title: Relative dose and vascular response after drug-eluting stent implantation: A dosimetric 3D-intravascular ultrasound study.
abstract: BACKGROUND
  In drug-eluting stents (DESs), the theoretical drug dose exposed to the vessel wall per stent surface area may vary due to the fixed loading dose and differences in the stent surface area once expanded in varying vessel sizes. The aim of this study was to evaluate the potential effects of different dose intensities, as estimated by 3D-IVUS dosimetry, on vascular response after DES implantation.
  
  
  METHODS
  Follow-up (6-9 months) 3D-IVUS was performed in 840 coronary lesions treated with a single DES of the following types: sirolimus (SES, n=148), paclitaxel (PES, n=162), Endeavor zotarolimus (E-ZES, n=233), Resolute zotarolimus (R-ZES, n=147), and everolimus (EES, n=150). Volume index (volume/length, mm(3)/mm) was obtained for vessel, lumen, plaque, stent, and neointima. In each lesion, exposed dose intensity was calculated as known loading dose divided by measured luminal surface area of the stented segment. Lesions were divided into tertiles based on the exposed dose intensity: high, medium, and low dose groups.
  
  
  RESULTS
  The exposed dose intensity ranged 0.74-1.76 μg/mm(2) for SES, 0.41-1.18 μg/mm(2) for PES, 0.71-1.57 μg/mm(2) for E-ZES, 0.72-1.63 μg/mm(2) for R-ZES, and 0.40-0.99 μg/mm(2) for EES. All types of DES showed no significant difference in neointimal hyperplasia among the 3 groups, except that E-ZES showed significantly less neointimal hyperplasia in the high dose group.
  
  
  CONCLUSIONS
  Detailed 3D-IVUS revealed significant lesion-to-lesion variability in dose intensity exposed to the vessel wall following DES implantation. However, the major types of DES appear to yield equally effective neointimal suppression, despite the varying dose intensity, except for E-ZES.
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kitahara
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Waseda
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Yamada
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Yock
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Fitzgerald
authors.affiliation: Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States. Electronic address: crci-cvmed@stanford.edu.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Honda
mesh_terms: D000368:Aged; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000628:therapy*; D004305:Dose-Response Relationship, Drug; D054855:Drug-Eluting Stents; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: Coronary artery disease; Drug-eluting stent; Intravascular ultrasound