To improve the mechanical function of bovine jugular vein by external stent

Objective To increase the mechanic characteristic of bovine jugular veins conduit (BJVC) by combined knitted stent outside made of nylon fiber. Methods Got rid of the cells of BJVC by enzymolysis,then combined a fabric stent with a acellular bovine jugular vein

Effect of external stents on prevention of intimal hyperplasia in a canine vein graft model

Background External stents have been used to reduce intimal hyperplasia of vein grafts. The aim of the present study was to define the size of an external stent appropriate for a particular graft by comparing vein grafts with different sizes of external stents. Methods A series of paired trials was performed to compare femoral vein grafts with different sizes of external stents, where 30 modeled canines were equally divided into three groups： 6-mm external stent vs non-stent control, 4-mm vs 6-mm external stent, and 4-mm vs 8-ram external stent. At day 3 after operation, color Doppler flow imaging （CDFI） was done to observe blood flow in the lumen. Four weeks later, CDFI was re-checked and the veins were harvested, stained and measured. Results All grafts were patent without formation of thrombosis. External stents significantly reduced intimal thickness of the vein grafts with a 6-mm external stent compared with the vein grafts without external stents （P〈0.05）.The vein grafts with the 4-mm external stent had similar intimal, medial and adventitial thicknesses compared with those with the 6-mm external stent and the 8-mm external stent. Conclusions External stents can reduce intimal hyperplasia of vein grafts. Stents of different diameters exert the similar effect on prevention of intimal hyperplasia.

Effects and mechanisms of non-restrictive external stent for prevention of vein graft restenosis in a rabbit model

Background Among various treatments preventing vein graft restenosis, external stent is receiving more and more attention. This study aimed to investigate the effect of non-restrictive external stent on the prevention of vein graft restenosis and the potential mechanisms of platelet-derived growth factor （PDGF） in the process of restenosis.Methods Thirty-six ＂New Zealand white rabbits＂ were randomly divided into two groups, stented group （group S） and control group （non-stented group, group NS）. Each rabbit underwent a reversed autologous external jugular vein into common carotid artery bypass grafting. In group S, the vein grafts were surrounded by a non restrictive stent which was 6 mm in diameter （a kind of Dacron vascular prosthesis）; and in group NS, there was no stent to support the vein grafts.The grafts were harvested at the first week （1W）, second week （2W） and fourth week （4W） after surgery respectively. The dimensions （including the thickness and area of the intima and media, luminal area） were measured by computer-aided image analysis system, and the intimal hyperplasia ratio was defined as the percentage of the area enclosed by the internal elastic lamina occupied by the intima.Results At 1W, the difference of the thickness and area of the intima between groups S and NS was not significant （P 〉0.05）; at 2W and 4W, the thickness and area of the intima and the intimal hyperplasia ratio in group S were less significant than those in group NS （P 〈0.05）; from 1W to 4W, the thickness and area of the media in group S were smaller than those in group NS （P〈0.05）. Immunocytochemistry staining of PDGF-B showed that the percentage of positive cells of intima in both two groups was peaked at 2W, and a significantly smaller percentage was detected in group S compared with that in group NS at 2W and 4W （P 〈0.05）; the percentage of PDGF-B positive cells of media in both two groups was also peaked at 2W, and that in group S was smaller than that in group NS from 1W to 4W （P 〈0.05）; and the percentage of PDGF-B positive cells of adventitia in group S was peaked at 4W, whereas the percentage of adventitia in group NS peaked at 2W, and the percentage of adventitia in group S was greater than in group NS at 4W （P 〈0.05）.Conclusions Non-restrictive external stenting inhibits the hyperplasia of the intima and media of the vein grafts and reduces the thickness and area of the intima and media; Non-restrictive external stenting inhibits the synthesis of PDGF and changes its distribution, and then inhibits the hyperplasia of the intima.

Endovascular stenting combined with external constriction valvuloplasty of superficial femoral vein for the treatment of Cockett syndrome

To evaluate the effect of endovascular stenting combined with external constriction valvuloplasty of superficial femoral vein for the treatment of Cockett syndrome.Methods Forty-two cases of Cockett syndrome with femoral veins reflux were treated with iliac vein stent implantation or venoplasy,and superficial femoral veins were constricted with ePTFE graft patch at the level of the first valves.Results All the iliac veins were patent after stent implantation.A follow-up of 8 to 45 months revealed that limb swelling disappeared in 38 cases with no varicose.Slight limb swelling was left over in 3 cases.Stent thrombosis,developed in one case two months later,subsided by a successful thrombolysis.Conclusion The procedure is mini-invasive,safe and effective for the treatment of Cockett syndrome.6 refs,1 fig.