Objective: To determine left ventricular isovolumic relaxation time (LV IRT) in normally developing and growth restricted fetuses (FGR) as an indicator of fetal cardiac afterload and neonatal systolic blood pressure. Study design: A prospective longitudinal study in 124 normally developing and 47 growth restricted fetuses (FGR). LV IRT, fetal heart rate (FHR) and umbilical artery pulsatility index (PI) were determined at 2-3 week intervals starting at 22-26 weeks of gestation until delivery. Renin and angiotensin I levels were measured by radioimmunoassay in umbilical venous blood after delivery. Systolic blood pressure was measured at day 1 and day 5 of postnatal life. To evaluate the association between LV IRT, gestational age and FHR, bivariate regression analyses were performed. Results: Mean LV IRT (62 ± 8 ms) was 29 percent longer in FGR as compared to the normal subset (47 ± 6 ms) at all gestational ages (p < 0.001). Mean postnatal active plasma renin level (7.78 ± S.D. 1.03 ng/ml) and postnatal angiotensin I level (4.21 ± 0.70 ng/ml) in the FGR subset were significantly higher (p < 0.001) than in the normal subset (4.81 ± 1.04 ng/ml, renin and 2.69 ± 0.44 ng/ml, angiotensin I). There was a significant difference (p < 0.01) in systolic blood pressure between the two subsets on postnatal day 1 (FGR 52 ± 6 mmHg vs. normal 46 ± 4 mmHg) and day 5 (FGR 76 ± 5 mmHg vs. normal 60 ± 6 mmHg). Conclusion: Left ventricular isovolumic relaxation time may act as a sensitive index of increased arterial afterload in the growth retarded fetus and may herald raised systolic blood pressure in the early neonatal period.

Additional Metadata
Keywords Adult, Angiotensin, Angiotensins, Biological Markers, Case-Control Studies, Female, Fetal, Fetal Blood, Fetal Growth Retardation, Growth restricted fetus, Heart Rate, Humans, Hypertension, Infant, Isovolumic relaxation time, Left, Newborn, Pregnancy, Prospective Studies, Renin, Renin-Angiotensin System, Ventricular Function, angiotensin I, article, controlled study, fetus, fetus heart rate, gestational age, heart afterload, heart left ventricle relaxation, human, intrauterine growth retardation, major clinical study, plasma renin activity, priority journal, radioimmunoassay, renin angiotensin aldosterone system, systolic blood pressure
Persistent URL dx.doi.org/10.1016/j.ejogrb.2008.02.005, hdl.handle.net/1765/15255
Citation
Pavel, P.B, Markova, T.V, Mikhailova, S.V, Hop, W.C.J, & Wladimiroff, J.W. (2008). Left ventricular isovolumic relaxation and renin-angiotensin system in the growth restricted fetus. European Journal of Obstetrics & Gynecology and Reproductive Biology, 140(1), 33–37. doi:10.1016/j.ejogrb.2008.02.005