Increased Salt Sensitivity of Ambulatory Blood Pressure in Women With a History of Severe Preeclampsia

Cardiovascular diseases are the principal cause of death in women in developed and developing countries and are importantly promoted by hypertension. Salt sensitivity of the blood pressure is considered as an important cardiovascular risk factor at any blood pressure level. Severe preeclampsia is a hypertensive disorder of the pregnancy that also arises as a risk factor for cardiovascular and renal diseases.

The major aim of this study is to examine the salt sensitivity of the ambulatory blood pressure in women with a history of severe preeclampsia (< 34 weeks gestation) compared with women with no history of pregnancy-related hypertensive complications. We plan to recruit 20 non-menopausal women with a history of severe preeclampsia, and 20 age, parity, race- matched premenopausal women as controls. The study has a case control randomized design. The salt sensitivity of the ambulatory blood pressure is defined as an increase of ≥4 mmHg in 24h ambulatory blood pressure on a high sodium diet. The high sodium diet is obtained by adding capsules of 6gr of NaCl/ day in the usual diet.

The participants are identified as women discharged from the Maternity of University Hospital of Geneva between 1999 and 2001 with a preeclampsia coding. Fetal and maternal data will be carefully recovered from hospital records to identify severe preeclampsia (PE), based on International Society for the Study of Hypertension in Pregnancy criteria. These criteria are systolic blood pressure ≥160mmHg and/or diastolic blood pressure ≥110 mmHg with severe proteinuria (≥ 5g /24h or 3+ dipstick) and one or more signs of multisystem disease developing after 20 weeks of gestation in previously normotensive women. Severe preeclampsia was also defined as occurring before 34wk of gestation. Women with a history of hypertension, diabetes mellitus, renal or cardiac impairment, polycystic ovary syndrome will be excluded. Other exclusion criteria are anti-inflammatory drugs, diuretics, aspirin, oral contraceptives and hormonal replacement therapy. The protocol is approved by the University Hospital Ethical Committee and written informed consent will be obtained from each individual in accordance with the declaration of Helsinki. The study is conducted between 2009 and 2012 at the University Hospitals of Geneva, Switzerland.