Imaging studies suggest potential value of computed tomography angiography for heart patients

February 23, 2016 – The DCRI’s Christopher Fordyce, MD, MSc, and Pamela Douglas, MD, reviewed the findings of the SCOT-HEART and PROMISE trials.

Two of the largest imaging outcomes trials have demonstrated the potential diagnostic value of coronary computed tomography angiography (CTA) for patients with stable chest pain.

Stable chest pain—known as angina—is highly prevalent among older men and women, occurring in about 10 percent of Americans aged 80 years or older. Approximately 4 million stress tests are performed annually in the United States to help diagnose patients experiencing chest pain. However, there are significant variations in diagnostic strategies for angina patients, particularly between the United States and Europe.

christopher-fordyceTwo recent trials—SCOT-HEART (Scottish Computed Tomography of the HEART) and PROMISE (PROspective Multicenter Imaging Study for Evaluation of chest pain)—were designed in part to review the evidence surrounding different approaches to noninvasive testing in stable chest pain.

An analysis of the two trials by the DCRI’s Christopher Fordyce, MD, MSc (pictured); Pamela Douglas, MD, and the University of Edinburgh’s David Newby, MD, PhD, was published this month in the Journal of the American College of Cardiology.

SCOT-HEART enrolled 4,146 Scottish patients between 18 and 75 years of age with suspected angina due to coronary heart disease. The participants were randomized into two groups, one that was diagnosed using CTA along with standard care, with the other group receiving standard care alone. SCOT-HEART’s researchers found that CTA was better than standard care alone for diagnosing and enabling targeted interventions. About one-quarter of CTA patients were given a different diagnosis after receiving the test compared to just 1 percent of patients who received standard care alone.

The PROMISE trial enrolled 10,003 patients in North America and randomized them to receive either a CTA or a functional stress test to detect whether their chest pains and shortness of breath were caused by a blocked blood vessel or not. Researchers found that compared to functional testing, CTA did not reduce the incidence of heart attacks, hospitalizations for unstable angina, major procedural complications or death over a median of 25 months of follow-up. However, the use of CTA may have accurately guided patients to more appropriate follow-up testing.

Taken together, Fordyce and his colleagues concluded, these two trials illustrate several important points about the current state of cardiac imaging. First, patients with stable chest pain appear to be at relatively low risk of clinical events, regardless of the diagnostic test used. Second, CTA is a reasonable first choice for routine assessment of chest pain, although stress testing still has value as a diagnostic tool. Finally, the role of CTA and other procedures in diagnosing and treating angina is still being evaluated. More research is needed to better understand how clinicians can use them to their fullest advantage.