Drugs for rapid treatment of very high blood pressure during pregnancy

Comparison of Intravenous Anti-hypertensives for Preoperative Blood Pressure Control in Hypertensive Disorders of Pregnancy and Effect of Oral Labetalol

BACKGROUND AND AIMS

Intravenous hydralazine and labetalol are recommended as first-line anti-hypertensives for controlling severe hypertension in pregnancy. Our study aimed at identifying the most effective drug with minimum side effects for preoperative management of severe hypertension in parturients scheduled for Caesarean delivery (CD). We also studied the effect of these drugs on patients already on oral labetalol in the antenatal period.

METHODS

A prospective observational study was done on 162 hypertensive parturients scheduled to undergo emergency CD who received hydralazine or labetalol in the preoperative period. Demographic data, booking status, hemodynamic data, time taken to reach adequate control of blood pressure (BP), drug efficacy, the incidence of persistent hypertension, adverse effects associated with the drugs, and maternal and fetal outcomes were noted.

RESULTS

The time taken for the control of BP was similar with both drugs (p-value = 0.425). The mean number of doses required to achieve target BP was significantly less with hydralazine compared to labetalol (p-value = 0.009). Patients on tablet labetalol in the antenatal period were poorly controlled when put on the same drug intravenously but had better control with hydralazine (p-value = 0.005). The incidence of persistent hypertension was lower in patients treated with hydralazine compared with labetalol (p-value = 0.008).

CONCLUSION

Both drugs took a similar time for BP control. However, hydralazine was more efficacious, produced adequate control of BP in a higher number of patients, and had a lower incidence of persistent hypertension.

Drugs for treatment of very high blood pressure during pregnancy

BACKGROUND

Very high blood pressure during pregnancy poses a serious threat to women and their babies. The aim of antihypertensive therapy is to lower blood pressure quickly but safety, to avoid complications. Antihypertensive drugs lower blood pressure but their comparative effectiveness and safety, and impact on other substantive outcomes is uncertain.

OBJECTIVES

To compare different antihypertensive drugs for very high blood pressure during pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (9 January 2013).

SELECTION CRITERIA

Studies were randomised trials. Participants were women with severe hypertension during pregnancy. Interventions were comparisons of one antihypertensive drug with another.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed trial quality. Two review authors extracted data and checked them for accuracy.

MAIN RESULTS

Thirty-five trials (3573 women) with 15 comparisons were included. Women allocated calcium channel blockers were less likely to have persistent high blood pressure compared to those allocated hydralazine (six trials, 313 women; 8% versus 22%; risk ratio (RR) 0.37, 95% confidence interval (CI) 0.21 to 0.66). Ketanserin was associated with more persistent high blood pressure than hydralazine (three trials, 180 women; 27% versus 6%; RR 4.79, 95% CI 1.95 to 11.73), but fewer side-effects (three trials, 120 women; RR 0.32, 95% CI 0.19 to 0.53) and a lower risk of HELLP (haemolysis, elevated liver enzymes and lowered platelets) syndrome (one trial, 44 women; RR 0.20, 95% CI 0.05 to 0.81).Labetalol was associated with a lower risk of hypotension compared to diazoxide (one trial 90 women; RR 0.06, 95% CI 0.00 to 0.99) and a lower risk of caesarean section (RR 0.43, 95% CI 0.18 to 1.02), although both were borderline for statistical significance.Both nimodipine and magnesium sulphate were associated with a high incidence of persistent high blood pressure, but this risk was lower for nimodipine compared to magnesium sulphate (one trial, 1650 women; 47% versus 65%; RR 0.84, 95% CI 0.76 to 0.93). Nimodipine was associated with a lower risk of respiratory difficulties (RR 0.28, 95% CI 0.08 to 0.99), fewer side-effects (RR 0.68, 95% CI 0.55 to 0.85) and less postpartum haemorrhage (RR 0.41, 95% CI 0.18 to 0.92) than magnesium sulphate. Stillbirths and neonatal deaths were not reported.There are insufficient data for reliable conclusions about the comparative effects of any other drugs.

AUTHORS' CONCLUSIONS

Until better evidence is available the choice of antihypertensive should depend on the clinician's experience and familiarity with a particular drug; on what is known about adverse effects; and on women's preferences. Exceptions are nimodipine, magnesium sulphate (although this is indicated for women who require an anticonvulsant for prevention or treatment of eclampsia), diazoxide and ketanserin, which are probably best avoided.

