COMPARISON OF DOBUTAMINE AND EXERCISE USING TC-99M SESTAMIBI IMAGING FOR THE EVALUATION OF CORONARY-ARTERY DISEASE

Studies using dobutamine thallium-201 myocardial perfusin imaging have suggested a high sensitivity and specificity for the detection of cor onary artery disease. However, few data are available comparing dobuta mine with exercise stress for the detection and localization of perfus ion defects. This study compared the effects of dobutamine and exercis e stress using technetium-99m sestamibi single-photon emission compute d tomographic imaging in the same patients in a prospective crossover trial. Twenty-four patients with a high likelihood of coronary artery disease underwent tomographic myocardial imaging at rest, after sympto m-limited treadmill exercise, and after intravenous dobutamine (maximu m 30 mug/kg/min). Tomograms of the left ventricle were divided into 20 segments and were interpreted without knowledge of patient identity o r stress protocol. Dobutamine was well tolerated by all patients. Segm ent-by-segment concordance between exercise and dobutamine images was highly significant (kappa = 0.56, p < 0.0001). Global first-order agre ement (normal vs abnormal) between exercise and dobutamine studies was 96% (kappa = 0.65, p = 0.02); global second-order agreement (normal v s fixed vs ischemic defect) was 88% (kappa = 0.45, p = 0.02). Regional first- and second-order agreement were 96 and 93%, respectively (p < 0.001 for both). Twenty patients underwent coronary angiography. compa risons between exercise and angiography and between dobutamine and ang iography were similar for both global agreement (95 vs 100%, p = NS) a nd regional agreement (77 vs 72%, p = NS). In conclusion, technetium-9 9m sestamibi tomograms obtained after exercise and dobutamine stress i n the same patients with a highly likelihood of coronary artery diseas e show very similar results with regard to the identification, localiz ation and reversibility of perfusion defects.