Optimal use of dobutamine stress for the detection and evaluation of coronary artery disease: combination with echocardiography or scintigraphy, or both?

OBJECTIVES: This study was conducted to examine the efficacy of dobutamine stress two-dimensional echocardiography and perfusion scintigraphy for the detection of coronary artery disease in routine practice, to establish the causes of erroneous results and to derive appropriate criteria for the selection of either or both tests. BACKGROUND: Dobutamine stress combined with echocardiography or perfusion scintigraphy may be used to detect coronary artery disease. Although both imaging approaches have demonstrated similar levels of accuracy, it is not known whether there may be particular indications for the use of one or the other technique or a rationale for their combination. METHODS: Two hundred seventeen patients without previous infarction were studied prospectively with dobutamine stress echocardiography and technetium-99m methoxy isobutyl nitrile (sestamibi) single-photon emission computed tomography at the time of diagnostic coronary angiography. The presence of coronary stenoses of > or = 50% diameter was compared with the presence of rest or stress-induced abnormalities of perfusion and regional function. The extent of these abnormalities was correlated with an equivalent score of extent of angiographic disease. RESULTS: Significant coronary artery disease was found in 142 patients; 102 (72%) were identified by dobutamine echocardiography and 108 (76%, p = NS) by perfusion imaging. In 75 patients without significant disease, the specificity of dobutamine echocardiography was 83% compared with 67% for scintigraphy (p = 0.05). Echocardiographic sensitivity was lower in patients unable to complete the test because of side effects (n = 64) than in the remainder (59% vs. 77%, p = 0.02); this influence was less apparent with scintigraphy (71% vs. 78%, p = NS). Selective use of scintigraphy in the 31 patients with a negative submaximal stress echocardiogram led to a sensitivity of 80% for this combination. Patients with left ventricular hypertrophy accounted for most of the difference in specificity between echocardiography and scintigraphy (94% vs. 59%, p = 0.02). Their respective accuracies were 76% and 73%. CONCLUSIONS: Dobutamine stress echocardiography and perfusion scintigraphy have equivalent accuracy. In patients with left ventricular hypertrophy, echocardiography appears to be the test of choice. Selective use of sestamibi scintigraphy in patients with a negative submaximal echocardiogram enhances the accuracy of stress echocardiography alone.

Selection of the optimal nonexercise stress for the evaluation of ischemic regional myocardial dysfunction and malperfusion. Comparison of dobutamine and adenosine using echocardiography and 99mTc-MIBI single photon emission computed tomography.

BACKGROUND: The mechanisms of action of exercise-simulating and vasodilator stressors support their combination with imaging techniques that evaluate left ventricular function and perfusion, respectively. However, reported accuracies of either pharmacological stress together with two-dimensional echocardiography (2DE) or single photon emission computed tomography (SPECT) of myocardial perfusion are similar. The purpose of this study was to establish the optimal stress for each imaging technique by comparing the results of digitized 2DE and 99mTc-methoxyisobutyl isonitrile (MIBI) SPECT using both dobutamine and adenosine stresses in the same patients and conditions. METHODS AND RESULTS: Ninety-seven consecutive patients without evidence of previous infarction undergoing coronary angiography for clinical indications were studied prospectively. Dobutamine was infused during clinical, ECG, and echocardiographic monitoring in dose increments from 5 to 40 micrograms.kg-1.min-1. Adenosine was infused under the same conditions in doses of 0.10, 0.14, and 0.18 mg.kg-1.min-1. For each protocol, the end points were achievement of peak dose, development of severe ischemia, or intolerable side effects. At peak stress, 20 mCi of MIBI was injected, and SPECT imaging was performed 2 hours later; abnormal poststress images were compared with resting SPECT: Digitized 2DE images were compared qualitatively before, during, and after stress in a cine-loop display. Significant coronary disease (n = 59 patients) was defined by the quantification of > 50% stenosis in a major epicardial vessel. The sensitivity of adenosine 2DE was 58%, less than those of adenosine MIBI (86%, p = 0.001), dobutamine 2DE (85%, p = 0.001), and dobutamine MIBI (80%, p = 0.01). Their respective specificities were 87%, 71%, 82%, and 74% (p = NS). The accuracy of adenosine 2DE was 69%, compared with 80% for adenosine MIBI (p < 0.001), 84% for dobutamine 2DE (p = 0.001), and 77% for dobutamine MIBI (p = 0.005); the latter three did not differ significantly in either sensitivity or accuracy. CONCLUSIONS: This prospective, direct comparison of alternative pharmacological stresses in patients without myocardial infarction shows vasodilator stress scintigraphy and dobutamine stress echocardiography and scintigraphy to share equivalent levels of sensitivity. All three are significantly more sensitive than adenosine stress echocardiography. Dobutamine stress may be used for wall motion or perfusion imaging, but adenosine stress is best combined with perfusion scintigraphy.