Background: Lipoprotein(a) (Lp(a)) is an independent, causal, genetic risk factor for cardiovascular disease (CVD). Coronary artery calcium (CAC), measured by computerised tomography (CT) scans, is a known marker for atherosclerosis. CT Agatston scores, also known as CAC scores, are thought to be better predictors of CVD than traditional risk factors. There is conflicting data regarding the relationship between Lp(a) levels and CAC. A preliminary study has suggested a positive association between Lp(a) and CAC scores within the United Kingdom population. Therefore, this study investigated the association between Lp(a) and coronary atherosclerosis, as measured by CAC, in a larger cohort. Traditional cardiovascular risk factors such as: diabetes mellitus and HbA1c levels, hypertension and smoking status as well as age and gender were also evaluated.
Methods: Data of 565 patients with recorded Lp(a) levels, CAC scores, age-and-gender-adjusted CAC percentiles and traditional cardiovascular risk factors were collected. Lp(a) levels <300 mg/l were considered normal. Patients were stratified according to CAC scores categorised into the following ranges: 0, >0400, >400 and across CAC percentile ranges of: 0, 175%, >75%. Variables were compared across the whole population and specifically in Caucasians and Asian Indians. Chi-squared tests were conducted.
Results: There was no significant association between Lp(a) levels and CAC scores along with corresponding CAC percentiles in the whole population and Asian subgroup. In the Caucasian subgroup, a significant association (P<0.05) was found between Lp(a) levels and CAC scores but not for the corresponding CAC percentiles. CAC scores and CAC percentiles significantly differed (P<0.05) with age and gender. Traditional cardiovascular risk factors were significantly associated (P<0.05) with higher CAC scores.
Conclusion: Although Lp(a) may be a good predictive biomarker for subclinical coronary atherosclerosis, as measured by CAC, in Caucasians, it was not in Asians.