The presence of even mild renal insufficiency is usually associated with an increased rate of cardiovascular events after coronary stenting. The aim of this study was to evaluate the impact of mild to moderate renal insufficiency on the chronic vascular responses to the implantation of paclitaxel-eluting stents (PES; Taxus) and bare-metal stents (BMS). In the TAXUS IV, TAXUS V, and TAXUS VI trials, patients with serum creatinine levels >2.0 mg/dl were excluded. In the present analysis, 816 patients with serum creatinine levels <or=2.0 mg/dl had intravascular ultrasound images acquired after the procedures and/or at 9-month follow-up (406 with PES, 410 with BMS). Patients were stratified by level of creatinine clearance (Ccr; group 1: Ccr <40; group 2: 40 <or=Ccr <60; group 3: 60 or/=Ccr <80; group 4: Ccr >or=80 ml/min/1.73 m(2)). For all levels of Ccr, patients with PES compared with those with BMS had less intimal hyperplasia area (group 1: 0.97 +/- 0.98 vs 2.94 +/- 1.89; group 2: 0.94 +/- 0.86 vs 2.30 +/- 1.21; group 3: 0.99 +/- 1.02 vs 2.53 +/- 1.29; group 4: 0.87 +/- 0.95 vs 2.12 +/- 1.29 mm(2), all p values <0.0001) and greater increases in peristent plaque and media area (group 1: 0.90 +/- 0.98 vs -0.02 +/- 0.98 mm(2), p = 0.03; group 2: 0.57 +/- 1.43 vs 0.20 +/- 1.14 mm(2), p = 0.11; group 3: 1.20 +/- 1.95 vs 0.02 +/- 1.17, p <0.0001; group 4: 0.35 +/- 1.44 vs -0.19 +/- 1.08 mm(2), p = 0.08). Neointimal growth and vessel remodeling were not affected by variations in Ccr after either BMS or PES implantation over the range studied. The incidence of incomplete stent apposition at follow-up was lowest in patients with the greatest renal impairment after BMS and PES implantation. In conclusion, neointimal proliferation was less prominent and expansive vessel remodeling was more prominent after PES than BMS implantation, independent of the severity of renal dysfunction.