OBJECTIVE: Post-acute coronary syndrome (post-ACS) patients experience very different survival patterns during the acute and chronic phases of their illness. To provide a clinically relevant life expectancy estimate for post-ACS patients and subgroups of unstable angina (UA) and recent (<6 week) myocardial infarction (MI) patients, we developed a two-component survival model which accounted for differences in acute and chronic survival and also extrapolated beyond the available follow-up data. METHODS: We included UA and MI patients who received an initial coronary angiography (cath) at Duke University Medical Center between 3/84 and 12/97. Patients with previous cardiac procedures or valvular disease were excluded. We defined the acute post-ACS phase as lasting from the initial cath through 1 year follow-up and chronic phase as the second follow-up year through end of life. RESULTS: Our population contained 10,398 patients with 12-year follow-up 95% complete. Initial treatment strategy, age, body mass index, history of diabetes, cerebral or peripheral vascular disease, and congestive heart failure were predictive of both acute and chronic phase survival (p <0.05). Recent MI and year of initial cath were predictive of acute phase survival whereas history of MI and smoking were predictive of chronic phase survival (p <0.05). While acute phase mortality was greater in MI than in UA patients (11.2% vs. 7.1%%), 12 year cumulative mortality was nearly identical (49.2% MI vs. 49.8% UA) in the two groups. Average post-ACS life expectancy was 15.604 years (15.460 UA and 15.649 MI). CONCLUSIONS: Despite significant differences in acute phase mortality, UA and MI patients have similar life expectancies.