There is a lack of consensus among cardiologists regarding the length of time patients should be hospitalized after an uncomplicated acute myocardial infarction (AMI) and successful direct percutaneous coronary intervention (d-PCI). The purpose of this study was to evaluate the feasibility and safety of early discharge (discharge <4 days after the procedure) for low risk patients with AMI who underwent successful d-PCI. From May 1996 through December 2001, d-PCI was performed in 898 consecutive patients with AMI Of these 898 patients, 463 (51.6%) were stratified to be at low risk. Lower risk was defined as: (1) Killip classification less than or equal to2 on admission; (2) the infarct-related artery achieved normal blood flow without recurrent ischemia or reinfarction in the first 24 hours; (3) no mechanical or electrical complications after d-PCI, (4) no acute renal failure, acute stroke, or major bleeding cornplication; (5) no advanced congestive heart failure (defined asgreater than or equal toNew York Heart Association functional class 3); and (6) no sepsis. Patients who were discharged <4 days after undergoing the procedure were enrolled in group 1 (n=266). Patients who were discharged >= 4 days after undergoing the procedure were enrolled in group 2 (n=197). Univariate analysis demonstrated that group 2 patients had a significantly longer hospital stay (P=0.0001) than group I patients. At the first 30-day follow-up examination, there were no significant differences in the combined major cardiac events (death, recurrent ischemia, reinfarction, revascularization, or advanced congestive heart failure) between the group I and group 2 patients (1.50% vs 1.52%, P=0.92). There were also no significant differences in the combined major noncardiac complications (acute stroke, acute renal failure, bleeding complications requiring blood transfusion, vascular sequelae, or sepsis) between the group I and group 2 patients (1.13% vs 0.51%, P=0.89). Early discharge was feasible in a majority of the patients who experienced AMI and were at lower risk 24 hours after successful d-PCI. Thus, the patients had a shortened hospital stay and no increased risk.