title: Long-term outcomes and risk stratification of patency following nitinol stenting in the femoropopliteal segment: retrospective multicenter analysis.
abstract: OBJECTIVE
  To investigate the long-term outcomes of nitinol stenting in femoropopliteal lesions and to determine the factors associated with restenosis.
  
  
  METHODS
  Between December 2003 and December 2009, 861 patients (603 men; mean age 72 years) underwent nitinol stenting of the femoropopliteal segment in 1017 limbs. A quarter (26%) of the patients had critical limb ischemia. Mean lesion length was 152±93 mm. Stent patency was assessed by either duplex ultrasound or angiography and analyzed by Kaplan-Meier estimation. The determinants of restenosis were explored with Cox proportional hazard regression analyses; the results are presented as the hazard ratio (HR) and 95% confidence interval (CI). Risk stratification of primary patency was subsequently analyzed using a score based on the significant prognostic factors identified in the multivariate model.
  
  
  RESULTS
  Stent fracture occurred in 10% (104 limbs) of the lesions. At 1, 3, and 6 years, the primary patency rates were 77%, 67%, and 63%; secondary patency rates were 91%, 87%, and 87%; freedom from femoropopliteal bypass grafting was 99%, 97%, and 96%, respectively. Multivariate Cox regression analysis identified female gender (HR 1.899; 95% CI 1.318 to 2.737, p<0.001), ankle-brachial index <0.6 (HR 1.921; 95% CI 1.348 to 2.736, p<0.001), TASC II C/D lesion (HR 2.068; 95% CI 1.346 to 3.177, p = 0.0009), stent fracture (HR 1.937; 95% CI 1.203 to 3.118, p = 0.006), and the absence of cilostazol administration (HR 2.102; 95% CI 1.394 to 3.172, p<0.001) as strong independent factors associated with restenosis. After assigning a risk score based on the outcomes of the multivariate regression analysis (1 each for female gender, ABI <0.6, TASC II C/D, stent fracture, and absence of cilostazol therapy), primary patency was found to be lower in limb groups with a higher cumulative score (12-month primary patency: score 0: 93%, score 1: 80%, score 2: 73%, score 3; 47%, score 4: 0%, respectively; p<0.001).
  
  
  CONCLUSIONS
  Endovascular therapy using nitinol stents for FP lesions yielded acceptable outcomes up to 6 years. Risk stratification for patency can play an important role in estimating future occurrence of restenosis after nitinol stent implantation in FP lesions.
authors.affiliation: Kansai Rosai Hospital Cardiovascular Center, Amagasaki, Hyogo, Japan. iida.osa@gmail.com
authors.forename: Osamu
authors.initials: O
authors.lastname: Iida
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Soga
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hirano
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Yokoi
authors.forename: Masakiyo
authors.initials: M
authors.lastname: Nobuyoshi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Naoto
authors.initials: N
authors.lastname: Inoue
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nanto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Uematsu
mesh_terms: D000497:Alloys; D057510:Endovascular Procedures / Q000009:adverse effects; D005260:Female; D005263:Femoral Artery / Q000473:pathology*; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D058729:Peripheral Arterial Disease / Q000628:therapy*; D011150:Popliteal Artery / Q000473:pathology*; D011474:Prosthesis Design; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects; D016896:Treatment Outcome; D014654:Vascular Patency
chemical_list: D000497:Alloys; C013616:nitinol