Relation of stent design and stent surface material to subsequent in-stent intimal hyperplasia in coronary arteries determined by intravascular ultrasound

doi:10.1016/S0002-9149(02)02347-0

The American Journal of Cardiology

Volume 89, Issue 12, 15 June 2002, Pages 1360-1364

https://doi.org/10.1016/S0002-9149(02)02347-0 Get rights and content

Abstract

A variety of different stent designs and coatings have become available. This study sought to determine the impact of stent design and gold-coating of stents on intimal hyperplasia (IH) in human atherosclerotic coronary arteries in relation to known predictors of restenosis. Angiographic and intravascular ultrasound (IVUS) studies were performed at 6-month follow-up on 311 native coronary lesions of 311 patients treated with 99 Multi-Link stents, 74 InFlow steel stents, 73 InFlow gold-coated stents, 41 Palmaz-Schatz stents, 12 NIR steel stents, and 12 gold-coated NIR Royal stents. Lumen and stent cross-sectional area (CSA) were measured at 1-mm axial increments. Mean IH CSA (stent CSA − lumen CSA) and mean IH thickness were calculated and averaged over the total stent length. IVUS demonstrated different levels of IH for the 6 stents. Mean IH thickness ranged from 0.20 ± 0.13 mm for Multi-Link stents to 0.43 ± 0.14 mm for InFlow goal-coated stents (p <0.001). Multivariate analysis proved non–Multi-Link stent design (odds ratio 3.45, 95% confidence intervals 1.13 to 11.11, p <0.034) and gold coating (odds ratio 3.78, 95% confidence intervals 1.88 to 7.54, p <0.001) to be the only independent predictors of IH thickness >0.3 mm. In conclusion, stent design and surface material have an important impact on the IH response to stents implanted in human coronary arteries. However, the differences in IH thickness between the analyzed stents were relatively small compared with the absolute lumen dimensions.

Section snippets

Patients and lesions:

Consecutive patients from 4 studies who required IVUS follow-up at 6 months were included in this study. A differenct stent design was used in each study. Lesion inclusion criteria were similar for the 4 studies. Coronary lesions had to be located in a native artery of 2.5 to 4.0 mm diameter and lesion length (up to 15 mm for Multi-Link stents [Guidant, Santa Clara, California], Palmaz-Schatz stents [Johnson & Johnson, Warren, New Jersey), and NIR stents [Scimed, Maple Grove, Michigan], and up

Results

Patient demographics are listed in Table 1.

Discussion

This IVUS study on 4 different stent designs and 2 different stent surface materials indicates that stent design, stent surface material, and diabetes mellitus have an important impact on the amount of IH thickness after coronary stent placement.

References (23)

S. Kasaoka et al.
Angiographic and intravascular ultrasound predictors of in-stent restenosis
J Am Coll Cardiol
(1998)
C. Bauters et al.
Predictors of restenosis after coronary stent implantation
J Am Coll Cardiol
(1998)
R. Hoffmann et al.
Intravascular ultrasound predictors of angiographic restenosis in lesions treated with Palmaz-Schatz Stents
J Am Coll Cardiol
(1998)
R. Mehran et al.
Validation of the in vivo intravascular ultrasound measurement of in-stent neointimal hyperplasia volumes
J Am Coll Cardiol
(1998)
A. Abizaid et al.
The influence of diabetes mellitus on acute and late clinical outcomes following coronary stent implantation
J Am Coll Cardiol
(1998)
R.S. Schwartz et al.
Restenosis and proportional neointimal response to coronary artery injuryresults in a porcine model
J Am Coll Cardiol
(1992)
R. Kornowski et al.
In-stent restenosis contributions of inflammatory responses and arterial injury to neointimal hyperplasia
J Am Coll Cardiol
(1998)
D.S. Baim et al.
Final results of a randomized trial comparing the NIR stent to the Palmaz-Schatz stent for narrowing in native coronary arteries
Am J Cardiol
(2001)
A. Kastrati et al.
Restenosis after coronary placement of various stent types
Am J Cardiol
(2001)
D. Fishman et al.
A randomized comparison of coronary stent placement and balloon angioplasty in the treatment of coronary artery disease
N Engl J Med
(1994)

P.W. Serruys et al.

A comparison of balloon expandable stent implantation with balloon angioplasty in patients with coronary artery disease

N Engl J Med

(1994)

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Relation of stent design and stent surface material to subsequent in-stent intimal hyperplasia in coronary arteries determined by intravascular ultrasound

Abstract

Section snippets

Patients and lesions:

Results

Discussion

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

Am J Cardiol

Am J Cardiol

A randomized comparison of coronary stent placement and balloon angioplasty in the treatment of coronary artery disease

N Engl J Med

A comparison of balloon expandable stent implantation with balloon angioplasty in patients with coronary artery disease

N Engl J Med