Central hemodynamics of hypertensive disorders in pregnancy

BACKGROUND: Preeclampsia is characterized by an increase in peripheral vasoconstriction. Studies of central hemodynamics are limited. Noninvasive evaluation of aortic stiffness and pressure waveform is possible by applanation tonometry. We determined pulse wave velocity (PWV), augmentation index (AI), subendocardial viability ratio (SEVR), and the central to brachial pressure amplification in normotensive, hypertensive, and preeclamptic pregnancies.

METHODS: In 51 normotensive, 38 hypertensive, and 33 preeclamptic pregnancies we measured carotid-femoral PWV. The AI, SEVR, and central pressures were determined by analysis of the aortic pressure waveform derived from the radial artery. Measurements were performed in lateral position after 10 min of rest. Linear regression models and ANOVA multiple comparisons were used for statistical analyses.

RESULTS: There were no differences in age or other baseline characteristics. The mean PWV for the normotensive, hypertensive, and preeclamptic groups was 5.1 m/sec (SD 0.6), 6.2 m/sec (SD 1.0), and 7.0 m/sec (SD 1.3), respectively. The AI was 6.7% (SD 14.0), 17.7% (SD 15.9), and 31.1% (SD 12.4), respectively. The SEVR was 1.38 (SD 0.2), 1.50 (0.2), and 1.48 (0.3), respectively. Central to brachial pressure amplification was 1.6 (SD 0.2), 1.4 (SD 0.2), and 1.3 (SD 0.2), respectively. After adjustment for blood pressure, no significant differences remained between the groups.

CONCLUSIONS: In hypertensive and preeclamptic pregnancies, aortic stiffness and augmentation are significantly higher as compared to normotensive pregnancy. Amplification of central pulse pressure is significantly lower in hypertensive and preeclamptic pregnancies, resulting in relatively higher central pressure. Nevertheless, the supply and demand ratio of the heart is not impaired in hypertensive and preeclamptic pregnancies.