Comparison of adenosine and exercise stress test for quantitative perfusion imaging in patients on beta-blocker therapy

Beta-blocker therapy is used to decrease myocardial ischemia during exercis e but may cause suboptimal diagnostic performance in exercise stress testin g. The aim of the present study was to compare results of quantitative tech netium-99-sestamibi single photon emission tomography (SPECT), following ex ercise stress test or pharmacological stress test with adenosine. We chose adenosine as comparison, since betablockers may not interfere with adenosin e induced vasodilatation and therefore possibly may not interfere with its diagnostic performance. Sixteen patients with angiographically documented c oronary disease (5 single-vessel, 6 two-vessel and 5 three-vessel disease), who were chronically treated with beta-blockers, performed SPECT imaging a t rest, following bicycle exercise and following adenosine infusion in rand om order. The SPECT data were analyzed visually and quantitatively, using d edicated computer software (CEqual). According to both visual and quantitat ive SPECT analysis, adenosine was superior to show reversibility. Higher re versibility extent (50 +/- 15 vs. 26 +/- 12 pixels, p < 0.01) and more inte nse reversibility severity (110 +/- 29 vs. 49 +/- 23 sum of SDs, p < 0.05) were observed during adenosine than exercise. Conclusions: Less myocardial perfusion abnormalities during exercise than during adenosine stress in pat ients treated with beta-blockers may indicate less ischemia but also an imp aired diagnostic performance. Thus adenosine stress test should be preferre d to optimize the diagnostic sensitivity in patients during beta-blocker tr eatment. Copyright (C) 2001 S. Karger AG. Basel.