Natriuretic peptides and hemodynamics in preeclampsia

OBJECTIVE: The purpose of this study was to evaluate the relationship between natriuretic peptides (NT-proANP and NT-proBNP) and hemodynamic parameters in preeclampsia. STUDY DESIGN: This was a cross-sectional study of 19 preeclamptic, 15 chronic hypertensive, and 26 normotensive women in the third trimester of pregnancy. Stroke index (SI), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI), and left cardiac work index (LCWI) were derived by whole-body impedance cardiography. Systolic blood pressure (SAP), diastolic blood pressure (DAP), and mean arterial pressure (MAP) were measured. The plasma levels of NT-proANP and NT-proBNP were determined with radioimmunoassays. RESULTS: NT-proANP and NT-proBNP concentrations were significantly higher in preeclamptic women compared to chronic hypertensive and normotensive pregnancies. Preeclamptic women had lower CI and HR and higher SAP, MAP, and SVRI than the control groups. In preeclampsia NT-proANP correlated significantly with SAP and SVRI; meanwhile, NT- proBNP correlated significantly with SVRI and Cl. These correlations persisted in the subgroup of non-medicated preeclamptic women, except in the case of NT-proBNP and CI. CONCLUSION: High NT-proANP and NT- proBNP concentrations in preeclampsia reflect the strain on the heart caused by high afterload, rather than the function of the heart expressed as SI or CI.