Prediction of hypertensive disorders after screening at 36 weeks' gestation: comparison of angiogenic markers with competing-risks model

OBJECTIVE

To compare the performance at 35 + 0 to 36 + 6 weeks' gestation of screening for delivery with pre-eclampsia (PE) at various timepoints, using one of three approaches: placental growth factor (PlGF) concentration, soluble fms-like tyrosine kinase-1 (sFlt-1) to PlGF concentration ratio, or the competing-risks model, which combines maternal risk factors with biomarkers to estimate patient-specific risk.

METHODS

This was a prospective observational study of women attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation at one of two maternity hospitals in England between 2016 and 2022. During the visit, maternal demographic characteristics and medical history were recorded and serum PlGF, serum sFlt-1 and mean arterial pressure (MAP) were measured. Detection rates (DRs) were evaluated for delivery with PE (defined as per American College of Obstetricians and Gynecologists 2019 criteria) within 1 week, within 2 weeks or at any time after screening, using the following strategies: (i) low PlGF (< 10th percentile); (ii) high sFlt-1/PlGF ratio (> 90th percentile); or (iii) the competing-risks model, in which maternal factors were combined with multiples of the median values of PlGF ('single test'), PlGF and sFlt-1 ('double test') or PlGF, sFlt-1 and MAP ('triple test'). Risk cut-offs corresponded to a screen-positive rate of 10%. DRs were compared between tests.

RESULTS

Of 34 782 pregnancies, 831 (2.4%) developed PE. In screening for delivery with PE at any time from assessment, the DR at 10% screen-positive rate was 47% by low PlGF alone, 54% by the single test, 55% by high sFlt-1/PlGF ratio, 61% by the double test and 68% by the triple test. In screening for delivery with PE within 2 weeks from assessment, the respective values were 67%, 74%, 74%, 80% and 87%. In screening for delivery with PE within 1 week from assessment, the respective values were 77%, 81%, 85%, 88% and 91%. For prediction of PE at any time, the DR was significantly higher with the triple test compared to PlGF alone or the sFlt-1/PlGF ratio, with a DR difference (95% CI) of 20.1% (16.7-23.0%) and 12.4% (9.7-15.3%), respectively. Similar results were seen for prediction of PE within 2 weeks (20.6% (14.9-26.8%) and 12.9% (7.7-17.5%), respectively) and prediction of PE within 1 week (13.5% (5.4-21.6%) and 5.4% (0.0-10.8%), respectively). The double test was superior to the sFlt-1/PlGF ratio and the single test was superior to PlGF alone in the prediction of PE within 2 weeks and at any time from assessment, but not within 1 week of assessment.

CONCLUSION

At 35 + 0 to 36 + 6 weeks' gestation, the performance of screening for PE by the competing-risks model triple test is superior to that of PlGF alone or the sFlt-1/PlGF ratio for the development of disease within 1 week, within 2 weeks and at any time from screening. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Effect of sildenafil on maternal hemodynamics in pregnancies complicated by severe early-onset fetal growth restriction: planned subgroup analysis from a multicenter randomized placebo-controlled double-blind trial

OBJECTIVES

Fetal growth restriction (FGR) is associated with maternal cardiovascular changes. Sildenafil, a phosphodiesterase type-5 inhibitor, potentiates the actions of nitric oxide, and it has been suggested that it alters maternal hemodynamics, potentially improving placental perfusion. Recently, the Dutch STRIDER trial was stopped prematurely owing to excess neonatal mortality secondary to pulmonary hypertension. The main aim of this study was to investigate the effect of sildenafil on maternal hemodynamics in pregnancies with severe early-onset FGR.

METHODS

This was a cardiovascular substudy within a UK multicenter, placebo-controlled trial, in which 135 women with a singleton pregnancy and severe early-onset FGR (defined as a combination of estimated fetal weight or abdominal circumference below the 10^th centile and absent/reversed end-diastolic flow in the umbilical artery on Doppler velocimetry, diagnosed between 22 + 0 and 29 + 6 weeks' gestation) were assigned randomly to receive either 25 mg sildenafil three times daily or placebo until 32 + 0 weeks' gestation or delivery. Maternal blood pressure (BP), heart rate (HR), augmentation index, pulse wave velocity (PWV), cardiac output, stroke volume (SV) and total peripheral resistance were recorded before randomization, 1-2 h and 48-72 h post-randomization, and 24-48 h postnatally. For continuous data, analysis was performed using repeated measures ANOVA methods including terms for timepoint, treatment allocation and their interaction.

