Chronic arterial responses to stent implantation: a serial intravascular ultrasound analysis of Palmaz-Schatz stents in native coronary arteries.
OBJECTIVE
We used intravascular ultrasound (IVUS) imaging to evaluate the chronic vessel responses to Palmaz-Schatz stents.


BACKGROUND
Palmaz-Schatz stents have been shown to inhibit early elastic recoil and late arterial remodeling while triggering neointimal hyperplasia. However, changes occurring in native vessels surrounding stent struts have not been well studied.


METHODS
Postintervention and follow-up (mean [+/-SD] 5.4 +/- 3.8 months) serial IVUS imaging was performed in 25 stents without restenosis and 24 with in-stent restenosis. Intravascular ultrasound imaging using automatic transducer pullback at 0.5 mm/s allowed measurement at 1-mm axial increments of external elastic membrane (EEM), stent and lumen cross-sectional areas (CSAs) and calculation of peristent plaque plus media (P + M = EEM - stent) CSA, intrastent plaque (stent-lumen) CSA, arterial remodeling (delta EEM CSA), tissue growth outside the stent (delta P + M CSA) and tissue growth within the stent (delta stent-lumen CSA). Volumes were calculated using the Simpson rule.


RESULTS
Mean EEM CSA increased significantly from 16.9 +/- 5.0 mm2 after intervention to 18.4 +/- 4.9 mm2 at follow-up (p < 0.0001), reflecting an increase in P + M CSA surrounding the stent (1.6 +/- 1.3 mm2). Greater tissue growth within the stent (2.4 +/- 2.2 mm2) correlated weakly, but directly with tissue growth surrounding the stent (r = 0.356, p = 0.0121). The ratio of peristent/intrastent tissue growth correlated weakly with arterial remodeling (r = 0.282, p = 0.0525). Restenotic stents had more tissue growth both within and surrounding the stent than did nonrestenotic stents. Volumetric measurements, which could be obtained in 15 lesions, showed similar results.


CONCLUSIONS
After implantation there is a chronic increase in plaque mass both within and surrounding the stents. The increase in peristent plaque mass is associated with adaptive remodeling.
Intravascular Ultrasound Imaging and Cardiac Catheterization Laboratories, Washington Hospital Center, Washington, D.C., USA.
R
R
Hoffmann
G S
GS
Mintz
J J
JJ
Popma
L F
LF
Satler
A D
AD
Pichard
K M
KM
Kent
C
C
Walsh
P
P
Mackell
M B
MB
Leon
D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000628:therapy; D011184:Postoperative Period; D012008:Recurrence; D015203:Reproducibility of Results; D015607:Stents / Q000009:adverse effects*; D017540:Tunica Media / Q000000981:diagnostic imaging; D018084:Ultrasonography, Interventional