Ascending aorta wall distensibility in healthy and hypertensive subjects: assessment by tissue Doppler velocity imaging

Purpose: The stiffening of aorta and other central arteries is a potential risk factor for increased cardiovascular morbidity and mortality. The purpose of this study was to investigate the potential clinical application of tissue Doppler imaging (TDI) for motion measurement of the aortic wall in healthy and hypertensive adults. Methods: We examined 31 hypertensive without a history of coronary artery disease (negative echo-stress test) and 31 age- and sex-matched healthy adults. Arterial pressure was measured with a mercury sphygmomanometer before echocardiography was performed. Pulse wave velocity (PWV) was measured as a standard parameter of arterial stiffness by oscillometric pulse wave analysis system (TensioMed Arteriograph, Hungary). Aortic M-mode and TDI parameters were measured 3 cm above the aortic valve. Aortic distensibility and aortic stiffness index (SI) were calculated using accepted formulae. Maximum velocity of the first and second systolic wall expansion peaks (S, S1,cm/sec), acceleration time (AT, msec), maximum velocity of early (E, cm/sec) and late (L, cm/sec) diastolic retraction velocity peaks of the ascending aorta and wall peak systolic strain (ps-e, %) were determined (EchoPAC, version 7.0, GE Ultrasound). Results: Observational variability was low. In hypertensive patients wall motion waveform showed lacking L, mixed S and S1 peaks, and blunted S compared with controls. S, E and ps-e were significantly lower in hypertensive than in healthy subjects. Reduced PWV and increased SI indicated increased aortic stiffness in both male and female hypertensive subjects. Age, diastolic blood pressure and sex were significant independent factors modulating S, while diastolic blood pressure and age were significant independent factors modulating E. PWV decreased with increasing age or systolic blood pressure. Duration of hypertension correlated with SI (r¼0.57, p,0.005), distensibility (r¼20.54, p,0.005) and S velocity (r¼20.62, p,0.001). There was a negative correlation between aortic stiffness and S velocity (r¼20.51, p,0.005). Multiple stepwise linear regression analysis in the hypertension group revealed that aortic S velocity (b¼0.35, p¼0.006), ps-e (b¼0.38, p¼0.007) and duration of hypertension (b¼20.51, p¼0.001) were the main predictors of aortic distensibility (overall R2 ¼ 0.53). Conclusions: Our data show that TDI measurement of ascending aortic wall motion provides qualitative and quantitative wall motion features differentiating hypertensive from healthy adults and reflecting aortic compliance changes related to age and sex.