Role of noninvasive imaging in asymptomatic high-risk patients

New sequential algorithm using Mac-2 binding protein glycosylation isomer to detect advanced carotid artery atherosclerosis

Background

Although carotid artery sonography is widely performed, most guidelines do not recommend this procedure in the general population. Appropriate indications and effective algorithms are needed to detect advanced carotid artery atherosclerosis in a community setting.

Methods

This study was designed as cross-sectional study. Adult subjects (n=228) who underwent a health check-up at our healthcare centre were included in the final analysis. Mac-2 binding protein glycosylation isomer (M2BPGi) quantification was based on a lectin antibody sandwich immunoassay. Subclinical atherosclerosis was diagnosed by carotid ultrasonography.

Results

The prevalence of subclinical atherosclerosis and advanced atherosclerosis was 37.2% (85/228) and 11.8% (27/228), respectively, in a community-based setting. Serum M2BPGi level was significantly higher in subjects with calcified plaque (0.6317) and luminal stenosis (0.6373) than in control groups (0.4913, all P<0.05). Pearson correlation analysis between M2BPGi and atherosclerotic cardiovascular disease (ASCVD) risk index (R=0.410, P<0.001) showed a positive relationship. The AUROC of serum M2BPGi for identifying calcified plaque or luminal stenosis was 0.679. The sequential algorithm using ASCVD and M2BPGi showed good negative predictive value (NPV) (93.6%) and reasonable positive predictive value (PPV) (53.8%) for identifying calcified plaque or luminal stenosis. When the sequential algorithm was used as an indicator for carotid ultrasonography, 35.0% (14/40) of subjects with intermediate-risk by ASCVD (≥7.5%) could avoid unnecessary carotid ultrasonography.

Conclusions

The sequential algorithm using ASCVD (≥7.5) and M2BPGi (≥0.525) provided reasonable indication for carotid artery sonography in a community-based setting.

Early identification of atherosclerotic disease by noninvasive imaging

Cardiovascular disease (CVD) is the leading cause of death worldwide, and its prevalence is expected to increase further, which will be associated with a substantial economic burden. High-risk or vulnerable plaques and, indirectly, the burden of atherosclerotic disease, are responsible for most major cardiovascular events. Most of the current prevention strategies are focused on identifying and managing the established risk factors (smoking, hypertension, hypercholesterolemia, diabetes, obesity, physical inactivity) for atherosclerosis. Another opportunity for further characterizing the population at high CVD risk would be to measure the occurrence and progression of subclinical (asymptomatic) atherosclerotic burden. The detection of subclinical atherosclerosis and high-risk plaques, if proven to predict cardiovascular events, may enable the establishment of earlier control of CVD risk factors and help preventing CVD. In this Review, we address the potential progress in CVD prevention brought about by the use of noninvasive imaging techniques to identify subclinical atherosclerosis.

Induced cardiovascular procedural costs and resource consumption patterns after coronary artery calcium screening: results from the EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) study

OBJECTIVES

We prospectively evaluated procedural costs and resource consumption patterns in the EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) study after coronary calcium (CAC) measurements.

BACKGROUND

Controversy surrounds expansion of cardiovascular disease (CVD) screening to include atherosclerosis imaging as the result of concern whether induced costs will outweigh any benefit.

METHODS

Detailed risk factor and CAC measurements with 4-year follow-up for CVD death or myocardial infarction and procedures were performed. Costs were estimated with the use of Medicare reimbursement rates (discounted and inflation corrected). Cox survival analysis was used to estimate procedures and events.

RESULTS

CAC scores varied widely but were skewed toward low scores with 56.7% of screened subjects having CAC scores<or=10 and only 8.2% having CAC scores>or=400. Noninvasive testing was infrequent and medical costs were low among subjects with low CAC scores, both rising progressively with increasing CAC scores (p<0.001), particularly in the 31 (2.2% of subjects) that had CAC scores>or=1,000. Similarly, invasive coronary angiography rose progressively with increasing scores (p<0.001) but occurred exclusively among subjects first undergoing noninvasive testing and overall, was performed in only 19.4% of subjects with CAC scores>or=1,000.

CONCLUSIONS

CAC scanning is associated with a marked differential in downstream frequency of medical tests and costs, ranging from a very low frequency of testing and invasive procedures among a predominantly large percentage of subjects with low CAC scores, to selectively concentrated testing and procedures among a small number of subjects with CAC scores>400. Thus, CAC scanning appears to foster efficient selective testing patterns among asymptomatic individuals at risk for CVD.