Fontaine A B, Spigos D G, Eaton G, Das Passos S, Christoforidis G, Khabiri H, Jung S
Department of Radiology, Ohio State University Hospitals, Columbus 43210.
J Vasc Interv Radiol. 1994 Sep-Oct;5(5):739-44. doi: 10.1016/s1051-0443(94)71593-1.
To evaluate possible differences in neointimal development resulting from overdilation of rigid versus flexible vascular stents.
Twelve vascular sheaths were placed bilaterally through femoral arteries in six swine. After angiographic measurement, 12 stents (six flexible and six rigid) were balloon expanded to 8-mm diameters in 12 6-mm iliac arteries (approximately 30% overdilation). All stents were similar in surface area, gauge, and type of wire (tantalum). The primary difference was longitudinal flexibility (low hoop strength) versus rigidity (high hoop strength). Stents were studied with angiography and intravascular ultrasound 5 weeks after implantation. The animals were killed, and the stented segments were removed and examined histologically.
Rigid stents maintained larger diameters than flexible stents: mean, 6.52 mm versus 5.82 mm (mean difference, 0.70; standard deviation [SD], 0.47; confidence interval [CI], +/- 0.49; P < .05). In addition, rigid stents developed a thicker, eccentric neointimal reaction relative to flexible stents: mean 1.08 mm versus 0.74 mm (mean difference, 0.338; SD, 0.315; CI, +/- 0.331; P < .05).
Rigid stents maintain larger diameters over the long term relative to flexible stents when overdilated in normal swine arteries. However, a thicker neointima develops within the lumen of rigid stents at follow-up (greater late loss).
评估刚性与柔性血管支架过度扩张导致的新生内膜发展的可能差异。
在六头猪身上经股动脉双侧放置12个血管鞘。血管造影测量后，在12条6毫米的髂动脉中将12个支架（6个柔性和6个刚性）球囊扩张至8毫米直径（约30%的过度扩张）。所有支架在表面积、规格和金属丝类型（钽）方面相似。主要区别在于纵向柔韧性（低环向强度）与刚性（高环向强度）。植入后5周用血管造影和血管内超声对支架进行研究。处死动物，取出带支架的节段并进行组织学检查。
刚性支架比柔性支架保持更大的直径：平均值分别为6.52毫米和5.82毫米（平均差异为0.70；标准差[SD]为0.47；置信区间[CI]为±0.49；P <.05）。此外，相对于柔性支架，刚性支架形成了更厚的、偏心的新生内膜反应：平均值分别为1.08毫米和0.74毫米（平均差异为0.338；SD为0.315；CI为±0.331；P <.05）。
在正常猪动脉中过度扩张时，刚性支架相对于柔性支架长期保持更大的直径。然而，随访时刚性支架管腔内会形成更厚的新生内膜（更大的晚期管腔丢失）。
