Risk Assessment with Duke Treadmill Score in Patients with Coronary Artery Disease: Comparison with Scintigraphic and Angiographic Findings

Kang, Do Young; Lee, Jaetae; Lee, Sang Woo; Chung, Shin Young; Ahn, Byeong Cheol; Yang, Dong Hun; Park, Hun Sik; Cho, Yong Keun; Chae, Shung Chull; Jun, Jae Eun; Park, Wee Hyun; Lee, Kyu Bo

Abstract

BACKGROUND AND OBJECTIVES: The Duke treadmill exercise score (DTS) has been used to stratify patients with coronary artery disease into low-, moderate-, and high-risk groups. To determine the coronary angiographic and myocardial scintigraphic correlates of these scores, we have compared the degree of risk assessed by the DTS and with those obtained by angiography and SPECT.
SUBJECTS AND METHODS
The subjects were classified into low risk (DTS >or= 5), moderate risk ( 4 > DTS >or= -11) and high risk (DTS < -11) groups according to their DTS. To evaluate the agreement in the risk assessment, 102 patients with angiographically proven coronary artery disease, were assessed for the extent of their coronary artery disease by the number of stenotic vessels, and from their exercise Tc-99m MIBI myocardial SPECT findings.
RESULTS
Of the 102 subjects, 52 (51%) had one-vessel, 25 (24.5%) had two-vessel, and 25 had three-vessel disease. With the results of the coronary angiography and SPECT, the patients were re-classified into three groups; group 1 (n=20) had three-vessel disease and/or >10 abnormal segments, group 3 (n=41) had one vessel disease and less than 5 abnormal segments, and group 2 (n=41) included the remaining subjects. Based on the DTS, 37 (36%) were in the low-risk, 44 (43%) in the moderate risk, and 21 (21%) in the high risk groups. In the low-risk DTS patients, 32.4% were in group 1, 35.2% in group 2 and 32.4% in group 3. In relation to the subjects with moderate risk DTS, there were 9, 16 and 55% in groups 1, 2 and 3, respectively. Whereas, there were 19, 24 and 57% in groups 1, 2 and 3 with high risk DTS subjects, respectively.
CONCLUSION
Although considerable overlap exists, the degree of risk assessed from the angiography and SPECT findings were different from those by DTS. We suggest that patients classified into the low-risk DTS group may have extensive coronary artery disease, or myocardial perfusion SPECT abnormalities, whereas patients in the high-risk DTS group may be normal, or have mild coronary artery disease or mild SPECT abnormalities.