Nonuniform strut distribution correlates with more neointimal hyperplasia after sirolimus-eluting stent implantation.
BACKGROUND
Little is known about causes of intimal hyperplasia (IH) after sirolimus-eluting stent (SES) implantation.


RESULTS
Intravascular ultrasound was performed in 24 lesions with intra-SES restenosis and a comparison group of 25 nonrestenotic SESs. To assess stent strut distribution, the maximum interstrut angle was measured with a protractor centered on the stent, and the visible struts were counted and normalized for the number of stent cells. In SES restenosis patients, minimum lumen site was compared with image slices 2.5, 5.0, 7.5, and 10.0 mm proximal and distal to this site. The minimum lumen site had a smaller IVUS lumen area at follow-up (2.7+/-0.9 versus 6.2+/-1.9 mm2; P<0.01), larger maximum interstrut angle (135+/-39 degrees versus 72+/-23 degrees; P<0.01), larger IH area (3.4+/-1.5 versus 0.6+/-1.1 mm2; P<0.01) and thickness (0.7+/-0.3 versus 0.1+/-0.2 mm; P<0.01) at maximum interstrut angle, and fewer stent struts (4.9+/-1.0 versus 6.0+/-0.5; P<0.01) even when normalized for the number of stent cells (0.78+/-0.15 versus 0.97+/-0.07; P<0.01). Compared with nonrestenotic SES, the restenosis lesions also had a smaller minimal lumen area, larger IH area, thicker IH at maximum interstrut angle, fewer stent struts, and larger maximum interstrut angle. Multivariate analysis identified the number of visualized stent struts normalized for the number of stent cells and maximum interstrut angle as the only independent IVUS predictor of IH cross-sectional area (P<0.01 and P<0.01), minimum lumen area (P<0.01 and P<0.01), and IH thickness (P<0.01 and P<0.01).


CONCLUSIONS
The number and distribution of stent struts affect the amount of neointima after SES implantation.
Takebayashi
Hideo
H
Cardiovascular Research Foundation, Lenox Hill Heart and Vascular Institute, New York, NY 10022, USA.
Mintz
Gary S
GS
Carlier
Stéphane G
SG
Kobayashi
Yoshio
Y
Fujii
Kenichi
K
Yasuda
Takenori
T
Costa
Ricardo A
RA
Moussa
Issam
I
Dangas
George D
GD
Mehran
Roxana
R
Lansky
Alexandra J
AJ
Kreps
Edward
E
Collins
Michael B
MB
Colombo
Antonio
A
Stone
Gregg W
GW
Leon
Martin B
MB
Moses
Jeffrey W
JW
D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000517:prevention & control; D023921:Coronary Stenosis / Q000628:therapy; D004343:Drug Implants; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D006801:Humans; D006965:Hyperplasia; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D020123:Sirolimus / Q000008:administration & dosage / Q000627:therapeutic use*; D015607:Stents; D017539:Tunica Intima / Q000000981:diagnostic imaging* / Q000473:pathology; D018084:Ultrasonography, Interventional
D004343:Drug Implants; D020123:Sirolimus