested and longitudinal and transverse histological sections from the proximal anastomosis were analyzed. Results. The PTB anastomoses (n = 5) were immediately watertight and patent. All animals survived the 28-day study duration. Angiography revealed patent grafts with no aneurysm or stenosis (n = 5). Histologic examination revealed integration of the venous endothelium with the arterial adventitia. Conclusion. Photochemical tissue bonding creates an immediate strong, watertight vascular anastomosis that can withstand physiologic arterial pressure and remains patent at 28 days without the need for intraluminal suture.

A systematic review of sutureless vascular anastomosis technologies

Vascular anastomoses typically involve a handsewn technique requiring significant surgical training, expertise, and time. The aim of our systematic review was to identify and describe sutureless vascular anastomosis techniques. We performed a systematic review of all sutureless vascular anastomosis technologies published in MEDLINE, PubMed, Embase, CINAHL, Cochrane, Web of Science, and Scopus Library databases and a patent review using US Patent and Trade Office Application, US Patent and Trademark Office Patent, Google Patents, Lens, Patent Quality Through Artificial Intelligence, SureChEMBL, and E-Space Net. Data from inclusion studies and patents published between January 1, 1980 and July 15, 2021 were abstracted to describe their category, anastomosis type and configuration, study types, and advantages and disadvantages encountered with each technology. Two hundred eleven original studies and 475 patents describing sutureless vascular anastomosis technologies were identified. In the literature, stents/stent-grafts/grafts (n = 61), lasers (n = 53), and couplers (n = 27) were the predominant device categories. In the patent review, adhesive technologies (n = 103), stents/stent-grafts/grafts (n = 68), and mechanical connectors (n = 61) predominated. The majority of studies involved in vivo animal studies (n = 193); 32.2% (n = 68) of investigations involved human trials; and 17.9% (n = 85) of patent technologies were approved by the US Food and Drug Administration. The main advantages described for sutureless anastomosis technologies included faster procedure time and greater patency rates compared with handsewn anastomoses. The main disadvantages included reduced vessel compliance, stenosis, leakage, and device costs. The appeal of sutureless technology is substantiated by numerous animal trials, but their use in humans remains limited. This may be a reflection of strict regulatory criteria and/or vascular complications associated with currently available technologies.

Biocompatibility and patency of a novel titanium vascular anastomotic device in a pig jugular vein

This study aimed to evaluate the biocompatibility and patency of our newly developed titanium vascular anastomotic device (TVAD) in a pig jugular vein. TVAD was made of commercially pure grade 2 titanium. The patency and anastomotic time were simultaneously confirmed in an ex-vivo system developed by the authors and in vivo using pig jugular veins. Five 8-month-old pigs, with body weights of 50–60 kg, underwent anastomosis of both jugular veins using the device. Graft patency was evaluated for 12 weeks by biplane angiography and sonography. All tissue biopsy samples were analysed by histology. In all 10 cases, the anastomosis was completed in < 5 min. The vessel lumen was not damaged, and the inner vessel wall was completely endothelialised at the anastomotic site. No foreign body reactions were observed at the vessel lumen, vessels, and outer vessel walls by histopathologic analysis. Patency and absence of leakage at the anastomotic site of the follow-up period were confirmed clearly by angiography and sonography. This preliminary animal study proved that our newly developed device is a very promising tool for intima-to-intima contact anastomosis. TVAD can be used as a feasible and safe medical tool for vessel anastomosis.

The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis

OBJECTIVE

Since the systemic drugs have been used to reduce the hyperplasic response in the tunica intima, the periadventitial local drug applications to the vascular wall have gained more popularity. In this study, we investigated the effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis to explore the effects of these two different agents.

METHODS

21 New Zealand male rabbits were randomly divided into three groups. The carotid artery transection and anastomosis was performed onthe control group. The bovine serum albumin-glutaraldehyde and the polyethylene glycol polymer were applied locally on the other two groups seperatley after transection and anastomosis of the carotid arteries. At the end of 28-day follow-up, the histological and the immunohistochemical results related to neointimal hyperplasia were compared.

RESULTS

The glue residues were detected in the BSA-glutaraldehyde group, but in the PEG polymer group there was no glue residue. The intima thickness and the intima/media thickness ratio in the control group was significantly higher (p<0.05) than the other groups. These values did not differ significantly between the BSA-glutaraldehyde group and the PEG polymer group (p>0.05). The lumen diameter and the area in the control group were significantly higher (p < 0.05) than the BSA-glutaraldehyde group. These values between the control group and the PEG polymer group did not differ significantly (p>0.05). aSMA-positive staining score in the Control group was found to be significantly lower (p < 0.05) than the BSA-glutaraldehyde and PEG polymer group and the VEGF-positive staining score in the control group was found to be significantly higher (p < 0.05) than the BSA-glutaraldehyde and the PEG polymer group.

