Abstract 3054: Comparison of Overlapping Non-Polymer versus Polymer-Based DES: Finding a Better Balance Between Neointimal Suppression and Arterial Healing
Background - Despite widespread use of polymer based Cypher drug-eluting stents (CDES), inflammatory responses to polymer coatings and delayed healing are important safety issues facing this technology. Whether non-polymeric stents perform better is unknown. This study compared overlapping DES coated using a novel nonpolymer rapamycin based drug-elution platform to CDES.
Methods. 26 New Zealand White Rabbits were randomly assigned to receive 2 overlapping DES in each iliac artery (polymer-free 1% Sirolimus-coated microporous DES (SRL) (n=8), polymer-free 1% Sirolimus + 1% 17beta-estradiol-coated microporous DES (SRL+ED) (n=8), bare metal Yukon DES (BMS) (n=10) or CDES (n=10) (mean length of overlap, 8.0 mm). Arteries were harvested at 28 days for histology and scanning electron microscopy (SEM) (n=3/group).
Results. Neointimal thickness within the overlap site of Cypher stents was significantly less than in SRL, SRL+ED, and BMS (0.07Â ±0.01 vs. 0.16Â ±0.01, 0.14Â ±0.01 and 0.15Â ±0.01 mm, respectively). Fibrin deposition at both non-overlapping and overlapping sites was significantly reduced in SRL, SRL+ED and BMS stents compared to CDES (figure A⇓). Endothelialization was significantly less in overlapping CDES vs. SRL, SRL+ED, and BMS (figure B⇓). % Giant cells were greater in CDES versus SRL+ED (60.7%Â ±3.2 vs. 34.6Â ±6.1, p<0.05.
Conclusions. Overlapping polymer-free microporous DES coated with SRL or SRL+ED are not as effective at reducing neointimal growth within the overlap site as CDES in this animal model, but result in less inflammation and markedly improved arterial healing at 28 days in the rabbit model.