Control of hypertension in pregnancy

The hypertensive disorders of pregnancy are a leading cause of maternal mortality and morbidity. Complications are not limited to preeclampsia but also complicate both preexisting hypertension and isolated gestational hypertension. Blood pressure (BP) management is important but is only one aspect of management of the hypertensive disorders of pregnancy, which may be caused or exacerbated by underlying uteroplacental mismatch between maternal supply and fetal demand. BP treatment thresholds and goals vary in international guidelines, largely reflecting differences in opinion rather than differences in published data. Because of short-term maternal risks, there is consensus that BP should be treated when sustained at greater than or equal to 160 to 170 mm Hg systolic and/or 110 mm Hg diastolic. There is no consensus regarding management of nonsevere hypertension, and randomized controlled trials involving just over 3000 women have not clarified the relative maternal and perinatal risks and benefits. Although antihypertensive therapy may decrease transient severe maternal hypertension, therapy may also impair fetal growth and perinatal health and outcomes. The CHIPS Trial (Control of Hypertension In Pregnancy Study) is recruiting to answer this question.

The diagnosis and treatment of hypertensive disorders of pregnancy: new findings for antenatal and inpatient care

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are among the leading causes of maternal and fetal morbidity and mortality. New guidelines and findings from clinical trials must be taken into account so that the diagnosis and treatment of HDP can be optimized.

METHODS

Current guidelines, Cochrane reviews, metaanalyses, and randomized, controlled trials were retrieved by a search in PubMed and the Cochrane Library for reports published from 2006 to March 2009. These publications were then analyzed and evaluated for their evidence levels (EL).

RESULTS AND CONCLUSIONS

Aside from hypertension and proteinuria, the definition of preeclampsia (PE) should also take organ dysfunction into account. Important aspects of antenatal care include the following: the early recognition of risk factors, measurement of the uterine arteries in the 1st and 2nd trimesters with Doppler ultrasonography (A diagnostic tool which is now well established), prophylactic oral administration of 100 mg of acetylsalicylic acid daily from the beginning of pregnancy, particularly in high-risk patients (EL I++), and appropriate measurement of blood pressure and urinary protein. Patients should be hospitalized whenever indicated. Therapeutic goals are adequate treatment of hypertension, as well as seizure prophylaxis with magnesium sulphate in severe preeclampsia to prevent maternal cerebrovascular complications (EL I++). If delivery is indicated, it should be performed, regardless of the gestational age (EL IV). Careful monitoring during the puerperium and a general medical review six weeks after delivery are essential. Women with preeclampsia have a significantly elevated long-term risk of developing cardiovascular diseases in later life (EL I++).

The management of severe hypertension

Although definitions of severe hypertension vary, thresholds of >or=160-170 mm Hg systolic and/or >or=110 mm Hg diastolic are in most common usage. A recent focus has been placed on systolic hypertension given the increased pulse pressure in these women. In pregnancy, there is a general consensus that severe hypertension should be treated. Among woman with pre-eclampsia, attention must be paid to other end organ dysfunction, as blood pressure (BP) management is but one aspect of care. The urgency of antihypertensive therapy will depend primarily on the absolute level of BP. However, most clinicians will also consider both the rate of BP rise and the presence of maternal symptoms. Most commonly, severe hypertension is treated with parenteral labetalol or hydralazine, or oral nifedipine (capsules or PA tablet). Other options will depend on local availability. MgSO(4) should not be relied on as an antihypertensive.

A review of the methodological features of systematic reviews in maternal medicine

BACKGROUND

In maternal medicine, research evidence is scattered making it difficult to access information for clinical decision making. Systematic reviews of good methodological quality are essential to provide valid inferences and to produce usable evidence summaries to guide management. This review assesses the methodological features of existing systematic reviews in maternal medicine, comparing Cochrane and non-Cochrane reviews in maternal medicine.

METHODS

Medline, Embase, Database of Reviews of Effectiveness (DARE) and Cochrane Database of Systematic Reviews (CDSR) were searched for relevant reviews published between 2001 and 2006. We selected those reviews in which a minimum of two databases were searched and the primary outcome was related to the maternal condition. The selected reviews were assessed for information on framing of question, literature search and methods of review.

