Angiotensin-converting enzyme inhibitors during pregnancy: a survey of 22 patients given captopril and nine given enalapril

South African medicinal plants displaying angiotensin-converting enzyme inhibition: Potential use in the management of preeclampsia

In resource-limited settings, such as South Africa, hypertensive disorders of pregnancy such as preeclampsia, is the most common direct cause of maternal deaths. Current management strategies of preeclampsia primarily involve the use of pharmaceutical drugs, which are frequently associated with undesirable side-effects. Moreover, these drugs are often not easily accessible due to financial and economic constraints. Consequently, many patients rely on traditional medicine obtained from medicinal plants to manage health-related conditions. Angiotensin-converting enzyme inhibitors are widely used drugs for the management of preeclampsia. This narrative review aims to highlight the use of indigenous medicinal plants from South Africa with Angiotensin-converting enzyme inhibitory activity whilst also evaluating their potential use in the treatment of hypertension in pregnancy. This information will influence traditional healers and sangomas in their patient management. Furthermore, the antihypertensive potential of these plants will be unraveled thus facilitating the development of new naturally occurring pharmaceutical products to reduce maternal and neonatal mortality and morbidity.

Is there an embryopathy associated with first-trimester exposure to angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists? A critical review of the evidence

Drugs that interfere with the renin-angiotensin system, such as angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), are widely used to manage hypertension and heart failure. Adequate functioning of the RAS is essential for normal fetal kidney development. The potential for ACEIs and ARBs to impair fetal and neonatal renal function if taken after the first trimester of pregnancy has been well documented. Although these drugs were not found to be teratogenic in animals, until recently little was known about the teratogenic effects of ACEIs and ARBs in humans when exposure was limited to the first trimester of pregnancy. New evidence from epidemiologic studies indicates that there may be an elevated teratogenic risk when these drugs are taken during the first trimester of pregnancy. However, this elevated risk does not appear to be specific to ACEIs and ARBs, but is instead related to maternal factors and diseases that typically coexist with hypertension in pregnancy, such as diabetes, advanced maternal age, and obesity. Women who become pregnant while being treated with an ACEI or ARB should be advised to avoid exposure to these drugs during the second and third trimesters of pregnancy by switching to a different class of antihypertensive drugs between weeks 8 and 10 after conception.

The Fetal Safety of Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are known to cause fetal renal damage in pregnancy. Due to conflicting reports in the literature, their safety after first trimester exposure has been debated. Our aim was to determine whether the use of ACE inhibitors or ARBs in the first trimester of pregnancy is associated with an increased risk for major malformations or other adverse outcomes. All subjects were prospectively enrolled from among women contacting a teratogen information service. At initial contact, details of maternal medical history and exposures were collected and follow-up interviews were conducted to ascertain pregnancy outcomes. Two comparator groups, women with hypertension treated with other antihypertensives, and healthy controls were also recruited. Baseline maternal characteristics were not different among the three groups. There were no differences in rates of major malformations. Both the ACE-ARBs and disease-matched groups exhibited significantly lower birth weight and gestational ages than the healthy controls (P < 0.001 for both variables). There was a significantly higher rate of miscarriage noted in the ACE/ARB group (P < 0.001). These results suggest that ACE inhibitors/ARBs are not major human teratogens; however, they may be associated with an increased risk for miscarriage.

Challenges posed to the maternal circulation by pregnancy

In primates, adequate growth of the fetus depends on the development of the uteroplacental unit. On the fetal side, this is achieved by the creation of the vascular network of the placenta. On the maternal side, the transformation of the spiral arteries into saccular nonreactive vessels by the trophoblast provides high blood flow to the intervillous space. Apart from the changes in the uterine arteries, the mother expands her plasma volume – at the expense of stimulating the renin-angiotensin-aldosterone system – and her cardiac output. In the maintaining of normotension in the face of an increased cardiac output and plasma volume, the renin-angiotensin-aldosterone system requires an enhanced vasodilator synthesis. Finally, in the late stages of pregnancy, a normal endothelial function is required to provide an ample margin to the activation provoked by deportation of syncytiotrophoblast fragments/factors to the maternal circulation. These four adaptative processes require various interrelated vasodilator systems. Deficient adaptations cause isolated or proteinuric arterial hypertension, intrauterine growth restriction, preterm delivery, and stillbirths, among others. Moreover, a normal or a defective adaptation to pregnancy influences maternal cardiovascular health in later life, as evidenced by various studies, most of them epidemiological; thus, pregnancy is now considered a stress test to the maternal cardiovascular system. Because of this, women planning to become pregnant should be screened for clinical and biochemical cardiovascular risks. Inversely, women presenting with hypertension in pregnancy should be thoroughly studied to detect and correct cardiovascular risks. The incorporation of the predictive value of a hypertensive pregnancy should help reduce cardiovascular disease in women.

