Resting multilayer 2D speckle-tracking transthoracic echocardiography for the detection of clinically stable myocardial ischemic segments confirmed by invasive fractional flow reserve. Part 1: Vessel-by-vessel analysis.

PURPOSE

To detect stable ischemic left ventricular (LV)-segments confirmed via invasive fractional flow reserve (FFR) by quantitative longitudinal-strain (LS) determined using resting multilayer TTE.

METHODS

A retrospective analysis of 39 stable patients (32 males; 65.8±11.9years) with 46 coronary arteries with ≥50% stenosis confirmed by invasive coronary angiography who underwent invasive FFR measurement and TTE (Vivid E9, GE). On TTE, regional LS (absolute values) were calculated in whole, endocardial, and epicardial layers perfused by stenotic coronary arteries.

RESULTS

Of the 46 vessels, FFR values of <0.75, ≥0.75, ≤0.80 and >0.80 were observed in 17, 29, 27 and 19 vessels, respectively. In a vessel-by-vessel analysis, the whole-layer and endocardial LS were significantly smaller in LV-segments perfused by vessels with an FFR<0.75 than in those with an FFR≥0.75, but epicardial LS was not. In ROC curves, the best cutoff values of whole-layer, endocardial and epicardial LS were, respectively, 14.0% (sensitivity, 94%; specificity 38%; area under the curve, 0.685), 10.0% (47%; 86%; 0.664) and 14.0% (100%; 24%; 0.640) to detect LV-segments with an FFR<0.75; and 14.0% (82%; 37%; 0.561), 10.0% (33%; 84%; 0.573), and 14.0% (89%; 21%; 0.538) to detect LV-segments with an FFR≤0.80.

CONCLUSION

For stable subjects with coronary arteries with ≥50% stenosis, the regional whole-layer and endocardial LS were significantly smaller in LV-segments perfused by vessels with an FFR<0.75 than in those with an FFR≥0.75, but epicardial LS was not; and that the whole-layer and endocardial LS had a modest diagnostic efficiency in identifying LV-segments perfused by vessels with an FFR<0.75.