HYPERTENSIVE PREGNANCIES– A 35 YEAR FOLLOW-UP ON CARDIOVASCULAR REGULATION – IS THE SYMPATHETIC ACTIVATION STILL PERSISTENT?: 9C.07

Abstract

Objective: Gestational hypertension is associated with an increased risk of developing primary hypertension later in life and preeclampsia has been shown to increase the risk of coronary artery disease. Preeclampsia is a condition associated with sympathetic over activity, which in turn, is thought to constitute a precursor of preeclampsia and hence cause hypertension. Whether the increased sympathetic drive in hypertensive pregnancies persists following delivery is however not known. The aim of the present study was to investigate sympathetic nerve activity and blood pressure level in women with hypertensive pregnancies (HP), 35 years following delivery. Design and Methods: Sympathetic nerve activity was recorded in 25 women with prior a) HP and present diagnosis of hypertension, b) HP without present diagnosis of hypertension and c) normotensive pregnancies, without present diagnosis of hypertension, serving as controls. Sympathetic nerve activity (MSNA) was expressed as burst frequency (BF), burst incidence (BI), relative median burst amplitude (MA%). Baroreflex slopes were determined by the relation between MSNA burst amplitude and corresponding diastolic blood pressure value. All subjects were investigated without withdrawal of ongoing medication. Results: The study groups were equal in terms of age, body mass index, heart rate and blood pressure level. MSNA BF, BI were however, significantly higher in the patient group with present hypertension as compared to the control (p = 0.02 for both) and patient group without hypertension (p = 0.04 and 0.01, respectively), whereas MSNA MA% did not differ. Baroreflex slopes were positively related to MSNA BF and BI (r = 0.5, p = 0.1, for both) for the whole study group. Conclusions: Our results show, that women with hypertensive pregnancies 35 years ago, still suffering from hypertension, have a persistent sympathetic activation despite ongoing antihypertensive medication. The difference in sympathetic outflow in this study can not be explained by differences in blood pressure level, since they did not deviate between the study groups.