Researchers Support CCTA as Frontline Cardiac Test
By Jim Knaub
Coronary CT angiography (CCTA) testing offers such a strong negative predictive value that it can reduce subsequent stress testing and should be considered the frontline test for patients with low to intermediate likelihood of coronary artery disease (CAD), according to research presented recently at the American Society of Nuclear Cardiology annual meeting.
“CCTA should be the test of choice in patients with chest pain, prior inconclusive or negative stress testing, and low to intermediate likelihood of CAD, as it reduces downstream testing,” study coauthor Karthik Ananthasubramaniam, MD, told MedPage Today. Ananthasubramaniam, from Henry Ford Hospital in Detroit, also suggests that CCTA should replace stress testing in low- to intermediate-risk patients. “CCTA has an extremely high negative predictive value and using this as the initial test completely stops downstream testing,” he added. “And that is going to be the future.”
The retrospective, single-center study looked at the histories of 181 patients who had clinically indicated CCTA exams in a 10-month period in 2006. In a three-year period before receiving CCTA exams, the patients had a total of 183 stress tests compared with 71 in the three years after.
In patient subgroup where no CAD was found on CCTA, stress testing decreased from 72 tests before the CCTA exam to 21 tests after the CCTA exams. Thirteen of the 21 tests after the CCTA findings were ordered by doctors who were unaware of CCTA results.
In a group of 78 patients with no CAD and a mean coronary artery calcium score of 3, only one patient subsequently was referred for cardiac catheterization during a median follow-up period of 1,476 days after the CCTA.
The data presented come from an unpublished single-site retrospective study, so the results should be considered accordingly, but the study raises valid questions about handling these low- to intermediate-risk patients. The researchers called CCTA “a very efficient gatekeeper for subsequent invasive procedures” for the patients in the study.
“The moment no significant CAD is diagnosed by CCTA, there is a clear reduction, although not optimal, in the number of downstream tests,” Ananthasubramaniam said in the MedPage Today article, “because if a CCTA is negative, you can tell the patient that the chest pain is not coming from the heart.”
The CCTA studies produced an average radiation exposure of 6 mSv (5 mSv if calcium scoring was not part of the exam), which compares to 13 to 15 mSv for a stress test, according to angioplasty.org. The most current scanners and techniques can reduce exposure from both exams.
— Jim Knaub is editor of Radiology Today |
