Small coronary calcium deposits and elevated plasma levels of oxidized low density lipoprotein are characteristic of acute myocardial infarction

Aim: Predictions of the onset of acute myocardial infarction (AMI) in high risk individuals are of great clinical importance. Among various, risk factors, elevated levels of oxidized low density lipoprotein (ox-LDL) in plasma have been shown to reflect unstable coronary plaques. Coronary calcification is a common finding in the elderly, however, its clinical implications as a risk factor for plaque rupture are controversial. This study was designed to investigate the clinical implications of plasma ox-LDL levels and coronary calcification detected by electron-beam computed tomography (EBCT), by comparing patients with AMI with those with stable angina pectoris (SAP). Methods: We measured plasma ox-LDL levels in AMI (n = 34) and SAP (n = 49) patients. In addition, a coronary calcium score was quantified with the Agatston system. The total coronary calcium score (TCS) was defined as the sum of the scores for each lesion. Results: TCS and total calcium area were significantly smaller in patients with AMI than in those with SAP. On the other hand, plasma ox-LDL levels were significantly higher in AMI patients than in SAP patients (P < 0.0005). Conclusion: These results suggest that a combined assessment of coronary calcium and plasma ox-LDL levels may be useful for screening patients with unstable coronary plaques.