RESTENOSIS OF ENDOVASCULAR STENTS FROM STENT COMPRESSION

Objectives, We sought to determine the basis for restenosis within sup erficial femoral arteries (SFAs) and hemodialysis conduits treated wit h balloon-expandable stents, Background. Use of stents within coronary and peripheral vessels continues to increase exponentially, The mecha nism of restenosis within stents placed at various vascular sites is n ot well understood, In particular, the implications of deploying a bal loon-expandable stent in a compressible site are not well understood, Methods. After the serendipitous detection of stent deformation during intravascular ultrasound (IVUS) examination of a restenosed dialysis fistula, we evaluated a consecutive series of patients with stents pla ced in compressible vascular sites, including the SFA (sis patients) a nd hemodialysis fistulae (five patients), Clinical, angiographic and I VUS examinations were performed to evaluate mechanisms of restenosis, Results, Stent compression was identified as the principal cause of re stenosis in all dialysis conduits and SFAs, Stent deformity was not re liably identified by angiography; however, IVUS identified compression of two forms: eccentric deformation, implicating two-point compressiv e force, and complete circumferential encroachment of stent struts aro und the catheter, suggesting multidirectional compressive force, Despi te redilation, secondary restenosis resulting from recurrent compressi on recurred in most sites, Conclusions. Restenosis within balloon-expa ndable endovascular stents may occur as a result of stent compression, a phenomenon readily detected by IVUS, but often not by angiography. These findings have significant implications for the use of balloon-ex pandable stents within vascular sites subject to extrinsic compression , such as hemodialysis conduits, the adductor canal segment of the SFA and carotid arteries, (C) 1997 by the American College of Cardiology.