| Objective: The purpose of this study was to evaluate elastic properties of the proximal aorta assessed by tissue Doppler imaging (TDI) in patients with dilated cardiomyo- pathy (DCM).Methods: Thirty-three patients with DCM (13 female, 20 male; mean age 45.24±11.29 years) were selected,while 30 healthy volunteers (12 female,18 male; mean age 45.57±11.77 years) matched with DCM group in age and gender as control group. After measuring arterial pressure, all subjects immediately examined by conventional echocardiography at left lateral decubitus position and linking ECG at the same time. Internal aortic systolic and diastolic diameters were obtained at 3cm above the aortic valve with M-mode echocardiography. Aortic distensibility (cm2·dynes-1) and aortic stiffness index were calculated using formulas. On long axis view of ascending aortic tissue velocity imaging (TVI), ascending aortic upper wall tissue velocities (Aortic S, E, A, cm/sec), time before acceleration and expanding acceleration were measured 3cm above the aortic valve (the same point as the former) on TVI curve. Left ventricular ejection fraction (LVEF) was calculated by modified Simpson's method.Results:1 The aortic stiffness index was significantly higher (3.38±0.72 vs 1.83±0.47, P<0.05), while aortic distensibility and aortic S velocity were significantly lower respectively (0.70±0.18cm2dynes-1 vs 1.24±0.32cm2dynes-1 p< 0.01; 4.40±0.69cm/s vs 6.45±1.29cm/s p<0.01) in patients with DCM than those in healthy subjects. Compared with those of healthy subjects, aortic E, A velocity and expanding acceleration were also lower in DCM patients, but no statistical significance. Statistical significance was noted in left ventricular ejection fraction between two groups(r=p<0.01).2 In DCM group, aortic S velocity showed a significant negative correlation with aortic stiffness(r=-0.68, p<0.01), and a positive correlation with aortic distensibility(r = 0.39, p<0.05); Aortic upper wall expanding acceleration was negatively correlated with (r=-0.37, p<0.05) aortic stiffness. In control group, significant negative correlation was noted between aortic S velocity and aortic stiffness (r=-0.69, p<0.01), and significant positive correlation between aortic S velocity and aortic distensibility(r=0.60, p<0.01); Aortic E velocity was negatively correlated well with aortic stiffness(r=-0.51, p<0.01), and positively with aortic distensibility(r=0.39, p<0.05). In both group aortic S velocity had a good correlation with artic stiffness. 3 In both group, significant positive correlation was found between age and aortic stiffness (r=0.45, p<0.05; r=0.63, p<0.01, respectively). In DCM group a negative correlation was noted between age and aortic distensibility(r = -0.38, p<0.05), and age was significantly negative correlated with aortic S wave velocity(r=-0.59, p<0.01). In the control group, age was significantly negative correlated with aortic distensibility and aortic S wave velocity(r=-0.63, p<0.01; r=-0.76, p<0.01, respectively).Conclusions: 1 Reduced aortic S velocity is associated with increased aortic stiffness. Elastic properties of the aorta can be assessed by direct measurement of the movements in the upper aortic wall with TDI; 2 In patients with DCM aortic stiffness increased and aortic S velocity reduced; 3 Age is a definitive clinical factor for aortic stiffness; 4 Compared with traditionary M-mode method, TDI is more simple, more direct and have relative fewer interference factors.
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