Migraine therapy during pregnancy and lactation

IMPORTANCE OF THE FIELD

Migraine affects about 25% of women during childbearing years but few data are available about the risks connected with most antimigraine drugs during pregnancy.

AREAS COVERED IN THIS REVIEW

In this report, we review the available data, mainly obtained from published studies, toxicology databases and clinical guidelines, on migraine treatment during pregnancy and lactation.

WHAT THE READER WILL GAIN

The following drugs should be preferred for the treatment of acute migraine attacks in pregnant women: paracetamol, NSAIDs and sumatriptan. Migraine prophylaxis should be undertaken when patients experience at least three prolonged severe attacks a month that are particularly incapacitating or unresponsive to symptomatic therapy and likely to result in complications. Non-pharmacologic approaches should be preferred, but if they are not effective, preventive treatment should include low doses of β-blockers and amitriptyline.

TAKE HOME MESSAGE

Migraine treatment is often necessary because maternal and fetal risks related to acute attacks may be more harmful than the therapy itself, especially if they are frequent, severe and associated with nausea, anorexia, vomiting, hypotension or dehydration. If non-pharmacologic treatments do not alleviate migraine symptoms, only few drugs can be used during pregnancy and lactation.

Hypertension in pregnancy: a comprehensive update

Hypertensive disorders of pregnancies remain a central public health concern throughout the world, and are a major cause of maternal mortality in the developing world. Although treatment options have not significantly changed in recent years, insight on the pathogenesis of preeclampsia/eclampsia has been remarkable. With improved animal models of preeclampsia and large-scale human trials, we have embarked upon a new era where angiogenic biomarkers based on mechanism of disease can be designed to assist in early diagnosis and treatment. There is also a growing recognition of how elusive the diagnosis of eclampsia can be, especially in the postpartum period. Proper treatment of these patients depends heavily on the correct diagnosis, especially by the emergency physician. Finally, large epidemiologic studies have revealed that preeclampsia, once thought to be a self-limited entity, now appears to portend real damage to the cardiovascular and other organ systems in the long term. This review will present the latest update on our understanding of the various hypertensive disorders of pregnancies and their treatment options.

Inadvertent relaxation of the ductus arteriosus by pharmacologic agents that are commonly used in the neonatal period

Premature birth and disruption of the normal maturation process leave the immature ductus arteriosus unable to respond to postnatal cues for closure. Strategies that advocate conservative management of the patent ductus arteriosus (PDA) in premature infants are dependent on identification of the symptomatic PDA and understanding the risk factors that predispose to PDA. Exposure of premature infants to unintended vasodilatory stimuli may be one of the risk factors for PDA that is under recognized. In this article, we summarize the clinical factors that are associated with PDA and review commonly used neonatal drugs for their vasodilatory properties. Data demonstrating relaxation of the ductus arteriosus by gentamicin and other aminoglycoside antibiotics, by cimetidine and other H2 receptor antagonists, and by heparin are provided as examples of neonatal therapies that have unanticipated effects that may promote PDA.

