BACKGROUND: Practice guidelines for non-ST-segment elevation acute coronary syndromes (NSTE ACS) recommend early invasive management (cardiac catheterization and revascularization within 48 hours of hospital presentation) for high-risk patients, but interhospital transfer is necessary to provide rapid access to revascularization procedures for patients who present to community hospitals without revascularization capabilities. METHODS: We analyzed patterns and factors associated with interhospital transfer among 19,238 patients with NSTE ACS (positive cardiac markers and/or ischemic ST-segment changes) from 124 community hospitals without revascularization capabilities in the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines quality improvement initiative from January 2001 through June 2004. RESULTS: Less than half of the patients (46.3%) admitted to community hospitals were transferred to tertiary hospitals, and fewer (20%) were transferred early (within 48 hours of presentation). Early transfer rates increased by 16% over 10 quarters in patients with a predicted low or moderate risk of inhospital mortality, compared with 5% in high-risk patients. By the last quarter of the analysis, 41.4% of low-risk patients were transferred early versus 12.5% of high-risk patients. Factors significantly associated with early transfer included younger age, lack of prior heart failure, cardiology inpatient care, and ischemic ST-segment electrocardiographic changes. Among patients who were not transferred, 29% had no further risk stratification performed with stress testing, ejection fraction measurement, or diagnostic cardiac catheterization (at hospitals with catheterization laboratories). CONCLUSIONS: Most patients with NSTE ACS presenting to community hospitals without revascularization capabilities are not rapidly transferred to tertiary hospitals, and lower-risk patients appear to be preferentially transferred early. Further investigation is needed to determine if improved risk-based triage at community hospitals can optimize transfer decision making for high-risk patients with NSTE ACS.