A randomized optical coherence tomography study of coronary stent strut coverage and luminal protrusion with rapamycin-eluting stents.
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).
Moore
Philip
P
Royal Brompton & Harefield NHS Trust, Middlesex, United Kingdom.
Barlis
Peter
P
Spiro
Jonathan
J
Ghimire
Gopal
G
Roughton
Michael
M
Di Mario
Carlo
C
Wallis
William
W
Ilsley
Charles
C
Mitchell
Andrew
A
Mason
Mark
M
Kharbanda
Rajesh
R
Vincent
Peter
P
Sherwin
Spencer
S
Dalby
Miles
M
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
D007166:Immunosuppressive Agents; D011108:Polymers; D020123:Sirolimus