Copyright © 2007, European Society of Cardiology
Overlapping paclitaxel-eluting stents: Long-term effects in a porcine coronary artery model
Department of Laboratory Medicine and Pathobiology, University of Toronto, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada and Clinical Sciences Organization, Boston Scientific Corporation, Natick, Massachusetts, USA
*Corresponding author. Room 1050, 525 University Avenue, Toronto, Ontario M5G 2L3. Tel.: +1 416 813 7654x2095; fax: +1 416 813 6306. Gregory.Wilson{at}sickkids.ca
Objective At 4-year follow-up, paclitaxel-eluting stents (PES, TAXUS®) have demonstrated clinical effectiveness in reducing restenosis without increasing death or myocardial infarction. Concerns remain with all drug-eluting stents, however, regarding potential interference with long-term healing, particularly in zones with adjacent stent overlap due to theoretical doubling in both drug release and tissue contact with coating polymer. Therefore, we evaluated long-term healing of overlapped TAXUS stents in an accepted animal model.
Methods Seventy-one non-injured swine underwent coronary artery placement of 138 overlapping stent-pairs (91 PES TAXUS Liberté 1 µg/mm2 slow release formulation, 3.0 or 3.5 mm diameter pairs and 47 control bare metal Liberté pairs) deployed at a 1.1:1 to 1.2:1 target stent-to-artery diameter ratio. Pathological analysis was performed at 30 (9 bare, 10 paclitaxel), 90 (9 bare, 10 paclitaxel), 180 (10 bare, 16 paclitaxel), 360 (10 bare, 21 paclitaxel), and 580 (9 bare, 22 paclitaxel) days.
Results At all time intervals overlapped TAXUS stents were consistently endothelialized and free of luminal thrombus or vascular dilatation. Full healing, however, was delayed compared to control, with macrophage processed para-strut fibrin and cellular debris still present, but reduced and sequestered from blood flow by an endothelialized neointima at 360 and 580 days. While neointimal thickness in TAXUS overlap zones was significantly less than control at 30 days, greater neointima formation was observed with TAXUS at 
90 days, but was stable and did not progress further from 90 to 580 days.
Conclusion In this porcine model TAXUS stents demonstrated safety and acceptable healing with prolonged time to resolution of para-strut deposits, and did not produce the sustained neointimal suppression seen clinically.
KEYWORDS Angioplasty/coronary intervention; Stents; Histopathology
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Shinke, J. Li, J. P. Chen, L. Pendyala, T. Goodchild, R. Jabara, S. Geva, T. Ueno, N. Chronos, K. Robinson, et al. High Incidence of Intramural Thrombus After Overlapping Paclitaxel-Eluting Stent Implantation: Angioscopic and Histopathologic Analysis in Porcine Coronary Arteries Circ Cardiovasc Intervent, August 1, 2008; 1(1): 28 - 35. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Aoki, G. S. Mintz, N. J. Weissman, J. T. Mann, L. Cannon, J. Greenberg, E. Grube, A.R. Z. Masud, J. Koglin, L. Mandinov, et al. Chronic Arterial Responses to Overlapping Paclitaxel-Eluting Stents: Insights From Serial Intravascular Ultrasound Analyses in the TAXUS-V and -VI Trials J. Am. Coll. Cardiol. Intv., April 1, 2008; 1(2): 161 - 167. [Abstract] [Full Text] [PDF]
|
|