[Quantitation of the severity of coronary artery disease using thallium-201 tomographic scores]

To evaluate coronary artery disease, a new quantitative thallium-201 (201T1)-tomographic scintigraphic score (TSS: modified Massie's score) using oxygen consumption (METS) was developed and compared with coronary angiographic score (CAG-S) in 27 patients (eight patients with normal coronary angiograms, and five, eight and six patients with one, two and three vessel disease, respectively) without previous myocardial infarction. All patients received both coronary angiography and the treadmill exercise test using 201T1-myocardial single photon emission computed tomography (SPECT) within two weeks. The redistribution area (RA) and washout rate area (WA) were derived from the circumferential profile analysis using apical (A), midventricular (M) and basal (B) short-axis images. To obtain TSS values, the sum of these values was divided both by percentage of the age-predicted maximal heart rate (%PMHR) and the METS value as follows: TSS = [RA (A, M, B) + WA (A, M, B)]/(%PMHR x METS). The results were as follows: 1. TSS values were 6.4 +- 1.6, 9.4 +/- 2.2, 24.2 +/- 12.0 and 30.6 +/- 5.0 (mean +/- SD) in normal, one, two and three vessel disease groups, respectively. Significant differences were found among each group except between two and three vessel disease groups. 2. The detectability of significant coronary artery disease was 89% (17/19) except in two patients with one vessel disease. 3. A high correlation coefficient was found between TSS (X) and CAG-S (Y), i.e., Y = 0.8X - 3.5 (r = 0.944, p less than 0.001). It was concluded that the tomographic scintigraphic score (TSS) is useful not only for detecting, multivessel disease but also for totally-evaluating its severity, extent and influence on collateral supply, and could be used for analyzing prognosis and the selection of therapeutic interventions.