Vasodilator factors in the systemic and local adaptations to pregnancy

We postulate that an orchestrated network composed of various vasodilatory systems participates in the systemic and local hemodynamic adaptations in pregnancy. The temporal patterns of increase in the circulating and urinary levels of five vasodilator factors/systems, prostacyclin, nitric oxide, kallikrein, angiotensin-(1-7) and VEGF, in normal pregnant women and animals, as well as the changes observed in preeclamptic pregnancies support their functional role in maintaining normotension by opposing the vasoconstrictor systems. In addition, the expression of these vasodilators in the different trophoblastic subtypes in various species supports their role in the transformation of the uterine arteries. Moreover, their expression in the fetal endothelium and in the syncytiotrophoblast in humans, rats and guinea-pigs, favour their participation in maintaining the uteroplacental circulation. The findings that sustain the functional associations of the various vasodilators, and their participation by endocrine, paracrine and autocrine regulation of the systemic and local vasoactive changes of pregnancy are abundant and compelling. However, further elucidation of the role of the various players is hampered by methodological problems. Among these difficulties is the complexity of the interactions between the different factors, the likelihood that experimental alterations induced in one system may be compensated by the other players of the network, and the possibility that data obtained by manipulating single factors in vitro or in animal studies may be difficult to translate to the human. In addition, the impossibility of sampling the uteroplacental interface along normal pregnancy precludes obtaining longitudinal profiles of the various players. Nevertheless, the possibility of improving maternal blood pressure regulation, trophoblast invasion and uteroplacental flow by enhancing vasodilation (e.g. L-arginine, NO donors, VEGF transfection) deserves unravelling the intricate association of vasoactive factors and the systemic and local adaptations to pregnancy.

Olmesartan medoxomil-induced acute renal failure in a premature newborn following maternal exposure during pregnancy: a case report and review of the literature

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (AT II) receptor blockers (ARBs) are widely used antihypertensives with well-recognized renoprotective and cardioprotective effects. Although treatment with these agents generally does not result in adverse metabolic consequences, their use during human pregnancy has been associated with negative reactions. Here we report a premature baby with a history of oligohydramnios and maternal exposure to the ARB olmesartan medoxomil who was transferred to our institution with acute renal failure. Conservative treatment with diuretics and meticulous management of fluids and electrolytes resulted in an improvement in renal function in the patient. We conclude that olmesartan medoxomil may cause reversible renal failure in premature neonates.

Mode of action: angiotensin-converting enzyme inhibition--developmental effects associated with exposure to ACE inhibitors

Relative to species tested in laboratory studies, the human fetus displays higher vulnerability to enalapril and other angiotensin-converting enzyme inhibitors (ACEI) exhibiting a malformative syndrome that does not appear to have a similar counterpart in experimental animals. An important reason for this higher vulnerability is the earlier intrauterine development of the kidney and the renin-angiotensin-aldosterone (RAS) system in humans, organ systems that are specific targets of ACEI's pharmacological effect. In humans, these systems begin developing prior to the onset of skeletal ossification at the end of the first trimester, with continuing vulnerability throughout the pregnancy. In most animal species tested, these target systems develop close to term, when the fetus is relatively more mature and less vulnerable to the effects of developmental toxicants. For this reason, animal studies that follow standard protocols and evaluate developmental toxicity only for exposures during embryogenesis will miss developmental effects arising secondary to disruption of target systems that develop after the period of major organogenesis. Thus, although the animal mode of action (MOA) for enalapril and other ACEI is plausible in humans, differences in the timing of development of critical target organ systems, particularly the renal system and RAS, explain the absence of definitive structural abnormalities in test animals.

Fetopathy associated with exposure to angiotensin converting enzyme inhibitors and angiotensin receptor antagonists

The renin-angiotensin system plays an important role in the regulation of blood pressure. The use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers both control hypertension by interruption of the production or action of angiotensin II, the major end-product of the renin-angiotensin system. The use of angiotensin converting enzyme inhibitors in pregnant women revealed serious and deleterious effects on fetal development including renal failure, renal dysplasia, hypotension, oligohydramnios, pulmonary hypoplasia, and hypocalvaria. The fetal effects of angiotensin converting enzyme inhibitors seem to be greatest during the 2nd and 3rd trimesters of pregnancy. The fetal effect of angiotensin converting enzyme inhibitors during the 1st trimester is controversial. These effects may represent the effect of hypoperfusion in the fetus and not a teratogenic effect. The effect of angiotensin receptor blockers is similar to converting enzyme inhibitors. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be avoided in all pregnant women. Alternative antihypertensive medications should be considered for use in women of childbearing years.

Cardiovascular Pharmacotherapeutic Considerations During Pregnancy and Lactation

Table 2 summarizes the recommendations regarding the use of cardiovascular drugs during pregnancy and lactation.

Adverse pregnancy outcomes associated with maternal enalapril antihypertensive treatment

BACKGROUND

Adverse pregnancy outcomes following the use of angiotensin-converting enzyme (ACE) inhibitors, including enalapril, have been reported in descriptive studies. However, no analytical studies on the relationship between the adverse outcomes and enalapril gestational exposures are available.

