title: Late incomplete stent apposition after sirolimus-eluting stent implantation: a serial intravascular ultrasound analysis.
abstract: OBJECTIVE
  We sought to identify the frequency of incomplete stent apposition (ISA) in sirolimus-eluting stents (SES) and clarify its findings and clinical sequelae.
  
  
  BACKGROUND
  Late-acquired ISA has been reported in bare-metal stents (BMS) and brachytherapy and recently in drug-eluting stents. However, the characteristics of late ISA in SES have not been clarified.
  
  
  METHODS
  From the SIRIUS trial, a randomized, multicenter study comparing SES and BMS, serial qualitative intravascular ultrasound (IVUS; at stent implantation and eight-month follow-up) was available in 141 patients (BMS: n = 61; SES: n = 80). The IVUS images were reviewed for the presence of ISA.
  
  
  RESULTS
  Incomplete stent apposition at follow-up was observed in 19 patients (BMS: n = 6 [9.8%]; SES: n = 13 [16.3%]; p = NS). Among these, 12 had ISA after intervention and at follow-up (persistent ISA). Late-acquired ISA was seen in the remaining seven cases, all from the SES group (BMS: n = 0; SES: n = 7 [8.7%]; p < 0.05). In late-acquired ISA, there was an increase in external elastic membrane area (after intervention: 16.2 +/- 2.7 m2; follow-up: 18.9 +/- 3.6 mm2; p < 0.05). The location of stent-vessel wall separation was primarily at the stent edges in persistent ISA cases, whereas late-acquired ISA in SES occurred mostly in the mid portion of the stent. There were no negative clinical events reported for any ISA cases at 12-month clinical follow-up.
  
  
  CONCLUSIONS
  Late ISA was observed in 8.7% of patients after SES implantation. There were no negative clinical events associated with this IVUS finding at 12-month clinical follow-up; however, careful long-term follow-up will be necessary.
authors.affiliation: Center for Research in Cardiovascular Interventions, Stanford University Medical Center, Stanford, California 94305-5637, USA.
authors.forename: Junya
authors.initials: J
authors.lastname: Ako
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Morino
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Honda
authors.forename: Ali
authors.initials: A
authors.lastname: Hassan
authors.forename: Shinjo
authors.initials: S
authors.lastname: Sonoda
authors.forename: Paul G
authors.initials: PG
authors.lastname: Yock
authors.forename: Martin B
authors.initials: MB
authors.lastname: Leon
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Moses
authors.forename: Heidi N
authors.initials: HN
authors.lastname: Bonneau
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Fitzgerald
mesh_terms: D003131:Combined Modality Therapy; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000209:etiology; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents / Q000009:adverse effects; D013997:Time Factors; D018084:Ultrasonography, Interventional
chemical_list: D020123:Sirolimus