CT Angiography in Diabetes With Suspected CAD: More PROMISE Than Stress Tests?

CT Angiography in Diabetes With Suspected CAD: More PROMISE Than Stress Tests?

Steve Stiles

March 07, 20190

It is possible that coronary CT angiography (CTA), compared with stress testing, might lead to fewer clinical events in patients with diabetes referred to noninvasive testing (NIT) for suspected coronary artery disease (CAD), researchers say on the basis of a post hoc analysis of data from a randomized trial.

“Although prospective confirmation is required, these results suggest that physicians caring for patients who have diabetes and symptoms suggestive of CAD should consider CTA as the initial NIT modality of choice,” the group writes.

Their analysis, based on patients in the PROMISE trial, showed an adjusted 62% risk reduction (= .010) for the composite of cardiovascular (CV) death and myocardial infarction (MI) in patients with diabetes assigned to CTA, compared with functional testing. There was no such significant effect in patients without diabetes (P = .887).

PROMISE had assigned about 10,000 patients with symptoms suggesting CAD to NIT with either CTA or functional testing, which consisted of stress tests with nuclear imaging, electrocardiography (ECG) only, or echocardiographic wall-motion studies.

In its primary analysis, published in 2015, the trial showed no significant difference between the two NIT groups over a median of 2 years for the primary end point of death, MI, unstable angina (UA) hospitalization, or major procedural complications.

The new secondary analysis, published online February 25 in the Journal of the American College of Cardiology (JACC), was limited to the trial’s 8966 patients with interpretable NIT results; 21% had diabetes.

It also found, unsurprisingly, that patients with diabetes were significantly more likely than those without to receive guideline-directed therapy, including statins and aspirin, but that was also true overall for those who went to CTA rather than stress testing.

Coronary CTA can delineate atherosclerosis burden, as opposed to stress testing, which is designed to identify any myocardial ischemia. And that, say the authors and some observers, might contribute to CTA’s observed clinical advantage over functional testing.

Functional testing usually produces a binary result — ischemic or no ischemia —whereas CTA can reveal CAD lesions that are severe, as well as those that are more moderate, perhaps driving more medical therapy, noted senior author Pamela S. Douglas, MD, Duke Clinical Research Institute, Durham, North Carolina.

With CTA, “the additional information in the presence of nonobstructive plaque, most of which would not be expected to be ischemic on stress testing, seems to be very important in terms of the prognostic value for CTA,” Douglas told theheart.org | Medscape Cardiology.