Abstract 12525: Association of Endothelium-dependent Coronary Vasomotor Response and Neointimal Coverage of Zotarolimus-Eluting Stents Three Months After Implantation
Background: Recent studies reported that zotarolimus-eluting stents (ZES) had a higher rate of neointimal coverage than the first-generation drug-eluting stents on optical coherence tomography (OCT). However, it is not clear whether neointimal coverage of stent struts detected can be used as a surrogate for endothelial function after ZES implantation.
Methods: OCT examinations were performed in 20 ZES at 3 months after stent implantation to evaluate stent strut coverage. The ZES strut condition was analyzed every 1 mm along the stented segment. A cross-section with uncovered strut was defined if one or more stent struts was uncovered on cross-section. Endothelium-dependent coronary vasomotion was estimated by infusing incremental doses of acetylcholine into the coronary ostium. The vascular response was quantitatively measured in the 10mm segments proximal and distal to ZES.
Results: The mean neointimal thickness was 217 μm, which results in approximately 17% of neointima over stent strut <100 μm. Of the 20 ZES evaluated, 15 (75%) were completely covered with neointima, however the remaining 5 partially covered ZES had only 0.9%, 2.5%, 2.1%, 3.6%, and 4.3% uncovered struts. Although low dose acetylcholine infusion produced no coronary vasoconstriction, high dose acetylcholine produced significant vasoconstriction in the proximal (−14.1+/−11.3%) and the distal stent segment (−17.5+/−12.5%). Degree of vasoconstriction to acetylcholine varied between individuals (from −0.6% to −77%). Although no relationship was observed between coronary vasomotor response to acetylcholine and average neointimal thickness, the number of cross-section with uncovered strut showed an inverse correlation with coronary vasomotor response in proximal and distal stent segment (r=−0.57, p=0.007 and r=−0.83, p<0.001, respectively).
Conclusions: Degree of vasoconstriction to acetylcholine and stent strut coverage varied between individuals. The existence of exposed struts was associated with abnormal vasoconstriction to acetylcholine at 3 months after ZES implantation. Our findings suggest that complete neointimal coverage of stent struts assessed by OCT could be used as a surrogate for healing of endothelial function at 3 months after ZES implantation.
- Drug eluting stents
- Endothelial function
- Coronary artery disease
- Intravascular ultrasound/Doppler
- © 2010 by American Heart Association, Inc.