[Coronary heart disease and lipoprotein (a): relationship with other lipid cardiovascular risk factors]

Abstract

Background: Lipoprotein (Lp) (a) is considered a risk factor for early coronary heart disease (CHD), and a discriminant cutoff of Lp(a) concentration has been suggested.

Methods: Serum Lp(a) concentrations have been determined by enzymoimmunoassay in 66 men with CHD and in 100 healthy control men. Serum cholesterol, serum triglycerides, high density lipoprotein (HDL)-cholesterol, and apoprotein (apo) A-I were also determined.

Results: Serum Lp(a) concentration was 21.7 +/- 16.9 mg/dl (mean +/- SD) in patients and 12.5 +/- 12.5 mg/dl in controls (p less than 0.001). Serum cholesterol was 5.63 +/- 1.22 mmol/l and 5.29 +/- 1.00 mmol/l (p less than 0.05) respectively; serum triglycerides were 1.99 +/- 1.23 mmol/l and 1.29 +/- 0.61 mmol/l (p less than 0.001) respectively; HDL-cholesterol was 0.97 +/- 0.27 mmol/l and 1.07 +/- 0.30 mmol/l (p less than 0.05) respectively; and apo A-I was 94 +/- 15 mg/dl and 144 +/- 41 mg/dl (p less than 0.001) respectively. Lp(a) concentrations were not correlated with other well-recognized cardiovascular risk lipidic factors, nor influenced by age either body mass index. Using 20 mg/dl as discriminant Lp(a) concentration between patients and controls, a ratio 2:1 in patients with respect to controls has been observed and exceeded some more when the threshold level was put on 30 mg/dl. A subset of normocholesterolemic and normotriglyceridemic patients (n = 17) and controls (n = 49) had serum Lp(a) concentration of 22.7 +/- 16.3 mg/dl and 9.1 +/- 8.2 mg/dl (p less than 0.001) respectively.

Conclusions: Increased concentration of Lp(a) constitutes an independent risk factor for CHD. On the other hand, Lp(a) concentrations of 20 mg/dl or 30 mg/dl as risk threshold levels are well-defined.