Abstract 23240: Evaluation of Vascular Response to Stenting of Coronary Arteries in Mature and Juvenile Swine
Objective: The objective of this study was to investigate potential differences in vascular response to stenting of coronary arteries with bare metal (BMS) and drug-eluting (DES) stents in juvenile versus mature swine.
Methods: Nine mature (>3 yrs) and nine juvenile (6–9 mo) Yucatan swine were implanted with 3 x 12 mm XIENCE V® DES and ML VISION® BMS, evenly distributed among the RCA, LCX, and LAD coronary arteries. After 7 and 28 days, vessels were analyzed using light, confocal (CM), and scanning electron microscopy (SEM), yielding a total of n=5–7 stented arteries for each age group per time point per analysis. For mRNA analysis, expression levels of a panel of inflammatory (VCAM-1, ICAM-1, MCP-1, CD40) and functional endothelial (EC) (eNOS, CD31, VE-CAD, VEGF, endothelin-1) gene markers were tested from homogenized DES and BMS stented coronary tissue at 7 and 28 days (n=3) using the Quantigene® Plex Assay (Affymetrix, Fremont, CA) according to manufacturer's instructions, with each gene normalized to β-actin. All data were expressed as mean + SD. A 2x2 ANOVA followed by t-tests were used to test for statistical significance for treatment and/or age effects (p<0.05).
Results: No differences in neointimal area and % stenosis were measured between age groups. Juvenile swine exhibited increased fibrin scores compared to mature swine (2.6 ± 0.5 vs 2.2 ± 0.5, p<0.05) at 7 days, with no differences between DES and BMS. At 28 days, DES exhibited an expected increase in para-strut fibrin deposition compared to BMS, with no difference between age groups. At 7 days, significant increases in para-strut foreign body inflammation (p<0.01) and in VCAM-1, ICAM-1, CD40, and MCP-1 gene expression (p<0.05) were observed in mature swine, but these differences were largely resolved by 28 days. By SEM, CM analysis of CD31 immunostaining, and CD31 gene expression, DES exhibited less EC coverage than BMS at 7 days, but this difference was abrogated by 28 days, with no difference between age groups.
Conclusions: Juvenile swine may exhibit a greater thrombotic response and a reduced foreign body response compared to mature swine at 7 days following stenting. However, as these differences resolve by 28 days, they are considered to be relatively insignificant.
- © 2010 by American Heart Association, Inc.