Effects of aging changes on the compliance of human umbilical cord vein as the material for vascular grafting

Wenchun LI; Yifei ZHANG; Jun WANG; Tiezhu HUANG

ABSTRACT

BACKGROUND:

So far it has not achieved satisfactory effects to use synthetic blood vessels (diameter＜ 6 mm) as the substitutes for human small arteries or veins when clinical reconstructive vascular operations are performed. So, study on the substitutes for small arteries and veins has been a problem demanding prompt solution at present.

OBJECTIVE:

To observe the pressure-volume (P-V) relationship of umbilical cord vein of different gestational ages so as to provide theoretical basis of biomechanical properties for the clinical application of human umbilical cord vein as material for vascular grafting.

DESIGN:

Non-randomized controlled experiment.

PARTICIPANTS:

The experiment was completed in the Laboratory of Medical Biomechanics, Yunyang Medical College in June 2004. Umbilical cord veins of 50 normal fetuses were collected on spontaneous miscarriage or labor with the pregnant women's permission by the Department of Obstetrics and Gynecology, Shiyan Taihe Hospital. The gestational age of the fetuses ranged from 24 to 42 weeks and the pregnant women aged 20to 30 years. Among them, 8 cases with gestational age of 24-27 weeks,7cases 28-32 weeks,8 cases 33-36 weeks,4 cases 37 weeks,5 cases 38weeks, 5 cases 39 weeks , 5 cases 40 weeks , 4 cases 41 weeks and 4cases 42 weeks.

INTERVENTIONS:

Umbilical cord veins of 50 normal fetuses were collected. A 2-cm long segment of each umbilical cord was measured and labeled at both ends. Then they were cut off and put into normal saline (NS). The umbilical veins were carefully stripped from the cord; its two ends were fixed on the biomechanical experiment stand of soft tissues. The P-V relationship of fetal umbilical cord vein was measured, and then the compliance calculated.MAIN OUTCOME

MEASURES:

Pressure, volume and compliance of different umbilical cord veincurve of pressure-volume relationship of the umbilical cord vein was similar at week 37 to 40 but decreased significantly at week 28 and week 42. After regression analysis twice, it was found that the absolute value of regression vein increased with the increasing of gestational age[24-27 weeks (2.22±0.34)cord vein collected at 37 to 40 weeks of gestational age was similar. When the umbilical cord veins older than 42 weeks or under 28 weeks were compared, there was significant difference in their compliance (F=65.84-86.52, P＜ 0.01).

CONCLUSION:

Human umbilical cord veins are good substitutes for The relationship between compliance and gestational age. Our studies suggest that the umbilical cord vein, whose gestational ages range from 37to 40 weeks, is a material of choice for the transplantation.