Principal Findings:

The IVUS catheter would not cross the lesion before balloon dilation in 4% of patients and after PTCA in 3% of patients. Dissection leading to impaired flow was treated with stenting in 5% at the lesion site and in 2% of patients distal to the lesion site. Crossover to stenting occurred in 44% of patients randomized to IVUS guided PTCA. The nominal size of the balloon was greater in the PTCA group (3.60 mm v. 3.37 mm, p=0.001). Procedure times (51 min v. 39 min, p=0.001) and fluoroscopy times (10.6 min v. 8.6 min, p=0.01) were significantly longer in patients treated with IVUS guided PTCA. Contrast usage was also higher in this group (192 mL v. 158 mL, p=0.001). The mean lumen diameter after intervention was larger in the stent group (2.55 mm v. 2.75 mm, p=0.013) as was the cross sectional area (7.28 mm v. 6.6 mm, p=0.02). The residual stenosis was larger in the PTCA group (16% vs. 13%, p=0.001). At 6-month angiographic follow-up, restenosis rates were not significantly different (18.1% stent v. 16.8% PTCA, p=0.70) and which was within the non-inferiority primary endpoint hypothesis. There were no significant differences in mean lumen diameter (2.03 +/- 0.62 vs 1.97 +/- 0.72 mm, p=0.38), percent diameter stenosis (28 +/- 17 vs 31 +/- 20 mm, p=0.14) or cross sectional area on IVUS (5.24 +/- 2.51 vs 5.12 +/- 2.80 mm, p=0.57). The in-stent restenosis rate was higher in the stent group (15.5% v 5%, p=0.02) and the late loss trended higher (0.71 +/- 0.54 vs 0.55 +/- 0.60 mm, p=0.06). There was no difference in the 1 year composite clinical endpoint of death, MI, unstable angina, or TVR (20% vs 16%, p=0.52).