BACKGROUND: The intracoronary stent implantation is regarded as an effective treatment modality to reduce restenosis. However, subacute stent thrombosis and subsequent anticoagulation therapy have been major problems after stenting. The high-pressure inflation stenting reduced the incidence of stent thrombosis and resulted in less need of anticoagulation therapy. We intended to analyze the high-pressure inflation stenting with intravascular ultrasound(IVUS) and to evaluate different IVUS criteria of optimal stenting. METHOD: One hundred and forty eight patients with 160 lesions were treated with 175 stents of various types. IVUS images were obtained after angiographic optimization (<10% of residual stenosis) with high-pressure inflation stenting. The quantitative and qualitative off-line measurements of IVUS parameters were performed. RESULTS: More high-pressure or larger-sized balloon inflation was needed in 32 lesions (20%) after IVUS. The incomplete stent apposition was observed in 5 lesions (3%). The edge dissection occurred distally or proximally to stented site in 19 lesions (12%). The plaque prolapse was observed within the stent in 24 lesions (15%). In single stent implantation for discrete lesions, optimal stent expansion defined by IVUS was achieved in 69% with minimal stent lumen area of 90% of distal reference lumen area and in 75% with minimal stent lumen area of 80% of average reference lumen area. The IVUS criteria of minimal stent lumen area 9mm2 and 7-9mm2 was met in 29% and 29%, respectively. In stents implantation for diffuse lesions including long stent,multiple overlapping stents and hybrid stents implantation, optimal stent expansion defined by IVUS was achieved in 69% with minimal stent lumen area of 90% of distal reference lumen area and in 67% with minimal stent lumen area of 80% of average reference lumen area. The IVUS criteria of minimal stent lumen area 9mm2 and 7-9mm2 was met in 17% and 23%, respectively. CONCLUSION: IVUS provided a valuable informations leading to additional intervention in 20% of the lesions after angiographic optimization with high-pressure balloon inflation. Even though additional interventions were performed with IVUS-guidance, the optimal stent expansion by IVUS criteria was achieved in about 70%. Therefore, we suggest that IVUS might be used more generally to improve the acute results after coronary stenting.