title: An optical coherence tomography study of a biodegradable vs. durable polymer-coated limus-eluting stent: a LEADERS trial sub-study.
abstract: OBJECTIVE
  Incomplete endothelialization has been found to be associated with late stent thrombosis, a rare but devastating phenomenon, more frequent after drug-eluting stent implantation. Optical coherence tomography (OCT) has 10 times greater resolution than intravascular ultrasound and thus appears to be a valuable modality for the assessment of stent strut coverage. The LEADERS trial was a multi-centre, randomized comparison of a biolimus-eluting stent (BES) with biodegradable polymer with a sirolimus-eluting stent (SES) using a durable polymer. This study sought to evaluate tissue coverage and apposition of stents using OCT in a group of patients from the randomized LEADERS trial.
  
  
  RESULTS
  Fifty-six consecutive patients underwent OCT during angiographic follow-up at 9 months. OCT images were acquired using a non-occlusive technique at a pullback speed of 3 mm/s. Data were analysed using a Bayesian hierarchical random-effects model, which accounted for the correlation of lesion characteristics within patients and implicitly assigned analytical weights to each lesion depending on the number of struts observed per lesion. Primary outcome was the difference in percentage of uncovered struts between BESs and SESs. Twenty patients were included in the analysis in the BES group (29 lesions with 4592 struts) and 26 patients in the SES group (35 lesions with 6476 struts). A total of 83 struts were uncovered in the BES group and 407 out of 6476 struts were uncovered in the SES group [weighted difference -1.4%, 95% confidence interval (CI) -3.7 to 0.0, P = 0.04]. Results were similar after adjustment for pre-procedure lesion length, reference vessel diameter, number of implanted study stents, and presence of stent overlap. There were three lesions in the BES group and 15 lesions in the SES group that had > or =5% of all struts uncovered (difference -33.1%, 95% CI -61.7 to -10.3, P < 0.01).
  
  
  CONCLUSIONS
  Strut coverage at an average follow-up of 9 months appears to be more complete in patients allocated to BESs when compared with SESs. The impact of this difference on clinical outcome and, in particular, on the risk of late stent thrombosis is yet to be determined.
authors.affiliation: Royal Brompton Hospital, Sydney Street, London, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Barlis
authors.forename: Evelyn
authors.initials: E
authors.lastname: Regar
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Dimopoulos
authors.forename: Willem J
authors.initials: WJ
authors.lastname: van der Giessen
authors.forename: Robert-Jan M
authors.initials: RJ
authors.lastname: van Geuns
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ferrante
authors.forename: Simon
authors.initials: S
authors.lastname: Wandel
authors.forename: Stephan
authors.initials: S
authors.lastname: Windecker
authors.forename: Gerrit-Anne
authors.initials: GA
authors.lastname: van Es
authors.forename: Pedro
authors.initials: P
authors.lastname: Eerdmans
authors.forename: Peter
authors.initials: P
authors.lastname: Jüni
authors.forename: Carlo
authors.initials: C
authors.lastname: di Mario
mesh_terms: D020341:Absorbable Implants; D023903:Coronary Restenosis / Q000175:diagnosis / Q000517:prevention & control*; D054855:Drug-Eluting Stents; D005260:Female; D006083:Graft Occlusion, Vascular / Q000175:diagnosis / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D011108:Polymers; D020123:Sirolimus / Q000008:administration & dosage* / Q000031:analogs & derivatives; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D050257:Tubulin Modulators / Q000008:administration & dosage*
chemical_list: D011108:Polymers; D050257:Tubulin Modulators; C518022:umirolimus; D020123:Sirolimus