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

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.