Clinical Research
Coronary Artery Disease
Quantification of Coronary Atherosclerosis and Inflammation to Predict Coronary Events and All-Cause Mortality

https://doi.org/10.1016/j.jacc.2010.10.043Get rights and content
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Objectives

This study sought to determine whether the evaluation of the combined presence of coronary artery calcium (CAC) and high-sensitivity C-reactive protein (hsCRP) improves discrimination and stratification of hard coronary events and all-cause mortality in the general population.

Background

Coronary atherosclerosis is a chronic inflammatory disease. Both hsCRP as a measure of inflammation and CAC as a measure of coronary plaque burden have been shown to improve risk appraisal.

Methods

Framingham risk variables, hsCRP, and CAC were measured in 3,966 subjects without known coronary artery disease or acute inflammation. After 5 years, incident coronary deaths, nonfatal myocardial infarction, and all-cause mortality were determined.

Results

CAC and hsCRP independently predicted 91 coronary events (adjusted hazard ratios [HRs]: log2(CAC+1) = 1.25 [95% confidence interval (CI): 1.16 to 1.34], p < 0.0001; hsCRP = 1.11 [95% CI: 1.02 to 1.21], p = 0.019) and 130 deaths (adjusted HRs: log2(CAC+1) = 1.12 [95% CI: 1.06 to 1.19], p < 0.0001; hsCRP = 1.11 [95% CI: 1.04 to 1.19], p = 0.004). For coronary events, net reclassification improvement (NRI) was 23.8% (p = 0.0007) for CAC and 10.5% (p = 0.026) for hsCRP. Adding CAC to Framingham risk variables and hsCRP further improved discrimination of coronary risk but not vice versa. Among persons without CAC, those with hsCRP >3 mg/l versus <3 mg/l had a significantly higher coronary risk (p = 0.006). For all-cause mortality, integrated discrimination improvement (IDI) was positive when CAC or hsCRP were added to age and sex (+0.51%, p < 0.001 and +0.43%, p = 0.012, respectively). Adjusted HRs in the highest versus lowest category of a risk index derived from established CAC and hsCRP thresholds (i.e., CAC = 100 and hsCRP = 3 mg/l) were 5.92 (95% CI: 3.14 to 11.16) for coronary events and 3.02 (95% CI: 1.82 to 5.01) for all-cause mortality (p < 0.0001 each). The adjusted HR for coronary events in intermediate risk subjects was 6.98 (95% CI: 2.47 to 19.73), p < 0.001.

Conclusions

The risk of coronary events and all-cause mortality that is mediated by the presence of coronary atherosclerosis and systemic inflammation can be estimated by CAC and hsCRP. An improvement in coronary risk prediction and discrimination was predominantly driven by CAC, whereas hsCRP appears to have a role especially in persons with very low CAC scores.

Key Words

all-cause mortality
coronary artery calcium (CAC)
coronary events
extended risk assessment
high-sensitivity C-reactive protein (hsCRP)

Abbreviations and Acronyms

AUC
area under the curve
BMI
body mass index
CAC
coronary artery calcium
CI
confidence interval
CVD
cardiovascular disease
EBCT
electron-beam computed tomography
FRS
Framingham risk score
HDL
high-density lipoprotein
HR
hazard ratio
hsCRP
high-sensitivity C-reactive protein
IDI
incremental discrimination improvement
LDL
low-density lipoprotein
NRI
net reclassification improvement

Cited by (0)

Supported by the Heinz Nixdorf Foundation, Germany (Chairman: Martin Nixdorf, past chairman: Dr. Jur G. Schmidt), the German Ministry of Education and Science (BMBF), and the German Aerospace Centre (Deutsches Zentrum für Luft- und Raumfahrt [DLR]), Bonn, Germany. Assessment of psychosocial factors and neighborhood-level information is funded by the German Research Council (DFG) (Project SI 236/8-1 and SI 236/9-1). Sarstedt AG & Co. (Nümbrecht, Germany) supplied laboratory equipment. The authors have reported that they have no relationships to disclose.