RESULTS

Included were 134 women assigned randomly to sildenafil (n = 69) or placebo (n = 65) who had maternal BP and HR recorded at baseline. At 1-2 h post-randomization, compared with baseline values, sildenafil increased maternal HR by 4 bpm more than did placebo (mean difference, 5.00 bpm (95% CI, 1.00-12.00 bpm) vs 1.25 bpm (95% CI, -5.38 to 7.88 bpm); P = 0.004) and reduced systolic BP by 1 mmHg more (mean difference, -4.13 mmHg (95% CI, -9.94 to 1.44 mmHg) vs -2.75 mmHg (95% CI, -7.50 to 5.25 mmHg); P = 0.048). Even after adjusting for maternal mean arterial pressure, sildenafil reduced aortic PWV by 0.60 m/s more than did placebo (mean difference, -0.90 m/s (95% CI, -1.31 to -0.51 m/s) vs -0.26 m/s (95% CI, -0.75 to 0.59 m/s); P = 0.001). Sildenafil was associated with a non-significantly greater decrease in SV index after 1-2 h post-randomization than was placebo (mean difference, -5.50 mL/m² (95% CI, -11.00 to -0.50 mL/m² ) vs 0.00 mL/m² (95% CI, -5.00 to 4.00 mL/m² ); P = 0.056).

CONCLUSIONS

Sildenafil in a dose of 25 mg three times daily increases HR, reduces BP and reduces arterial stiffness in pregnancies complicated by severe early-onset FGR. These changes are short term, modest and consistent with the anticipated vasodilatory effect. They have no short- or long-term clinical impact on the mother. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The effect of calcium supplementation on blood pressure in non-pregnant women with previous pre-eclampsia: An exploratory, randomized placebo controlled study

BACKGROUND

Epidemiological findings suggest that the link between poverty and pre-eclampsia might be dietary calcium deficiency. Calcium supplementation has been associated with a modest reduction in pre-eclampsia, and also in blood pressure (BP).

METHODS

This exploratory sub-study of the WHO Calcium and Pre-eclampsia (CAP) trial aims to determine the effect of 500mg/day elemental calcium on the blood pressure of non-pregnant women with previous pre-eclampsia. Non-pregnant women with at least one subsequent follow-up trial visit at approximately 12 or 24weeks after randomization were included.

RESULTS

Of 836 women randomized by 9 September 2014, 1st visit data were available in 367 women of whom 217 had previously had severe pre-eclampsia, 2nd visit data were available in 201 women. There was an overall trend to reduced BP in the calcium supplementation group (1-2.5mmHg) although differences were small and not statistically significant. In the subgroup with previous severe pre-eclampsia, the mean diastolic BP change in the calcium group (-2.6mmHg) was statistically larger than in the placebo group (+0.8mmHg), (mean difference -3.4, 95% CI -0.4 to -6.4; p=0.025). The effect of calcium on diastolic BP at 12weeks was greater than in those with non-severe pre-eclampsia (p=0.020, ANOVA analysis).

CONCLUSIONS

There is an overall trend to reduced BP but only statistically significant in the diastolic BP of women with previous severe pre-eclampsia. This is consistent with our hypothesis that this group is more sensitive to calcium supplementation, however results need to be interpreted with caution.

A survey of Canadian practitioners regarding the management of the hypertensive disorders of pregnancy

BACKGROUND

How Canadian practitioners are managing the hypertensive disorders of pregnancy (HDP) is not known, particularly in relation to the 1997 guidelines published by the Canadian Hypertension Society (CHS).

METHODS

A survey, with French and English versions (and covering diagnosis, evaluation, and management of pregnancy hypertension), was mailed to all members of the Society of Obstetricians and Gynaecologists of Canada (SOGC) (N = 1757, including obstetricians, family doctors practicing obstetrics, and midwives). Additionally, internists [i.e., all nephrologists (N = 191) and a random sample of 25% of general internists (N = 450)] registered with the Royal College of Physicians and Surgeons of Canada were sampled. The survey was distributed in two mailings and one reminder card. Data were entered into Microsoft Access, and Graph Pad Prism used to summarize responses [N (%)]. Differences in practice between specialties were examined, with a Bonferroni correction used to calculate a significant p value based on the number of comparisons and alpha of 0.05.

RESULTS

Respondents numbered 1187 (49.5%), with 466 not informative for the purpose of the study (due to retirement, or practices that do not include pregnant women with hypertension). The final analysis included 721 completed surveys. For all types of HDP, most internists, family doctors, and midwives initiate nonpharmacological therapy (most common advice to quit work) at dBP 80-89 mmHg (i.e., primary prevention). Only for preeclampsia do obstetricians most frequently use this threshold; otherwise, dBP 90-99 mmHg is usually chosen. For nonsevere hypertension, antihypertensive drug therapy (most commonly methyldopa or labetalol) is started by most practitioners at dBP 90-99 mmHg, although obstetricians are more likely to choose a higher threshold (p < 0.0001). There is little agreement about dBP treatment goal; most internists and family doctors normalize dBP, whereas obstetricians appear to be divided on dBP goals of 80-89 (46-51%) vs. 90-99 mmHg (41-44%) for all HDP (p = 0.66). Severe hypertension is commonly treated with parenteral hydralazine, labetalol, or magnesium sulphate. Short-acting or sustained release nifedipine is used rarely/never by most practitioners. Approximately one-third of obstetricians and family doctors use diazepam to treat eclampsia. The vast majority use MgSO4 prophylactically in women with preeclampsia.

INTERPRETATION

This survey has clarified current stated management of women with HDP, and identified the need for both research into the dBP treatment goal that optimizes pregnancy outcomes among women with HDP, and translation of definitive studies into clinical practice.