Coronary CT angiography (CTA) and functional testing came out on more or less equal footing for diagnosing coronary artery disease (CAD) in symptomatic patients, according to results from the PROMISE trial presented March 14 at the American College of Cardiology scientific session. But CTA pulled ahead in other ways.

PROMISE (PROspective Multicenter Imaging Study for Evaluation of chest pain) compared outcomes in 10,003 patients who were randomized to undergo nonurgent, noninvasive anatomical or functional testing to evaluate suspected CAD. The primary endpoint was the composite of death from any cause, MI, hospitalization for unstable angina and major complications from cardiovascular procedures or diagnostic testing.

Anatomical testing consisted of CTA while functional testing was either exercise electrocardiography, exercise or pharmacological nuclear stress or stress echocardiography. They enrolled patients between 2010 and 2013, with a median follow-up of 25 months.

Of five cardiovascular risk factors, the patients had a mean of 2.4, with most participants reporting either chest pain or dyspnea. At follow-up, the primary endpoint occurred in 3.3 percent of the CTA group and 3 percent of the functional group. The rates for invasive cardiac catheterization added to the primary endpoint at 12 months were similar as well, at 5.1 percent and 5.9 percent, respectively.

At 90 days, 12.2 percent of the CTA group and 8.1 percent of the functional testing group underwent a cardiac catheterization; 27.9 percent of the CTA group had no obstructive CAD compared with 52.5 percent of the functional testing group. A higher percentage of patients in the functional testing group underwent catheterizations that found no obstructions (4.3 percent vs. 3.4 percent).

While median radiation was lower in the CTA group, mean exposure was higher. Almost a third of the patients in the functional testing group had no exposure, though, which contributed to the finding for CTA’s overall higher exposure. Compared with nuclear stress, CTA had lower radiation exposure,

Pamela S. Douglas, MD, of the Duke Clinical Research Institute in Durham, N.C., presented the findings on behalf of the PROMISE investigators. The results were published simultaneously online in the New England Journal of Medicine.