Echocardiographic assessment of left ventricular structure and function in hypertensive disorders of pregnancy at six months and two years postpartum

Purpose

Hypertensive disorders of pregnancy (HDP) are associated with longer term postpartum cardiovascular sequelae, including double the risk of ischaemic heart disease and cardiovascular mortality (1).

Transthoracic echocardiograms (TTE) were performed in women with pregnancies complicated by gestational hypertension and pre-eclampsia, or uncomplicated pregnancy, at six months and two years postpartum. The aim was to longitudinally assess cardiac structure and function in women with HDP and compare this to women who had a normotensive pregnancy. The six-month results have been previously reported, we now present the two-year data.

Methods

A prospective cohort study was conducted in a pre-specified subgroup of 126 patients within a single, tertiary referral centre as part of the P4 (Post Partum, Physiology, Psychology, and Paediatric Follow Up) study (2). 74 (59%) women had a normotensive pregnancy, and 52 (41%) had a pregnancy complicated by HDP.

Women with pre-existing hypertension were excluded from the study. The mean patient age at time of six-month postpartum TTE was 32 years (range 22–47 years). TTEs were performed by blinded experienced sonographers and reported by a single blinded imaging cardiologist.

Results

Six months postpartum. 126 women underwent TTE at six months postpartum. Although all results fell within normal ranges, compared to women with a normotensive pregnancy, those with HDP had increased left ventricle (LV) wall thickness, higher relative wall thickness, and increased LV mass. E/A ratio was lower, and E/E' ratios higher in the group with pregnancy complicated by HDP, indicating a trend towards poorer diastolic function (2,3).

Two years postpartum. 35 women completed a two year postpartum TTE (18 normotensive, 17 HDP). Measurements fell within normal ranges in both groups of women.

At two years postpartum, women with HDP had larger BSA (1.9 vs 1.71 m2 p=0.003), larger LV internal diastolic diameter (48.4 vs 45.5mm p=0.017) and increased inter-ventricular septum thickness (8.5 vs 7.7mm p=0.007) compared to those with normotensive pregnancy. LV mass was greater in women with HDP (98.1 vs 81.5g), as was LA volume indexed (25.4 vs 23.4 cm3/m3), however these differences did not reach significance (p=0.053 and 0.196 respectively). Compared to normotensive women, those with HDP had higher septal (8.7 vs 7.3 p=0.014) and lateral (6.6 vs 5.4 p=0.017) E/E' ratios, indicating a trend towards diastolic dysfunction.

Conclusion

Despite measurements falling within normal ranges, our results indicate that women with HDP have changes in cardiac structure and function that persist out to two years postpartum. Limitations exist due to incomplete follow up, leading to small sample size; this was partially due to restrictions on service provision in the context of the COVID-19 pandemic.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The St George and Sutherland Research Foundation.Philanthropic donation from Emeritus Professor Richard Henry.

The P4 study: Subsequent pregnancy maternal physiology after hypertensive and normotensive pregnancies

OBJECTIVES

Hypertensive disorders of pregnancy are associated with subsequent increased risk of cardiometabolic disease. Adverse cardiometabolic measures are noted soon after hypertensive versus normotensive pregnancy (NP); to what degree these persist into a subsequent pregnancy (SP) is unknown. This study aimed to assess women's physiology early in SP after hypertensive pregnancy (HP: preeclampsia or gestational hypertension) or NP and compare SP to 6 months postpartum findings from the index pregnancy.

STUDY DESIGN

Prospective sub-study of the P4 (Postpartum, Physiology, Psychology and Paediatric) observational cohort. Measurements six months after NP versus HP, and the SP at 11-13 weeks gestation.

MAIN OUTCOME MEASURES

Blood pressure (BP), blood and urine tests (urine ACR, HOMA-IR, LDL cholesterol), body composition, and contribution of maternal characteristics and inter-pregnancy factors to BP and body fat (FM%) in SP.

RESULTS

49 women (34 NP, 15 HP). In the SP, post-HP women had higher BP (112/70 mmHg HP vs 102/64 mmHg NP; p < .001), with no significant drop from six months postpartum to early SP. On regression analysis, systolic and diastolic BP at 6-months were the major predictors for SP systolic (p < 0.001) and diastolic (p = 0.009) BP respectively in the SP. Longer interpregnancy interval and increased FM% 6-months postpartum were associated with higher SP FM% (p < 0.001).

CONCLUSIONS

BP and body fat six months postpartum were similar early in the SP for HP group, and postpartum BP and FM% were major predictors of their corresponding SP measurements. Postpartum/inter-pregnancy intervention programs to improve these cardiometabolic risk markers might help improve women's long-term health and require investigation.

