Usefulness of pulse-wave Doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT
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False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58 +/- 8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56 +/- 7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 mu g / kg / min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and / or left circumflex coronary artery (CX) with narrowing (greater than or equal to 50 % diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E / A ratio was lower in patients with CAD when compared to patients without CAD (0.78 +/- 0.2 versus 1.29 +/- 0.11 p < 0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19 +/- 0.3 versus 0.78 +/- 0.2 p < 00001). When the cut off point for the E / A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E / A were 89% and 86 %, respectively. The peak stress EIA ratio was higher than I in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54 % +/- 17 versus 99% +/- 24 p = 0.01). The analysis of S velocity increase yielded 81% sensitivity and 76 % specificity for prediction of CAD when a 70 % increase was accepted as a cut-off value. Pulse-wave Doppler tissue sampling during DSE may help to identify false positive inferior wall defects detected by SPECT.