Background: We sought to assess prospectively the evidence for silent coronary artery disease (CAD) in asymptomatic patients with type 2 diabetes mellitus by stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging, coronary artery calcium (CAC) scoring, and multislice computed tomographic (MSCT) coronary angiography.
Methods: One hundred asymptomatic patients (aged 30 to 72 years) with type 2 diabetes mellitus and one or more risk factors for CAD were prospectively recruited from an outpatient diabetes clinic. All patients underwent adenosine technetium-99m sestamibi SPECT imaging, CAC scoring, and 64-slice MSCT coronary angiography.
Results: Twenty-three patients (23%) had abnormal stress SPECT imaging, consistent with inducible myocardial ischemia, whereas 60 patients (60%) had positive CAC scoring (18 patients [18%] with significant CAC >401), and 70 patients (70%) had abnormal MSCT coronary angiography (24 patients [24%] with significant, >or=50% stenosis). Of 77 patients with normal SPECT, 44 had a positive CAC score (10 patients [13%] >401), and 54 showed CAD on MSCT angiography (16 patients [21%] with >or=50% stenosis). Of 23 patients with an abnormal SPECT, 16 patients had a positive CAC score (8 patients [35%] >401), and 16 patients had CAD on MSCT angiography (8 patients [35%] with >or=50% stenosis). Overall, 17 patients (17%) had more than 2 significantly abnormal diagnostic test results, and 5 patients had three tests with significantly abnormal results.
Conclusions: In this cohort of asymptomatic patients with type 2 diabetes mellitus, different modalities visualized different aspects of silent coronary atherosclerosis. Anatomic evidence of coronary atherosclerosis (CAC and MSCT) occurred more frequently than functional evidence (stress SPECT). However, clinically significant manifestations of CAD were observed in about one-quarter to one-fifth of patients by each modality, either separately or combined. The relative prognostic value of each modality needs to be determined by a follow-up of this cohort.