Bioresorbable zinc stent with ultra-thin center struts attenuates stent jail in porcine femoral artery bifurcations

Abstract

Introduction An ultra-thin, fracture-resistant and bioresorbable stent may be advantageous for provisional stenting in vessel bifurcations, if catheter passage and side-branch post-dilatation is facilitated to prevent a ‘stent jail’ by struts obstructing the orifice of a major side branch. Material and methods We studied a highly radiopaque, slowly bioresorbable zinc alloy stent characterized by a novel design of a radiopaque-marked region of ultra-thin struts in the center of the stent. The stent is characterized by an extended range flexibility and high fracture resistance. Zn-stents and Zn-drug eluting stents (DES) were implanted opposite to rigid Nitinol stents into both femoral artery bifurcations of 21 juvenile pigs, followed for one and three months and studied by angiography and histomorphometry. Results and conclusion: Bare Zn-stents with thinner stent struts showed less neointimal hyperplasia compared to Zn-stents with thicker struts. Neointimal formation was further reduced by 12% in Zn-alloy DES. Both, bare Zn-stents and Zn-DES, can be precisely positioned into the femoral artery bifurcation, allowing easy balloon catheter passage through the very thin strut mesh. Side branch orifices remained open after Zn-stent deployment without stent jailing. No stent fractures or particles emboli occurred after the deployment. A Zn-stent with ultra-thin center struts may be useful for provisional stenting in vessel bifurcations.