Fabrication And Mechanical Characterization Of A Two-ply Cross Fiber Stent And Fibers Comprising Blends Of Poly(L-lactic Acid)

Abstract

Recent studies indicate that stabilization of vulnerable atherosclerotic plaques is critical for minimizing acute coronary syndromes. In this regard a new biodegradable stent design, the Two-ply cross fiber stent, has been developed to reduce stent-imposed stresses on such plaque and to provide increased drug reservoir capability. A comparative study of the mechanical properties of Two-ply and Single-ply stent designs was performed. Fibers comprising PLLA blends were developed and their thermal and mechanical properties were determined. Lateral spreading of helical fibers upon deployment of the Two ply design was observed that, in theory, may reduce stresses on the plaque surface. The results indicate that the 1.5 mm furled Two-ply cross fiber stent can be expanded fully, to 3.1 ± 0.1 mm diameter, with an inflation pressure of less than 5 atm. Use of two fiber plies increased the hoop strength without significantly affecting the longitudinal flexibility, thereby maintaining maneuverability whilst improving collapse resistance after deployment. Calorimetry measurements indicate that blends containing up to 50% of 100kD PLLA are suitable for incorporation of the anti-inflammatory drug Curcumin by melt extrusion.