Indications for delivery in pre-eclampsia

OBJECTIVE

Examine the frequency with which the most accepted indicators for delivery in pre-eclampsia are used in a population with predominantly late-onset (birth > 32 weeks) pre-eclampsia (PE).

METHODS

Retrospective cohort study using the St George Public Hospital (SGH) Hypertension in Pregnancy database. Demographic, pregnancy, and outcome details were extracted and verified by comparison with data collection sheets.

RESULTS

From 2001 to 2013, 908 women (970 babies) with PE were included, of which a subgroup of 303 women (33%) had clearly delineated delivery triggers available. This subgroup of women had similar demographic and outcome characteristics to the total PE population. In this group, the most common maternal trigger for delivery apart from gestational age 37+ weeks was difficult to control/severe hypertension (114 cases, 38%) and the most common fetal trigger intrauterine growth restriction (IUGR: 14 cases, 4%). 78 (35%) of term women had no specific delivery trigger other than gestation. A primary maternal trigger and/or associated complication was slightly more common in those delivering <37 weeks vs 37+ weeks (52 vs 38%, p = .03), while a fetal or combined maternal/fetal complication was over four times more common in preterm women (25 vs 6%, p < .001).

CONCLUSION

In our population of predominantly late-onset PE, maternal triggers for delivery (predominantly severe hypertension) far outweigh fetal triggers (predominantly IUGR). Fetal and mixed indicators for delivery were relatively more common in women delivering preterm, possibly reflecting the severity of placental dysfunction in this subgroup.

OS096. Characteristics of hypertensive disorders in twin versus singleton pregnancies

INTRODUCTION

Pre-eclampsia is well characterised in single pregnancies but less well in twin pregnancies, where the risks are higher.

OBJECTIVES

The aim of this study, therefore, was to determine the characteristics of hypertensive disorders of pregnancy (HDP) in twin compared with singleton pregnancies.

METHODS

We performed an analysis of 4976 prospectively recorded hypertensive pregnancies. These included pre-eclampsia (PE), gestational hypertension (GH) and chronic hypertension (CH). The rates and characteristics of these disorders were compared between singleton and twin pregnancies as was the progression of GH to PE for both groups. Maternal outcomes for severe hypertension (BP⩾170/⩾110mmHg), eclampsia, total antihypertensive medication requirements and maternal death were compared. Neonatal outcomes evaluated included birth weight, small for gestational age (SGA) and perinatal mortality.

RESULTS

After exclusion of higher order pregnancies (triplets (n=2), a quadruplet pregnancy (n=1)), those with known secondary HT, white coat HT, or not fulfilling strict criteria for an accurate diagnosis (n=470) and those without an initial diagnosis recorded, there were 4156 women comprising 3942 singleton and 214 (5%) twin pregnancies.Hypertension (GH or PE) in twin pregnancy was diagnosed earlier than in singleton pregnancy (34±3 v 36±3 weeks, p<0.001). In the singleton pregnancies with de novo hypertension (n=3161), 60% had an initial diagnosis of GH and 40% had PE. In the twin pregnancies with de novo hypertension (n=199), 35% of women were initially diagnosed with GH and 65% with PE (p<0.001, single v twins). At delivery, 46% of the singletons had GH and 54% had PE, compared with twin pregnancies where 23% had GH and 77 % had PE (p<0.001). The progression from GH to PE for twins was greater than that for singleton pregnancies (34% v 15%, p<0.001). There were also781 singleton pregnancies and 15 twin pregnancies with CH. Twin pregnancies complicated by CH were more likely to progress to PE than singletons (54% v 18%, p<0.01). Women carrying twins were older (p<0.01) and they required less medication compared to those carrying singleton pregnancies(0.9±1.2 v 1.3±1.5 medication score, p<0.05). Other maternal outcomes did not differ between the two groups. For neonatal outcomes, the gestation at delivery was earlier for twin than singleton pregnancies (36±2 v38±2 weeks, p<0.001) and SGA (less than 10th percentile) for twins was higher than singleton pregnancies (22% v 12%, p<0.001).No difference in perinatal mortality was noted.

CONCLUSION

Women carrying twins who develop hypertension during pregnancy are more likely to present earlier, have initial PE rather than GH and to subsequently progress from GH to PE than in singleton pregnancy. Neonatal outcomes are worse in such pregnancies. It is thus reasonable for pregnant women with twins who develop de novo hypertension to be considered very high risk and possibly be managed in hospital.

Can we predict recurrence of pre-eclampsia or gestational hypertension?

OBJECTIVE

To estimate the rates of recurrence of pre-eclampsia or gestational hypertension in a subsequent pregnancy and to determine factors predictive of recurrence.

DESIGN

Retrospective cohort study.

SETTING

St George Public and Private Hospitals, teaching hospitals without neonatal intensive care units.

