Is coronary stent deployment and remodeling affected by predilatation? An intravascular ultrasound randomized study Stenting with or without predilation: an IVUS study Jacques Boschat 1 , Herve´ Le Breton 2 , P. Commeau 3 , Bernard Huret 3 , Marc Bedossa 2 & Martine Gilard 1 (For the Stent Without BAlloon Predilatation (SWIBAP) Study Group) 1 Department of Cardiology, CHUR La Cavale Blanche, Brest; 2 Centre Cardio Pneumologique, Unite ´ d’He´modynamique et de Cardiologie interventionnelle, CHU Pontchaillou, Rennes; 3 Clinique Saint Martin, Caen, France Received 8 May 2002; accepted in revised form 17 May 2002 Key words: coronary artery angioplasty, coronary artery ultrasound, stent Abstract In this intravascular ultrasound (IVUS) randomized trial we compared a strategy of direct stenting (DS) without predilation (n ¼ 30) vs. conventional stenting with predilation (SWP) (n ¼ 30) in patients with suitable type A or B non-calcified lesions in native vessels 3 mm. Optimal deployment was achieved using angiographic criteria without interactive IVUS. The goal of our study was to determine whether stent expansion and coronary remodeling were similar. Maximal pressure inflation was comparable in the two groups (11.4 ± 2.2 vs. 11.8 ± 1.9 atm; NS). Stent deployment was obtained in all patients with complete apposition to the vessel wall. DS and SWP resulted in comparable lumen enlargement (5.4 ± 2.5 vs. 5.5 ± 2.1 mm 2 ) with an identical mechanism: 66% of lumen enlargement was due to increased enlarged elastic membrane (EEM)-cross sectional area (CSA) (D ¼ 3.7 ± 2.1 mm 2 and D ¼ 2.4 ± 6.8 mm 2 , re- spectively, p < 0.49) and 34% was due to a reduced P+M-CSA (D ¼ 0.02 ± 6.9 mm 2 and D ¼ 1.2 ± 6.3 mm 2 , respectively, p < 0.50). We conclude that at the same maximal pressure inflation the mechanisms of stent expansion are similar in both DS and SWP groups. In this observational study, the IVUS data showed clearly under-expansion of stents in both groups in comparison with previously pub- lished CSA values (minimum stent CSA of 7.5 mm 2 ). Introduction Coronary stenting is a well established treatment for coronary artery disease. Randomized trials have demonstrated that stenting improves proce- dural success and reduces restenosis and target vessel revascularization, compared with balloon angioplasty [1–3]. The standard stent implantation technique requires routine predilatation of the target lesion with a balloon catheter in order to allow an easy and uncomplicated passage of the stent and, subsequently, a complete expansion after deployment. Due to technical progress [4], new stent designs with improved flexibility, acceptable crossing profile, and stable adherence on the bal- loon delivery system have been developed, which allow to avoid predilatation in some cases. When non-calcified coronary lesions are considered, di- rect stenting (DS) without predilatation provides a way to rationalize stent implantation, less balloons used, shorter radiation exposure time, and less trauma of the vessel wall [5]. Selected clinical series have reported encouraging initial procedural re- sults [5–7]. However there was no advantage for The International Journal of Cardiovascular Imaging 18: 399–404, 2002. Ó 2002 Kluwer Academic Publishers. Printed in the Netherlands. 399