Venous Biomechanics of Angioplasty and Stent Placement: Implications of the Poisson Effect.

PURPOSE: To characterize the Poisson effect in response to angioplasty and stent placement in veins and identify potential implications for guiding future venous-specific device design.

MATERIALS AND

METHODS

In vivo angioplasty and stent placement were performed in 3 adult swine by using an established venous stenosis model. Iron particle endothelium labeling was performed for real-time fluoroscopic tracking of the vessel wall during intervention. A finite-element computational model of a vessel was created with ADINA software (version 9.5) with arterial and venous biomechanical properties obtained from the literature to compare the response to radial expansion.

RESULTS

In vivo angioplasty and stent placement in a venous stenosis animal model with iron particle endothelium labeling demonstrated longitudinal foreshortening that correlated with distance from the center of the balloon (R2 = 0.87) as well as adjacent segment narrowing that correlated with the increase in diameter of the treated stenotic segment (R2 = 0.89). Finite-element computational analysis demonstrated increased Poisson effect in veins relative to arteries (linear regression coefficient slope comparison, arterial slope 0.033, R2 = 0.9789; venous slope 0.204, R2 = 0.9975; P < .0001) as a result of greater longitudinal Young modulus in veins compared with arteries.

CONCLUSIONS

Clinically observed adjacent segment narrowing during venous angioplasty and stent placement is a result of the Poisson effect, with redistribution of radially applied force to the longitudinal direction. The Poisson effect is increased in veins relative to arteries as a result of unique venous biomechanical properties, which may be relevant to consider in the design of future venous interventional devices.