The natural tapering of coronary arteries often creates a dilemma for optimal balloon sizing during stenting. The influence of different balloon types, namely, a tapered balloon and a conventional cylindrical balloon, on the mechanical performance of the stent as well as arterial mechanics was investigated via the finite element method. Stent free‐expansion and stent deployment in a stenotic tapered artery were investigated numerically. The biomechanical behavior of the two balloon types was compared in terms of stent foreshortening, stent deformation, stent stress distribution, and arterial wall stress distribution. Results indicate that balloon types affect the transient behavior of the stent and the arterial mechanics. Specifically, a tapered balloon could maintain the natural tapering of the coronary artery after stent expansion. In contrast to a cylindrical balloon, tapered balloon also mitigated the foreshortening of the stent (7.69%) as well as the stress concentration in the stent and artery (8.61% and 4.17%, respectively). Hence, tapered balloons should be used in tapered arteries as they may result in low risk of artery injury. This study might provide insights for improved balloon choice and presurgical planning.

No abstract

In-stent restenosis (ISR), which is a common complication after stent intervention, affects the long-term outcome of stent intervention. Suitable implantation planning will effectively reduce the incidence of ISR. The aim of this study is to investigate the effect of different implantation planning on the mechanical behavior of stents in tapered vessels with multiple stenoses and select a better implantation planning. The finite element method (FEM) was used in this study. A different planning was designed as follows: (a) using a cylindrical balloon to deploy cylindrical stent (plan CC), (b) using the tapered balloon to deploy cylindrical stent (plan TC) and (c) using the tapered balloon to deploy tapered stent (plan TT). When the stent was expanded to the maximum diameter, the position of maximum vascular stress all appeared at distal plaque in three implantation plans. After balloon was deflated, the vascular stress in plan TC was the minimum. Using tapered balloon to deploy cylindrical stent has advantages in the tapered vessels with multiple stenoses and could reduce the probability of ISR. Moreover, this method could assess the mechanical properties of stent deployment in multiple stenoses and then select a better implantation planning.

The torsional performance is a major mechanical property of stent. A stent with good torsional performance is easy to deform along blood vessels without damaging the vascular wall to avoid in-stent restenosis (ISR). Therefore, this study aimed to study the effect of stent parameters on torsional performance. The effect of stent parameters on torsional performance was studied via finite element method (FEM). The twist metric (TM) and stress distribution of various stents were compared. The TM values of stents with I-, S-, M-, C-, and V-shaped linkers were 0.0190, 0.0191, 0.0184, 0.0141, and 0.0201[Formula: see text][Formula: see text], respectively. In addition, the TM value of the stent increased by 35.85 times when the number of linkers was increased from 2 to 8 and the stent was twisted at the same angular displacement in clockwise direction. The TM value of the stent with 1.13∘ tapering was 0.010 [Formula: see text], which was lower by 47.64% compared with that of cylindrical stent. Compared with the shape of the linker, the number of linkers had a more remarkable effect on torsional performance. Torsional performance was observably enhanced with the decrease in the number of linkers. Among the five stents with different linker shapes, the torsional performance of the stent with C-shaped linker was the best. Besides, the torsional performance of the tapered stent was better than that of the cylindrical stent. Moreover, the torsional performance increased by increasing the stent tapering. This work might provide insights into better stent design and clinical decisions.