The maternal cerebral circulation in pre-eclampsia: investigations using Laplace transform analysis of Doppler waveforms
Article first published online: 12 AUG 2005
BJOG: An International Journal of Obstetrics & Gynaecology
Volume 107, Issue 4, pages 492–500, April 2000
How to Cite
Brackley, K. J., Ramsay, M. M., Pipkin, F. B. and Rubin, P. C. (2000), The maternal cerebral circulation in pre-eclampsia: investigations using Laplace transform analysis of Doppler waveforms. BJOG: An International Journal of Obstetrics & Gynaecology, 107: 492–500. doi: 10.1111/j.1471-0528.2000.tb13268.x
- Issue published online: 12 AUG 2005
- Article first published online: 12 AUG 2005
- Accepted 16 November 1999
Objective To compare the maternal cerebral circulation in pre-eclampsia and normal pregnancy using an alternative method of Doppler waveform analysis called the Laplace transform analysis, which provides haemodynamic data additional to standard Doppler indices.
Design A prospective cross-sectional study.
Setting Department of Obstetrics and Gynaecology, Nottingham University Hospital.
Sample The study involved 17 women in the third trimester of a normal pregnancy, 11 with pregnancyinduced hypertension and 26 with pre-eclampsia.
Methods Doppler recordings were obtained from the internal and external carotid and middle cerebral arteries, with the measurements in hypertensive women being carried out before any treatment was given. The waveforms were then subjected to Laplace transform analysis which provides information on vessel wall stiffness and upstream and downstream flow conditions.
Main outcome measures The determination of the Laplace transform analysis parameters, including alpha, the natural frequency of oscillation and real pole, and pulsatility index.
Results Laplace transform analysis demonstrated a significant increase in vessel wall stiffness in all the arteries in hypertensive pregnancies, but this was more marked in pre-eclampsia. The data were also consistent with, but do not prove, increased downstream resistance in the middle cerebral artery in women with pre-eclampsia but not in those with pregnancy-induced hypertension.
Conclusions The Laplace transform analysis of Doppler waveforms yields important physiological information concerning the cerebral circulation in pre-eclampsia, not detected using conventional Doppler indices. The results suggest that both pre-eclampsia and pregnancy-induced hypertension are associated with increased cerebral arterial wall stiffness and that, in addition, there may be cerebral vasoconstriction in pre-eclampsia.