Maternal cardiac function at 19-23 weeks' gestation in prediction of pre-eclampsia.

OBJECTIVES: First, to examine the factors from maternal characteristics and medical history that affect maternal cardiovascular indices, and, second, to examine the potential value of maternal cardiovascular indices at 19-23 weeks' gestation, on their own and in combination with maternal factors and the established biomarkers of pre-eclampsia (PE), including uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP), serum placental growth factor (PlGF) and serum soluble fms-like tyrosine kinase-1 (sFlt-1), in the prediction of subsequent development of PE.
METHODS: This was a prospective observational study in women attending for a routine hospital visit at 19 + 1 to 23 + 3 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, assessment of maternal E/A ratio, E/e' ratio, myocardial performance index, global longitudinal systolic strain, left ventricular ejection fraction, peripheral vascular resistance, left ventricular cardiac output and left ventricular mass indexed for body surface area, and measurement of MAP, UtA-PI, serum PlGF and serum sFlt-1. The measurements of the eight maternal cardiac indices were standardized to remove the effects of maternal characteristics and elements from the medical history. The competing-risks model was used to estimate the individual patient-specific risks of delivery with PE and determine the detection rate, at a 10% false-positive rate, in screening by a combination of maternal demographic characteristics and medical history with biomarkers.
RESULTS: The study population of 2853 pregnancies contained 76 (2.7%) that developed PE. In pregnancies that subsequently developed PE, there was evidence of altered cardiac geometry, impaired myocardial function and increased peripheral vascular resistance. All maternal cardiovascular indices were affected significantly by maternal demographic characteristics and elements of medical history known to be associated with an increased risk for subsequent development of PE. After adjustment for maternal demographic characteristics and medical history, the only cardiovascular index that was affected significantly by subsequent development of PE was peripheral vascular resistance. Peripheral vascular resistance multiples of the median (MoM) was correlated with MAP MoM, which is not surprising because blood pressure is involved in the estimation of both. There were weak correlations between several cardiovascular indices and MAP MoM, but none was correlated with MoM values of UtA-PI, PlGF or sFlt-1. The performance of screening for delivery with PE at < 37 weeks' gestation or delivery with PE at any gestational age in screening by maternal demographic characteristics and medical history or combinations of maternal factors with MAP, UtA-PI, PlGF and sFlt-1 was not improved by the addition of peripheral vascular resistance.
CONCLUSION: Assessment of maternal cardiovascular function provides information on the pathophysiology of PE but is not useful in the prediction of PE.