Aims Angioplasty of lesions in small coronary arteries remains a significant problem because of the increased risk of restenosis. The aim of this study was to compare the efficacy of elective coronary stent placement and optimal balloon angioplasty in small vessel disease. Methods One hundred and twenty patients with lesions in small coronary arteries (de novo, non-ostial lesion and reference diameter <3 mm) were randomly assigned to either balloon angioplasty or elective stent pacement (7-cell NIR stent). The primary end-point was restenosis at 6 months follow-up. Optimal balloon angioplasty was defined as diameter stenosis <less than or equal to>30% and the absence of major dissection after the angioplasty, and crossover to stenting was allowed. Results Baseline clinical and angiographic characteristics were similar in the two groups. Procedure was successful in all patients, and in-hospital events did not occur in any patient. However, 12 patients in the angioplasty group were stented because of suboptimal results or major dissection. Postprocedural lumen diameter was significantly larger in the stent group than in the angioplasty group (2.44+/-0.36mm vs 2.14+/-0.36, P<0.05, respectively), but late loss was greater in the stent group (1.12+/-0.67mm vs 0.63 +/- 0.48, P<0.01. respectively). The angiographic restenosis rate was 30.9% in the angioplasty group, and 35.7% in the stent group (P=ns). Clinical follow-up was available in all patients(15.9+/-5.7 months) and clinical events during the follow-up were similar in both groups. Conclusions These results suggest that optimal balloon angioplasty with provisional stenting may be a reasonable approach for treatment of lesions in small coronary arteries. (Eur Heart J 2000; 21: 1785-1789, doi:10,1053/euhj, 1999, 1947) (C) 2000 The European Society of Cardiology.