RESULTS

Out of 2846 citations, 68 reviews were selected. Among these, 39 (57%) were Cochrane reviews. Most of the reviews (50/68, 74%) evaluated therapeutic interventions. Overall, 54/68 (79%) addressed a focussed question. Although 64/68 (94%) reviews had a detailed search description, only 17/68 (25%) searched without language restriction. 32/68 (47%) attempted to include unpublished data and 11/68 (16%) assessed for the risk of missing studies quantitatively. The reviews had deficiencies in the assessment of validity of studies and exploration for heterogeneity. When compared to Cochrane reviews, other reviews were significantly inferior in specifying questions (OR 20.3, 95% CI 1.1-381.3, p = 0.04), framing focussed questions (OR 30.9, 95% CI 3.7- 256.2, p = 0.001), use of unpublished data (OR 5.6, 95% CI 1.9-16.4, p = 0.002), assessment for heterogeneity (OR 38.1, 95%CI 2.1, 688.2, p = 0.01) and use of meta-analyses (OR 3.7, 95% CI 1.3-10.8, p = 0.02).

CONCLUSION

This study identifies areas which have a strong influence on maternal morbidity and mortality but lack good quality systematic reviews. Overall quality of the existing systematic reviews was variable. Cochrane reviews were of better quality as compared to other reviews. There is a need for good quality systematic reviews to inform practice in maternal medicine.

Pathophysiology and medical management of systemic hypertension in preeclampsia

Hypertension that complicates preeclampsia in pregnancy is a disorder that requires special consideration in both prevention and pharmacologic treatment. In recent years, few advances have been made regarding the pathophysiology and prevention of preeclampsia; however, there have been some promising results from studies on possible modes of screening women for preeclampsia before clinical signs and symptoms are apparent. The recommendations for first-line drug therapy for the hypertensive complications of preeclampsia have changed little, primarily because first-line medications have had the advantage of extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive complications of preeclampsia; whether these therapies can eventually replace the standard recommended first-line medications will require more extensive long-term investigation.

Insufficient efficacy of intravenous ketanserin in severe early-onset pre-eclampsia

OBJECTIVE

To analyze the efficacy of intravenous ketanserin in controlling blood pressure of severe early-onset pre-eclamptic patients.

STUDY DESIGN

Pre-eclamptic patients (n=47) with a gestational age (GA) between 21 and 32 weeks were treated with intravenous ketanserin in a maximum dosage of 14 mg/h, to obtain a diastolic blood pressure of 90 mmHg or below. The number of patients reaching and maintaining target blood pressure was retrospectively assessed. Patient characteristics associated with an adequate or inadequate response to ketanserin treatment were identified.

RESULTS

With a maximum intravenous dosage of ketanserin, target blood pressure was not achieved in 15 (32%) patients. A high systolic blood pressure at the start of treatment was significantly (p=0.02) associated with failure of ketanserin treatment. The median period of ketanserin treatment in the responding group was 3 days (range 1-10 days). In 26 (55%) of initially successfully treated patients, additional antihypertensive drugs had to be added to maintain adequate blood pressure control.

CONCLUSION

Intravenous ketanserin lacks antihypertensive efficacy in a substantial proportion of severe pre-eclamptic patients, despite high dosages. In patients who initially respond well to ketanserin treatment, additional antihypertensive treatment is often necessary to maintain adequate blood pressure control.

Hydralazine for treatment of severe hypertension in pregnancy: meta-analysis

OBJECTIVE

To review outcomes in randomised controlled trials comparing hydralazine against other antihypertensives for severe hypertension in pregnancy.

STUDY DESIGN

Meta-analysis of randomised controlled trials (published between 1966 and September 2002) of short acting antihypertensives for severe hypertension in pregnancy. Independent data abstraction by two reviewers. Data were entered into RevMan software for analysis (fixed effects model, relative risk and 95% confidence interval); in a secondary analysis, risk difference was also calculated.

RESULTS

Of 21 trials (893 women), eight compared hydralazine with nifedipine and five with labetalol. Hydralazine was associated with a trend towards less persistent severe hypertension than labetalol (relative risk 0.29 (95% confidence interval 0.08 to 1.04); two trials), but more severe hypertension than nifedipine or isradipine (1.41 (0.95 to 2.09); four trials); there was significant heterogeneity in outcome between trials and differences in methodological quality. Hydralazine was associated with more maternal hypotension (3.29 (1.50 to 7.23); 13 trials); more caesarean sections (1.30 (1.08 to 1.59); 14 trials); more placental abruption (4.17 (1.19 to 14.28); five trials); more maternal oliguria (4.00 (1.22 to 12.50); three trials); more adverse effects on fetal heart rate (2.04 (1.32 to 3.16); 12 trials); and more low Apgar scores at one minute (2.70 (1.27 to 5.88); three trials). For all but Apgar scores, analysis by risk difference showed heterogeneity between trials. Hydralazine was associated with more maternal side effects (1.50 (1.16 to 1.94); 12 trials) and with less neonatal bradycardia than labetalol (risk difference -0.24 (-0.42 to -0.06); three trials).

