P3432Coronary artery calcium score is of limited sensitivity in detecting subclinical atherosclerosis in young individuals with family history of coronary artery disease

Abstract

Abstract Introduction Family history of premature coronary artery disease (CAD) is known to predispose individuals to adverse CAD events, often at a younger age. Current risk stratification strategy is suboptimal, as up to 50% of individuals were considered “low-risk” prior to their first presentation of myocardial infarction. Coronary artery calcium score (CACS) is a marker of atherosclerosis and provides incremental value in risk stratification. However, the utility of CACS may be limited in younger patients as they often have non-calcified atherosclerotic plaques. In this study, we evaluate the sensitivity of CACS in detecting subclinical atherosclerosis in different age groups. Method From 310 referrals to a specialized unit in the management of early atherosclerosis, 222 individuals with a family history of premature CAD (defined as CAD events in first-degree family members, male<55 and female<65) and aged between 35 and 55 were enrolled for assessment of their CAD risks. Individuals with possible, probably or definite familial hypercholesterolemia were excluded. In addition to clinical and risk factor evaluation, cardiac CT and CACS were performed in select individuals, at the discretion of the treating physician. Results Of the 141 (59% male, mean age 45.9±6.0 year) individuals that completed clinical evaluation, 65 (73% male, mean age 47.4±6.9 years) have subclinical atherosclerosis (defined by the presence of atherosclerotic plaques in any of the coronary artery segments in cardiac CT). Of them, 52 have CACS>0, giving an overall sensitivity of 80%. The breakdown by age group is shown in table 1. The sensitivity of CACS in detecting subclinical atherosclerosis is quite modest in younger individuals (60% in individuals <45 year-old) but improves with patient age (>85% in >45 years). Table 1. Sensitivity of CACS in different age groups Age group True Positive Fast Negative Sensitivity N (CAC+ CTCA+) (CAC+ CTCA−) (%) <40 6 4 60 10 41–45 7 4 55 11 46–50 19 3 86 22 51–55 20 1 95 21 Conclusion In younger individuals (<45 years) with family history of premature CAD, CACS is of limited sensitivity in detecting subclinical atherosclerosis, and should not be used to rule out CAD. Further studies are warranted.