Use of dobutamine stress echocardiography in detecting silent myocardial ischaemia in asymptomatic diabetic patients: a comparison with thallium scintigraphy and exercise testing.

AIMS: Silent myocardial ischaemia is frequent in diabetic patients. The aim of this study was to compare the efficacy of thallium-201 single-photon emission computed tomography (201Tl SPECT) coupled with exercise stress testing (EST), and dobutamine stress echocardiography (DSE) in the detection of asymptomatic coronary artery disease.
METHODS: Fifty-six asymptomatic diabetic patients, with a known duration of diabetes > 15 years for Type 1 and > 5 years for Type 2, having at least three added risk factors, but without rest ECG abnormalities, were enrolled in this prospective study. All of them were submitted to DSE with a maximum infusion rate of 40 microg/kg per min dobutamine +/- i.v. atropine, and to 201Tl SPECT coupled with EST. Coronary angiography was performed if at least one test was abnormal.
RESULTS: Diabetic patients were 37 males and 19 females, aged mean (sd) 60 +/- 10 years, 10 Type 1 and 46 Type 2, with a known duration of disease of mean (sd) 17 +/- 9 years. Feasibility of DSE was 91%. No serious complication occurred during the test. Coronary angiography was performed in 26 patients (47%); 17 were abnormal (30% of the whole group): six patients had a one-vessel, six a two-vessel and five a three-vessel disease. Predictive positive value was 69% for DSE, 75% for 201Tl SPECT and 60% for EST. DSE was falsely negative in four cases vs. eight for 201Tl SPECT and nine for EST.
CONCLUSIONS: Asymptomatic coronary disease is common in diabetes associated with other risk factors. DSE appears useful in its detection and a good alternative to 201Tl SPECT.