Coronary fractional flow reserve (FFR) as an invasive, and dobutamine stress echocardiography (DSE) as a noninvasive technique were used to detect critical coronary stenosis. This study was undertaken to assess correlation between these two techniques by using tissue Doppler, strain rate (SR), and strain imaging (S).
Methods: In 17 patients (aged 54.9+/-12.6, 4 F), a total of 22 vessels were studied. On dobutamine stress echocardiography, baseline and peak systolic (Sm), early (Em) and late (Am) diastolic myocardial velocities, SR and S were recorded from parasternal view (mid-posterior segment) for radial and apical view (mid-septum) for longitudinal deformation. Then coronary FFR was performed by using intracoronary adenosine infusion, and the value of < or = 0.75 was accepted as critical coronary stenosis.
Results: FFR was found to be significant in 10 vessels (FFR critical). Baseline Sm, Em/Am, SR, S values, and peak Em/Am, SR, S values were similar between critical or noncritical FFR groups. Baseline Sm and Em, and change between baseline and peak Sm and S were significantly higher in noncritical FFR group (p < 0.01, < 0.05, < 0.001, < 0.001, respectively). In all vessels, FFR after adenosine infusion showed a poor correlation with WMSI, Em, Am, Em/Am values, and the change in SR values (r = -0.22, 0.16, -0.14, 0.21, 18, respectively) showed a good correlation with the change in S (r = 0.51; p = 0.014), and a very good correlation with the change in Sm values (r = 0.77; p < 0.001) during DSE. When FFR values at left coronary system were analyzed for longitudinal SR and S values, it had a mild correlation with SR (r = 0.47, p = 0.044) and a good correlation with S (r = 0.66, p = 0.002).
Conclusion: The quantification of regional myocardial deformation by using DSE rather than the motion would be more appropriate in detecting the ischemic dysfunctional segment supplied by the critical coronary stenosis. Strain measurement during the dobutamine infusion may provide an information on the FFR results of the culprit vessel.