Biocompatibility of phosphorylcholine coated stents in normal porcine coronary arteries

Objective-To improve the biocompatibility of stents using a phosphorylcholi ne coated stent as a form of biomimicry. Interventions-Implantation of phosphorylcholine coated (n = 20) and non-coa ted (n = 21) stents was performed in the coronary arteries of 25 pigs. The animals were killed after five days (n = 6), four weeks (n = 7), and 12 wee ks (n = 8), and the vessels harvested for histology, scanning electron micr oscopy, and morphometry. Main outcome measures-Stent performance was assessed by studying early endo thelialisation, neointima formation, and vessel wall reaction to the synthe tic coating. Results-Stent thrombosis did not occur in either group. Morphometry showed no significant differences between the two study groups at any time point. At five days both the coated and non-coated stents were equally well endoth elialised (91% v 92%, respectively). At four and 12 weeks there was no diff erence in intimal thickness between the coated and non-coated stents. Up to 12 weeks postimplant the phosphorylcholine coating was still discernible i n the stent strut voids, and did nut appear to elicit an adverse inflammato ry response. Conclusion-In this animal model the phosphorylcholine coating showed excell ent blood and tissue compatibility, unlike a number of other polymers teste d in a similar setting. Given that the coating was present up to 12 weeks p ostimplant with no adverse tissue reaction, it may be a potential candidate polymer for local drug delivery.