Nongated Chest CT Calcium Scores Accurately Predict Cardiovascular Risk: Study
USA: Researchers have found in an analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) that coronary artery calcium (CAC) scores obtained from nongated chest CT scans appear to predict cardiovascular risk as effectively as scores from ECG-gated CT scans.
Clinical implication: Routine nongated chest CT scans may provide a convenient opportunity to assess CAC and improve cardiovascular risk stratification without requiring a dedicated gated cardiac CT scan.
The findings, published in Circulation, were reported by Dhiran Verghese, MD, of the Division of Cardiovascular Medicine, Department of Medicine, Massachusetts General Hospital, Mass General Brigham, Boston, and colleagues.
CAC is an established marker of coronary atherosclerosis and is commonly measured using ECG-gated cardiac CT. However, many patients undergo chest CT for other clinical indications, and these scans are typically performed without ECG gating. Whether CAC detected incidentally on such scans provides comparable information about future cardiovascular events has remained less certain.
For the study, investigators analyzed paired gated and nongated chest CT scans from the fifth MESA examination. Between April 2010 and December 2011, 2,601 participants underwent both scans on the same day. After excluding individuals with previous coronary or cardiovascular disease and those with incomplete clinical information, 2,472 participants were included.
The study population included 53% women, with participants identifying as White, Chinese, Black, and Hispanic/Latino, reflecting the multiethnic design of MESA. CAC measurements from both scan types were assessed independently at a core laboratory that was blinded to the scanning method.
Researchers then examined whether CAC detected on nongated scans was associated with subsequent coronary heart disease (CHD) and cardiovascular disease (CVD) events. They also compared the agreement and predictive performance of nongated and gated CAC measurements.
Key findings included:
- Participants with moderate nongated CAC scores (101–299) had a higher risk of CHD than those with no detectable CAC, with a hazard ratio of 2.67.
- Severe nongated CAC (≥300) was associated with more than fivefold higher CHD risk, with a hazard ratio of 5.22.
- Moderate and severe CAC were also associated with increased overall cardiovascular disease risk, with hazard ratios of 1.32 and 2.89, respectively.
- CAC measurements from gated and nongated scans showed a very strong correlation (r=0.961).
- Measures of discrimination and prediction, including area under the receiver operating characteristic curve, C-statistic, and Brier score, were statistically comparable between the two scanning approaches.
The findings suggest that CAC assessment on routine nongated chest CTs could help detect previously unrecognized coronary atherosclerosis without requiring an additional cardiac CT. The authors noted that incorporating CAC evaluation into routine chest imaging could provide a practical, scalable tool for cardiovascular risk stratification and guide preventive and lipid-lowering strategies.
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