title: A randomized optical coherence tomography study of coronary stent strut coverage and luminal protrusion with rapamycin-eluting stents.
abstract: OBJECTIVE
  We used optical coherence tomography, which has a resolution of <20 microm, to analyze thin layers of neointima in rapamycin-eluting coronary stents.
  
  
  BACKGROUND
  Lack of neointimal coverage has been implicated in the pathogenesis of drug-eluting coronary stent thrombosis. Angiography and intracoronary ultrasound lack the resolution to examine this.
  
  
  METHODS
  We conducted a randomized trial in patients receiving polymer-coated rapamycin-eluting stents (Cypher, Cordis, Johnson & Johnson, Miami, Florida) and nonpolymer rapamycin-eluting stents (Yukon, Translumina, Hechingen, Germany) to examine neointimal thickness, stent strut coverage, and protrusion at 90 days. Twenty-four patients (n = 12 for each group) underwent stent deployment and invasive follow-up at 90 days with optical coherence tomography. The primary end point was binary stent strut coverage. Coprimary end points were neointimal thickness and stent strut luminal protrusion.
  
  
  RESULTS
  No patient had angiographic restenosis. For polymer-coated and nonpolymer rapamycin-eluting stents, respectively, mean (SD), neointimal thickness was 77.2 (25.6) microm versus 191.2 (86.7) mum (p < 0.001). Binary stent strut coverage was 88.3% (11.8) versus 97.2% (6.1) (p = 0.030). Binary stent strut protrusion was 26.5% (17.5) versus 4.8% (8.6) (p = 0.001).
  
  
  CONCLUSIONS
  Mean neointimal thickness for the polymer-coated rapamycin-eluting stent was significantly less than the nonpolymer rapamycin-eluting stent but as a result coverage was not homogenous, with >10% of struts being uncovered. High-resolution imaging allowed development of the concept of the protrusion index, and >25% of struts protruded into the vessel lumen with the polymer-coated rapamycin-eluting stent compared with <5% with the nonpolymer rapamycin-eluting stent. These findings may have important implications for the risk of stent thrombosis and, therefore, future stent design. (An optical coherence tomography study to determine stent coverage in polymer coated versus bare metal rapamycin eluting stents. ORCA 1, from the Optimal Revascularization of the Coronary Arteries group; ISRCTN42475919).
authors.affiliation: Royal Brompton & Harefield NHS Trust, Middlesex, United Kingdom.
authors.forename: Philip
authors.initials: P
authors.lastname: Moore
authors.forename: Peter
authors.initials: P
authors.lastname: Barlis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Spiro
authors.forename: Gopal
authors.initials: G
authors.lastname: Ghimire
authors.forename: Michael
authors.initials: M
authors.lastname: Roughton
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Mario
authors.forename: William
authors.initials: W
authors.lastname: Wallis
authors.forename: Charles
authors.initials: C
authors.lastname: Ilsley
authors.forename: Andrew
authors.initials: A
authors.lastname: Mitchell
authors.forename: Mark
authors.initials: M
authors.lastname: Mason
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kharbanda
authors.forename: Peter
authors.initials: P
authors.lastname: Vincent
authors.forename: Spencer
authors.initials: S
authors.lastname: Sherwin
authors.forename: Miles
authors.initials: M
authors.lastname: Dalby
mesh_terms: D016001:Confidence Intervals; D003324:Coronary Artery Disease / Q000188:drug therapy; D023903:Coronary Restenosis / Q000517:prevention & control*; D003331:Coronary Vessels / Q000187:drug effects* / Q000473:pathology; D054855:Drug-Eluting Stents; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011108:Polymers; D020123:Sirolimus / Q000627:therapeutic use*; D041623:Tomography, Optical Coherence
chemical_list: D007166:Immunosuppressive Agents; D011108:Polymers; D020123:Sirolimus