Improvement in Primary Prevention of Cardiovascular Disease Using Novel Risk Markers
September 30, 2012 4 minutes read
Improvement in Primary Prevention of Cardiovascular Disease Using Novel Risk Markers
Abstract & Commentary
By Harold L. Karpman, MD, FACC, FACP
Clinical Professor of Medicine, UCLA School of Medicine
Dr. Karpman reports no financial relationships relevant to this field of study.
Synopsis: Coronary artery calcium, ankle-brachial index, high-sensitivity CRP, and family history are all independent predictors of incident coronary heart disease/cardiovascular disease in intermediate-risk individuals. Coronary artery calcium scoring provided superior discrimination and risk reclassification compared with the other risk markers.
Source: Yeboah J, et al. Comparison of novel risk markers for improvement in cardiovascular risk assessment in intermediate-risk individuals. JAMA 2012;308:788-795.
CURRENT TRENDS AND GUIDELINES FOR THE PRIMARY PREvention of cardiovascular disease (CVD) have emphasized the need to treat individuals based on their global cardiovascular risk.1 There are few clinical questions about how to treat low-risk and/or high-risk subjects. However, the most major current concerns are about how to treat the intermediate-risk subjects, especially since many of these patients will fall either into low-risk or high-risk categories if appropriate risk markers are determined and utilized.
The risk markers under consideration include the coronary artery calcium score (CAC), carotid intima-media thickness, ankle-brachial index, brachial flow-mediated dilatation, high-sensitivity C-reactive protein (CRP), and family history of coronary heart disease (CHD). Yeboah and his colleagues observed that the clinical significance of these six risk markers had never been compared for CVD risk prediction in a single cohort. Therefore, they conducted a study2 to compare improvement in prediction of incident CHD/CVD utilizing these six risk markers within the intermediate-risk group among the participants of the Multi-Ethnic Study of Atherosclerosis (MESA). They determined that the CAC score, ankle-brachial index, high-sensitivity CRP, and family history were all independent predictors of incident CHD/CVD among the intermediate-risk subjects and the CAC score provided superior discrimination and risk reclassification when compared to the other risk markers.
Commentary
Current standard practice guidelines recommend classifying individuals as high, intermediate, or low CVD risk using the Framingham Risk Score (FRS) or other similar CVD risk prediction models.3,4 However, there has been an increasing recognition of the imprecision of these classifications based solely on the FRS because the intermediate-risk group includes both a composite of higher-risk individuals for whom more aggressive drug therapy should be utilized and lower-risk individuals whose CVD risk should be managed only with lifestyle measures and not with drugs. Therefore, it makes the most sense to have additional proven risk markers to help reclassify and guide more specific therapy for these intermediate-risk individuals.
The Yeboah study2 suggests that compared to other risk markers, the CAC score provides the highest improvement in discrimination over the FRS in subjects who have been classified as intermediate risk. These findings have also been confirmed in multiple other studies.5 Of course, it must be recognized that the CAC scoring procedure is burdened with a small but nontrivial amount of ionizing radiation (approximately 0.9-1.1 mSv). However, this dose will almost certainly be reduced in the future because major efforts have been made to standardize equipment and imaging protocols in order to reduce radiation exposure during CAC imaging. Some authors remain concerned about the magnitude of long-term cancer risks, since even the lowest possible radiation dose during CAC imaging could possibly translate into a large number of avoidable cancers if CAC scoring were to be uniformly applied to the estimated 23 million adults in the United States currently classified in the intermediate-risk category by the FRS.6 It should be recognized that the CAC score changes very slowly; therefore, obtaining a baseline score that rarely is repeated in less than 5 to 7 years will provide invaluable information in the primary prevention of CVD. A zero CAC score is an extremely important negative-predictive value risk marker and an elevated CAC score adds important information in determining when to institute statin therapy, especially in patients who have elevated total cholesterol/LDL cholesterol levels, known CAD, and/or diabetes mellitus.
In summary, the results of the Yeboah study2 confirm many previous studies suggesting that a CAC score is one of the most valuable risk markers that can be used in the primary prevention of CAD, especially in intermediate-risk subjects. Recognizing the small radiation risk and the economic cost of the study, it should be used as frequently as possible in intermediate-risk patients unless there are specific contraindications to its use from a medical and/or economic point of view.
References
1. Hayward RA, et al. Ann Intern Med 2010;152:69-77.
2. Yeboah J, et al. JAMA 2012;308:788-795.
3. Collins, GS. BMJ 2009;339:b2584.
4. Expert panel on detection, evaluation, and treatment of high blood cholesterol in adults. JAMA 2001;285: 2486-2497.
5. Kavousi M, et al. Ann Intern Med 2012;156:438-444.
6. Ford ES, et al. J Am Coll Cardiol 2004;43:1791-1796.
Coronary artery calcium, ankle-brachial index, high-sensitivity CRP, and family history are all independent predictors of incident coronary heart disease/cardiovascular disease in intermediate-risk individuals. Coronary artery calcium scoring provided superior discrimination and risk reclassification compared with the other risk markers.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content