Stent and artery geometry determine intimal thickening independent of arterial injury

Background-Clinical trials show that larger immediate postdeployment stent diameters provide greater ultimate luminal size, whereas animal data show t hat arterial injury and stent design determine late neointimal thickening. At deployment, a stent stretches a vessel, imposing a cross-sectional polyg onal luminal shape that depends on the stent design, with each strut servin g as a vertex. We asked whether this design-dependent postdeployment lumina l geometry affects late neointimal thickening independently of the extent o f strut-induced injury. Methods and Results-Stainless steel stents of 3 different configurations we re implanted in rabbit iliac arteries for 3 or 28 days. Stents designed wit h 12 struts per cross section had 50% to 60% less mural thrombus and 2-fold less neointimal area than identical stents with only 8 struts per cross se ction. Sequential histological sectioning of individual stents showed that immediate postdeployment luminal geometry and subsequent neointimal area va ried along the course of each stent subunit, Mathematical modeling of the s hape imposed by the stent on the artery predicted late neointimal area, bas ed on the re-creation of a circular vessel lumen within the confines of the initial stent-imposed polygonal luminal shape. Conclusions-Immediate postdeployment luminal geometry, dictated by stent de sign, determines neointimal thickness independently of arterial injury and may be useful for predicting patterns of intimal growth for novel stent des igns.