Validation of a new noninvasive, method (contrast-enhanced transthoracic second harmonic echo Doppler) for the evaluation of coronary flow reserve - Comparison with intracoronary Doppler flow wire

OBJECTIVES We tested the hypothesis that coronary flow reserve (CFR) in the left anterior descending coronary artery (LAD) as assessed by a new noninv asive method (contrast-enhanced transthoracic second harmonic echo Doppler) is in agreement with CFR measurements assessed by intracoronary Doppler fl ow wire. BACKGROUND Contrast-enhanced transthoracic second harmonic echo Doppler is a novel noninvasive method to detect blood flow velocity and reserve in the LAD. However, it has not yet been validated versus a gold-standard method. METHODS Twenty-five patients undergoing CFR assessment in the LAD by Dopple r flow wire were also evaluated by contrast-enhanced transthoracic Doppler to record blood flow in the distal LAD at rest and during hyperemia obtaine d by adenosine IV infusion. In five patients CFR was evaluated twice (befor e and after angioplasty). RESULTS As a result of the combined use of IV contrast and second harmonic Doppler technology, feasibility in assessing coronary flow reserve equaled 100%. The agreement between the two methods was high. In fact, in all but f ive patients the maximum difference between the two CFR measurements was 0. 38. Overall, the prediction (95%) interval of individual differences was -0 .69 to +0.72. Reproducibility of CFR measurements was also high. The limits of the agreement (95%) between the two measurements were -0.32 to +0.32. CONCLUSIONS Coronary flow reserve in the LAD as assessed by contrast-enhanc ed transthoracic echo Doppler along with harmonic mode concurs very closely with Doppler flow wire CFR measurements. This new noninvasive method allow s feasible, reliable and reproducible assessment of CFR in the LAD. (J Am C oll Cardiol 1999;34:1193-200) (C) 1999 by the American College of Cardiolog y.