CONCLUSIONS

Although the both agents have positive results on neointimal hyperplasia, it would be favorable to use polyethylene glycol polymer, since it does not seem to affect the lumen area and the lumen diameter of the vessel.

Experimental Devices Versus Hand-Sewn Anastomosis of the Aorta: A Systematic Review and Meta-Analysis

BACKGROUND

To minimize complications associated with the construction of the hand-sewn aortic anastomosis, alternative experimental methods have been pursued. This study aimed to evaluate the efficacy of experimental anastomotic devices in relation to time and point of rupture of the anastomosis in comparison to the conventional technique.

MATERIALS AND METHODS

An electronic search was performed using MEDLINE, Scopus, Science Direct, and Cochrane Library databases by two independent authors. Our exclusion criteria referred to studies reporting results solely from end-to-side anastomosis, results on vessels other than the aorta, studies that did not involve animal experiments, and non-English publications. The last search date was January 1, 2020.

RESULTS

The meta-analysis included 22 studies with 34 anastomosis samples and a total of 316 animals. The pooled mean automated anastomosis time was 10.38 min, and the mean point of rupture was 32.7 N. In the subgroup analysis of automated anastomosis time by device category, the anastomotic stenting technique reported significantly lower anastomosis time but also showed significantly lower point of rupture. Comparing the efficacy of experimental devices and the hand-sewn technique, our pooled analysis showed that automated devices significantly decrease the time needed to perform the anastomosis (weighted mean difference -7.24 min). On the other hand, the automated anastomosis is also associated with decreased tensile strength (weighted mean difference -20.68 N).

CONCLUSIONS

Although experimental devices seem to offer a faster anastomosis, they lack endurance when compared with the hand-sewn technique. Further research is needed for the development of an "ideal" anastomotic technique.

Surface modification of small intestine submucosa in tissue engineering

With the development of tissue engineering, the required biomaterials need to have the ability to promote cell adhesion and proliferation in vitro and in vivo. Especially, surface modification of the scaffold material has a great influence on biocompatibility and functionality of materials. The small intestine submucosa (SIS) is an extracellular matrix isolated from the submucosal layer of porcine jejunum, which has good tissue mechanical properties and regenerative activity, and is suitable for cell adhesion, proliferation and differentiation. In recent years, SIS is widely used in different areas of tissue reconstruction, such as blood vessels, bone, cartilage, bladder and ureter, etc. This paper discusses the main methods for surface modification of SIS to improve and optimize the performance of SIS bioscaffolds, including functional group bonding, protein adsorption, mineral coating, topography and formatting modification and drug combination. In addition, the reasonable combination of these methods also offers great improvement on SIS surface modification. This article makes a shallow review of the surface modification of SIS and its application in tissue engineering.

Α systematic review and meta-analysis of the efficacy of aortic anastomotic devices

OBJECTIVE

One of the factors contributing to complications related to open repair of the aorta is the construction of a hand-sewn anastomosis. Aortic anastomotic devices (AADs), such as the intraluminal ringed graft (IRG), and the anastomotic stenting technique have been developed to perform a sutureless and less complicated anastomosis. This study performed a systematic review and meta-analysis of the literature reporting clinical use of AADs and aimed to assess, primarily, the effect of each device on 30-day overall and operation-related mortality and aortic cross-clamping time and, secondarily, the rate of successful two-sided application of the IRG device and the operation-related morbidity for each device.

METHODS

An electronic search was performed using MEDLINE, Scopus, ScienceDirect, and Cochrane Library by two independent authors. Our exclusion criteria included studies incorporating fewer than three patients and studies reporting results solely from animals or in vitro testing, results solely from end-to-side anastomosis, and results solely from endarterectomy procedures. The last search date was February 1, 2018.

RESULTS

A total of 41 studies were identified that reported outcomes for the use of three different device types: IRG, anastomotic stenting technique, and surgical staplers. The last two types were classified together as the non-IRG group. The meta-analysis included 27 studies with 50 cohorts incorporating 1260 patients. The median age of the incorporated patients was 61.4 years (range, 51-73 years), and 68.9% were male. The operations were performed for the treatment of acute aortic dissection in 82.3%. The pooled overall 30-day mortality rate varied by device type; IRG devices had a mean rate of all-cause mortality of 9.71%, whereas non-IRG devices were associated with a significantly (I² = 15.78%; P for Cochrane Q test < .19) lower rate of death (1.47%). The pooled mean aortic cross-clamping time was 35.83 minutes. Metaregression showed that the performance of two-sided anastomosis with the IRG device significantly decreased the aortic cross-clamping time. However, a successful two-sided ringed anastomosis was performed in approximately half of the cases.

