Sutureless anastomoses using magnetic rings in canine liver transplantation model

Abstract

Background: In the first posttransplant month, the most frequent complications are due to technical problems related to complex vascular and bile duct reconstructions during the operation. Moreover, despite great improvements in suturing technique and materials, severe organ ischemia-reperfusion caused by time-consuming hand suturing is still an important factor in graft survival. During the operation, severe hypotension, hypoxic acidosis, hyperkalemia, and renal dysfunction may occur during the anhepatic phase due to the prolonged venous clamping time required for hand suturing. Therefore, hand suturing is a handicap in the development of further advancements in liver transplantation. In this study, we aimed to test a new "mechanical installation method" for rapid vascular reconstruction.

Methods: The magnetic pinning-ring device was developed consisting of paired magnetic rings coated with titanium oxide and embedded in a polypropylene shell. The rings were equipped with alternately spaced holes and titanium pins. Forty adult mongrel dogs were randomly divided into groups: A (n = 16), all vascular and bile duct reconstruction by magnetic ring without venous bypass; B (n = 16), all vascular and bile duct reconstruction by hand suturing with venous bypass; C (n = 8), sham transplantation group, transection of all vessels and common bile duct followed by anastomosis with the magnetic rings without liver transplantation. From groups A and B, dogs were randomly selected as donors (n = 8) or recipients (n = 8) of liver transplantations. We recorded operation time, vascular and bile duct anastomosis time, anhepatic time, administration of supplemental fluids during operation, and survival; blood samples were collected for the detection of liver damage (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and tumor necrosis factor α level. Patency was confirmed using ultrasound scans at various time points as late as 24 wk after surgery. Angiography was used to evaluate the anastomoses formed with magnetic rings. In group C, gross observation, histologic staining, and scanning electron microscopy were used to evaluate the vessels and bile ducts 12 wk postoperatively.

Results: In group A, the total operation time, inferior vena cava, and portal vein anastomosis times were significantly shortened, and the anhepatic phase was reduced to about one-fifth that of group B, which was a significant difference between the two groups (P < 0.01). The mean total operative time was 2.54 ± 0.45 h. In order to maintain adequate blood pressure, the mean fluid volume infused was 800.56 ± 60.56 mL in the recipients of group A, which was lower than that in group B (2241.67 ± 390.78 mL, P < 0.01). Use of a pressor agent in group A was unnecessary. After operation, five of eight animals in group A survived more than 7 d after operation. The main cause of death was acute rejection. Only three of eight animals in group B survived more than 1 wk after operation due to chronic anastomotic bleeding, kidney failure, heart failure, and gastrointestinal bleeding. There was a statistically significant difference (P < 0.01) between the short-term survival rate in the two groups (75.0% versus 37.5%). The ALT (1544.46 ± 286.27) U/L and AST (1710.74 ± 252.27) U/L levels after operation in the animals with hand suturing were significantly higher than those in the sutureless group (ALT = 1116.41 ± 210.55 U/L; AST = 1176.95 ± 248.25) U/L after reperfusion (P < 0.01). The serum tumor necrosis factor α levels (45.56 ± 10.78) ng/L in group B were significantly higher than those of group A (26.64 ± 10.84) ng/L after reperfusion (P < 0.01). Re-endothelialization was confirmed in all vessels in group C, with neither formation of aneurysms nor thickening of the vascular wall noted after 12 wk. The bile duct anastomoses also healed well.

Conclusions: The magnetic pinning-ring device offers a simple, fast, reliable, and efficacious technique for nonsuturing vascular and bile duct anastomoses. Use of this device shortens operation time, maintains a high patency rate, and improves the healing of tissue. Application of the magnetic ring anastomosis technique can effectively reduce the complications caused by hand suturing, and can reduce the extent of ischemia-reperfusion injury, leading to smoother operations and improved prognosis.

Keywords: Anastomosis; Ischemia-reperfusion injury; Liver transplantation; Magnetic pinned-ring device; Nonsuture technique.