Evaluation Of Carotid Arterial Function And Ventricular-carotidarterial Coupling In Pregnancy-induced Hypertension Using Ultrasound Radio-frequency Technique

BackgroundPregnancy is a special physical condition, where maternal multi-systems,especially the cardiovascular system, would have dramatic changes in order tokeep the fetus normal growth. Pregnancy-induced hypertension (PIH) is one ofthe severe complications of pregnancy, which is commonly defined ashypertension and proteinuria occurring after the20th week of gestationin apreviously normotensive woman. The mechanism of PIH remains unclear. Thebasic pathophysiological changes include small arterial spasm all over the body.However, whether the peripheral elastic artery, like carotid artery, would haveabnormal changes has not been fully elucidated. Though cardiac structural andfunctional changes have been studied, the ventricular-arterial coupling is still notfully understood.Purpose1) To evaluate the carotid artery stiffness and elasticity in normal pregnancyusing ultrasound radio-frequency technique,and explore its coupling withcardiac function. 2) To assess carotid intima-media thickness and stiffness and to observe theventricular-carotid arterial coupling in PIH women using ultrasoundradio-frequency technique and traditional echocardiography.Methods1) Thirty-seven NP women were included and thirty age-matched non-pregnanthealthy women severed as controls. Carotid arterial structure, stiffness andcardiac function were evaluated using Quality Intima-Media Thickness(QIMT) and Quantitative Artery Stiffness (QAS) techniques with Esaote MyLab70color Doppler diagnostic Instrument.2）Thirty-two PIH women with mean brachial blood pressure of108mmHgwere included and37age-matched normal pregnant women severed ascontrols.The same parameters were obtained using the same ultrasoundtechniqueas mentioned above.Results1) Normal pregnancy:①The carotid maximal and minimal flow velocities,resistance index (RI), pulsatility index (PI), distensibility coefficient (DC),compliance coefficient (CC) and augmentation index (AIx) were allsignificant lower in NP women than those in non-pregnant women (P＜0.01); Stiffness parameters (α、β), pulse wave velocity (PWV), pressure atinflection point (PT1) and augmented pressure (AP) were all dramaticallyhigher in NP women compared to those in non-pregnant women(P＜0.01).②The carotid maximal and minimal flow velocities, systolic pressure, meanarterial pressure, PT1and PWV gradually increased with the increase ofgestational age, while RI decrease (P＜0.05).③Heart rate, cardiac output,transmitral Doppler flow velocity during early diastole (E) and aortic peakflow velocity were significant higher,buttran smitral E/A ratio was lower in NP women than those in non-pregnant women; Doppler tissue imaging (DTI)showed that a wave velocities on both anterior and lateral sides of the leftventricular wall were significantly higher, while e/a ratio was lower in NPwomen than those in non-pregnant women.④Close and positive correlationwas found between E/A ratio and DC (r=0.2761，P＜0.05); E/A negativelycorrelated with PWV (r=-0.3203，P＜0.01); e/a ratio on the anterior side ofleft ventricular wall was closely and positively correlated with AIx(r=0.3022，P＜0.05).2) PIH:①Carotid IMT, PWV, PT1, AP and AIx were all significantly greater inPIH women compared with NP women (P＜0.01).②Left atrial andventricular sizes, IVS thickness, stroke volume as well as transmitral andaortic flow velocities were all significantly increased in PIH compared withthose in NP (P＜0.01), and E/anterior e and E/lateral e were higher in PIHthan those in NP (P＜0.01).③E/A was not significantly correlated withPWV (r=-0.08432，P＞0.05) in PIH women.Conclusions1) Compared with non-pregnant women, NP women has greater carotidstiffness, which is closely related with cardiac function parameters. With theincrease of gestational age, carotid arterial stiffness significantly increased inNP, while no significant changes were found in IMT.2) Compared with NP women, PIH women had significant thicker carotid IMTand increased stiffness. Cardiac changes included enlarged left atrium andventricle, thickened IVS and impaired left ventricular diastolic function.Ultrasound RF-data technique could be reliably used to assess themorphological and functional changes of the carotid artery both in NP andPIH women. 3）RF-data technique could be reliably used to assess the morphological andfunctional changes of the carotid artery both in NP and PIH women.