Long-term vessel response to a self-expanding coronary stent: a serial volumetric intravascular ultrasound analysis from the ASSURE Trial.A Stent vs. Stent Ultrasound Remodeling Evaluation.
OBJECTIVE
We sought to investigate the in vivo mechanical properties of a new self-expanding coronary stent (RADIUS) and, particularly, the subsequent vessel response over time.


BACKGROUND
Preclinical studies have suggested that self-expanding stents may produce less vessel wall injury at initial deployment, leading to larger follow-up lumens than with balloon-expandable stents. However, the influence of the chronic stimulus from self-expanding stents on the vessel wall remains unknown.


METHODS
Sixty-two patients were randomly assigned to either the RADIUS self-expanding stent group (n = 32) or the Palmaz-Schatz balloon-expandable stent group (n = 30). Intravascular ultrasound was performed after stent deployment and at six-month follow-up.


RESULTS
At follow-up, the RADIUS stents had increased 23.6% in overall volume, while the Palmaz-Schatz stents had remained unchanged. Due to the greater mean neointimal area (3.0 +/- 1.7 mm2 vs. 1.9 +/- 1.2 mm2, p = 0.02) in the RADIUS group, no significant difference in net late lumen loss was observed between the two groups. On the other hand, analysis at the peristent margins demonstrated that mean late loss was significantly smaller in the RADIUS group than it was in the Palmaz-Schatz group (0.1 +/- 2.1 mm2 vs. 1.9 +/- 2.4 mm2, p = 0.02).


CONCLUSIONS
Serial volumetric IVUS revealed that the RADIUS stents continued to enlarge during the follow-up period. In this stent implantation protocol, this expansion was accompanied by a greater amount of neointima than the Palmaz-Schatz stents, resulting in similar late lumen loss in both configurations. In the peristent margins, however, late lumen loss was minimized with the RADIUS stents.
Kobayashi
Y
Y
Center for Research in Cardiovascular Interventions, Stanford University Medical Center, California 94305-5637, USA.
Honda
Y
Y
Christie
G L
GL
Teirstein
P S
PS
Bailey
S R
SR
Brown
C L
CL
Matthews
R V
RV
De Franco
A C
AC
Schwartz
R S
RS
Goldberg
S
S
Popma
J J
JJ
Yock
P G
PG
Fitzgerald
P J
PJ
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation*; D002404:Catheterization / Q000295:instrumentation*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000293:injuries*; D018084:Ultrasonography, Interventional