Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease

Abstract

Background: The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives: The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods: PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results: Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions: In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550).

Keywords: cardiovascular outcomes; chest pain; coronary computed tomographic angiography; diabetes; stress testing.

Figure 1.. Kaplan-Meier curves for the composite of death/myocardial infarction/unstable angina hospitalization by randomized noninvasive testing modality and diabetes history

. (A) Patients with diabetes. Adjusted hazard ratio between patients randomized to CTA vs. functional testing, 0.74; 95% confidence interval, 0.47–1.18; p-value = 0.207. (B) Patients without diabetes. Adjusted hazard ratio between patients randomized to CTA vs. functional testing, 1.18; 95% confidence interval, 0.88–1.57; p-value = 0.269. CTA, computed tomographic angiography.

Figure 2. [central illustration]. Kaplan-Meier curves for the composite of cardiovascular death/myocardial infarction by randomized noninvasive testing modality and diabetes history

. (A) Patients with diabetes. Adjusted hazard ratio between patients randomized to CTA vs. functional testing, 0.38; 95% confidence interval, 0.18–0.79; p-value = 0.01 (B) Patients without diabetes. Adjusted hazard ratio between patients randomized to CTA vs. functional testing, 1.03; 95% confidence interval, 0.69–1.54; p-value = 0.887. CTA, computed tomographic angiography.