Noninvasive 64-row multidetector computed tomography angiography may replace conventional angiography for initial diagnosis of coronary artery disease in selected patients, according to a late-breaking clinical trial presentation at the annual meeting of the American Heart Association.

The Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography trial (CORE-64), the first study of its kind, evaluated the diagnostic accuracy of multi-detector spiral CT angiography compared with conventional coronary angiography. A total of 291 patients in nine centers internationally were evaluated: There were three centers in the United States and one each in Brazil, Germany, Japan, the Netherlands, Canada and Singapore.

All patients were scheduled to undergo conventional angiography for suspected coronary artery disease. Patients first underwent coronary calcium imaging and scoring followed by computed tomographic angiography prior to cardiac catheterization. Both sets of images were analyzed by independent core laboratories.

Computed tomographic angiography was performed using 0.5-mm slice thickness with 64 simultaneous detector rows. More than 98 percent of coronary arteries as small as 1.5 mm in diameter could be seen.

Noninvasive imaging had good diagnostic ability for detecting blockages greater than 50 percent occluded (sensitivity, 85 percent; specificity, 90 percent). Furthermore, computed tomographic angiography had diagnostic ability comparable with that of conventional angiography in its ability to identify patients who had sufficiently severe disease to be referred for angioplasty or bypass surgery, although it was less able to determine specifically which artery was blocked compared with conventional angiography.

“In patients with suspected coronary artery disease (CAD) and calcium scores less than 600, 64-row MDCTA can assess the presence of significant CAD and the likelihood physicians will refer for coronary revascularization,” said Julie M. Miller, MD, lead investigator of the study and assistant professor of medicine at Johns Hopkins Hospital, Johns Hopkins University in Baltimore, Md.

“The strong performance of 64-row MDCT in this multicenter trial supports its use as a diagnostic test to help us diagnose symptomatic patients who may have significant coronary obstruction. “