189. Non-invasive study of haemodynamic parameters in normotensive versus hypertensive pregnancies

Abstract

Background/Objectives Major physiological cardiovascular system adaptations during pregnancy include decreased systemic vascular resistance (SVR) and increased cardiac output (CO). In hypertensive disorders of pregnancy, especially preeclampsia, these usual cardiovascular adaptations maybe deficient. This study aims to evaluate differences in cardiac function and haemodynamic parameters using point-of-care, non-invasive testing, in women with normotensive and hypertensive (chronic hypertension, CH, gestational hypertension, GH preeclampsia, PE) pregnancies. Methods Normotensive (NT, n = 70) and hypertensive (HT, n = 65; 23 CH, 22 GH, 20 PE) pregnant women aged 18–45 with a singleton pregnancy studied cross-sectionally from 20 weeks’ gestation in this ongoing prospective study. Haemodynamic parameters were obtained non-invasively via the Ultrasound Cardiac Output Monitor (USCOM) and liquid crystal sphygmomanometer. Women are followed prospectively and pregnancy outcomes, including preeclampsia development, ascertained. Results There was no statistically significant difference in average stroke volume (73 mL/NT, 69 mL/CH, 70 mL/GH, 73 mL/PE; p = 0.838), cardiac output (5.9/5.7/5.5 and 5.7L respectively; p = 0.802) and cardiac output index between groups (3.2/2.8/2.7/2.9L/min/m2; p = 0.16) between groups. Pre-eclamptic pregnancies had significantly higher SVR (1851 ± 1111 versus 1215 ± 396 dyne/se/cm−5; p ⩽ 0.001) and systematic vascular resistance index (3653 ± 2189 versus 2274 ± 912dyne/s/cm−5/m−2; p ⩽ 0.001) than NT pregnancies. As expected, HT participants had significantly higher mean arterial pressure, systolic (110 ± 12,129 ± 11, 129 ± 10, 138 ± 12; p ⩽ 0.001) and diastolic blood pressure (70 ± 9, 79 ± 9, 83 ± 8, 87 ± 12 mmHg respectively; p ⩽ 0.001) than NT. Conclusions In this pilot study of non-invasive (USCOM) haemodynamic measurements, significant differences in systemic vascular resistance, but not overall cardiac output, were seen between normotensive and hypertensive pregnancies. A larger sample size is needed for further investigation, including determining whether USCOM may be useful in predicting which pregnancies will progress from gestational hypertension and/or chronic hypertension, to preeclampsia.