Carotid Arterial Stiffness, Left Ventricular Function And Ventricular-Arterial Coupling In Middle And Old Age Male Patients With Metabolic Syndrome

Objective:This study aims to evaluate carotid arterial stiffness and left ventricular function in middle and old age male patients with metabolic syndrome using ultrasonic technology, and to explore the clinical application value of ultrasonic technology in assessing ventricular-arterial coupling in these patients.Methods:86 subjects with metabolic syndrome(MetS) were divided into 2 groups:normal left ventricular ejection fraction(EF) group(MetSN), EF≥50%,n=52) and abnormal EF group(MetSA,EF<50%,n=34). MetS was defined according the new unified definition proposed by six leading academic institutions such as the International Diabetes Federation Task Force on Epidemiology and Prevention, American Heart Association (AHA) and National Heart, Lung and Blood Institution(NHLBI). Additionally,35 age-matched healthy males who are free metabolic disorders and cardio-vascular diseases verified by a detailed history, physical examination, blood tests and biochemical assays, ultrasonic testing and ECG examination.The following measures were used in the present study:the measurement of left brachial blood pressure at rest, recording of the systolic pressure(SBP) and diasolic pressure(DBP), the assessment of common carotid arterial intima-media thickness(IMT) and diameters which were measured during end diastole(Dd) and end systole(Ds) using high frequency ultrasonography. Ultrasound and concomitant brachial blood pressure measurements were used to calculate the following indices of arterial elasticity:carotid arterial distensibility coefficient(DC), Young’s elastic modulus(YEM), and stiffness index(SI); Left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume(LVESV), left ventricular stroke volume(SV), left ventricular isovolumic contraction time(ICT), ejection time(ET), left ventricular isovolumic relaxation time(IRT) were measured by echocardiography. Finally, the following indices of cardiovasular function were calculated including left ventricular Tei index(Tei), effective arterial elastance(Ea), left ventricular end-systolic elastance(Ees) and ventricular-vascular coupling index(VVI).Result:This study revealed several findings. First, compared with patients in the control group, the DC was decreased respectively (0.0014± 0.0005mmHg-1,0.0012±0.0004mmHg-1vs.0.0032±0.0009mmHg-1) and the YEM (331.76±105.46kPa,377.06±114.60kPa vs.171.54±44.3kPa), SI(7.06± 2.03,8.09±2.4 vs.3.83±0.89) were increased respectively in the MetSN and MetSA groups (P<0.05). Regarding the DC, the YEM and the SI have not been observed significant difference in the MetSN and MetSA groups(P>0.05). Second, compared with the control, the EF was decreased (0.37±0.07 vs.0.71±0.06) in MetSA group(P<0.05). The EF has no significant difference in the control and MetSN groups(0.70±0.07)(P>0.05); In addition,The Tei index (0.99±0.20 vs.0.38±0.4) was increased in MetSA group, which was higher than MetSN group (0.58±0.10). And the Tei in MetSN group was higher than the control(P<0.05). Third, compared with the control, the Ea was increase respectively(1.95±0.50 mmHg/ml,1.89±0.43mmHg/ml vs.1.51±0.19mmHg/ml) in the MetSN and MetSA groups(P<0.05). And the Ea has no significant difference in the MetSN and MetSA groups(P>0.05); Furthermore the Ees was increased (4.59±1.56mmHg/ml vs.3.62±0.92mmHg/ml) in the MetSN group, and it was decreased(1.04±0.37mmHg/ml) in the MetSA group(P<0.05); Besides, the VVI was increased (1.94±0.59 vs.0.42±0.13) in the MetSA group, which was higher than the MetSN group (0.44±0.14) (P<0.05). And the VVI has not been observed significant difference in the control and MetSN groups(P>0.05). Forth, the simple regression analysis showed that the VVI was positively correlated with the Tei (b=2.72, P<0.01), and R2= 0.565. But the Tei index did not contribute to the VVI in the control and MetSN groups(P>0.05).Conclusion:In middle and old age male patients with MetS, the stiffness of carotid artery is increased, and the left ventricular global function reduce which is obvious in the EF<50% group. The ventricular-arterial coupling is abnormal in the MetSA group, and this state of suboptimal coupling is deteriorated with the decrease of left ventricular global function; In MetSN group, the left ventricular end-systolic elastance and the Tei index is increased and the ventricular-arterial coupling is normal, which indicates that in these patients with EF of 50% or more, it is possible that the left ventricular diastolic function is decreased, while left ventricular contractility is compensatory increased to maintain the normal state of ventricular-arterial coupling and meet the demands of the metabolizing tissues. And ultrasonic techonolgy is safe, sensitive and accurate in assessing cardiovascular function.