A Preliminary Study In The Value Of Doppler Ultrasonography On The Assessment Of Large-Arterial Stiffness

Backgrounds and ObjectivesIncreased large-arterial stiffness caused by aging and hypertension is of predictive significance for cardiovascular events. It is important to search noninvasive parameters for arterial stiffness. This study aims to preliminarily investigate the feasibility and applicability of tissue and doppler ultrasound, by which aging changes and arterial stiffness of abdominal aorta were assessed, for evaluation of large-arterial stiffness in hypertensive patients. MethodsThe study population were recruited from outpatient, inpatient and physical examination center of our hospital from September 2015 to December 2015.The normal aging group(N)consisted of 119 parcitipants(58 male) with a median age of 49 years(range, 18 to 75 years). Patients with cardiovascular diseases, severe liver disease, renal disease, pulmonary disease, Metabolic disorders and connective tissue disease, which could have an adverse effect on the cardiac structure and function, were excluded. The HT group included 98 subjects with primary hypertension(men 60) with a mean age of 64.76 +/- 9.42 years. Patients with secondary hypertension, coronary heart disease, pulmonary heart disease and cardiomyopathy were excluded.44 subjects(22 men, mean age 64.66±6.22 years) were selected from the normal group as the normal control group(NC),whose age and gender matched with the HT group. HT group were divided into three groups based on the duration of hypertension: group HT-a(?5 years, n=38),group HT-b(5-10 years,n=20),and group HT-c(?10years,n=40). Echocardiography and electrocardiograph were performed simultaneously to acquire conventional echocardiographic parameters, including LV diameter in systole and diastole, left ventricular wall thickness, LVEF, early and late diastolic velocity of transmitral inflow(E, A), early diastolic velocity of mitral annulus( e, e1), average velocity of e and e1,E/A, E/eave, the arterial-stiffness parameters including Va-p(velocity difference of arterial and posterior wall motion), Tt'(the mechenical wave transmit time adjusted by height from the onset of left ventricular contraction to anterior motion of anterior wall of abdominal aorta), Tf'(flow wave transmit time adjusted by height from the onset of left ventricular ejection to contraction of of abdominal aorta).To find the transmit time,we measured the time interval(Tt1/Tt2/Tf1/Tf2) from R wave of QRS to the foot of the waveform,and subtracted Tf1/Tt1 from Tf2/Tt2(Tf=Tf2-Tf1/Tt=Tt1-Tt2).The foot of the Doppler waveform was identified by the intersection of the upstroke of the wave with the baseline of zero frequency. ResultsThere was significant correlation between age and Va, Va-p, Tt',Tf'(r=-0.360,-0.484,-0.629,-0.566,respectively, all p<0.01),and age is the most powerful independent risk factor for Va, Va-p, Tt',Tf'in normal group(p<0.01).Compared with NC group, Va-p was lower in the whole HT group(p<0.01),whereas Tf',Tt'were lower only in subgroup HT-c(p<0.05).There was no difference for Va between HT subgroups. SBP was negatively correlated with Va-p, Tt',Tf'(r=-0.294?-0.447?-0.481,respectively,all p<0.01)and an independent risk factor of Va-p, Tt',Tf'in HT group(p<0.05);In N group, there were significant correlations between parameters of arterial stiffness and those of diastolic function [eave:r=0.353—0.436,p<0.01);E/A: r=0.334—0.490,p<0.01;E/eave:r=-0.211—-0.292,p<0.05)].In HT group,there were correlations between Tf', Tt'and eave(r=0.262?0.375,respectively, all p<0.05),E/eave(r=-0.211?-0.304,respectively, all p<0.05). Va was also related to E/eave(r=-0.233,p<0.05).However, there were no correlations between parameters of arterial stiffness and LVEF among all groups. ConclusionsAmong all Doppler-derived parameters of arterial stiffness, Va,Va-p,Tt',Tf'are parameters which can reflect the aging-related changes of large-arterial stiffness in normal. SBP is an independent predictor of Va-p?Tt'?Tf',and can reflet changes of large-arterial stiffness in different degree in hypertension,which can provide methodoligical basis for assessment of large-arterial stiffness.Parameters related to changes of aging of artery in normal and arterial stiffness in hypertensive patients are correlated with those on diastolic function to a certain degree, but not associated with those on systolic function.