Patients with high Calcium Scores and Lipoprotein (a) levels are at the highest risk for cardiovascular events

Background High coronary artery calcium score (CACS) and Lipoprotein (Lp) (a) levels are individually associated with atherosclerotic cardiovascular (CV) disease, but their combination in the occurrence of CV events has not been investigated. Aim Investigate the association of CACS and Lp(a) in CV event´s prediction in a Portuguese population free of CV disease. Methods 1276 asymptomatic participants from our Research Unit dataset were included. CACS was determined and distributed into three categories: CACS 0, 1-99, and ≥100. Lp(a) levels were measured, the median determined (13.3 mg/dl) and two groups defined as low (below the median) and high (above the median). For the combination CACS and Lp(a), six groups were constructed: 1 - CACS 0 + Lp(a)≤ 13.3; 2 - CACS 0 + Lp(a)>13.3; 3 - CACS 1-99 + Lp(a)≤13.3; 4 - CACS 1-99 + Lp(a)>13.3; 5 - CACS≥100 + Lp(a)≤13.3 and 6 - CACS≥100 + Lp(a)>13.3. The outcomes involved a combination of all-cause vascular morbidity, acute coronary syndrome, myocardial infarction, unstable angina, revascularization (percutaneous or surgical), readmission due to heart failure or ischemic stroke and CV mortality. Demographic, traditional, clinical and biochemical risk factors were investigated. Bivariate analyses were made to assess its association with CV events. The independent association of CACS and Lp(a) models with atherosclerotic CV events risk was evaluated using adjusted Cox regression models. Survival events-free were evaluated using Kaplan-Meier estimate analysis. Results Only two combination groups (CACS≥100 + Lp(a)>13.3 and CACS≥100 + Lp(a)≤13.3) are significantly and independently associated with CV events risk with an HR of 3.99 (p=0.008) and HR=3.65 (p=0.013), respectively. However, when high Lp(a) is associated with high CACS, the risk vastly increases with greater significance. Survival at, approximately, 18 years presents the sixth group with the lowest survival time, followed by the fifth, with the first and second with the best survival free of CV events. Conclusion The joint association of CACS and Lp(a) is independently associated with CV events risk and survival time and may be used concurrently to guide primary prevention therapy decisions. Further research is needed to define algorithms that employ these quantitative assays optimally for cardiovascular risk stratification in appropriate cases.