Lipoprotein(a) Is Related to the Extent of Lesions in the Coronary Vasculature and to Unstable Coronary Syndromes

BACKGROUND: Lp(a) is a highly atherogenic particle with a prothrombotic effect. Until now its relation to the extent and severity of the atheromatic lesions had not been established by standard procedures. HYPOTHESIS: This study examined the correlation of Lp(a) to the extent and severity of coronary artery disease (CAD) and its relation to unstable clinical events (not including sudden death). METHODS: In 202 patients undergoing coronary angiography, plasma lipids were measured with the usual procedures and Lp(a) with the enzyme-linked immunosorbent assay. The extent of CAD was expressed in the number of diseased vessels and its severity in terms of the severity coefficient and the obstruction coefficient. RESULTS: A very strong relationship between LP(a) and the number of diseased vessels (p = 0.0007) signifying diffuse atherosclerosis, but no relation with the severity of the lesions. was found. However, it was the only lipid that correlated significantly with the number of totally occluded vessels (p = 0.0003). The thrombogenic ability of Lp(a) was manifested by increased incidence of myocardial infarction and unstable angina episodes in patients with elevated Lp(a) (p = 0.0157). CONCLUSION: Elevated Lp(a) predisposes to the extent of CAD and total occlusions but not to the severity of lesions. Patients with increased Lp(a) levels and unstable angina are at increased danger of suffering myocardial infarction. Thus, Lp(a) may predispose to plaque destabilization and thrombosis of noncritical lesions.