Abstract 6140: Value of Baseline Inferolateral Myocardial Contractile Function Assessed by Tissue Doppler Imaging to Predict Reduction of Functional Mitral Regurgitation with Low-Dose Dobutamine in Patients with Dilated Cardiomyopathy
Dobutamine (DOB) has the ability to reduce functional mitral regurgitation (FMR) in dilated cardiomyopathy (DCM) and DOB stress echocardiography might be useful to make an optimal selection of surgical treatments such as isolated myocardial revascularization or in combination with valve repair. The purpose of this study was to investigate the relationship between baseline echocardiographic parameters including regional myocardial function and reduction of FMR with DOB. We studied 38 DCM patients with reduced left ventricular ejection fraction (LVEF) (33±11%) and FMR. Standard and tissue Doppler echocardiography were performed at rest and with low-dose DOB (10 μg/kg/min), and we obtained LV volume, LVEF, tenting area of mitral valve (enclosed between the annular plane and leaflets), mitral annular area (MAA), FMR fraction and, longitudinal peak systolic strain rate (Ssr; absolute value) in the 6 segments at mid-LV level using apical images. According to the reduction of FMR with DOB, patients were divided into a large reduction group (%FMR reduction ≥ 30%) and a small reduction group (<30%), 17 and 21 patients, respectively. DOB increased LVEF and Ssr in all segments, and decreased LV volumes, tenting area, MAA, and FMR fraction (%FMR reduction = 28±19%) in all subjects. Regarding the baseline parameters, tenting area and FMR fraction in large reduction group were significantly smaller, and anterolateral Ssr and inferolateral Ssr in large reduction group were significantly larger than those in small reduction group. However, there was no difference in baseline LV volume, LVEF, MAA, nor Ssr in any other segments. In ROC curve analysis, the area under the curve for tenting area, FMR fraction, anterolateral Ssr, and inferolateral Ssr were 0.69, 0.70, 0.72, and 0.81, and baseline inferolateral Ssr > 1.00/s was the best predictor of DOB-induced %FMR reduction ≥30% with a sensitivity of 88% and a specificity of 75%. Baseline inferolateral myocardial contractile function was associated with DOB-induced reduction of FMR, suggesting that assessment of inferolateral myocardial preserved function is important for an optimal selection of surgical treatment in patients with FMR.