Stainless steel/nitinol braid coronary stents: Braiding structure stability and cut section treatment evaluation

Abstract

This study proposes braid coronary stents with a form of reticular tube by using a braiding technique. Stainless steel fibers with a diameter of 0.08 mm and nitinol fibers are braided with various tooth numbers on the take-up gear and a specified tooth number on the braid gear with a hollow braiding technique in order to have different braiding angles. The resulting braids are then immersed in a polyvinyl alcohol solution in a custom-made mold to form braid coronary stents. A stereomicroscope is used to observe the cut section, a scanning electron microscope is used to examine the treatment for sharp points of the fibers, and Image Pro Plus software is used to analyze braiding angles and metal cover rate. The experiment results show that braiding angle influences the braiding structure; in addition, the larger the braiding angle, the less easily the fiber interaction points move. The immersion in polyvinyl alcohol solution can effectively bond the fiber interaction points, resulting in a better braiding structure. Metal cover rates are all below 20.9%. This study successfully creates novel braid coronary stents.

Finite element modeling and experimental validation of 2D reinforcement braided thin wall structures under internal pressure at various braid angles

“…Ueng et al. [13] characterized stainless steel/nitinol braid coronary stents. They used a stereomicroscope to observe the cut section, scanning electron microscope to examine the treatment for sharp points of the fibers and Image Pro Plus software to analyze braiding angles and metal cover rate.…”

A Review on Manufacturing and Post-Processing Technology of Vascular Stents

“…Ueng et al [39] fabricated vascular stents by braiding stainless-steel fibers combined with nitinol fibers (0.08 mm in diameter). Sun et al [40] applied the braiding technique for biodegradable stent fabrication by using poly(p-dioxanone) (PPDO) monofilaments and PCL/PPDO composite filaments, and mechanical testing results showed that the mechanical properties of the braided biodegradable stents were comparable to metallic stents including elastic recovery rate, deformation rate, and expansion behavior, as shown in Figure 1.…”

“…Braiding technique [39,40] Easy to process Limited to simple structure Poor radial stiffness Micro-injection molding [41][42][43] High production efficiency Good surface quality High consistency…”

“…At present, design optimization mainly focuses on the following aspects including bridge/link [25][26][27][28][29], representative volume element/representative unit cell [30][31][32][33][34], and patient-specific structure [35][36][37][38]. Then, the commonly used manufacturing technologies of vascular stents mainly include the braiding technique [39,40], micro-injection molding [41][42][43], laser cutting [44][45][46][47][48][49][50][51][52][53][54][55][56], and 3D printing [57][58][59][60][61][62][63][64]. Each processing method has its advantages and disadvantages.…”

Structural Design of Vascular Stents: A Review

“…As the precise medical device, the manufacturing methods of vascular stents mainly include braided method ( Figure 7 a) [ 75 , 76 , 77 , 78 ], laser cutting method ( Figure 7 b) [ 79 , 80 , 81 , 82 ], electrospinning technology ( Figure 7 c) [ 83 , 84 , 85 , 86 ] and additive manufacturing technology ( Figure 7 d) [ 87 , 88 , 89 , 90 , 91 ]. The braided method is to first wind the wire on the carrier.…”