Abstract 20621: Reduction of Neointimal Hyperplasia With Clopidogrel or Ticagrelor in a Canine Model of Coronary Stent Implantation
Introduction: Ticagrelor is a reversible P2Y12 receptor inhibitor that has emerged to replace clopidogrel for thromboprophylaxis after coronary stent placement, with a quicker onset and more potent inhibition of platelet aggregation. Although clopidogrel is also known to reduce neointimal hyperplasia (NIH) in experimental models, limited data exist on the efficacy of ticagrelor.
Hypothesis: Ticagrelor is more potent than clopidogrel to supress NIH formation after stent placement.
Methods: Eighteen dogs were administered aspirin (Group A, n=5), clopidogrel (Group C, n=5) or ticagrelor (group T, n=6) with a dose titrated to obtain between 70% to 90% inhibition of platelet aggregation. After 4 days, they underwent placement of a bare metal stent in the right coronary artery. Antiplatelet treatment was completed up to 45 days, then the dog’s hearts were harvested and pressure-fixed in formaldehyde. Stented artery segments were embedded in methyl methacrylate, and thin sections (approximately 8 μm) from each stented artery block were stained with hematoxylin and eosin (H&E) and Verhoeff-van Gieson (VVG). Intra-stent NIH development was assessed by total intimal area measurement and computerized determination of mean intimal thickness.
Results: Intimal areas for Groups A, C and T were 1.68±0.49, 1.22±0.30 and 1.02±0.15 mm2, respectively (p=0.02 by ANOVA). The combined Groups C and T had a significantly lower intimal area compared to Group A (1.11±0.24 vs. 1.68±0.49 mm2, p=0.006), but there was only a trend towards reduction in NIH development in Group T compared to Group C (p=018). Mean intimal thickness was also different between Groups A (0.23±0.07 mm), C (0.16±0.04 mm) and T (0.14±0.03 mm, p=0.02 by ANOVA). Mean intimal thickness in the combined Groups C and T was significantly lower than for Group A (0.15±0.03 vs. 0.23±0.07 mm, p=0.008). The difference between Groups C and T was not significant (p=0.25).
Conclusions: Aggressive antiplatelet therapy with P2Y12 receptor inhibitors results in a significant reduction in NIH development after coronary stent implantation in a canine model. Despite a trend towards more important NIH suppression with ticagrelor compared with clopidogrel, no statistically significant difference was found between these drugs.
Author Disclosures: P. Voisine: None. J. Rodes-Cabau: None. M. Ruel: Honoraria; Modest; Medtronic (MICS CABG Proctor), Abbott Medical. C. Couture: None. M. Urena: None. L. Nombela: None. H. Ribeiro: None. D. Simard: None. J. Kingma: None.
- © 2016 by American Heart Association, Inc.