Transcranial Doppler in Preeclampsia and Its Complications.

Plain-language summary

Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality. It is defined by new-onset hypertension after 20 weeks of gestation, often associated with proteinuria and/or systemic complications such as thrombocytopenia, renal impairment, hepatic dysfunction, neurological symptoms, pulmonary edema, or intrauterine growth restriction. Neurological involvement is particularly severe, as it may progress to eclampsia, intracerebral hemorrhage, or ischemic stroke. Detecting early cerebral hemodynamic changes is therefore essential. Transcranial Doppler (TCD) is a non-invasive ultrasound technique that measures cerebral blood flow velocities, particularly in the middle cerebral artery (MCA). It provides systolic, diastolic, and mean velocity values, and calculates indices such as pulsatility index (PI), resistance index (RI), cerebral perfusion pressure (CPP), resistance area product (RAP), cerebral flow index (CFI), and Lindegaard index (LI). These parameters can detect impaired cerebral autoregulation, hyperemia, vasospasm, or cerebral hypoperfusion. Although several studies suggest that preeclampsia is associated with altered cerebral hemodynamics, the diagnostic and prognostic role of TCD remains insufficiently defined. The objective of this prospective, observational, case-control study is to evaluate the diagnostic and prognostic value of TCD in preeclampsia and its complications. The study will be conducted at the Maternity and Neonatology Center of Tunis (Departments of Anesthesia, Intensive Care, and Gynecology-Obstetrics A-D) over six months, from January to June 2025. Participants will be pregnant women in their third trimester, divided into two groups: * Group A: preeclamptic women, defined by hypertension and proteinuria after 20 weeks of gestation, or hypertension/proteinuria with at least one severity criterion (hematologic, hepatic, renal, pulmonary, neurological, or fetal). * Group B: normotensive, non-preeclamptic controls. Exclusion criteria include chronic hypertension, chronic kidney disease, epilepsy, hematologic disease, cardiac or liver disease, COPD, severe anemia, technical difficulties preventing TCD, loss to follow-up, or diagnostic uncertainty. Women with isolated gestational hypertension will also be excluded. TCD will be performed via the temporal window using a 2 MHz pulsed Doppler probe, mainly focusing on the MCA. In Group A, measurements will be obtained before and after antihypertensive therapy, before and after magnesium sulfate administration when indicated, and before and after any complications. In Group B, a single TCD will be performed during the third trimester. The study will compare cerebral blood flow velocities and indices between groups and monitor their evolution over time. Data interpretation will allow classification of findings into patterns such as systemic hypoperfusion, cerebral hypoperfusion with elevated intracranial pressure, hyperemia, or vasospasm. The expected outcome is to establish whether TCD can serve as a reliable diagnostic and prognostic tool in preeclampsia. The results will contribute to a better understanding of cerebrovascular physiology in this condition and may help identify women at higher risk of neurological or systemic complications. Ultimately, this work aims to highlight TCD as a simple, reproducible, and non-invasive tool for clinical management and risk stratification in preeclampsia.

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