Comparative Value of Coronary Artery Calcium and Multiple Blood Biomarkers for Prognostication of Cardiovascular Events

Study Questions:

What is the added value of coronary artery calcium (CAC) scoring for prediction of cardiovascular (CV) events compared to a panel of plasma biomarkers?

Methods:

A total of 1,286 asymptomatic participants without known coronary artery disease (CAD) were followed 4.1 ± 0.4 years for the primary outcome of combined CV disease (CVD) (cardiac death, myocardial infarction [MI], stroke, and late target vessel revascularization). CAC was calculated by the method of Agatston. Biomarkers measured were C-reactive protein, interleukin-6, myeloperoxidase, B-type natriuretic peptide, and plasminogen activator-1.

Results:

Thirty-five participants developed CVD events including cardiac deaths (6%), MI (23%), strokes (17%), and late revascularizations (54%). After adjusting for Framingham risk score (FRS), presence of log CAC beyond FRS was associated with increased hazards for CVD events (hazard ratio, 1.7; p < 0.001). Multiple biomarker score was also associated with increased risk beyond FRS (hazard ratio, 2.1; p = 0.02) per 1-U increase in score; however, the c-statistic did not increase significantly (0.75; p = 0.32). The c-statistic increased when log CAC was incorporated into FRS without or with multiple biomarker score (c-statistic, 0.84; p = 0.003 and p = 0.008). Addition of CAC to risk factors showed significant reclassification improvement (p = 0.007), whereas addition of multiple biomarker score did not.

Conclusions:

The authors concluded that in asymptomatic subjects without known CVD, addition of CAC, but not biomarkers, substantially improved risk reclassification for future CVD events beyond traditional risk factors.

Perspective:

CAC scoring is appealing for risk stratification because it is a noninvasive, direct measure of a vasculopathic process. This study demonstrates that CAC scoring may add additional prognostic information to conventional risk scoring methods, and performs better than a panel of plasma biomarkers. CAC scoring may be useful if it proves to be a cost-effective means to identify additional subjects who will achieve benefit from preventive therapies such as statins.

Keywords: Prognosis, Natriuretic Peptides, Coronary Artery Disease, Myocardial Infarction, Stroke, C-Reactive Protein, Biomarkers, Plasminogen, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Interleukin-6, Peroxidase


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