Incremental Prognostic Value of Multi-Slice Computed Tomography Coronary Angiography Over Coronary Artery Calcium Scoring in Patients with Suspected Coronary Artery Disease

OBJECTIVES: The purpose of this study was to assess the relationship between calcium scoring (CS) and multi-slice computed tomography coronary angiography (MSCTA) and to determine if MSCTA has an incremental prognostic value to CS.

METHODS: In 432 patients (59% male, age 58 +/- 11 years) referred for cardiac evaluation owing to suspected coronary artery disease (CAD), CS and 64-slice MSCTA were performed. The following events were combined in a composite endpoint: all-cause mortality, non-fatal infarction, and unstable angina requiring revascularization.

RESULTS: CS was 0 in 147 (34%) patients, CS 1-99 was present in 122 (28%), CS 100-399 in 75 (17%), CS 400-999 in 56 (13%), and CS > 1000 in 32 (7%). MSCTA was normal in 133 (31%) patients, MSCTA 30-50% stenosis was observed in 190 (44%), and MSCTA > 50% stenosis in 109 (25%). During follow-up [median 670 days (25th-75th percentile: 418-895)], an event occurred in 21 patients (4.9%). After multivariate correction for CS, MSCTA > 50% stenosis, the number of diseased segments, obstructive segments, and non-calcified plaques were independent predictors with an incremental prognostic value to CS.

CONCLUSIONS: MSCTA provides additional information to CS regarding stenosis severity and plaque composition. This additional information was shown to translate into incremental prognostic value over CS.

PMID: 19567382

Schoenhagen Paul

Cardiovascular Imaging
Imaging Institute and
Heart&Vascular Institite
Cleveland Clinic
Cleveland, OH
Posted in Computed Tomography and tagged , .

2 Comments

  1. Interesting study, it suggests a potential incremental value of contrast-enhanced CTA over non-contrast enhanced (and lower radiation dose) calcium scoring.
    However, it is important to consider the patient population: In the current report patients with suspected obstructive coronary artery disease were included. In these patients, after multivariate correction for calcium score, CTA criteria including 50% stenosis, the number of diseased segments, obstructive segments, and non-calcified plaques were independent predictors with an incremental prognostic value to CS.
    In contrast, CTA is currently not considered indicated in asymptomatic intermediated risk patients, in whom screening with calcium scoring has demonstrated incremental value.

  2. Another consideration, which the authors mention, is the large difference in radiation dose of these 2 examinations. Especially, since the MDCTA protocol used appears to have been retrospectively gated, it would be interesting to see if these findings translate to MDCTA with prospective gating – where the number of segments that may not be interpretable will potential increase.

    Also, a recent interesting paper by Bauer et al, (PMID: 19620437), revealed that in patients with clinically indicated MDCTA, non-calcified plaque burden was a better predictor of the finding of myocardial ischemia at stress myocardial perfusion imaging than were CS and degree of stenosis. This would intuitively further support the findings of the above paper.

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