Effects of medical therapy on outcome assessment using exercise thallium-201 single photon emission computed tomography imaging - Evidence of a protective effect of beta-blocking antianginal medications

OBJECTIVES The purpose of this study was ro determine whether antianginal m edications modify the prognostic significance of exercise single photon emi ssion computed tomography (SPECT) ischemia. BACKGROUND Antianginal medications (especially beta-adrenergic blocking age nts) limit exercise SPECT ischemia, but it is not known whether such medica tions also modify the prognostic effect of exercise SPECT ischemia. METHODS We included 352 patients with coronary heart disease, who had exerc ise T1-201 SPECT and coronary angiography, and who were initially treated m edically. Survival Cox models were applied in patients for whom classes of antianginal medications taken at exercise SPECT were the same as those pres cribed for follow-up (GI; n = 136), and in patients for whom new classes of antianginal medications, including beta-blockers (GII; n = 79) or not incl uding beta-blockers (GIII; n = 113), were added for follow-up. RESULTS During a mean 5.3 +/- 1.6 years of follow-up, 45 patients had cardi ac death or myocardial infarction. Variables reflecting necrosis (irreversi ble defect extent, left ventricular ejection fraction) and those from coron ary angiography provided equivalent prognostic information in the three gro ups. In contrast, the SPECT variable reflecting ischemia (reversible defect extent), which provided comparable prognostic information in GI (p = 0.005 ) and Gm (p = 0.004), lost its prognostic significance (p = 0.54) in GII, a nd was associated with a lower relative risk in GII than in GI or GIII (bot h p < 0.05). CONCLUSIONS In patients with coronary heart disease, the introduction of an tianginal medications, when including beta-blockers, appears to have a favo rable effect on the deleterious prognostic effect of exercise ischemia. (C) 1999 by the American College of Cardiology.