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

AUTHORS

Frances Conti-Ramsden MBBS Academic Clinical Fellow, Carolyn Gill PhD BRC Research Assistant, Paul T Seed MSc CStat Senior Lecturer in Medical Statistics, Kate Bramham PhD Clinical Senior Lecturer in Nephrology Lucy C Chappell PhD NIHR Research Professor in Obstetrics, Fergus P McCarthy PhD Clinical Senior Lecturer in Obstetrics and Gynaecology.

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.