Relationship of subclinical coronary atherosclerosis and National Cholesterol Education Panel guidelines in asymptomatic Brazilian men

Abstract

Background and objective: Coronary heart disease (CHD) is the leading cause of death worldwide including Brazil. Improved precision in detecting early coronary disease may aid in more targeted preventive therapy. The National Cholesterol Education Program (NCEP) provides guidelines for determining the aggressiveness of primary prevention strategies including lipid lowering based on Framingham risk equation. Identification of subclinical atherosclerosis and coronary plaque burden is a step towards identifying high-risk individuals. This investigation was designed to determine how the updated NCEP guidelines classify asymptomatic individuals with presence of any as well as advanced CACS (coronary artery calcium score), a powerful intermediary for CHD events, in asymptomatic Brazilian men.

Methods and results: Five hundred forty-six asymptomatic Brazilian men (mean age: 46+/-7 years) presented to a single electron beam tomography (EBT) facility in Sao Paulo. The study population was categorized into low risk (0-1 risk factors, n=166, 30%), intermediate risk (> or = 2 risk factors but < 10% risk of CHD over 10 years, n=150, 27%), moderately high risk (2 risk factors and 10-20% risk of hard CHD events in 10 years, n=147, 28%) and high-risk (> or = 2 risk factors and > 20% risk of hard CHD events in 10 years, n=83, 15%), respectively. In our study population, overall no CACS, mild CACS (1-99.9), moderate-severe CACS (> or = 100) were observed in 317 (58%), 160 (29%) and 69 (13%) men, respectively. Advanced calcification (CACS > or = 75th percentile for age) was present in 19% (n=104) men. Based on the LDL-C cutoffs recommended by the NCEP guidelines for initiation of lipid lowering, overall only 55% with CACS > or = 100 and 42% men with CACS > or = 75th percentile qualified for pharmacotherapy. As a result nearly half of individuals with CACS > or = 100 (45%) and CACS > or = 75th percentile (48%) missed eligibility for drug therapy.

Conclusion: Our findings reveal the potential limitation of NCEP guidelines in identifying asymptomatic Brazilian men with significant coronary atherosclerosis who are potential candidates for aggressive primary prevention. Assessment of CACS may provide incremental value to global risk assessment in high-risk Brazilian men.