Diagnostic Value of Coronary Artery Calcium Score for Cardiovascular Disease in African Americans: The Jackson Heart Study

Abstract

BackgroundThe role of coronary artery calcium (CAC) as a screening tool for cardiovascular disease (CVD) risk in African Americans (AAs) is unclear. We compared the diagnostic accuracy for CVD prevalence using the CAC score and the Framingham Risk Score (FRS) in an adult population of AAs.MethodsCAC was measured in 2944 participants AAs. Approximately 8% of this cohort had known CVD defined as prior myocardial infarction, stroke, percutaneous coronary intervention, coronary artery bypass grafting and peripheral artery disease. Logistic regression, receiver operating characteristic (ROC) and net reclassification index (NRI) analysis were used adjusting for age, gender, systolic blood pressure (SBP), total and high-density lipoprotein (HDL) cholesterol, smoking status, diabetes mellitus (DM), body mass index (BMI), blood pressure medication and statin use. Participants with prevalent clinical CVD and DM were classified as high FRS risk.ResultsThe mean age of participants was 60 years, 65% were females, 26% had DM, 50% were obese and 30% were current or former smokers. Prevalent CVD was associated with older age, higher SBP, lower HDL and total cholesterol, and higher CAC. The prevalence of CAC was 83% in participants with prevalent CVD and 45% in those without CVD. CAC was independently associated with prevalent CVD in our multivariable model [OR (95% CI): 1.22 (1.12–1.32), p< 0.0001]. In ROC analysis, CAC improved the diagnostic accuracy (c statistic) of the FRS from 0.617 to 0.757 (p < 0.0001) for prevalent CVD. Addition of CAC to FRS resulted in net reclassification improvement of 4% for subjects with known CVD and 28.5% in those without CVD.ConclusionIn AAs, CAC is independently associated with prevalent CVD and improves the diagnostic accuracy of FRS for prevalent CVD by 14%. Addition of CAC improves the NRI of those with prevalent CVD by 4% and the NRI of individuals without CVD by 28.5%. Determination of CAC may be useful in CVD risk stratification in AAs.

Subclinical Atherosclerosis, Statin Eligibility, and Outcomes in African American Individuals

“…Therefore, we relied on detection of vascular calcification at visit 2 (median interval between visit 1 and 2: 4.5 years; interquartile range 4.3–5.0 years). Heart and abdominal imaging was obtained with a 16-channel multi-detector CT using a prospective ECG-triggered protocol (Lightspeed 16 Pro; GE Healthcare, Milwaukee, WI), as published 10,17 . Quality control and image analysis were performed by a central core laboratory.…”

“…Recent data from the Framingham Heart Study suggest that statin eligibility by ACC/AHA guidelines more effectively identify Caucasians with coronary artery calcification and long-term CVD events 7 . Despite a lower prevalence of vascular calcification in African Americans 9 , the presence of coronary calcium appears to identify Blacks at higher risk for CVD, incremental to older risk estimates (Framingham risk score 10 ). Therefore, a critical next step is to determine whether newer clinical guidelines that more broadly advocate statin therapy for primary prevention accurately identify African Americans with high-risk vascular phenotypes and high downstream risk and whether measurement of vascular calcium provides additional information.…”

Coronary Calcium Score and Cardiovascular Risk

“…The Jackson Heart Study measured CAC during follow-up. Among African Americans, CAC predicted risk beyond the traditional risk factors and has been shown to better identify individuals most likely to benefit from preventive therapies (64,65).…”

Relative predictive value of lung cancer screening CT versus myocardial perfusion attenuation correction CT in the evaluation of coronary calcium

“…For CCT, LCSCT, and ACCT scans, CACS was calculated using the Agatston method[ 7 ]. Coronary artery calcium scoring was performed using previously described methods for other epidemiologic studies[ 8 , 9 ], and images were viewed and scored using a Carestream Vue PACS (Carestream Health) imaging workstation. In brief, the calcium scoring application in the Carestream Vue PACS displays axial image slices for the reader.…”

“…ECG-gated CCT defines coronary calcium by a threshold attenuation coefficient measurement of 130 Hounsfield units (HU) with an area of ≥1 mm 2 , and CACS are then determined by the product of calcified plaque area and relative density as determined by attenuation[ 7 ]. Other large epidemiologic studies have used a threshold of 130 HU with an area of ≥1.48 mm 2 to identify coronary calcium[ 8 , 9 ]. In line with the goals of precision medicine, the addition of coronary artery calcium score to prediction models based on traditional risk factors significantly improves risk stratification and can place more individuals in the most extreme risk categories, thus having potential to influence decision making with regards to medical therapy[ 10 , 11 ].…”