[Six-month intravascular ultrasound follow-up of coronary bifurcation lesions treated with rapamycin-eluting stents: technical considerations]

Abstract

Introduction and objectives: In vitro studies show that stents deform when dilated laterally to access a side branch. This phenomenon may be avoided by use of a kissing balloon at the end of the procedure. However, to date, no in vivo data are available. Our objectives were to investigate the main vessel stent using intravascular ultrasound (IVUS) at six-month follow-up in 55 patients with bifurcation lesions treated using rapamycin-eluting stents and to examine the effect of technical factors.

Patients and method: All patients were treated using provisional or T stents. At 6 months, IVUS measurements were made in the main vessel at both proximal and distal ends of the stent, in reference segments, immediately below the side branch ostium, and at the points where the lumen was smallest and where stent expansion was greatest.

Results: The lumen area immediately below the side branch ostium was significantly smaller than that at the point of maximum stent expansion (6.7 [1.8] vs 5.1 [1.3] mm2; P<.05). Underexpansion was not influenced by use of a kissing balloon (stent area immediately under the side branch ostium: 5.5 [0.9] vs 5.6 [1.6] mm2; P=NS) and only one patient experienced restenosis at this point. The lumen areas at the proximal and distal edges of the stent were almost identical in patients who did or did not undergo balloon dilation beyond the ends of the stent.

Conclusions: Stent underexpansion below the side branch ostium was frequently found following provisional or T stenting of bifurcation lesions. This minor stent deformity was not prevented by use of a kissing balloon nor by any specific side branch treatment and had no significant impact on the restenosis rate.