PARTICIPANTS

A total of 1515 women with a diagnosis of pre-eclampsia or gestational hypertension between 1988 and 1998 were identified from the St George Hypertension in Pregnancy database, a system designed initially for ensuring quality outcomes of hypertensive pregnancies. Of these, 1354 women were followed up, and a further 333 records from women coded as having a normal pregnancy during that period were selected randomly as controls.

MAIN OUTCOME MEASURES

Likelihood of recurrent pre-eclampsia or gestational hypertension and clinical and routine laboratory factors in the index pregnancy predictive of recurrence of pre-eclampsia or gestational hypertension.

METHODS

The index cases from our unit's database were linked to the matched pregnancy on the State Department of Health database, allowing us to determine whether further pregnancies had occurred at any hospital in the State. The outcome of these pregnancies was determined by review of medical records, using strict criteria for diagnosis of pre-eclampsia or gestational hypertension.

RESULTS

Almost all women with a normal index pregnancy had a further normotensive pregnancy. One in 50 women hypertensive in their index pregnancy had developed essential hypertension by the time of their next pregnancy. Women with pre-eclampsia in their index pregnancy were equally likely to develop either pre-eclampsia or gestational hypertension (approximately 14% each), while women with gestational hypertension were more likely to develop gestational hypertension (26%) rather than pre-eclampsia (6%) in their next pregnancy. Multiparous women with gestational hypertension were more likely than primiparous women to develop pre-eclampsia (11 versus 4%) or gestational hypertension (45 versus 22%) in their next pregnancy. Early gestation at diagnosis in the index pregnancy, multiparity, uric acid levels in the index pregnancy and booking blood pressure parameters in the next pregnancy significantly influenced the likelihood of recurrence, predominantly for gestational hypertension and less so for pre-eclampsia. No value for these parameters was significant enough to be clinically useful as a discriminate value predictive of recurrent pre-eclampsia or gestational hypertension.

CONCLUSIONS

Approximately 70% of women with pre-eclampsia or gestational hypertension will have a normotensive next pregnancy. The highest risk group for recurrent hypertension in pregnancy in this study was multiparous women with gestational hypertension. No readily available clinical or laboratory factor in the index pregnancy reliably predicts recurrence of pre-eclampsia.

Automated self-initiated blood pressure or 24-hour ambulatory blood pressure monitoring in pregnancy?

OBJECTIVE

To determine whether self-initiated and recorded automated blood pressure measurement can provide an accurate estimate of ambulatory blood pressure in pregnant women suspected of having 'white coat hypertension'.

DESIGN

A prospective observational study.

SETTING

Women's and Children's Health Unit, St George Hospital, a teaching hospital of the University of New South Wales.

POPULATION

Pregnant women being assessed for possible 'white-coat hypertension'.

METHODS

Sixty-six pregnant women who were undergoing 24 hour ambulatory blood pressure monitoring (ABPM) in their home or work environment also measured their blood pressure six times during this interval using a self-initiated automated blood pressure recorder (Omron HEM 705CP). Agreement between awake ABPM and Omron recorded blood pressures was tested by Bland-Altman analysis.

MAIN OUTCOME MEASURE

Limits of agreement between blood pressures measured by each device.

RESULTS

Average blood pressures obtained by the two devices were identical (125/77 mmHg) but limits of agreement were wide, -20 to +23 mmHg for systolic blood pressure and -9 to +15 mmHg for diastolic blood pressure.

CONCLUSION

The Omron HEM 705CP is a useful device for measuring group average blood pressures in pregnant women suspected of having white coat hypertension but cannot reliably replace ABPM for clinical management of individual pregnant women.

Cortisol and hypertension

1. In humans, the hypertensive effects of adrenocorticotropic hormone (ACTH) infusion are reproduced by intravenous or oral cortisol. Oral cortisol increases blood pressure in a dose-dependent fashion. At a dose of 80-200 mg/day, the peak increases in systolic pressure are of the order of 15 mmHg. Increases in blood pressure are apparent within 24 h. 2. Cortisol-induced hypertension is accompanied by a significant sodium retention and volume expansion. Co-administration of the type I (mineralocorticoid) receptor antagonist spironolactone does not prevent the onset of cortisol-induced hypertension. Thus, sodium retention is not the primary mechanism of cortisol-induced hypertension. 3. Direct and indirect measures of sympathetic activity are unchanged or suppressed during cortisol administration, suggesting that cortisol-induced hypertension is not mediated by increased sympathetic tone. 4. Preliminary evidence in humans suggests that suppression of the nitric oxide system may play a role in cortisol-induced hypertension. 5. These potential mechanisms of cortisol action may be relevant in a number of clinical contexts, including Cushing's syndrome, apparent mineralocorticoid excess, the hypertension of liquorice abuse and chronic renal failure. There is also preliminary evidence suggesting a role for cortisol in essential hypertension.