OBJECTIVES

To explore the association between enalapril exposure and adverse outcomes in pregnancy, taking into account other possible risk factors.

METHODS

We analyzed a series of all usable cases reported to the FDA between 1986 and 2000 in which enalapril was a suspect drug for the observed adverse outcomes (N = 110). Parameters of exposure and reported outcomes as well as information on potentially confounding variables were systematically abstracted from this series by a single physician. Because exposure to ACE inhibitors after the first trimester of pregnancy had been associated with adverse outcomes in the existing literature, we divided the cases into those exposed in the first trimester only (considered as the baseline group) and cases exposed beyond or after this time. Frequency of reported adverse outcomes in the second group was compared with those in the baseline group; odds ratios were computed, taking account of potentially confounding variables by logistic regression where appropriate.

RESULTS

Exposure to enalapril after the first trimester of pregnancy was strongly associated with oligohydramnios and specific adverse outcomes thought to be secondary to reduced amniotic fluid volume (limb deformities, cranial ossification deficits, lung hypoplasia), as well as with neonatal renal failure. The relationship did not change after taking numerous potential confounders into account, including duration of exposure, concomitant drug use, maternal age, concurrent disease, neonatal gender, and gestational age at birth. Such a pattern of abnormalities is considered to be a consequence of the effect of ACE inhibition on fetal renal function that develops after the first trimester.

CONCLUSION

The specificity and temporality of the observed adverse manifestations suggest a causal relationship to enalapril exposure.

The effect of antihypertensive drugs on the fetus

A critical review of the literature on the effects of antihypertensive drugs on the fetus in pregnant women is presented. The survey covers the alpha-adrenergic receptor agonists, beta-blockers including topical eye medications, alpha-beta blockers, calcium antagonists, diuretics, and angiotensin-converting enzyme (ACE) inhibitors. The lack of data on angiotensin II receptor blockers is noted although effects are considered to be similar to those reported with ACE inhibitors and therefore to be avoided. Analysis of the literature underscores that some antihypertensive drugs can be used safely at certain stages of pregnancy, while others are suspect and to be avoided at all costs. The lack of placebo-controlled studies on the treatment of severe hypertension in pregnancy due to ethical considerations is discussed against the background of the pressing need to treat these women despite the possible deleterious effects of antihypertensive drugs.

Partial ureteral obstruction dysregulates the renal renin-angiotensin system in the fetal sheep kidney

OBJECTIVES

To investigate whether partial ureteral obstruction (PUO) in the fetus induces dysregulation of the renin-angiotensin system (RAS) and of transforming growth factor-beta 1 (TGF-beta1) and tissue inhibitors of metalloproteinase (TIMP1) expression. Previous studies have indicated that renal and urinary tract development depend on an intact renal RAS. Fetal urinary obstruction is distinct from postnatal obstruction. It has been suggested in postnatal animal studies that dysregulation of the RAS, and subsequent increased expression of TGF-beta1 and TIMP1, leads to changes in extracellular matrix composition.

METHODS

Bilateral PUO was created in 4 fetal sheep. Seven animals (four obstructed and three controls) were killed at birth and their kidneys removed. Semiquantitative reverse transcriptase-polymerase chain reaction was used to quantify the levels of renin, angiotensinogen, angiotensin receptor type 1 (AT1 receptor), angiotensin receptor type 2 (AT2 receptor), TGF-beta1, and TIMP1. These messages were normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA.

RESULTS

All obstructed animals had moderate to severe hydronephrosis with enlarged kidneys (mean weight 22.0 g versus 9.4 g for the control animals; P <0.05). The increase in the levels of renin, angiotensinogen, AT1 receptor, TGF-beta1, and TIMP1 mRNA was significant in the PUO group compared with the control group (P <0.05). AT2 receptor levels did not increase, but the AT1/AT2 mRNA ratio was significantly increased over normal (P <0.005). Also, a significant linear correlation was found between the increased renal weight and increased TGF-beta1 mRNA levels (P <0.005).

