Markers of maternal cardiac dysfunction in pre-eclampsia and superimposed pre-eclampsia

Authors: Frances Conti-Ramsden MBBS Academic Clinical Fellow ¹ , Carolyn Gill PhD BRC Research Assistant ¹ , Paul T Seed MSc CStat Senior Lecturer in Medical Statistics ¹ , Kate Bramham PhD Clinical Senior Lecturer in Nephrology ² , Lucy C Chappell PhD NIHR Research Professor in Obstetrics ¹ , Fergus P McCarthy PhD Clinical Senior Lecturer in Obstetrics and Gynaecology ^1,3 . Objectives: To determine whether glycogen phosphorylase isoenzyme B (GPBB) and/or brain natriuretic peptide (BNP) concentrations are elevated in pre-eclampsia and superimposed pre-eclampsia (SPE), demonstrating cardiac ischaemia and strain. Study design: A nested case-control study was performed using samples and clinical data available from a prospective pregnancy cohort. Four groups were selected: healthy pregnant controls (n = 21), pre-eclampsia (n = 19), pre-existing chronic hypertension (CHT) and/or chronic kidney disease (CKD) without (n = 20) or with superimposed pre-eclampsia (SPE) (n = 19). Plasma samples were taken at time of disease or the third trimester in controls. Main outcome measures: Plasma concentrations of GPBB and BNP. Results: There was no significant difference in GPBB plasma concentrations between controls and pre-eclampsia (geometric mean (GM) [95% CI]: 4.74 [2.54–8.84]ng/mL vs 5.01 [2.58–9.74]ng/mL, p = 0.90)), or between CHT and/or CKD and SPE (GM [95% CI]: 9.49 [4.93–18.25]ng/mL vs 10.24 [5.27–19.92]ng/mL, p = 0.87). BNP plasma concentrations were significantly raised in women with pre-eclampsia compared to controls (GM [95% CI]: 31.83 [20.18–50.22]pg/mL vs 11.33 [7.34–17.51]pg/mL, p = 0.001). Women with CKD, but not CHT, who developed SPE had elevated BNP concentrations. There were no significant differences in BNP concentration between women with comorbidity (CHT and/or CKD) and controls. Conclusions: GPBB has a limited role as a biomarker in hypertensive disorders of pregnancy. BNP concentrations were elevated in pre-eclampsia compared to controls. This suggests cardiac strain at the time of pre-eclampsia. Further studies are needed to examine whether BNP can identify women at increased risk of cardiovascular disease.