A 320-detector CT scanner can accurately identify which people with chest pain need, or don’t need, an invasive procedure such as cardiac angioplasty or bypass surgery to restore blood flow to the heart, according to the results of the CORE 320 study presented Aug. 28 at the European Society of Cardiology Congress in Munich.
"We found an excellent correlation in results when we compared the 320-detector CT testing with the traditional means of assessment using a stress test with imaging and cardiac catheterization," Joao A. C. Lima, MD, senior author of the study and professor of medicine and radiology at the Johns Hopkins University School of Medicine in Baltimore, said in a release.
CORE 320 is the first prospective, multicenter study to investigate CT’s diagnostic accuracy for assessing blockages in blood vessels and determining which blockages are preventing blood flow to the heart, according to Lima.
Findings apply to individuals who are experiencing chest pain but are not having a heart attack, as many in that situation are referred for invasive angiography, according to the researchers. Approximately 30 percent of people who undergo such catheterization are found to have minimal disease or no blockage requiring further intervention. Lima also noted that SPECT is limited because while it shows reduced blood flow to the heart, it doesn’t indicate the number or specific location of blockages.
The researchers aimed to assess the diagnostic performance of an integrated approach combining CT angiography (CTA) and CT myocardial perfusion (CTP) using a 320-detector CT scanner. A total of 381 patients from 16 hospitals in eight countries participated in the study. Patients underwent traditional SPECT tests and invasive angiography in addition to CTA-CTP.
Results showed the prevalence of obstructive coronary artery disease (CAD) was 59 percent as defined by invasive angiography, and 38 percent as defined on SPECT myocardial perfusion imaging. Lima and colleagues reported the area under the receiver operating characteristic curve of integrated CTA-CTP for detecting or excluding flow-limiting CAD was 0.87 with a 50 percent stenosis threshold.
"We found that the 320-detector CT scanner allowed us to see the anatomy of the blockages as well as determine whether the blockages were causing a lack of perfusion to the heart. We were therefore able to correctly identify the patients who needed revascularization within 30 days of their evaluation," lead author Carlos E. Rochitte, MD, of the Instituto do Coracao in Sao Paulo, Brazil, said in the release.
CTP increased the diagnostic accuracy of CTA alone in delineating flow-limiting disease, raising the area under the receiver operating characteristic curvefrom 0.81 to 0.87.
The fast CT scanner was also associated with lower radiation exposure, according to the authors. The combined CTA-CTP test exposed patients to about half the radiation amount they received from the traditional evaluation methods of angiogram and SPECT stress testing.
Lima and colleagues will continue to follow patients in the study for up to five years, tracking cardiac events such as heart attacks, hospital admissions, procedures or surgeries.