The value of multi-slice-computed tomography coronary angiography for risk stratification

Multi-slice-computed tomography coronary angiography (CTA) provides direct non-invasive anatomic assessment of the coronary arteries allowing for early identification of coronary artery disease (CAD). This information is useful for diagnosis of CAD, particularly the rule out of CAD. In addition, early identification of CAD with CTA may also be useful for risk stratification. The purpose of this review is to provide an overview of the current literature on the prognostic value of CTA and to discuss how the prognostic information obtained with CTA can be used to further integrate the technique into clinical practice. Non-invasive anatomic assessment of plaque burden, location, composition, and remodeling using CTA may provide prognostically relevant information. This information has been shown to be incremental to the Framingham risk score, coronary artery calcium scoring, and myocardial perfusion imaging. Characterization of atherosclerosis non-invasively has the potential to provide important prognostic information enabling a more patient-tailored approach to disease management. Future studies assessing outcome after CTA-based risk adjustments are needed to further understand the value of detailed non-invasive anatomic imaging

Assessment of coronary artery calcium by using volumetric 320-row multi-detector computed tomography: comparison of 0.5 mm with 3.0 mm slice reconstructions

The purpose of this study was to assess the performance of 0.5 versus 3.0 mm slice reconstructions in depicting coronary calcium with special attention to patients having zero calcium scores at 3.0 mm reconstructions by using computed tomography (CT). Imaging was performed by volumetric 320-detector row CT. Scans of 100 patients with a negative and 100 patients with a positive Agatston score at 3.0 mm reconstructions were consecutively selected. Non-overlapping volume sets with 3.0 and 0.5 mm slice thickness were reconstructed from the same raw data and Agatston and volume scores were obtained. The Wilcoxon signed ranks test was used to determine statistical differences between 3.0 and 0.5 mm calcium scores. Agatston and volume scores obtained at 0.5 mm were significantly higher than at 3.0 mm reconstructions (mean Agatston score: 266 ± 495 vs. 231 ± 461. Mean volume score: 223 ± 399 vs. 206 ± 385, both P < 0.01). In 21% of patients with zero 3.0 mm Agatston scores, a positive Agatston and/or volume score was found at 0.5 mm reconstructions. With volumetric 320-detector row CT, prospective ECG-triggered calcium scoring at 0.5 mm compared to 3.0 mm reconstructions leads to an increase in Agatston and volume scores and small amounts of coronary calcium are earlier depicted. This may be of special interest in patients with zero calcium scores with traditional 3.0 mm measures, where 0.5 mm reconstructions may help in superior depicting or ruling out coronary artery disease

Effect of dose reduction on image quality and diagnostic performance in coronary computed tomography angiography

To evaluate the effect of radiation dose reduction on image quality and diagnostic accuracy of coronary computed tomography (CT) angiography. Coronary CT angiography studies of 40 patients with (n = 20) and without (n = 20) significant (≥50 %) stenosis were included (26 male, 14 female, 57 ± 11 years). In addition to the original clinical reconstruction (100 % dose), simulated images were created that correspond to 50, 25 and 12.5 % of the original dose. Image quality and diagnostic performance in identifying significant stenosis were determined. Receiver–operator-characteristics analysis was used to assess diagnostic accuracy at different dose levels. The identification of patients with significant stenosis decreased consistently at doses of 50, 25 and 12.5 of the regular clinical acquisition (100 %). The effect was relatively weak at 50 % dose, and was strong at dose levels of 25 and 12.5 %. At lower doses a steady increase was observed for false negative findings. The number of coronary artery segments that were rated as diagnostic decreased gradually with dose, this was most prominent for smaller segments. The area-under-the-curve (AUC) was 0.90 (p = 0.4) at 50 % dose; accuracy decreased significantly with 25 % (AUC 0.70) and 12.5 % dose (AUC 0.60) (p < 0.0001), with underestimation of patients having significant stenosis. The clinical acquisition protocol for evaluation of coronary artery stenosis with CT angiography represents a good balance between image quality and patient dose. A potential for a modest (<50 %) reduction of tube current might exist. However, more substantial reduction of tube current will reduce diagnostic performance of coronary CT angiography substantially

Influence of smoking on the prognostic value of cardiovascular computed tomography coronary angiography

Aims Computed tomography coronary angiography (CTA) is an important non-invasive imaging modality increasingly used for the diagnosis and prognosis of coronary artery disease (CAD). The purpose of the current study was to determine the influence of smoking status on the prognostic value of CTA in patients with suspected or known CAD. Methods and results In 1207 patients (57% male, age 57 ± 12 years) referred for CTA, the presence of significant CAD (≥50% stenosis) was determined. During follow-up (FU) the following events were recorded: all cause mortality, and non-fatal infarction. The prognostic value of CTA in smokers and non-smokers was compared using an interaction term in the Cox proportional hazard regression analysis. Significant CAD was observed in 327 patients (27%), and 273 patients (23%) were smokers. During a median FU time of 2.2 years, an event occurred in 50 patients. After correction for baseline characteristics including smoking in a multivariate model, significant CAD remained an independent predictor of events. Furthermore, a significant interaction (P < 0.05) was observed between significant CAD and smoking. The annualized event rate in smokers with significant CAD was 8.78% compared with 0.99% in smokers without significant CAD (P < 0.001). In non-smokers with significant CAD the annualized event rate was 2.07% compared with 1.01% in non-smokers without significant CAD (P= 0.058). Conclusion The prognostic value of CTA was significantly influenced by smoking status. The event rates in patients with significant CAD were approximately four-fold higher in smokers compared with non-smokers. These findings suggest that smoking cessation needs to be aggressively pursued, especially in smokers with significant CA

Prognostic value of coronary vessel dominance in relation to significant coronary artery disease determined with non-invasive computed tomography coronary angiography

Aims Limited information is available regarding the relationship between coronary vessel dominance and prognosis. Therefore, the purpose of this study was to determine the prognostic value of coronary vessel dominance in relation to significant coronary artery disease (CAD) in patients referred for computed tomography coronary angiography (CTA). Methods and results The study population consisted of 1425 patients (869 men, 57 ± 12 years) referred for CTA. To evaluate the impact of vessel dominance and significant CAD on CTA on outcome, patients were followed during a median period of 24 months for the occurrence of non-fatal myocardial infarction and all-cause mortality. The presence of a left dominant system was identified as a significant predictor for non-fatal myocardial infarction and all-cause mortality (HR: 3.20; 95% CI: 1.67-6.13, P < 0.001) and had incremental value over baseline risk factors and severity of CAD on CTA. In addition, in the subgroup of patients with significant CAD on CTA, patients with a left dominant system had a worse outcome compared with patients with a right dominant system (cumulative event rates: 9.5% and 35% at 3-year follow-up for a right and left dominant coronary artery system, respectively, log-rank P < 0.001). Conclusions The presence of a left dominant system was identified as an independent predictor of non-fatal myocardial infarction and all-cause mortality, especially in patients with significant CAD on CTA. Therefore, the assessment of coronary vessel dominance on CTA may further enhance risk stratification beyond the assessment of significant CAD on CT

Incremental prognostic value of multi-slice computed tomography coronary angiography over coronary artery calcium scoring in patients with suspected coronary artery disease

Aims 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 and results 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. 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. Conclusion MSCTA provides additional information to CS regarding stenosis severity and plaque composition. This additional information was shown to translate into incremental prognostic value over C