CONCLUSIONS

The results are not robust enough to guide clinical practice, but they do not support use of hydralazine as first line for treatment of severe hypertension in pregnancy. Adequately powered clinical trials are needed, with a comparison of labetalol and nifedipine showing the most promise.

Hydralazine for treatment of severe hypertension in pregnancy: meta-analysis

OBJECTIVE

To review outcomes in randomised controlled trials comparing hydralazine against other antihypertensives for severe hypertension in pregnancy.

STUDY DESIGN

Meta-analysis of randomised controlled trials (published between 1966 and September 2002) of short acting antihypertensives for severe hypertension in pregnancy. Independent data abstraction by two reviewers. Data were entered into RevMan software for analysis (fixed effects model, relative risk and 95% confidence interval); in a secondary analysis, risk difference was also calculated.

RESULTS

Of 21 trials (893 women), eight compared hydralazine with nifedipine and five with labetalol. Hydralazine was associated with a trend towards less persistent severe hypertension than labetalol (relative risk 0.29 (95% confidence interval 0.08 to 1.04); two trials), but more severe hypertension than nifedipine or isradipine (1.41 (0.95 to 2.09); four trials); there was significant heterogeneity in outcome between trials and differences in methodological quality. Hydralazine was associated with more maternal hypotension (3.29 (1.50 to 7.23); 13 trials); more caesarean sections (1.30 (1.08 to 1.59); 14 trials); more placental abruption (4.17 (1.19 to 14.28); five trials); more maternal oliguria (4.00 (1.22 to 12.50); three trials); more adverse effects on fetal heart rate (2.04 (1.32 to 3.16); 12 trials); and more low Apgar scores at one minute (2.70 (1.27 to 5.88); three trials). For all but Apgar scores, analysis by risk difference showed heterogeneity between trials. Hydralazine was associated with more maternal side effects (1.50 (1.16 to 1.94); 12 trials) and with less neonatal bradycardia than labetalol (risk difference -0.24 (-0.42 to -0.06); three trials).

CONCLUSIONS

The results are not robust enough to guide clinical practice, but they do not support use of hydralazine as first line for treatment of severe hypertension in pregnancy. Adequately powered clinical trials are needed, with a comparison of labetalol and nifedipine showing the most promise.

Emergency management of eclampsia and severe pre-eclampsia

Eclampsia and severe pre-eclampsia are rare, but potentially life-threatening conditions that emergency physicians must be able to diagnose and treat promptly, because initial presentations to the ED are real possibilities. The treatment of the major complications of this disorder, hypertension and seizures, have been the focus of much research. Magnesium sulphate is now the first line agent for acute treatment and prophylaxis of seizures in eclampsia and pre-eclampsia. Severe pre-eclampsia should be treated with magnesium to prevent progression to eclampsia. Severe hypertension requires treatment with an intravenous antihypertensive agent familiar to the clinician. No single antihypertensive has been proven to be better than another, although in Australia, hydralazine is probably the initial intravenous agent of choice. Routine use of invasive haemodynamic monitoring and volume expansion is not recommended and consultation with obstetric colleagues is essential.

