Prognostic value of dobutamine stress technetium-99m-sestamibi single-photon emission computed tomography myocardial perfusion imaging: Stratification of a high-risk population

OBJECTIVES This work was undertaken to define the intrinsic cardiac risk of the patient population referred for dobutamine stress perfusion imaging an d to determine whether dobutamine technetium-99m (Tc-99m)-sestamibi single- photon emission computed tomography (SPECT) imaging is capable of risk stra tification in this population. BACKGROUND In animal models, dobutamine attenuates the myocardial uptake of Tc-99m-sestamibi resulting in underestimation of coronary stenoses. Theref ore, we hypothesized that the prognostic value of dobutamine stress Tc-99m- sestamibi SPECT myocardial perfusion imaging might be impaired, owing to re duced detection of coronary stenoses. METHODS We reviewed the clinical outcome of 308 patients (166 women, 142 me n) who underwent dobutamine stress SPECT Tc-99m-sestamibi imaging at our in stitution from September 1992 through December 1996. RESULTS During an average follow-up of 1.9 +/- 1.1 years, there were 33 har d cardiac events (18 myocardial infarctions [MI] and 15 cardiac deaths) cor responding to an annual cardiac event rate of 5.8%/year, which is significa ntly higher than the event rate for patients referred for exercise SPECT im aging at our institution (2.2%/year). Event rates were higher after an abno rmal dobutamine Tc-99m-sestamibi SPECT study (10.0%/year) than after a norm al study (2.3%/year) (p < 0.01), even after adjusting for clinical variable s. In the subgroup (n = 29) with dobutamine-induced ST-segment depression a nd abnormal SPECT imaging, the prognosis was poor, with annual cardiac deat h and nonfatal MI rates of 7.9% and 13.2%, respectively. CONCLUSIONS Patients referred for dobutamine perfusion imaging are a high-r isk population, and dobutamine stress Tc-99m-sestamibi SPECT imaging is cap able of risk stratification in these patients. (J Am Coll Cardiol 2001;38:1 511-7) (C) 2001 by the American College of Cardiology.