Background: Duke Treadmill score (DTS) is an index that provides prognostic information calculated at exercise stress test (EST). 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. Aim: The present study aims to investigate the relationship between the Duke Treadmill score (DTS) and fractional flow reserve (FFR). Methods: The study population consisted of a total of 106 patients who have single-vessel disease, as confirmed by the coronary angiography (CAG), performed following EST, and whose FFRs have been 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, as FFR<0.80 and FFR≥0.80. Results: 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). Conclusion: 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 an invasive management. Background: Duke Treadmill score (DTS) is an index that provides prognostic information calculated at exercise stress test (EST). 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. Aim: The present study aims to investigate the relationship between the Duke Treadmill score (DTS) and fractional flow reserve (FFR). Methods: The study population consisted of a total of 106 patients who have single-vessel disease, as confirmed by the coronary angiography (CAG), performed following EST, and whose FFRs have been 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, as FFR<0.80 and FFR≥0.80. Results: 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). Conclusion: 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 an invasive management.

Background and Objectives: Whole Blood Viscosity (WBV), estimated using the De Simone formula, is a key hemodynamic parameter linked to endothelial dysfunction and atherosclerosis. Its association with significant coronary calcification, defined as a high Coronary Artery Calcium Score (CACS ≥ 100), remains unclear. This study investigated whether calculated WBV predicts high CACS. Materials and Methods: In this single-center, retrospective, cross-sectional study, 403 patients undergoing coronary computed tomography angiography for suspected stable coronary artery disease were included. Participants were stratified into CACS < 100 (n = 258) and CACS ≥ 100 (n = 145). WBV was calculated at High Shear Rate (HSR) and Low Shear Rate (LSR) using the De Simone formula. Multivariate binomial logistic regression adjusted for conventional cardiovascular risk factors was used to identify independent predictors of high CACS. Results: Patients with CACS ≥ 100 were older, more frequently male, and had a higher prevalence of diabetes and hypertension (all p < 0.01). Mean WBV did not differ significantly between groups: WBV-HSR, 4.3 ± 0.5 cP vs. 4.4 ± 0.5 cP (p = 0.456); WBV-LSR, 29.9 ± 8.0 cP vs. 30.4 ± 8.6 cP (p = 0.505). In multivariate models, neither WBV-HSR (OR: 0.489; p = 0.462) nor WBV-LSR (OR: 0.987; p = 0.520) independently predicted high CACS. Age and sex were the strongest independent predictors (p < 0.001). Conclusions: No independent association was found between calculated WBV and high CACS in this cross-sectional study.