COMBINED EXERCISE RADIONUCLIDE ANGIOCARDIOGRAPHY AND SINGLE PHOTON-EMISSION COMPUTED-TOMOGRAPHY PERFUSION STUDIES FOR ASSESSMENT OF CORONARY-ARTERY DISEASE

Although there is widespread use of exercise thallium 201 scintigraphy and radionuclide angiocardiography in patients with coronary artery disease (CAD), little is known about the independence, concordance, or relative importance of these studies in the diagnosis, prognosis, and assessment of the outcome of therapy. The use of both tests in the same patient has been impractical because of the logistic considerations imposed by two exercise tests on separate days and excessive radiation exposure. New technetium 99m-labeled radiopharmaceuticals with high myocardial extraction now permit the simultaneous assessment of myocardial perfusion (single photon emission computed tomography [SPECT]) and ventricular function (radionuclide angiocardiography [RNA]) during treadmill exercise (exercise tolerance test [ETT]). The ability to perform all three tests during a single exercise session offers a very attractive technique to evaluate patients with CAD. The investigators studied 86 patients with chronic CAD using the same-day perfusion and function protocol combined with treadmill exercise. The results demonstrate good concordance between myocardial perfusion and ventricular function as indicated by a significant correlation between tomographic perfusion defect size and ejection fraction (P<.0001, R=0.75 at rest and P<.0001, R=0.76 during exercise). Stepwise logistic regression was used to model ETT, RNA, and SPECT variables against the presence of one or more 60% stenoses by quantitative angiography, an end point present in 47 patients. Univariable analysis showed all three tests (ETT, RNA, and SPECT) to be significant predictors of the end points (χ2=5.1, P<.05; χ2=12.5, P<.001; and χ2=16.1, P<.001, respectively). Multivariable analysis demonstrated that SPECT provided more diagnostic information than ETT and RNA (χ2=16.1, P<.001). However, RNA contributed independent information (χ2=7.1, P<.05), and maximal diagnostic power (χ2=23.2) requires assessment of cardiac function and myocardial perfusion. © 1991 W.B. Saunders Company. All rights reserved.