C. Yutani et al., Histologic evidence of foreign body granulation tissue and de novo lesionsin patients with coronary stent restenosis, CARDIOLOGY, 92(3), 1999, pp. 171-177
Citations number
28
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Objectives: We examined the relative contributions of foreign body granulat
ion and de novo lesions to neointimal hyperplasia in atherectomized specime
ns of restenosis after coronary stenting. Background: Clinicopathological s
tudies have suggested that smooth muscle cell (SMC) hyperplasia is the most
likely cause of restenosis after coronary stenting. It is not yet fully un
derstood how SMC hyperplasia occurs or how SMCs stimulation can lead to int
imal hyperplasia. Although inflammation has been postulated to be a major c
ontributor to restenosis after coronary stenting, there is a paucity of dat
a on the relationsip between inflammation and subsequent neointimal formati
on in humans. Only in a porcine experimental model of stent restenosis, for
eign body granulation tissue as a cause of inflammation in stent restenosis
was reported. Methods: Tissue specimens were retrieved by directional athe
rectomy from 11 patients in whom stent restenosis developed after percutane
ous revascularization of coronary artery disease. For specimens preserved i
n 10% buffered formalin, analysis of cellular composition was performed qua
ntitatively after cell-specific immunostaining, i.e. CD68, UCHL-1, HLA-DR,
smooth muscle actin, vimentin, desmin, PCNA and TGF-beta. Results: Five of
the 11 patients showed granulation tissues 3-6 months after stent implantat
ion, of whom 3 patients revealed foreign body multinucleated giant cells ar
ound the stent struts where PCNA- and vimentin-positive SMCs were demonstra
ted. Calcification and de novo lesions in medial and adventitial tissues we
re observed in 3 other patients, and fresh and/or organized thrombi were do
cumented in 3 of the 11 patients. Conclusions: These findings support the n
otion that stent restenosis results from SMC hyperplasia and suggest that t
he foreign body granulation tissue against metals of the stents and de novo
lesions could play an important role in chronic inflammation leading to in
timal hyperplasia and subsequently to stent restenosis in some patients. Cl
inicians should thus consider whether a patient may be allergic to stent co
mponents with unknown reaction, e.g. haptens. Copyright (C) 2000 S. Karger
AG. Basel.