Percutaneous interventions for lower-extremity peripheral atherosclerotic disease.

Patients with peripheral arterial disease frequently develop symptoms of claudication that interfere with ambulation and adversely affect quality of life, and some develop critical limb ischemia. Many of these patients have coexisting coronary artery disease, and surgical revascularization poses risks of perioperative myocardial infarction and cardiovascular death. Peripheral catheter-based interventions are a feasible alternative. Percutaneous treatment can preserve the surgical option and is often used as an adjunct to surgery by addressing inflow stenoses and limiting the extent of surgical reconstruction that is necessary. Iliac artery balloon angioplasty has been shown to have a high rate of initial procedural success and long-term patency, and the use of stents is promising, especially in cases complicated by flow-limiting dissection or significant residual stenosis. Percutaneous revascularization of the femoropopliteal arteries has shown high restenosis rates and stents should be confined, at present, to flow-limiting dissections or inadequate results from balloon angioplasty alone. The indication for percutaneous revascularization below the knee is typically limited to those patients with critical limb ischemia who are at high risk for surgical reconstruction; short-term results with modern equipment have been promising and can salvage ischemic limbs.

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 that arterial injury and stent design determine late neointimal thickening. At deployment, a stent stretches a vessel, imposing a cross-sectional polygonal luminal shape that depends on the stent design, with each strut serving as a vertex. We asked whether this design-dependent postdeployment luminal geometry affects late neointimal thickening independently of the extent of strut-induced injury. METHODS AND RESULTS: Stainless steel stents of 3 different configurations were implanted in rabbit iliac arteries for 3 or 28 days. Stents designed with 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 section. Sequential histological sectioning of individual stents showed that immediate postdeployment luminal geometry and subsequent neointimal area varied along the course of each stent subunit. Mathematical modeling of the shape imposed by the stent on the artery predicted late neointimal area, based 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 design, determines neointimal thickness independently of arterial injury and may be useful for predicting patterns of intimal growth for novel stent designs.