Imaging for subclinical atherosclerosis improved cardiovascular risk prediction beyond conventional factors, with coronary artery calcification showing the highest added value (NRI 14% to 25%).
Systematic Review (n=25)
Does imaging for subclinical atherosclerosis improve risk prediction for fatal or non-fatal cardiovascular events in asymptomatic individuals compared to conventional risk factor assessment alone?
Imaging for subclinical atherosclerosis, particularly CAC and carotid plaque, provides added predictive value for cardiovascular events beyond conventional risk factors, especially in asymptomatic individuals at intermediate risk.
Effect estimate: c-index difference 0.05-0.13 and NRI 14-25% for CAC
CONTEXT: Imaging for subclinical atherosclerosis on top of conventional risk factor assessment may improve risk prediction for the occurrence of cardiovascular disease events in asymptomatic individuals. OBJECTIVE: To systematically review the available evidence on this issue. DATA SOURCES: PubMed MEDLINE was systematically searched on 7 September 2011. STUDY SELECTION: Studies were included that evaluated the added value of flow mediated dilation (FMD), carotid intima-media thickness (CIMT), carotid plaques and/or coronary artery calcification (CAC) scoring in the prediction of risk for developing fatal or non-fatal cardiovascular events. DATA EXTRACTION: Data on general study characteristics and the added predictive performance of imaging markers in terms of discrimination, calibration and (re)classification were extracted. RESULTS: 25 studies were selected that provided information on added predictive value of FMD (n=2), CIMT (n=12), carotid plaques (n=6) and/or CAC (n=9). Heterogeneity existed across studies in the conventional risk models that were used and in the measurements of the imaging marker. The added predictive value, quantified by the difference in c-index, of FMD, CIMT, carotid plaques or CAC ranged from 0.00 to 0.01 for FMD, from 0.00 to 0.03 for CIMT, from 0.01 to 0.05 for carotid plaque and from 0.05 to 0.13 for CAC. The reported net reclassification improvement (NRI) by the imaging markers ranged from -1.4% to 12% for CIMT, 8% to 11% for carotid plaques, 14% to 25% for CAC and 29% for FMD). Although the definition of intermediate cardiovascular risk varied across studies, the NRI was the highest in those at intermediate cardiovascular risk. CONCLUSIONS: Published evidence on the added value of atherosclerosis imaging varies across the different markers, with limited evidence for FMD and considerable evidence for CIMT, carotid plaque and CAC. The added predictive value of additional screening may be primarily found in asymptomatic individuals at intermediate cardiovascular risk. Additional research in asymptomatic individuals is needed to quantify the cost effectiveness and impact of imaging for subclinical atherosclerosis on cardiovascular risk factor management and patient outcomes.
Peters et al. (Thu,) conducted a systematic review in Subclinical atherosclerosis in asymptomatic individuals (n=25). Imaging for subclinical atherosclerosis (FMD, CIMT, carotid plaques, CAC) vs. Conventional risk factor assessment was evaluated on Added predictive performance (discrimination, calibration, reclassification) for fatal or non-fatal cardiovascular events (c-index difference 0.05-0.13 and NRI 14-25% for CAC). Imaging for subclinical atherosclerosis improved cardiovascular risk prediction beyond conventional factors, with coronary artery calcification showing the highest added value (NRI 14% to 25%).
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