Strain-based dobutamine stress echocardiography and Doppler-derived coronary flow reserve in ischemic heart disease

Aims. The aim of this study was to evaluate whether assessment of coronary flow velocity (CFV) and coronary flow reserve (CFR) in left anterior descending coronary artery (LAD) by transthoracic Doppler echocardiography (TTDE) adds diagnostic information to both conventional 2D and strain-based dobutamine stress echocardiography (DSE). Methods. Forty-one patients underwent DSE and subsequent coronary angiography. Wall motion score index (WMSI) was assessed with a 17-segment model. Systolic (Sw), early (Ew) and late (Aw) diastolic myocardial velocities and strain rate (SR) and strain (e) parameters were recorded at rest and during low and peak dobutamine doses in apical 4-chamber, 3-chamber and 2-chamber views. CFR was calculated as the ratio of mean diastolic velocity at peak dobutamine to baseline mean diastolic velocity. Results. CFV was successfully recorded in 38 patients (92%) at baseline and during dobutamine infusion. DSE. Significant LAD stenosis (>50%) was identified in 25 patients. Peak CFR was 2.3±0.6 in the study population and 3.5±0.7 in patients without LAD stenosis (p<0.001). Sensitivity and specificity of abnormal CFR (<2) to detect LAD stenosis were 86% and 63%, respectively. WMSI had a sensitivity and specificity of 65% and 86%. Strain parameters had a sensitivity and specificity of 77% and 89%. In a regression multivariate analysis an abnormal CFR provided independent information compared to WMSI and SR (c2 Model=31.78, incremental p value=0.0002). Conclusions. Thus, left ventricular deformation parameters and Doppler-derived coronary flow reserve have a complementary role in detecting myocardial ischemia. An abnormal CFR by TTDE adds diagnostic value to 2D-strain-based DSE.