Relationship between neointimal thickness and shear stress after Wallstent implantation in human coronary arteries.
BACKGROUND
In-stent restenosis by excessive intimal hyperplasia reduces the long-term clinical efficacy of coronary stents. Because shear stress (SS) is related to plaque growth in atherosclerosis, we investigated whether variations in SS distribution are related to variations in neointima formation.


RESULTS
In 14 patients, at 6-month follow-up after coronary Wallstent implantation, 3D stent and vessel reconstruction was performed with a combined angiographic and intravascular ultrasound technique (ANGUS). The bare stent reconstruction was used to calculate in-stent SS at implantation, applying computational fluid dynamics. The flow was selected to deliver an average SS of 1.5 N/m(2). SS and neointimal thickness (Th) values were obtained with a resolution of 90 degrees in the circumferential and 2.5 mm in the longitudinal direction. For each vessel, the relationship between Th and SS was obtained by linear regression analysis. Averaging the individual slopes and intercepts of the regression lines summarized the overall relationship. Average Th was 0.44+/-0.20 mm. Th was inversely related to SS: Th=(0.59+/-0.24)-(0.08+/-0.10)xSS (mm) (P<0.05).


CONCLUSIONS
These data show for the first time in vivo that the Th variations in Wallstents at 6-month follow-up are inversely related to the relative SS distribution. These findings support a hemodynamic mechanism underlying in-stent neointimal hyperplasia formation.
Department of Cardiology, Thoraxcenter, Erasmus Medical Centre Rotterdam and Erasmus University Rotterdam, and the Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands.
J J
JJ
Wentzel
R
R
Krams
J C
JC
Schuurbiers
J A
JA
Oomen
J
J
Kloet
W J
WJ
van Der Giessen
P W
PW
Serruys
C J
CJ
Slager
D003326:Coronary Circulation; D003331:Coronary Vessels / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015607:Stents / Q000009:adverse effects*; D013314:Stress, Mechanical; D017539:Tunica Intima / Q000473:pathology*