title: [Intravascular ultrasonographic evaluation of direct stents, implanted without predilatation. Comparison of results according to lesion types].
abstract: OBJECTIVE
  Direct stenting is a safe and feasible technique in selected lesions yielding excellent angiographic results. However, there are no studies providing intravascular ultrasonographic examination after direct stenting. The aim of this study was to evaluate direct stent expansion with ultrasonography 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 tortuosity or angulation, a length 15 mm and a reference lumen diameter 2.5 mm. Intravascular ultrasonography was performed after stent implantation. The ultrasonographic criteria for optimal expansion were: complete apposition and a minimal intrastent lumen area > 80% of the average reference luminal area and 90% of the distal reference lumen area.
  
  
  RESULTS
  We included 40 patients (50 lesions). The final angiographic result was good in all the patients but in one case an additional stent was used due to dissection. The ultrasonographic examination did not show significant 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 ultrasonographic 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 results could be even improved if a balloon artery ratio 1.1-1.2 is used. Taking into consideration the selection criteria the differences observed between lesion types A and B are not significant.
authors.affiliation: Unidad de Hemodinámica y Cardiología Intervencionista. Hospital Universitario Marqués de Valdecilla. Santander.
authors.forename: J M
authors.initials: JM
authors.lastname: de la Torre Hernández
authors.forename: I
authors.initials: I
authors.lastname: Gómez González
authors.forename: F
authors.initials: F
authors.lastname: Rodríguez Entem
authors.forename: N
authors.initials: N
authors.lastname: Royuela
authors.forename: F M
authors.initials: FM
authors.lastname: Antolín Juárez
authors.forename: J
authors.initials: J
authors.lastname: Zueco
authors.forename: A
authors.initials: A
authors.lastname: Figueroa
authors.forename: T
authors.initials: T
authors.lastname: Colman
mesh_terms: D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D018084:Ultrasonography, Interventional