CONCLUSIONS

Taking into account that the majority of operations were performed for the treatment of acute aortic dissection, AADs had a relatively low rate of 30-day mortality. Despite the observed heterogeneity in study protocols and the small sample size in the non-IRG group, the non-IRG group presented with the lowest 30-day mortality rate. Specific device-related complications between the different device types need further investigation.

Surface heparinization and blood compatibility modification of small intestinal submucosa (SIS) for small-caliber vascular regeneration

OBJECTIVES

This study aims to investigate the small intestinal submucosal (SIS) surface after heparinization with the hypothermia plasma technique, to improve the blood compatibility of SIS, and to explore the possibility of construction of small-caliber vascular grafts with modified SIS scaffolds in vivo.

METHODS

SIS films prepared from jejunums of pigs were processed for surface treatment at different time periods with the argon plasma initiation technique under vacuum, and were then immediately immersed in 4% (m/v) heparin sodium solution for 24-h heparinization. The surface morphologies of heparinized SIS were observed under a scanning electron microscope (SEM). The antithrombogenicity of the modified SIS films was tested by measuring the water contact angle, blood coagulation time, activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and observation of platelet adherence by SEM. Heparinized SIS films were sewn into a small caliber (3-mm) tube and implanted into the defect of a canine femur by anastomosis as a vascular graft. The efficiency of the SIS graft was evaluated according to the patency for the circulation of blood with Doppler color ultrasonography and hematoxylin-eosin staining.

RESULTS

Heparinized SIS showed a significantly different surface morphology compared with that of untreated SIS. The SIS surface resembles wrinkled film, but the heparinized SIS surface is uniformly coated with microdots, and appears to have a layer of heparin adhesion.

CONCLUSION

Heparin was attached to the SIS surface after hypothermia plasma treatment. Hydrophilicity and antithrombogenicity of heparinized SIS were clearly increased. The heparinized SIS vascular graft showed great potential for replacement of defective small-caliber vessels.

Sutureless open vascular anastomosis connector: An experimental study

The objective of this study was to assess the safety of a new developed sutureless vascular adapter system in a porcine model. In five pigs, 4-cm-long polyester prosthesis (6 mm diameter) were implanted and anastomosed with the newly developed adapter proximally and suture anastomosis distally. The integration of the adapter was investigated in comparison to the suture anastomosis. These investigations were performed by light microscopy and scanning electron microscopy. Median operative time for performing the adapter anastomosis was significantly shorter compared to suture anastomosis (66 s vs. 246 s, p < 0.05). Median estimated blood loss during adapter anastomosis implementation was 22.5 mL (range 19.0–25.0 mL) compared to 48.2 mL (range 45.4–63.5 mL, p < 0.05). In five hand-sewn anastomoses, overall eight additional stitches were necessary whereas all adapter anastomoses showed primary leak tightness. This in vivo study shows the technical feasibility of the newly developed adapter.

Clinical, mechanical, and immunohistopathological effects of tissue adhesives on the colon: An in-vivo study

BACKGROUND

Tissue adhesives may be useful for sealing bowel anastomoses by preventing anastomotic leakage. Prior to clinical implementation, an in-depth analysis of the clinical and immunohistopathological effects of tissue adhesives on the target tissue and of the mechanical strength of the adhesive bond in an in vivo model is needed.

MATERIALS AND METHODS

In 84 rats, two bowel segments were glued using one of the following tissue adhesive: Bioglue, Gelatin-resorcinol-formaldehyde (GRF), Glubran 2, Histoacryl Flex, Omnex, Duraseal Xact, or Tissucol. Rats were followed for 7 or 28 days. Endpoints were clinical complication rate, mechanical strength, and immunohistopathological reactions.

RESULTS

Of the seven tissue adhesives, GRF and Bioglue showed the highest rates of bowel wall destruction and ileus and the most severe immunohistopathological tissue reactions at 7 and 28 days. Cyanoacrylates (Histoacryl Flex, Omnex, Glubran 2) showed high mechanical strength and mild immunohistopathological reactions at 7 and 28 days. Duraseal Xact and Tissucol were the most inert tissue adhesives, but exhibited low mechanical strength. At 28 days, mechanical strength was significantly correlated to CD8, CD68, and Ki67 cell counts.

CONCLUSION

Based on the clinical and immunohistopathological outcomes, GRF and Bioglue were found to be the least suitable tissue adhesives for colonic use. Duraseal Xact and Tissucol were inert but also showed low mechanical strength. Cyanoacrylates exhibited mild clinical and immunohistopathological effects while maintaining high strength, which makes them promising as colonic sealants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 846-854, 2017.