California Medical Innovation Institute, San Diego, CA, USA.
The RANE Center, 971 Lakeland Drive, Suite 401, Jackson, MS, 39216, USA.
Sci Rep. 2023 Jun 23;13(1):10201. doi: 10.1038/s41598-023-36165-6.
Conduits are commonly used for treating lesions in arteries and veins. The conventional stents are cylindrical in shape, which increases flow resistance with length. This study presents a design of stents and conduits where the conduit caliber expands gradually to reduce resistance while avoiding flow separation. Inflow was provided from a header tank at two different pressures (i.e., 10 and 25 mm Hg pressure) into a cylindrical or expanding conduit. The initial conduit calibers were 2-, 3-, 4-, and 5-mm and 160-, 310-, and 620-mm lengths in each case. The flow rates of expanding caliber conduits (at a rate of r/cm where r is the initial conduit radius) were compared to traditional cylindrical conduits of constant radius. The expanded caliber yields a significantly increased flow of 16-55% for R/L expansion, 9-44% for R/L expansion, and 1-28% for R/L expansion. Simulated flow models using computational fluid dynamics (CFD) were used to validate and expand the experimental findings. Flow separation was detected for certain simulations by flow pathlines and wall shear stress (WSS) calculations. The results showed that a caliber expansion rate of r/cm is the optimal rate of expansion for most potential applications with minimum flow separation, lower resistance, and increased flow.
导管通常用于治疗动脉和静脉中的病变。传统的支架呈圆柱形，随着长度的增加会增加流动阻力。本研究提出了一种支架和导管的设计，其中导管口径逐渐扩大以降低阻力，同时避免流动分离。入口在两个不同的压力（即 10 和 25mmHg 压力）下从一个集管提供到一个圆柱形或扩张的导管。初始导管口径为 2、3、4 和 5mm，长度分别为 160、310 和 620mm。扩张口径导管的流速（其中 r 是初始导管半径，r/cm）与具有恒定半径的传统圆柱形导管进行了比较。扩张口径产生了显著增加的流量，对于 R/L 扩张为 16-55%，对于 R/L 扩张为 9-44%，对于 R/L 扩张为 1-28%。使用计算流体动力学（CFD）的模拟流模型验证并扩展了实验结果。通过流路径线和壁面剪切应力（WSS）计算检测到某些模拟中的流动分离。结果表明，r/cm 的口径扩张率对于大多数潜在应用是最佳的扩张率，具有最小的流动分离、更低的阻力和增加的流量。
