Coupling of heart rate and systolic blood pressure in hypertensive pregnancy.

INTRODUCTION This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Studying Cardiovascular and Respiratory Systems". BACKGROUND Hypertensive pregnancy disorders affect 6 - 8 percent of all pregnancies and can result in severe complications for both the mother and the fetus. OBJECTIVES The aim of this study was to improve risk stratification of pregnant women suffering from hypertension and pre-eclampsia (PE) by applying bivariate Segmented Poincaré plot analysis (BSPPA). METHODS From 35 pregnant women suffering from chronic hypertension, gestational hypertension and PE, 30 minutes of noninvasive systolic blood pressure and beat- to-beat intervals were continuously recorded and analyzed by applying BSPPA to quantify their couplings. RESULTS We revealed significant different couplings between chronic hypertension (CH), gestational hypertension and PE, indicating that cardiovascular regulation can be considerably altered depending on the type of hypertensive disorder. The optimal multivariate set of two BSPPA indices was determined which distinguish best between CH and PE. It achieved a sensitivity of 100%, a specificity of 77.8% and an area under the receiver operator characteristic curve of 90.8%. CONCLUSIONS The BSPPA method a) provides improved risk stratification for pregnant women suffering from hypertension and PE, b) increases the ability to diagnose pathological changes, and c) could contribute substantially to the differential diagnosis of hypertensive pregnancy disorders.