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. 2000 Mar;83(3):338–345. doi: 10.1136/heart.83.3.338

Biocompatibility of phosphorylcholine coated stents in normal porcine coronary arteries

D Whelan 1, W J van der Giessen 1, S Krabbendam 1, E A van Vliet 1, P Verdouw 1, P Serruys 1, H M M van Beusekom 1
PMCID: PMC1729350  PMID: 10677417

Abstract

OBJECTIVE—To improve the biocompatibility of stents using a phosphorylcholine coated stent as a form of biomimicry.
INTERVENTIONS—Implantation of phosphorylcholine coated (n = 20) and non-coated (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 weeks (n = 8), and the vessels harvested for histology, scanning electron microscopy, and morphometry.
MAIN OUTCOME MEASURES—Stent performance was assessed by studying early endothelialisation, neointima formation, and vessel wall reaction to the synthetic 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 endothelialised (91% v 92%, respectively). At four and 12 weeks there was no difference in intimal thickness between the coated and non-coated stents. Up to 12 weeks postimplant the phosphorylcholine coating was still discernible in the stent strut voids, and did not appear to elicit an adverse inflammatory response.
CONCLUSION—In this animal model the phosphorylcholine coating showed excellent blood and tissue compatibility, unlike a number of other polymers tested in a similar setting. Given that the coating was present up to 12 weeks postimplant with no adverse tissue reaction, it may be a potential candidate polymer for local drug delivery.


Keywords: phosphorylcholine; stents; coatings; biocompatible materials

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Figure 1  .

Figure 1  

A macroscopic view of the divYsio stent.

Figure 2  .

Figure 2  

Schematic representation of the phosphorylcholine coating applied to the divYsio stent (modified from Campbell and colleagues8).

Figure 3  .

Figure 3  

(A) Light microscopy of the intimal thickening at five days postimplant, showing granulation tissue over the stent wire void (*), with occasional leucocytes (arrowheads) attached to the endothelium (bar = 30 µm). NI, neointima; M, media; haematoxylin and eosin. (B) SEM of a stent strut (S) at five days, showing an incomplete endothelial lining (arrow), with leucocytes (arrowheads) and macrophages (*) occupying areas devoid of endothelium (bar = 20 µm).

Figure 4  .

Figure 4  

Overview (left) of a stented artery at four weeks showing an asymmetric neointima (bar = 500 µm), with detail (right) showing cells in a haphazard orientation with thrombus remnants (arrowhead) in the intimal/medial border zone (bar = 100 µm). NI, neointima; M, media; A, adventitia; haematoxylin and eosin.

Figure 5  .

Figure 5  

Figure 5  

(A) Detail of purple stained coating (arrowheads) observed in the stent strut void (*) 12 weeks after implantation of a phosphorylcholine coated stent (bar = 45 µm). NI, neointima; M, media; haematoxylin and eosin. (B) Detail of the cut surface of a stent strut from a non-implanted coated stent (bar = 20 µm). The phosphorylcholine coating (arrow) seen at the strut edge is similar in appearance to that seen in A. Haematoxylin and eosin.

Selected References

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