Prevalence of subclinical coronary artery atherosclerosis in the general population- apollo subclinical coronary atherosclerosis project (ASCAP)

Abstract

Abstract Background Coronary artery disease (CAD) is a major cause of mortality and morbidity in our country. CAD affects Indian population at least a decade earlier than the people of European ancestry, often impacting the most productive years of an individual’s life. CAD is often silent or may strike without warning, underscoring the importance of prevention. We used computerized tomography (CT) coronary angiography (CT-CAG) to determine the prevalence, severity, and characteristics of CAD and its association with coronary artery calcium (CAC) scores in general population. Purpose Detection of coronary atherosclerosis using CT-CAG, in addition to CAC score, may help in early preventive strategies. In doing so, we can identify population at risk at an early stage and manage them accordingly either by lifestyle modifications, medications or if needed further intervention. Methods This study included 451 individuals aged 40 years and above with no known CAD (no previous myocardial infarction or cardiac procedures) and with high-quality results from CT-CAG. Non-contrast images were used for calculating CAC score. CT-CAG was reported per segment, defined as- no atherosclerosis, 1% to 49% stenosis (insignificant atherosclerosis), or ≥50% stenosis (significant atherosclerosis). Results Out of the 451 individuals, 72% were men and 27.9% were women. Any CT-CAG detected atherosclerosis was found in 60%; any significant stenosis (≥50%) in 27.7%; no stenosis in 39.9% and any noncalcified plaque <50% in 32.3% of this population. (Table 1) Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending (LAD) artery. Prevalence of CT-CAG detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all the individuals had atherosclerosis and 95.8% had significant stenosis. In those with zero CAC score, 59.4% had no atherosclerosis and 7.5% had significant stenosis. (Table 2) Conclusion Using CT-CAG in a large sample of the general population without CAD, has shown that silent coronary atherosclerosis is more common than expected. High CAC scores convey a significant probability of substantial stenosis, and zero CAC score does not exclude atherosclerosis, particularly in those at higher baseline risk.