Association between fractional flow reserve and Duke treadmill score in patients with single-vessel disease

Duke treadmill score (DTS) is an index that provides prognostic information calculated at exercise stress test. Fractional flow reserve (FFR) is an invasive method used to evaluate intermediate coronary stenosis. The direct relation of DTS and FFR has not been studied to date.

The present study aims to investigate the relationship between the DTS and FFR.

The study population consisted of a total of 106 patients with single-vessel disease, as confirmed by coronary angiography performed following EST, and whose FFRs were measured. The patients were separated into three groups according to the DTS values: low risk (DTS ≥ +5), intermediate risk (-10 ≤ DTS ≤ +4), and high risk (DTS ≤ -11). According to the FFR values, the patients were separated into two groups: FFR < 0.80 and FFR ≥ 0.80.

Angina symptoms and chronic heart failure were more frequent in the group with FFR < 0.80 than the group with FFR ≥ 0.80; respectively, 95% vs. 69.8%, p = 0.020 and 15% vs. 3.5%, p = 0.045. The mean DTS value was lower in the group with FFR < 0.80 than the group with FFR ≥ 0.80 (1.60 vs. 5.07; p = 0.011). However, there were no statistically significant differences in the DTS risk groups among the FFR groups (p = 0.070). A weak positive correlation was found between the numerical DTS and FFR values (r = 0.139; p = 0.156). When the patients with high-risk were excluded, a statistically significant relationship was determined between the FFR and in the groups with low- and intermediate-risk in terms of the DTS values (p = 0.029).

In conclusion, our study results showed an association with FFR and in the groups with low and intermediate risk in terms of the DTS values. DTS levels can be useful to determine patients who require invasive management.