Stent-and-glue sutureless vascular anastomosis

Mechanical Viability and Functionality Assessment of a New Sutureless Endoluminal Microvascular Device: A Preliminary In Vivo Rabbit Study

Our group has developed a new nitinol endoluminal self-expandable device for microvascular anastomosis. It attaches to each vessel ending with opposite directed microspikes and reaches complete expansion at body temperature, using the nitinol shape memory capacity. The main purpose of this first in vivo trial is to evaluate the mechanical viability of the device and its immediate and early functionality. A recuperation study with seven New Zealand White rabbits was designed. A 1.96 mm outer diameter prototype of the new device was placed on the right femoral artery of each rabbit. Each anastomosis was reassessed on the seventh postoperative day to reevaluate the device function. The average anastomosis time with the new device was 18 min and 45 seg (±0.3 seg). It could be easily placed in all the cases with an average of 1.14 (1) complementary stitches needed to achieve a sealed anastomosis. Patency test was positive for all the cases on the immediate assessment. On the 1 week revision surgery, patency test was negative for the seven rabbits due to blood clot formation inside the device. The new device that we have developed is simple to use and shows correct immediate functionality. On the early assessment, the presence of a foreign body in the endoluminal space caused blood clot formation. We speculate that a heparin eluting version of the device could avoid thrombosis formation. We consider that the results obtained can be valuable for other endoluminal sutureless devices.

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.

Evaluation of a novel thermosensitive heparin-poloxamer hydrogel for improving vascular anastomosis quality and safety in a rabbit model

Despite progress in the design of advanced surgical techniques, stenosis recurs in a large percentage of vascular anastomosis. In this study, a novel heparin-poloxamer (HP) hydrogel was designed and its effects for improving the quality and safety of vascular anastomosis were studied. HP copolymer was synthesized and its structure was confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (¹H-NMR). Hydrogels containing HP were prepared and their important characteristics related to the application in vascular anastomosis including gelation temperature, rheological behaviour and micromorphology were measured. Vascular anastomosis were performed on the right common carotid arteries of rabbits, and the in vivo efficiency and safety of HP hydrogel to achieve vascular anastomosis was verified and compared with Poloxamer 407 hydrogel and the conventional hand-sewn method using Doppler ultrasound, CT angiograms, scanning electron microscopy (SEM) and histological technique. Our results showed that HP copolymer displayed special gel-sol-gel phase transition behavior with increasing temperature from 5 to 60 °C. HP hydrogel prepared from 18 wt% HP solution had a porous sponge-like structure, with gelation temperature at approximately 38 °C and maximum elastic modulus at 10,000 Pa. In animal studies, imaging and histological examination of rabbit common jugular artery confirmed that HP hydrogel group had similar equivalent patency, flow and burst strength as Poloxamer 407 group. Moreover, HP hydrogel was superior to poloxamer 407 hydrogel and hand-sewn method for restoring the functions and epithelial structure of the broken vessel junctions after operation. By combining the advantages of heparin and poloxamer 407, HP hydrogel holds high promise for improving vascular anastomosis quality and safety.