Background: Plasma lipoprotein (a) levels in the Indian population are varied; this study was undertaken to determine the relationship between plasma lipoprotein (a) levels and their phenotypes in a group of south Indian patients with coronary artery disease.
Methods and results: A total of 104 patients with angiographically proven coronary artery disease were compared with 104 age- and sex-matched controls with no risk factors such as hypertension, diabetes and smoking. Lipoprotein (a) levels were measured by an in-house ELISA method and its phenotyping was done by SDS agarose gel electrophoresis. Plasma lipoprotein (a) levels were significantly elevated in patients with coronary artery disease as compared to controls (33.4+/-26.1 mg/dl v. 21.4+/-12.8 mg/dl; p<0.01). Lipoprotein (a) phenotyping showed that low-molecular weight isoforms were found only in 19.2% of the patients with coronary artery disease and their plasma lipoprotein (a) levels were significantly elevated compared to coronary artery disease patients with higher molecular weight isoforms (50.9+/-34.2 mg/dl v. 29.24+/-20.06 mg/dl; p<0.001).
Conclusions: Plasma lipoprotein (a) levels are significantly elevated in patients with coronary artery disease as compared to controls. The commoner phenotype in a South Indian population is the larger apolipoprotein (a). in which the lipoprotein (a) levels are lower. Hence the contribution of lipoprotein (a) phenotype to the lipoprotein (a) levels in our population, if any, is modest.