INDEPENDENT AND INCREMENTAL PROGNOSTIC VALUE OF EXERCISE SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHIC (SPECT) THALLIUM IMAGING IN CORONARY-ARTERY DISEASE

Objectives. The objective of this study was to examine the independent and incremental prognostic value of exercise single-photon emission c omputed tomographic (SPECT) thallium imaging in patients with angiogra phically defined coronary artery disease. Background. Previous studies showed the importance of exercise thallium-201 in risk stratification . However, most of these studies used planar imaging techniques. Metho ds. Follow-up data were obtained in 316 medically treated patients wit h coronary artery disease. Cox proportional hazards regression models were used to examine the independent and incremental prognostic values of clinical, exercise, thallium and cardiac catheterization data. Res ults. There were 35 events (cardiac death or nonfatal myocardial infar ction) at a mean follow-up time of 28 months. Univariate analysis show ed that gender (chi-square = 5.1), exercise work load (chi-square = 3. 1), extent of coronary artery disease and left ventricular ejection f raction (chi-square = 14.8) and thallium variables (chi-square = 22.7) were prognostically important. The thallium data provided incremental prognostic value to catheterization data (chi-square = 33.7, p < 0.01 ). The extent of the perfusion abnormality was the single best predict or of prognosis (chi-square = 14). Patients with a large perfusion abn ormality had a worse prognosis than that of patients with a mild or no abnormality (Mantel-Cox statistics = 10.6, p < 0.001). Conclusions. I n medically treated patients with coronary artery disease, exercise SP ECT thallium imaging provides independent and incremental prognostic i nformation even when catheterization data are available. The extent of the perfusion abnormality is the single most important prognostic pre dictor.