To assess the impact of cardiovascular risk scores in acute coronary syndrome(ACS), we analyzed 90 consecutive patients who underwent intervention. Standard IVUS measures were performed each 1 mm. TIMI (Thrombolysis in myocardial infarction) risk score and GRACE (Global registry of acute coronary events) score assessment in individual patients were determined. Results:Pts age were 59.37짹12.08yrs in STEMI vs 63.32짹9.08yrs in UA/NSTEMI(p=0.08), and 15.7% were diabetic in STEMI vs 32.4% in UA/NSTEMI. TIMI risk score was correlated with GRACE score(r=0.466, p=0.0006 in STEMI, r=0.394, p=0.0158 in UA/NSTEMI), however, both of GRACE score(p=0.01) and TIMI risk score(p=0.0079) were higher in STEMI. As shown in the table, minimal lumen area was similar and the plaque area was greater in STEMI(11.38짹5.35 mm2 vs 9.10짹4.22 mm2, p=0.036), however external elastic membrane area was larger(p=0.028). The patients with a higher risk score ( ���3 TIMI risk score or ���150 GRACE score) showed larger calcium(p=0.043 in STEMI, p=0.4027 in UA/NSTEMI). Maximum calcium was correlated with GRACE score in STEMI (r=0.2328, p=0.033).Conclusion:IVUS measured atherosclerosis may contribute to events that are predicted by these commonly used primary risk-assessment algorithms.