Carotid-radial Pulse Wave form and Velocity in Normotensive and Hypertensive Pregnant Women at University Teaching Hospital (UTH), Lusaka, Zambia

Background: Hypertensive disease in pregnancy continues to be one of the leading causes of maternal death. Pregnancy induced hypertension (PIH) is said to be accompanied by several cardiovascular pathophysiological changes including increases in arterial stiffness. Pulse wave velocity (PWV) is a method for measuring arterial stiffness. Both the pulse wave form and the velocity are said to change in PIH. However, studies documenting these characteristics of the pulse wave have mainly been in the Caucasian population.

Aims and Objectives: To establish the characteristics of the carotid-radial (cr) pulse wave in normotensive (NTN) and hypertensive (HTN) pregnant black African women at the UTH in Lusaka, Zambia.

Methodology: This cross-sectional study comprised of 26 systemically selected pregnant women between the ages 18-45 years old who met the criteria. A structured interview was used to collect socio demographic data. Anthropometric measurements were taken. After a 15 minute rest, peripheral systolic and diastolic blood pressures (BP) were measured. The PWV measurement involved applying non-invasive piezoelectric sensors on the skin over the carotid artery in the neck and the radial artery on the wrist (carotid-radial segment crPWV). Using IBM® SPSS® version 20.0 analyses were made using mann - whitney and spearman correlation tests. A 95% confidence interval (CI) and P-value of <0.05 were set. Quality recordings were obtained from the crPWV recording processes showing the wave forms and specific measurements were made.

Results: The anthropometric measurements were comparable between the 2 groups. There were significant changes in the pulse wave forms. While the normotensive participants had the type C wave form, the type A wave form was recorded from hypertensive participants. The augmentation pressure (AP) in NTN was 4±5 mmHg while it was 9±8 mmHg in HTN, indicating an increase in pressure difference from the systolic shoulder to the peak of the pulse wave (p <0.05). There was also a significant increase in the augmentation index (Aix) (1±22% vs 16±23%) (p<0.05). The hypertensive pregnant women also had a significantly higher PWV (9±4 m/s vs 13±7 m/s) (p<0.05).

Conclusion: Distinct differences were seen in the cr pulse wave forms and velocity between normotensive and hypertensive individuals with PIH indicating an increase in arterial stiffness. These findings suggest the presence of significant peripheral vascular changes that may underly the pathophysiology of PIH.