2 Renin-angiotensin-aldosterone profiles predictive of superimposed preeclampsia

Abstract

Introduction Women with preexisting, or chronic hypertension (CHT) in pregnancy are at heightened risk for significant morbidity and death, primarily due to further elevations in blood pressure (BP) and development of superimposed preeclampsia (SPE). The pathophysiology for the elevations in BP remains unresolved. Objectives We investigated the hypothesis that renin–angiotensin aldosterone profiles (RAAS) are associated with BP and SPE. Methods We performed a prospective, longitudinal trial of 108 women with CHT (RO1 HL 48846. PI: P. August). We measured plasma renin activity (PRA), 24h urine Na, K and aldosterone (UA) at 12, 20, 28, and 36weeks gestation and post-martum to investigate the association between these potentially pathophysiologic parameters and elevations in BP and SPE. Results Mean Arterial Pressure (MAP) was inversely related to PRA ( r =−0.23, P r =−0.11, P =0.047). PRA and UA were significantly and positively associated with each other ( r =0.5327, P P =0.005) and UA ( P =0.039) were significantly lower at 28weeks in those who developed SPE compared to those who did not develop SPE. Interestingly, PRA was significantly lower in black women compared to other racial groups ( p =0.026 at 36weeks and P P =0.0018) were significant predictors of PRA, while gestational age ( P P =0.0001), urine K ( P P =0.0005) were predictors of UA. Conclusions We conclude that renin–angiotensin–aldosterone profiles, ascertained in the third trimester of pregnancy, foretell the development of SPE in pregnant women with CHT. The RAAS profiles characterized in our investigation, in addition to serving as prognostic biomarkers, advance sodium retention as the primary mechanism for the elevation in BP in women with SPE.