Regional Myocardial Work Measured by Echocardiography for the Detection of Myocardial Ischemic Segments: A Comparative Study With Invasive Fractional Flow Reserve

Figures

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  Figure 1. A representative case of the ischemic LAD with intermediate stenosis. (A) Invasive coronary angiogram demonstrates 50% narrowing in the LAD (red arrow). (B) The corresponding FFR value was 0.72, which was below the ischemic threshold of 0.75, indicating a functionally significant stenosis. (C) The bull's eye plot shows decreased peak systolic longitudinal strains in the apex-anterior, mid-anterior segments. (D) MWI values were impaired mostly in the anterior wall (supplied by the LAD). The regional MWI was 1,411.62 mmHg% and MCW was 1,686.62 mmHg%. (E) LV pressure-strain loop diagram. FFR, fractional flow reserve; LAD, left anterior descending; MCW, myocardial constructive work; MWI, myocardial work index.

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  Figure 2. The MWI and MCW values of left ventricular segments with FFR ≤ 0.75, 0.76–0.80, and >0.80 in the total-vessel group and single-vessel stenosis subgroup. The MWI and MCW values for segments with FFR ≤ 0.75 were significantly lower compared to those with FFR 0.76–0.80, and FFR > 0.80. *p < 0.05, **p < 0.01. FFR, fractional flow reserve; MCW, myocardial constructive work; MWI, myocardial work index.

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  Figure 3. Scatter plots of the MWI (A) and MCW (B) in the total-vessel stenosis group, and of the MWI (C) and MCW (D) in the single-vessel stenosis subgroup vs. FFR values. Both MWI and MCW showed mild but significant positive correlations with FFR values (r = 0.394, p = 0.000 and r = 0.410, p = 0.000 in total group; r = 0.452, p = 0.000 and r = 0.466, p = 0.000 in single vessel group). FFR, fractional flow reserve; MCW, myocardial constructive work; MWI, myocardial work index.

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  Figure 4. ROC analyses of MW parameters for the diagnosis of left ventricular segments with FFR values ≤ 0.75 (A) and ≤ 0.80 (B) in the total-vessel group, and FFR values ≤ 0.75 (C) and ≤ 0.80 (D) in the single-vessel subgroup. (A) The best MWI cutoff value to detect LV segments perfused by vessels with an FFR value ≤ 0.75 in the total-vessel group was 1,623.7 mmHg% [sensitivity, 78.4%; specificity, 72.2%; AUC, 0.768 (0.653–0.883)]. (B) In the total-vessel group, the best cutoff value was 1,962.4 mmHg% [77.0%; 72.2%; 0.767 (0.661–0.872)] for MCW. (C) In the single-vessel subgroup, the best cutoff value was 1,412.1 mmHg% [93.5%; 63.6%; 0.808 (0.652–0.965)] for MWI. (D) In the single-vessel subgroup, the best cutoff value was 1,943.3 mmHg% [(84.8%; 72.7%; 0.800 (0.657–0.943)] for MCW. FFR, fractional flow reserve; MW, myocardial work; ROC, receiver operator characteristics.