Abstract 4227: Jeopardized Myocardium Showed Abnormal Transmural Myocardial Strain Gradient during Adenosine Stress
Visual assessment of wall motion is of limited sensitivity in detecting mild to moderate coronary artery disease. Coronary hyperemia by adenosine infusion has been reported to result in hyperkinetic wall motion in normal myocardium. Recent advances in 2-dimensional speckle tracking technique enable echocardiographic measurement of inner- and outer- myocardial strain separately. We assessed the hypothesis that subendocardial functional reserve is impaired in patients with normal wall motion but impaired coronary flow reserve.
Methods: To evaluate myocardial transmural strain profiles, we performed adenosine-gated myocardial perfusion SPECT and echocardiography[GBP1] . Twenty-five segments with reversible perfusion and 40 segments with normal perfusion were analyzed. Total-, inner-, and outer-myocardial peak radial strains (RS) were derived on the mid-left ventricular short-axis view using newly developed speckle tracking software (Toshiba Medical Systems, Tokyo, Japan) at pre-, peak-, and post-adenosine infusion.
Results: Total-RS in both the reversible and normal perfusion segments was significantly increased during adenosine infusion, and in normal segments, both inner- and outer-RS were greater than the pre-adenosine value (Figure⇓). In contrast, in reversible perfusion segments, inner-RS did not increase during adenosine, and only outer-RS was greater than the pre-and post-adenosine values.
Conclusion: Impaired subendocardial hyperemic functional reserve derived by 2-dimensional speckle tracking may be related to an abnormal hyperemic response shown by SPECT.