PREDICTION OF THE SEVERITY OF CORONARY-ARTERY DISEASE BY MEASUREMENT OF LIPOPROTEIN (A)

Background: A number of clinical studies have shown that high serum lipoprotein (a) [Lp(a)] levels are associated with coronary artery disease (CAD). It is, however, unclear whether increased serum concentration of Lp(a) alone is a significant risk factor for CAD. Methods: We studied 120 consecutive patients who underwent selective coronary angiography: 34 with old myocardial infarction, 47 with angina pectoris, and 39 without ischemic heart disease. Results: Serum Lp(a) concentrations measured by an enzyme immunoassay method were significantly higher in both the myocardial infarction (mean 23.5 mg/dL, P < 0.01) and angina pectoris (22.6 mg/dL, P < 0.05) groups than in the no ischemic heart disease group (14.1 mg/dL). On multiple regression analysis with Friesinger's severity score (F score) as the criterion variable, the factors that were independently related to F score were Lp(a) (standard regression coefficient [beta] = 0.326, P < 0.01), high-density lipoprotein cholesterol (-0.251, P < 0.01), and low-density lipoprotein cholesterol (0.225, P < 0.01); other coronary risk factors were not related to the score. Serum Lp(a) levels rose as the number of affected arteries (greater-than-or-equal-to 75% stenosis) increased (13.3, 21.7, 21.8, and 30.1 mg/dL for zero, one, two, and three affected vessels, respectively). Very similar results were obtained in 78 selected subjects with normal serum cholesterol (< 220 mg/dL). Conclusions: We conclude that Lp(a) is an independent risk factor for CAD and further predicts its severity.