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Randomized Comparison of 64-Slice Single- and Dual-Source Computed Tomography Coronary Angiography for the Detection of Coronary Artery Disease - Randomized Comparison of 64-Slice Single- and Dual-Source Computed Tomography Coronary Angiography for the Detection of Coronary Artery Disease
Description:
The goal of this trial was to evaluate the impact of heart rate control on single versus dual-source multi-detector computed tomography (MDCT) in the detection of coronary artery stenoses.
Hypothesis:
Adequate heart rate control will be necessary for correctly classifying coronary stenoses with the use of single-source MDCT.
Study Design
Study Design:
Patients Enrolled: 200
Mean Follow Up: In-hospital
Mean Patient Age: 63
Female: 43
Patient Populations:
Patients referred for CT angiogram for suspected coronary artery disease
Exclusions:
• Known coronary artery disease
• Previous coronary artery stents or coronary bypass surgery
• Non-sinus rhythm
• Impaired renal function (creatinine >1.5 mg/dl)
• Other contraindications to iodinated contrast agent
• Patients unable to achieve a breath-hold of at least 10 seconds
Primary Endpoints:
Proportion of patients with evaluable images
Secondary Endpoints:
• Sensitivity and specificity in “evaluable” patients
• Negative and positive predictive values in “evaluable” patients
• Proportion of correctly classified stenoses
Drug/Procedures Used:
Patients referred for diagnostic evaluation of suspected coronary artery disease were randomized to single-source MDCT (n = 100) or dual-source MDCT (n = 100). Patients within each group were further randomized to heart rate control through the use of beta-blockers or no additional heart rate control.
Concomitant Medications:
Patients randomized to heart rate control received 100 mg oral atenolol 45 minutes before the MDCT scan, if their resting heart rate was more than 60 bpm. If this did not achieve an adequate heart rate, patients received 5 mg intravenous metoprolol until satisfactory response or a total of 20 mg had been given.
Principal Findings:
In the single-source MDCT group, the mean heart rate was 60 bpm with heart rate control versus 70 bpm with no heart rate control (p = 0.0003). In the dual-source MDCT group, the mean heart rate was 59 bpm with heart rate control versus 69 bpm with no heart rate control (p = 0.0003). Satisfactory heart rate control was achieved in 57% of patients.
In the single-source MDCT group, the proportion of evaluable patients was 93% with heart rate control and 69% with no heart rate control (p = 0.005). Similarly, sensitivity was 86% and 79% (p = ns), specificity was 83% and 73% (p = ns), and correctly classified stenoses were 78% and 57% (p = 0.04), respectively.
In the dual-source MDCT group, the proportion of evaluable patients was 96% with heart rate control and 98% with no heart rate control (p = ns). Similarly, sensitivity was 100% and 95% (p = ns), specificity was 85% and 94% (p = ns), and correctly classified stenoses were 87% and 93% (p = ns), respectively.
Interpretation:
Among patients referred for MDCT evaluation of suspected coronary disease, heart rate control was beneficial with single-source imaging, although not with dual-source imaging. With single-source MDCT, heart rate control significantly improved the proportion of evaluable patients, as well as the proportion of correctly classified stenoses. There was no apparent difference with either sensitivity or specificity.
In contrast, with dual-source MDCT, there was no apparent difference in the proportion of evaluable patients, sensitivity, specificity, or proportion of correctly classified stenoses with heart rate control.
The clinical implication is that for patients who are candidates for heart rate control, the use of single-source MDCT is reasonable. Among patients who are not candidates for heart rate control due to comorbidities or clinical instability, the use of a dual-source MDCT may be preferable.
Dual-source imaging results in somewhat more radiation than single-source imaging, which will also need to be considered. For example, dual-source with no heart rate control delivered 14.5 mSv, compared with 12.0 mSv for single-source imaging with heart rate control. There was also no apparent difference in correctly classified stenoses between single-source CT with heart rate control versus dual-source CT with no heart rate control.
References:
Achenbach S, Ropers U, Kuettner A, et al. Randomized Comparison of 64-Slice Single- and Dual-Source Computed Tomography Coronary Angiography for the Detection of Coronary Artery Disease. J Am Coll Cardiol Img 2008;1:177-186.
Keywords: Coronary Artery Disease, Coronary Stenosis, Coronary Angiography, Tomography, X-Ray Computed, Comorbidity, Constriction, Pathologic, Heart Rate
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