CORE-64: Multidetector CTA effective alternative to coronary angiography

The new technology could be ideal for imaging heart blockages noninvasively.

ORLANDO — Researchers evaluating the diagnostic accuracy of a powerful new 64-slice multidetector computed tomography angiography scanner are hopeful the tool could possibly replace more invasive procedures like traditional coronary angiography.

The results of the Coronary Artery Evaluation Using 64-Row Multidetector CT Angiography (CORE-64) trial showed a comparable diagnostic accuracy with that of conventional coronary angiography on a per-patient, per-vessel basis. The multicenter trial was the first of its kind. Results were presented at the 2007 American Heart Association Scientific Sessions.

CTA vs. angiography

Julie M. Miller, MD, assistant professor of medicine at Johns Hopkins University, and colleagues analyzed 898 vessels from 291 patients with calcium scores <600. Patients underwent the 64-slice multidetector CTA scan and coronary catherization procedures, and researchers followed up at 30-days and six-months for clinical events, including revascularization.

The researchers, measuring area under the curve vs. specificity determined that the 64-slice multidetector CTA scanner yielded 91% specificity, 83% sensitivity, a positive predictive value of 92% and a negative predictive value of 81% compared with conventional coronary angiography. According to the investigators, these values were not significantly different from the diagnostic accuracy of conventional coronary angiography. The researchers concluded based on the results of CORE-64 that the diagnostic abilities of multidetector CTA appeared to be superior on a per-patient basis than on a per-vessel basis when compared with conventional quantitative coronary angiography.

Some physicians, however, urged further analysis of CTA technology and larger trials before definitive clinical conclusions can be drawn about its use.

“The CORE-64 study confirms prior studies, showing reasonable diagnostic accuracy among patients who happen to be referred for coronary angiography,” said study discussant Michael S. Lauer, MD, of the National Heart, Lung, and Blood Institute. “However, we know nothing of the diagnostic accuracy of CT angiography in the real world; we have minimal data on its prognostic value. Most important of all, we have no evidence that the use of CTA saves lives or prevents heart attacks. We have a technology with no real evidence of benefit and, because it emits a radiation dose, a real concern for harm.”

Toshiba, the manufacturer of the 64-slice CTA scanner used in CORE-64, is currently sponsoring the Screening For Asymptomatic Obstructive Coronary Artery Disease Among High-Risk Diabetic Patients Using CT Angiography Following CORE-64 (FACTOR-64) trial, which will attempt to improve early diagnosis of CAD in asymptomatic patients with diabetes using 64-slice multidetector CTA scanning. The trial researchers plan to enroll more than 1,000 patients in the United States. – by Eric Raible

There are important limitations on this study. Twenty-five percent of the patients enrolled were excluded from analyses. Coronary arterial segments with intracoronary stents, or segments that were <1.5 mm in diameter were excluded from analysis. These initial findings comparing multi-detector 64-detector CT with contrast coronary angiography indicate that CT may have a role in identifying individuals with >50% coronary arterial luminal narrowings. Importantly though, data from this study are unavailable to determine the utility of CTA in those with advanced coronary calcification or intracoronary stents. For individuals without calcification or intracoronary stents, the diagnostic utility of this form of noninvasive imaging is lower than contrast coronary angiography. Consideration of these data are important when trying to determine individual patient suitability for a 64-detector CT coronary angiogram.

– W. Gregory Hundley, MD

Cardiology Today Imaging Section Editor

This is a highly selected patient population and the results cannot be transferred to the general cardiology patient population. The researchers confirm that CTA and catheterization has a good correlation predicting significant CAD in a patient (but not so good for an individual vessel) if one follows their quite stringent selection process. This is, however, not the end of diagnostic catheterization, and the investigators do not confirm the general notion (without any multicenter randomized scientific proof so far) that the best broad indication to use CTA of coronaries is to rule out significant CAD in the patient with low to intermediate pre-test likelihood for having significant CAD.

– Carsten Schmalfuss, MD

Adjunct Clinical Professor of Medicine
University of Florida.

For more information:

• Miller J, Rochitte C, Dewey M, et al. Coronary artery evaluation using 64-row multidetector computed tomography angiography (CORE-64): Results of a multicenter, international trial to assess diagnostic accuracy compared with conventional coronary angiography. #PS-03. Presented at: American Heart Association 30th Annual Scientific Sessions; Nov. 3-7, 2007; Orlando.