Viscoelastic evaluation of fetal umbilical vein for reconstruction of middle cerebral artery

The transplantation of artificial blood vessels with 〈 6 mm inner diameter as substitutes for human arterioles or veins has not achieved satisfactory results. Umbilical vein has been substituted for ar- tery in vascular transplantation, but it remains unclear whether the stress relaxation and creep be- tween these vessels are consistent. In this study, we used the fetal umbilical vein and middle cere- bral artery from adult male cadavers to make specimens 15 mm in length, 0.196-0.268 mm in tu- nica media thickness, and 2.82-2.96 mm in outer diameter. The results demonstrated that the stress decrease at 7 200 seconds was similar between the middle cerebral artery and fetal umbilical vein specimens, regardless of initial stress of 18.7 kPa or 22.5 kPa. However, the strain increase at 7 200 seconds of fetal umbilical veins was larger than that of middle cerebral arteries. Moreover, the stress relaxation experiment showed that the stress decrease at 7 200 seconds of the fetal umbilical vein and middle cerebral artery specimens under 22.5 kPa initial stress was less than the decrease in these specimens under 18.7 kPa initial stress. These results indicate that the fetal umbilical vein has appropriate stress relaxation and creep properties for transplantation. These properties are advantageous for vascular reconstruction, indicating that the fetal umbilical vein can be transplanted to repair middle cerebral artery injury.

Fetal umbilical vein transplantation for the repair of middle cerebral artery injury

It is necessary to investigate the longitudinal tensile mechanical characteristics of the middle cere- bral artery and the fetal umbilical vein prior to applying fetal umbilical vein transplantation for repair of injured middle cerebral artery. Fifteen fresh fetal umbilical vein specimens and 15 normal human fresh cadaver middle cerebral artery specimens were collected for longitudinal tensile testing at the speed of 0.5 mm/min and at normal human temperature. The results showed that under 16.0 kPa physiological stress, the strain value of fetal umbilical vein specimens was larger, while the maximal stress and elastic modulus values were less than those of middle cerebral artery specimens. Our findings indicate that fetal umbilical vein has good elastic properties and the stress-strain curve of the fetal umbilical vein is similar to that of the middle cerebral artery. Fetal umbilical vein transplan- tation can, therefore, potentially repair the injured middle cerebral artery.

Clinical Application of Fetal Umbilical Vein Doppler Parameters in Maternal Preeclampsia

Objective: To observe the changes of fetal umbilical vein (UV) Doppler parameters in pregnant women with preeclampsia (PE) and analyze their predictive values for maternal PE. Methods: Forty-six patients with PE who underwent systematic ultrasound examination in our hospital from December 2017 to May 2021 were included as the subjects, which were divided into two groups according to the severity of the disease (23 cases in each group). And 120 normal pregnant women who underwent health examination in our hospital during the same period were enrolled as the control group. Color Doppler ultrasonography was used to monitor the umbilical vein flow (QUV), left portal vein flow (QLPV), venous catheter flow (QDV), left portal vein (LPV) shunt rate and venous catheter (DV) shunt rate. And the sensitivity and specificity of the related indexes were calculated and analyzed according to the gold standard for clinical diagnosis of PE. Results: As the severity of PE increased, the fetal QUV, QLPV and LPV shunt rates decreased, and the QDV and DV shunt rates increased, with statistically significant differences compared with the control group (P < 0.05). The specificity and sensitivity of the combination of fetal QUV, QLPV, QDV, LPV shunt rate and DV shunt rate in predicting PE were higher than those of the indexes used alone (P < 0.05). Conclusion: The fetal umbilical vein Doppler parameters QUV, QLPV, QDV, LPV shunt rate, and DV shunt rate have some value in predicting PE, but their combination showed greater value, as well as higher diagnostic and clinical significance.