CONCLUSIONS

Our findings suggest that fetal PUO can cause upregulation of the renal RAS and increased expression of TGF-beta1 and TIMP1, which may alter the balance between the generation and degradation of the extracellular matrix. The coordinate increases in renin, angiotensinogen, and AT1 receptor mRNA levels in chronic fetal PUO may represent a maladaptive response that contributes to interstitial fibrosis and prolonged vasoconstriction. RAS components and growth factors, particularly TGF-beta1, may be considered relevant targets in the prevention and treatment of congenital obstructive nephropathy.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and renal damage in childhood uropathies

BACKGROUND

The activation of the renin-angiotensin system in various renal disorders is well established. Congenital urological abnormalities, such as obstruction and reflux, are common causes of renal failure in children contributing to approximately 25% of chronic renal failure in this age group. While the outlook relates to the severity of initial renal damage, there is considerable heterogeneity in renal parenchymal destruction among individuals and the reasons for this heterogeneity are not fully understood. A polymorphism within intron 16 of the angiostensin-converting enzyme (ACE) gene has been shown to influence the activity of the renin-angiotensin system, thus, it may also have an impact on the expression of renal disorders. We have determined the incidence of this ID polymorphism of the ACE gene in 47 Kuwaiti children with different urological abnormalities leading to variable degrees of renal impairment and in 48 healthy control subjects with a similar ethnic background.

METHODS

Blood samples were collected from the patients (n = 47) and controls (n = 48), total genomic DNA extracted and the ACE genotypes were determined using a polymerase chain reaction-based method.

RESULTS

The DD genotype was detected in 27/47 (57%) cases compared with 25/48 (52%) controls (P = 0.439). The heterozygous genotype ID was found in 14/47 (29%) cases compared with 22/48 (46%) controls (P = 0.0138). The homozygous II genotype was detected in 6/47 (13%) cases compared with 1/48 (2%) controls (P = 0.0247). The D allele of ACE gene was detected in 41/47 (87%) uropathy cases when individuals with homozygous DD and heterozygous ID genotypes were considered collectively. The incidence of parenchymal damage was considerably higher in uropathy cases with DD genotype (62%) compared with those having ID (26%) and II (12%) genotypes.

CONCLUSIONS

Our data suggest an association of D allele of the ACE gene insertion/deletion polymorphism and congenital urological abnormalities, which result in parenchymal damage in Kuwaiti Arab children.

Enhancement of neonatal rat ductal responsiveness to prostaglandin E2 after maternal treatment with enalapril or captopril

This work was conducted to determine whether the angiotensin-converting enzyme inhibitors (ACEIs) (enalapril and captopril) administered to mother rats prenatally can potentiate a re-opening of the neonatal ductus arteriosus (DA) induced by prostaglandin E2 (PGE2) after postnatal closure. A subcutaneous injection of PGE2 (4 micrograms) was administered to newborn rats 3 hr after a Cesarean delivery from females which had been orally given 0.1, 1 or 10 mg/kg/day of enalapril or 15 or 150 mg/kg/day of captopril from day 14 to day 20 of gestation. The ratio of the DA to the pulmonary artery (PA) was determined at intervals after the injection. The DA/PA ratio was significantly higher in the newborn rats of mothers who were transplacentally administered these agents compared to the controls, except at the low dose (0.1 mg/kg) group of enalapril. We found that the level in the neonatal lungs of 15-hydroxy prostaglandin dehydrogenase, a key enzyme that catalyzes PGE2 to convert it to its inactive metabolite 15-keto-PGE2, was not affected after maternal treatment with enalapril or captopril. These results indicate that the increased ductal responsiveness to PGE2 in newborn rats was a common response after maternal ACEI treatment, but the catabolism of PGE2 in the lungs did not contribute to this response.

Assessing the teratogenic potential of angiotensin-converting enzyme inhibitors in pregnancy

To assess the teratogenic potential of angiotensin-converting enzyme (ACE) inhibitors, we report on 20 prospective pregnancies and 85 identified from articles in the literature. The anomaly rate was 20.6% in small series <10 entrants (95% CI 8.7-37.9%) and 1.4% in larger series > or =10 entrants (95% CI 0.03-7.3%) p=0.0016. The most consistent anomaly seen, skull hypoplasia, along with renal dysfunction appear to be more related to prolonged or late pregnancy exposure than to first trimester exposure. There is little supportive evidence that ACE inhibitors (captopril or enalapril) are teratogenic. There seems to be no absolute reason to discontinue these 2 medications prior to pregnancy, nor to create anxiety when a patient is identified with the combination of early pregnancy and treatment with these medications. There appears to be reason to discontinue the medication in pregnancy but the adverse event rate cannot be assessed because of inadequate prospective information.

