| Objective: In order to optimize the bypass surgery, increase the long-term patency rates of implanted vein, common carotid artery was reconstructed with anterior facial vein in rabbits, the effect of expanded poly tetra fluoro ethylene(ePTFE) cuff on vein filtration velocity changes of bypassed facial vein graft after different time course of postoperation was investigated.Methods: Thirty-six healthy rabbits(2.5±0.5 kg) were randomly divided into 2groups, namely experimental group and control group. Veins in experimental group were enclosed by ePTFE, and control group were not enclosed. Right carotid arteries were reconstructed with facial veins(2 cm long) in the same side using two fixed-point end-to-side anastomosis methods under surgery microscope. Blood supply was recovered and the patency rates and errhysis of the anastomotic of implanted vein were observed after bypass surgery. Blood routine measurements, including white blood cell(WBC) count, lymphocyte(LYM) count, neutrophil(GRAN) count and monocyte(MONO) count were tested at 1 d preoperatively, 1, 5 and 14 d postoperatively. The original incision was opened up, implanted veins pulse and the caliber of the lumen were observed after 2, 4 and 8 w postoperatively. Then, infusion reservoir for filtration velocity determination was installed and debugged. Implanted veins and left carotid arteries were harvested and connected to the infusion system.Outer dimensions(length and diameter) and the filtration velocity were measured under 100 mm Hg transmural pressure. Pathological sections were conducted and vascular intimal thickness of implanted veins were analyzed and determined.Results: Results were as follows:1. General observation:Blood supply was recovered after bypass surgery, the anastomotic of implanted vein had no errhysis and the vessel lumina were obviously dilated. No animals died either intraoperative or postoperative. The implanted veins were pulsated well and ruddy. Vessel walls had good elasticity, high patency rates and varying degrees of thickening. The lateral wall of ePTFE cuffs had slight adhesion with surroundingtissue. The medial wall of ePTFE cuffs had few adhesions with implanted vein.2. Changes of blood routine examination:Compared with 1 d preoperatively, WBC and GRAN were extremely increased( P<0.01) in control and experimental group at 1 d postoperatively, which were19.84±2.69×109/L ? 20.65±3.14×109/L ? 5.94±1.12×109/L and 6.18±1.13×109/L,respectively, and they returned to normal at 5 d postoperatively in control group, but compared with control group, WBC was significantly increased( P<0.05) at 5 d postoperatively, and it returned to normal at 14 d postoperatively in experimental group. MONO was significantly increased(P<0.05)at 5 d postoperatively in control and experimental group, but LYM had no significant difference(P>0.05).3. Outer diameters changes of implanted veins:Following increase of time course, outer diameters of implanted veins in control group were extremely decreased(P<0.01). Compared with 2 w, outer diameters of implanted veins were significantly or extremely decreased at 4 w and 8 w postoperatively in experimental group, which were 0.46±0.03 cm and 0.39±0.01 cm,respectively. Compared with control group, outer diameters of implanted veins were extremely decreased(P<0.01)at 2 w, but had no significant difference(P>0.05) at 4 w and 8 w postoperatively in experimental group.4. Filtration velocity changes of implanted veins:Filtration velocity decreased following increase of time course. Implanted veins in control group had a significantly higher filtration velocity than experimental group at 2 and 4 w postoperatively(P<0.01), which were 13.35±0.67×10-6 cm/s ?13.57±0.32×10-6 cm/s?24.95±1.15×10-6 cm/s and 19.96±0.92×10-6 cm/s, respectively,but filtration velocity of implanted veins in control group was lower than that of experimental group at 8 w postoperatively(P<0.05), which were 7.19±0.22×10-6 cm/s and 7.95±0.15×10-6 cm/s, respectively. Compared with contralateral arteries, all implanted veins had extremely high filtration velocity at 2, 4 and 8 w postoperatively(P<0.01).5. Thickness changes of implanted veins:Compared with normal veins, thickness of implanted veins was significantlyincreased in control and experimental group at each time point. At 2 w postoperatively,thickness of implanted veins in control and experimental group increased to49.47±7.43 ?m and 43.82±6.25 ?m, respectively. Compared with 2 w, thickness of implanted veins reached its peak and extremely increased(P<0.01) in control, but which was significantly increased(P<0.05) in experimental group at 4 w postoperatively; At 8 w postoperatively, thickness of implanted veins was decreased( P<0.05) in control, but it had no significant change in experimental group.Compared with control group, thickness of implanted veins was extremely decreased( P<0.01) at 4 w postoperatively and had no significant difference at other time points in experimental group.Conclusions: ePTFE cuff could reduce filtration velocity and increase the long-term patency rates of implanted veins by protecting venous grafts from excessive distention. |
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