[Implications of late expansion of self-expanding stents on neointimal response: a serial study with intravascular ultrasound].
OBJECTIVE
A unique property of self-expanding stents is the continuous force exerted against the vessel wall, which may induce additional arterial damage with implications on restenosis. The main purpose of this study is to evaluate the consequences of late self-expansion of coronary Wallstents.


METHODS
Eleven patients with Wallstents implanted in native coronary arteries, in whom baseline, post-stenting, after high pressure balloon inflation and at 6-month follow-up intravascular ultrasound were performed. The stented segments were divided in 2-mm cross-sections, that were analyzed independently and carefully matched at each situation using anatomic landmarks. Multiple regression analysis was performed.


RESULTS
Late expansion was present in 93% of the studied sections (mean increase in stent area of 2.0 1.9 mm2) and was clearly related to stent oversizing (r = 0.45; p < 0,0001). Although late expansion was a significant positive predictor of neointimal growth (r = 0.63; p < 0.0001), it showed a negative correlation with late luminal loss (r = 0.33; p < 0.0001). No significant correlation was found between optimization of angiographic results with high pressure inflations and late luminal loss.


CONCLUSIONS
Late expansion is a common phenomenon after Wallstent implantation and is mainly determined by stent oversizing. Despite the fact that this phenomenon is associated with greater neointimal proliferation, it seems to have a net beneficial effect on late luminal loss.
Sanmartín
Marcelo
M
Servicio de Cardiología Intervencionista, Instituto Cardiovascular, Hospital Clínico San Carlos, Madrid, Spain.
Goicolea
Javier
J
Alfonso
Fernando
F
Escaned
Javier
J
Flores A
Alex
A
Fernández-Ortiz
Antonio
A
Bañuelos
Camino
C
Hernández-Antolín
Rosa Ana
RA
Macaya
Carlos
C
D023903:Coronary Restenosis / Q000000981:diagnostic imaging; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D013997:Time Factors; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional
Implicaciones de la expansión tardía de los stents autoexpandibles sobre la respuesta neointimal: estudio seriado con ecografía intravascular.