Value of Duke treadmill score in prediction of degree of coronary artery disease

AIM:To assess the value of Duke treadmill score (DTS) in prediction of the degree of coronary artery diseases. METHODS: Enrolled in the study were 169 patients who had positive or doubtful positive treadmill exercise test (TET) and who underwent coronary angiography (CAG) in Tai'an Central Hospital. According to the DTS value, patients were divided into three groups: low-risk DTS group (DTS ≥+5, n=35), moderate-risk DTS group (DTS: -10 to +4, n=77) and high-risk DTS group (DTS ≤-11, n=57). Correlation between DTS and coronary angiography Gensini score was evaluated. Duke formula was as follows: Treadmill score=(exercise duration in minutes)-(5×ST-segment deviation in millimeters)-(4×treadmill angina index) where the treadmill angina index=0 for no-exercise angina, 1 for exercise angina and 2 for exercise-limiting angina. RESULTS: In the high-risk group and moderate-risk DTS group there were more exercise-limiting angina cases and more ST depression ≥1 mm cases, more ST-segment deviation, emergence time and persistence time, and more maximal ST depression and ECG with leads number, but less nonangina, less exercise time, and lower peak heart rate compared with those in low-risk DTS group (P<0.05, P<0.01). In TET, the DTS was found to be related to the degree of coronary artery stenosis. In low-risk DTS group, 69% had no coronary stenosis and 26% had single-vessel stenosis. By comparison, 63% in the high-risk DTS group had 3-vessel or left main coronary disease. Patients with high-risk DTS all had severe coronary artery disease. DTS correlated negatively with Gensini score of CAG (r=-0.74, P<0.05). Gensini score in low-risk DTS group was much lower than that in moderate-risk DTS group and high-risk DTS group. CONCLUSION: DTS is correlated with the severity of coronary artery lesions and is useful for clinical diagnostic and prognostic evaluation for patients suspected of ischemic heart diseases.