[Application of a new temporary intravascular shunt device in limb injury of dogs].

OBJECTIVE: To explore the effectiveness and safety of a new temporary intravascular shunt (TIVS) device for limb injury in dogs.
METHODS: Eighteen adult beagle dogs, male or female, weighing (20±2) kg, were taken for experiment. A semi-amputated limb model was made by circular amputating the knee joint of one hindlimb, which retained only skin, femoral artery, femoral vein, femoral nerve, and femur. Then the femoral artery was clamped for 2 hours in all animals, resulting in the ischemic environment of the distal limbs. The animals were randomly divided into 3 groups ( n=6). In group A, the bypass was started by using a new TIVS device and replenishing saline through the infusion port; In group B, after intravenous injection of heparin sodium solution, the bypass was started by using a new TIVS device and replenishing 3% heparin sodium solution through the infusion port; In group C, the bypass was started by using the self-made bypass tube. The bypass was end after 12 hours. The general vital signs (body temperature, heart rate, blood pressure) before and after bypass were measured, and the time required for the insertion of the bypass tube, the patency during the bypass, shedding, and thrombosis were recorded. Routine blood test and blood coagulation indicators [white blood cell (WBC), red blood cell (RBC), platelet (PLT), hemoglobin (HGB), activated partial thromboplastin time (APTT), fibrinogen (Fib)] and biochemical indicators [lactic dehydrogenase (LDH) and creatine kinase (CK)] were recorded before bypass and after 3, 6, 9, and 12 hours of bypass, respectively. The gastrocnemius muscles on the surgical side before and after bypass were harvested and the muscle necrosis, the wet-to-dry weight ratio, and the content of malondialdehyde (MDA) and myeloperoxidase (MPO) were measured. In addition, the gastrocnemius muscle and femoral artery were observed after bypass by HE staining.
RESULTS: There was no significant difference in body temperature, heart rate, and blood pressure between groups before and after bypass ( P>0.05). Compared with groups A and B, the time required for the insertion of the bypass tube in group C was significantly longer ( P<0.05), and the number of thrombus in the bypass tube, the blockage time significantly increased ( P<0.05). Shedding and sliding of bypass tube occurred in 3 cases of group C, but no shedding or sliding of bypass tube occurred in groups A and B; there was no significant difference in the incidence of shedding between groups ( P=1.000). There was no significant difference ( P>0.05) in routine blood test, blood coagulation indicators, LDH, CK, MPO, MDA, and wet-to-dry weight ratio between groups before bypass. After bypass, the routine blood test and blood coagulation indicators of the 3 groups did not change significantly, and the differences between groups was not significant ( P>0.05); LDH and CK gradually increased ( P<0.05), and group C significantly higher than groups A and B at 12 hours ( P<0.05). After bypass, thrombosis was seen in the bypass tube, the distal gastrocnemius muscle necrosis occurred in group C, and the femoral artery injury was slightly heavier than that in groups A and B.
CONCLUSION: The new TIVS device is safe and effective and has the advantages of convenient implantation, lower thrombosis rate, and less limb ischemia-reperfusion injury.