Optimizing through computational modeling to reduce dogboning of functionally graded coronary stent material.

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Cardiovascular Research

Background:

• Coronary artery disease (CAD) is a leading cause of mortality globally.
• Balloon angioplasty with stenting is a primary treatment for CAD.
• Functionally graded materials (FGMs) offer potential advantages in stent mechanical behavior over uniform materials.

Purpose of the Study:

• To optimize the configuration of Functionally Graded Material (FGM) stents for improved performance in coronary artery disease treatment.
• To evaluate different material combinations and heterogeneous indices for Palmaz-Schatz stent geometry.
• To identify the optimal FGM stent design minimizing undesirable mechanical outcomes like dogboning.

Main Methods:

• Utilized a combination of the finite element method (FEM) and an optimization algorithm to simulate and analyze stent performance.
• Investigated three distinct stent configurations using Palmaz-Schatz geometry.
• Assessed objective functions including dogboning and non-uniform deformation, with the heterogeneous index as the control variable.

Main Results:

• The third condition, a CoCr alloy (L605)/CoCr alloy (F562) combination, exhibited poor performance.
• For steel/CoCr alloy (L605) stents, a heterogeneous index of 0.374 resulted in the lowest maximum dogboning.
• A heterogeneous index of 5 in steel/CoCr alloy (L605) stents led to more uniform deformation.

Conclusions:

• The steel/CoCr alloy (L605) stent with a heterogeneous index of 0.374 is recommended as the optimum configuration due to its superior reduction in dogboning.
• FGM stent design, specifically the heterogeneous index, significantly impacts mechanical performance.
• Optimized FGM stent design holds promise for enhancing angioplasty outcomes.