Pre-eclampsia and the hypertensive disorders of pregnancy

Pre-eclampsia is a multisystem disorder, of unknown aetiology, usually associated with raised blood pressure and proteinuria. Although outcome for most women and their babies is good, it remains a major cause of morbidity and mortality. A wide range of interventions for prevention and treatment of pre-eclampsia have been evaluated in randomized trials. This evidence provides the basis for a rational approach to care. Overall, there is insufficient evidence for any firm conclusion about the effects of any aspect of diet or lifestyle during pregnancy. Antiplatelet agents are associated with a 19% reduction in the risk of pre-eclampsia (relative risk 0.81; 95% CI 0.75, 0.88), a 7% reduction in the risk of preterm birth (RR 0.93; 95% CI 0.89, 0.98), a 16% reduction in the risk of stillbirth or neonatal death (RR 0.84; 95% CI 0.74, 0.96) and an 8% reduction in the risk of a small for gestational age baby (RR 0.92; 95% CI 0.85, 1.00). For mild to moderate hypertension, trials evaluating bed rest are too small for reliable conclusions about the potential benefits and hazards. Antihypertensive agents halve the risk of progression to severe hypertension (RR 0.52; 95% CI 0.41, 0.64), but with no clear effect on pre-eclampsia (RR 0.99; 95% CI 0.84, 1.18), or any other substantive outcome. For severe hypertension, there is no good evidence that one drug is any better than another. Plasma volume expansion for severe pre-eclampsia seems unlikely to be beneficial, although the trials are small. The optimum timing of delivery for pre-eclampsia before 34 weeks is unclear. Magnesium sulphate more than halves the risk of eclampsia (RR 0.41; 95% CI 0.29, 0.58) and probably reduces the risk of maternal death (RR 0.54; 95% CI 0.26, 1.10). It is also the drug of choice for treatment of eclampsia.

Interventionist versus expectant care for severe pre-eclampsia before term

BACKGROUND

Severe pre-eclampsia can cause significant mortality and morbidity for both mother and child, particularly when it occurs well before term. The only known cure for this disease is delivery. Some obstetricians advocate early delivery to prevent the development of serious maternal complications, such as eclampsia (fits) and kidney failure. Others prefer a more expectant approach in an attempt to delay delivery and, hopefully, reduce the mortality and morbidity for the child associated with being born too early.

OBJECTIVES

The objective of the review was to compare the effects of a policy of interventionist care and early delivery with a policy of expectant care and delayed delivery for women with early onset severe pre-eclampsia.

SEARCH STRATEGY

We search the register of trials maintained by the Cochrane Pregnancy and Childbirth Group (April 2002) and the Cochrane Controlled Trials Register (The Cochrane Library, Issue 2, 2002).

SELECTION CRITERIA

Randomised trials comparing the two intervention strategies for women with early onset severe pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using the criteria set out in the Cochrane Reviewers' Handbook. Data were extracted and checked independently by both reviewers.

MAIN RESULTS

Two trials (133 women) are included in this review. There are insufficient data for reliable conclusions about the comparative effects on outcome for the mother. For the baby, there is insufficient evidence for reliable conclusions about the effects on stillbirth or death after delivery (relative risk (RR) 1.50, 95% confidence interval (CI) 0.42 to 5.41). Babies whose mothers had been allocated to the interventionist group had more hyaline membrane disease (RR 2.3, 95% CI 1.39 to 3.81), more necrotising enterocolitis (RR 5.5, 95% CI 1.04 to 29.56) and were more likely to need admission to neonatal intensive care (RR 1.32, 95% CI 1.13 to 1.55) than those allocated an expectant policy. Nevertheless, babies allocated to the interventionist policy were less likely to be small for gestational age (RR 0.36, 95% CI 0.14 to 0.90). There were no statistically significant differences between the two strategies for any other outcomes.

REVIEWER'S CONCLUSIONS

There are insufficient data for any reliable recommendation about which policy of care should be used for women with severe early onset pre-eclampsia. Further large trials are needed.

Plasma volume expansion for treatment of women with pre-eclampsia

BACKGROUND

Plasma volume is reduced amongst women with pre-eclampsia. This association has led to the suggestion that expanding the plasma volume might improve maternal and uteroplacental circulation, and so potentially improve outcome for both the woman and her baby.

OBJECTIVES

The aim of this review was to assess the effects of plasma volume expansion for the treatment of women with pre-eclampsia.

SEARCH STRATEGY

The register of trials maintained by the Cochrane Pregnancy and Childbirth Group, and the Cochrane Controlled Trials Register Issue 1 1999 were searched for trials meeting the selection criteria.

SELECTION CRITERIA

Randomised trials were included. Quasi-random designs were excluded. Participants were women with hypertension during pregnancy, with or without proteinuria. Women who were postpartum at trial entry were excluded. Interventions were any comparison of plasma volume expansion with no expansion, or of one plasma volume expander with another.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers. Discrepancies were resolved by discussion. There was no blinding of authorship or results.

MAIN RESULTS

Three trials involving 61 women were included in this review. All compared a colloid solution with no plasma volume expansion. For every outcome reported, the confidence intervals are very wide and cross the no effect line.

REVIEWER'S CONCLUSIONS

There is insufficient evidence for any reliable estimates of the effects of plasma volume expansion for women with pre-eclampsia.