Abstract:Objective To evaluate the effect of external stents on preventing vein graft neointima formation and medial thickening with non-restrictive macro porous polyester stent around porcine vein grafts. Methods Studies were performed by using ＂white race＂ pigs （n= 10） weight 25-30 kg. All the animals underwent bilateral saphenous vein into carotid artery bypass grafting. In each animal, a maeroporous stent was placed around a graft on one side and a control （unstented） graft on the opposite side. The polyester stent was shaped to cover both anastomoses completely. The size of the stem allowed unrestricted expansion of the graft in initial response to arterial pressure. After 35 days of surgery,all animals were taken to remove the grafts. Graft wall dimensions, platelet- derived growth factor （PDGF） expression and cell proliferation using proliferating cell nuclear antigen （PCNA） were measured on histological sections. Results Stents significantly reduced neointimal thickening （0. 4872 ± 0. 0706 mm vs. 0. 2259± 0. 0553mm,P〈0. 01）and medial thickening （0. 6246±0. 0859mm vs. 0. 4201±0. 0615mm,P〈0. 01）. Stents significantly reduced the percentage of cells expressing PDGF and PCNA. Media, intimal PCNA index was reduced from 7. 980/00± 4. 060/00 to 3.35±0.95%（P〈0.01）, PDGF index was reduced from 9.47%±5.35% to 2.67%± 0.97% （P 〈0. 01）. Conclusion External non-restrictive polyester stent can significantly inhibit neointimal formation and medial thickening, and may prevent late vein grafts restenosis.
ObjectiveTo evaluate the clinical value of in vitro fenestration and branch stent repair in the treatment of thoracoabdominal aortic aneurysm in visceral artery area assisted by 3D printing.MethodsThe clinical data of 7 patients with thoracoabdominal aortic aneurysm involving visceral artery at the Department of Vascular Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University from March 2016 to May 2019 were analyzed retrospectively. There were 5 males and 2 females with an average age of 70.2±3.9 years. Among them 4 patients had near-renal abdominal aortic aneurysm, 3 had thoracic aortic aneurysm, 4 had asymptomatic aneurysm, 2 had acute symptomatic aneurysm and 1 had threatened rupture of aneurysm. According to the preoperative CT measurement and 3D printing model, fenestration technique was used with Cook Zenith thoracic aortic stents, and branch stents were sewed on the main stents in vitro, and then the stents were modified by beam diameter technique for intracavitary treatment.ResultsAll the 7 patients completed the operation successfully, and a total of 18 branch arteries were reconstructed. The success rate of surgical instrument release was 100.0%. The average operation time was 267.0±38.5 min, the average intraoperative blood loss was 361.0±87.4 mL and the average hospital stay was 16.0±4.2 d. Immediate intraoperative angiography showed that the aneurysms were isolated, and the visceral arteries were unobstructed. Till May 2019, there was no death, stent displacement, stent occlusion, ruptured aneurysm or loss of visceral artery branches. Conclusion3D printing technology can completely copy the shape of human artery, intuitively present the anatomical structure and position of each branch of the artery, so that the fenestration technique is more accurate and the treatment scheme is more optimized.