Figure 1.
(A) Finite-element simulation show that at low inflation pressures the cuffed tri-folded balloon expands first in the extremities of the device slightly larger than the inner diameter of the vessel. The vessel must compensate by (B) stretching radially outwards, pulling tissue at margins inwards creating axial strain. For the middle region, the expansion of the device in proximal and distal regions creates axial tensile strain. At some time-point t2, this axial strain caused a negative radial strain (inward) of ~2% (0.05mm radial inwards displacement) at this midpoint. (C) Ex-vivo deployment of the generic stent (used animal study) in an explanted swine coronary artery of 3.1mm inner diameter (3.3mm outer diameter), shows that nominal inflation the device created some overstretch in the proximal and distal segments, and partial shrinkage in the middle segment indicating a lumen diameter and cross-sectional area shrinkage of 3% and 6%.