Can pulse wave velocity be measured in the fetal ascending aorta?

Abstract

BackgroundRoutine ultrasound exams are conducted to assess fetus development. Heart defects and cardiac function are the main areas investigated in an ultrasound assessment. However, prenatal assessment of the fetal arterial stiffness is yet to be established in the ascending aorta.AimTo investigate whether pulse wave velocity (PWV) can be determined in the fetus ascending aorta using ultrasound examination.Methods35 fetuses (19 normal, 16 growth restricted) were included in the study. High quality recordings were achieved in 6 normal and 8 fetuses diagnosed with fetal growth restriction (FGR). Images of the diameter and blood velocity in the ascending aorta were recorded (Voluson, GE and Samsung) with a curvilinear probe 2–8MHz/1–7MHz. The diameter and velocity waveforms were extracted from DICOM images, offline, using in-house developed codes in Matlab. The extraction was based on thresholding of the grey-scale images. Local PWV was determined using the ln(D) U-loop method [1].ResultsPWV in the fetal ascending aorta increased with gestational age in both normal (r2 = 0.77) and FGR (r2 = 0.55) fetuses. Mean PWV in the fetal ascending aorta per gestational week was 0.045m/s in normal and 0.066m/s in FGR fetuses, with a percentage difference of 32%.Figure 1PWV vs gestational age in weeks for normal (blue diamond ♦) and FGR (red squares ■) fetuses and the trendlines with equations describing them and their r2 values. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)ConclusionsDespite the challenging ultrasound images of the fetal ascending aorta, local PWV measurement has proven to be possible through recordings of diameter and blood velocity. PWV increases with gestational age and it is higher in FGR than normal fetuses. Further studies are needed to determine the potential clinical predictive value of fetus PWV.