Jmd. Hernandez et al., Intravascular ultrasonographic evaluation of direct stents, implanted without predilatation. Comparison of results according to lesion types, REV ESP CAR, 53(10), 2000, pp. 1335-1341
Introduction. Direct stenting is a safe and feasible technique in selected
lesions yielding excellent angiographic results. However, there are no stud
ies providing intravascular ultrasonographic examination after direct stent
ing. The aim of this study was to evaluate direct stent expansion with ultr
asonography and to know whether there are differences in the results based
on lesion types.
Methods. Patients with amenable lesions for direct stenting were enrolled;
including patients with no occlusion, no calcification, no significant tort
uosity or angulation, a length less than or equal to 15 mm and a reference
lumen diameter greater than or equal to2.5 mm. Intra vascular ultrasonograp
hy was performed after stent implantation. The ultrasonographic criteria fo
r optimal expansion were: complete apposition and a minimal intrastent lume
n area >80% of the average reference luminal area and greater than or equal
to 90% of the distal reference lumen area.
Results. We included 40 patients (50 lesions). The final angiographic resul
t was good in all the patients but in one case an additional stent was used
due to dissection. The ultrasonographic examination did not show significa
nt differences between type A and B lesions. Optimal expansion was achieved
in 14/21 (66%) of type A lesions and 17/29 (58%) of type B lesions (p = 0.
5). The balloon/artery ratio was the only factor significantly related to u
ltrasonographic results. When this ratio was 1.1-1.2 (25 cases), 76% of the
stents were optimally expanded and when the ratio was <1.1 (25 cases) only
in a 48% an optimal result was achieved (p < 0.05).
Conclusions. Direct stenting in selected lesions provides ultrasonographic
results comparable to those expected with conventional stenting and these r
esults could be even improved if a balloon artery ratio 1.1-1.2 is used. Ta
king into consideration the selection criteria the differences observed bet
ween lesion types A and B are not significant.