patients (0.7%) after failed PCI. Seven patients (0.7%) required placement of an intra-aortic balloon pump due to hemodynamic instability, while coronary perforations oc- curred in nine patients (0.9%). Periprocedural death oc- curred in two patients (0.2%). None required emergency CABG. Conclusions: Elective PCI can be performed safely in centers without cardiac surgery on-site. Perspective: Although emergency PCI for acute myocardial infarction in facilities without cardiac surgery on-site has recently been approved by state regulatory agencies in the United States following endorsement of the American Col- lege of Cardiology/American Heart Association guidelines for PCI, elective PCI in facilities without cardiac surgery on-site continues to be contraindicated. The result of this single-center study suggests that in the appropriate setting, and with experienced operators, elective PCI can be per- formed safely in facilities without cardiac surgery on-site. However, a recent analysis from the Medicare database using a much larger multicenter dataset has shown worse outcomes and an increased risk of death for patients under- going elective PCI in facilities without cardiac surgery on- site, and particularly in low-volume institutions. Thus, it appears that elective PCI without cardiac surgery on-site is not yet ready for prime time, and that we will need more data before its use can be endorsed. MM Therapeutic Implications of In-stent Restenosis Located at the Stent Edge: Insights From the Restenosis Intra-stent Balloon Angioplasty Versus Elective Stenting (RIBS) Randomized Trial Alfonso F, Melgares R, Mainar V, et al. for the Restenosis Intra- stent: Balloon Angioplasty versus Elective Stenting (RIBS) Investigators. Eur Heart J 2004;25:1829 –35. Study Question: In patients with in-stent restenosis (ISR), several anatomic subgroups have been identified. The ISR affecting the stent edge (EDG) is a poorly characterized subgroup with undefined therapeutic implications. The investigators sought to determine the implications of ISR affecting the EDG. Methods: A total of 450 patients included in the Restenosis Intra-stent: Balloon angioplasty vs elective Stenting (RIBS) randomized study were analyzed. The EDG ISR was pre- defined in the protocol and the pattern of ISR analyzed in a centralized core laboratory. Results: Fifty-two patients (12%) had EDG ISR (29 stent group, 23 balloon arm). Patients with EDG ISR had less severe (minimal lumen diameter [MLD] [0.780.3 vs. 0.660.3 mm; p=0.05]) and shorter lesions (lesion length 10.26 vs. 13.27 mm; p=0.003). Patients with EDG ISR more frequently required crossover (12% vs. 3%; p=0.006) but eventually both the immediate angiographic result and the long-term clinical and angiographic outcomes were similar to that found in patients without EDG ISR. Patients with EDG ISR treated in the balloon and stent arms had similar baseline characteristics. However, after interven- tion, the immediate angiographic result was better in the stent arm (MLD 2.790.4 vs. 2.350.3 mm; p=0.001). This difference persisted at late follow-up: MLD (1.930.7 vs. 1.390.7 mm; p=0.01), recurrent restenosis (20% vs. 50%; p=0.03). In addition, the 1-year event-free survival was significantly better (83% vs. 52%, log rank p=0.01; Cox HR 0.28; 95% CI 0.09 – 0.79) in the stent arm. More- over, stent implantation was an independent predictor of freedom from target-vessel revascularization (HR 0.15; 95% CI 0.03– 0.67; p=0.003). Conclusions: The investigators concluded that in patients with EDG ISR, repeat stent implantation provides better clinical and angiographic outcome than conventional bal- loon angioplasty. Perspective: Patients with EDG ISR represent a relatively small but unique subgroup of patients, with major thera- peutic implications, thus allowing an early triage. The cur- rent study suggests that in these patients, repeat stenting provides better long-term clinical and angiographic results than does conventional balloon angioplasty and, therefore, may be the preferred approach. DM A Randomized Controlled Trial of Intravenous N- acetylcysteine for the Prevention of Contrast- Induced Nephropathy After Cardiac Catheterization: Lack of Effect Webb JG, Pate GE, Humphries KH, et al. Am Heart J 2004;148: 422–9. Study Question: What is the effectiveness of N-acetylcysteine in reducing the risk of contrast nephropathy following cardiac catheterization in patients with pre-existing base- line renal insufficiency? Methods: A total of 487 patients with baseline renal dys- function defined as glomerular filtration rate (GFR) of less than 50 mL/min were randomized in a blinded fashion to receive either 500 mg of N-acetylcysteine intravenously (242 patients) or to receive placebo (245 patients). The study drug was administered over 15 min starting within 1 h of the procedure and before the first injection of con- trast. The primary end point was a decline in creatinine clearance greater than 5 mL/min. Additional end points included: 1) change in glomerular filtration rate (GFR) 5 mL/min; 2) an increase in serum creatinine of 0.5 mg/dL; filtration rate (GFR) 5 mL/min; 2) an in- crease in serum creatinine of 0.5 mg/dL; cardiac catheter- ization using low-osmolarity contrast media, and all pa- tients received 200 mL of IV saline before contrast administration and 1.5 mL/kg/h of saline following the procedure for 6 h or until discharge. Results: No significant differences existed in the incidence of the primary end point (23.3% in the N-acetylcysteine group and 20.7% in the placebo group, p=0.51). There ACC CURRENT JOURNAL REVIEW February 2005 47