title: Predictors of restenosis in the use of helical interwoven nitinol stents to treat femoropopliteal occlusive disease.
abstract: BACKGROUND
  The femoropopliteal arteries are subjected to considerable axial and bending deformity due to flexion at the hip and knee joints. The Supera helical interwoven nitinol stent system (IDEV Technologies, Inc/Abbott Laboratories, Inc, Webster, Tex) has good conformability and flexibility, with a very low incidence of mechanical fatigue. This study reviewed our experience with the use of Supera stents for femoropopliteal atherosclerotic lesions and identified risk factors for restenosis or occlusion.
  
  
  METHODS
  Patients with symptomatic femoropopliteal atherosclerotic diseases who underwent lower limb angioplasty and Supera stent insertion were studied. All patients had regular clinical follow-up and underwent a Doppler ultrasound examination at 3 months and then every 6 months, and radiography of the stents at 6, 12, 18, 24, 30, and 36 months. Patency rates were analyzed using Kaplan-Meier curves. We also evaluated the prospectively maintained cohort to identify predictors of restenosis.
  
  
  RESULTS
  From October 2011 to December 2014, 164 legs in 153 symptomatic patients (96 male, 57 female) with femoropopliteal occlusive disease, with mean age of 76.7 years (range, 46-100 years), were included. Ninety-five patients (58%) had claudication, nine (5%) had rest pain, and 60 (37%) had tissue loss. Disease distribution was 64 proximal superficial femoral arteries (SFAs; 39%), 107 middle SFAs (65%), 127 distal SFAs (77%), 78 above-knee popliteal arteries (48%), and 19 below-knee popliteal arteries (12%). Lesion classification by TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) A, B, C, and D was 49 (30%), 79 (48%), 31 (19%), 3 (1%), respectively. The mean lesion length was 105.6 mm (range, 3-400 mm), and more than one Supera stent was inserted in 26 patients. Procedure success (residual stenosis <30%) was achieved in 100% of procedures. The primary patency rates (>50% patency) at 6, 12, 24, and 30 months were (±standard error) 86.7% ± 3.1%, 81.4% ± 3.7%, 79.9% ± 4.0%, and 77 ± 3.0%, respectively. The ankle-brachial pressure index increased from 0.57 ± 0.15 preoperatively to 0.87 ± 0.14 postoperatively. No stent fractures occurred. There were three 30-day deaths not related to the procedure or device, one major amputation 3 months after revascularization, and 29 late deaths (>30 days) of unrelated medical causes in follow-up. In-stent restenosis was associated with younger patient age and with dyslipidemia, long lesion, and stent length.
  
  
  CONCLUSIONS
  Our midterm experience showed that the implantation of the helical interwoven nitinol stents in patients with femoropopliteal occlusive disease is safe and effective, with encouraging patency rates and clinical results.
authors.affiliation: Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China. Electronic address: ycchan88@hkucc.hku.hk.
authors.forename: Yiu Che
authors.initials: YC
authors.lastname: Chan
authors.affiliation: Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Cheng
authors.affiliation: Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China.
authors.forename: Grace C
authors.initials: GC
authors.lastname: Cheung
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation*; D016009:Chi-Square Distribution; D003251:Constriction, Pathologic; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D006723:Hong Kong; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D011150:Popliteal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D011474:Prosthesis Design; D011859:Radiography; D012008:Recurrence; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler; D014654:Vascular Patency
chemical_list: D000497:Alloys; C013616:nitinol