Angiotensin converting enzyme inhibitors in pregnancy

Angiotensin converting enzyme (ACE) inhibitors are excellent antihypertensive agents and are becoming widely used as first-line therapy for chronic hypertension in women of reproductive age owing to their efficacy and few side effects. Reports of adverse fetal and neonatal effects from the use of ACE inhibitors in pregnancy in both animal and human studies prompted recommendations against their use in human pregnancy by several authors. This review discusses the mechanism of action of ACE inhibitors and the use of ACE inhibitors in pregnancy both in experimental animals and use in human pregnancy. ACE inhibitors used during pregnancy may have untoward effects on the fetus. Based on reports in the literature, one should avoid starting ACE inhibitors during pregnancy and discontinue them in current users if at all possible.

Captopril inhibits angiogenesis and slows the growth of experimental tumors in rats

Captopril, an inhibitor of angiotensin converting enzyme, is widely used clinically to manage hypertension and congestive heart failure. Here captopril is shown to be an inhibitor of angiogenesis able to block neovascularization induced in the rat cornea. Captopril acted directly and specifically on capillary endothelial cells, inhibiting their chemotaxis with a biphasic dose-response curve showing an initial decrease at clinically achievable doses under 10 microM and a further slow decline in the millimolar range. Captopril inhibition of endothelial cell migration was not mediated by angiotensin converting enzyme inhibition, but was suppressed by zinc. Direct inhibition by captopril of zinc-dependent endothelial cell-derived 72-and 92-kD metalloproteinases known to be essential for angiogenesis was also seen. When used systemically on rats captopril inhibited corneal neovascularization and showed the antitumor activity expected of an inhibitor of angiogenesis, decreasing the number of mitoses present in carcinogen-induced foci of preneoplastic liver cells and slowing the growth rate of an experimental fibrosarcoma whose cells were resistant to captopril in vitro. These data define this widely used drug as a new inhibitor of neovascularization and raise the possibility that patients on long term captopril therapy may derive unexpected benefits from its antiangiogenic activities.

Characteristics and treatment of hypertension in women: a review of the literature

Although there are documented differences between women and men in frequency and severity of hypertension and in the relation between hypertension and cardiovascular risk, few studies have been designed to evaluate efficacy and safety of antihypertensive therapy in women. Efficacy of nonpharmacologic interventions to lower blood pressure may differ between the sexes; women have greater difficulty losing weight than men but may respond better than men to dietary sodium reduction. In general, women and men do not respond differently to antihypertensive therapy; however, there may be differences in response to certain classes of antihypertensives. There are limited data on safety of specific antihypertensive agents in women. In some studies, researchers found a greater incidence of adverse effects in women. Effects on sexual functioning and pharmacokinetic and pharmacodynamic characteristics of antihypertensive drugs in women have been studies inadequately. More data are needed to guide the management of hypertension in women.

Primary aldosteronism in pregnancy--should it be treated surgically?

We report a case of primary aldosteronism in pregnancy that was treated surgically by removal of the adenoma in the 2nd trimester. Only a few cases have been reported in the English literature due to the rarity of the condition. Primary aldosteronism follows a variable course in pregnancy. In the majority of cases the hypertension and hypokalaemia are made worse, necessitating antihypertensive medication to control the blood pressure. Some of the drugs required for treatment are known to affect the fetus. In a minority of cases the hypertension improves with pregnancy. This is thought to be due to the high levels of progesterone which is an aldosterone antagonist. Primary aldosteronism invariably gets worse in the post partum period, irrespective of the antenatal course of the disease. Surgery seems to be the treatment of choice for this condition, provided the adenoma is localised. It has the advantage of offering an immediate solution, avoids fetal complications of medical treatment and possible deterioration in the post partum period.

Angiotensin-converting enzyme activity and contractile effects of angiotensin I and II in human uteroplacental arteries

OBJECTIVE

Our purpose was to study local angiotensin-converting enzyme activity and the mechanical effects of angiotensin I and II in human uteroplacental arteries.

STUDY DESIGN

Angiotensin-converting enzyme activity was measured by a simple radioimmunoassay with tritiated benzoyl-glycyl-glycyl-glycine as substrate in isolated human intramyometrial arteries from nonpregnant (n = 8) and term pregnant women (n = 8) and placental (n = 8) stem villous arteries. Moreover, in these vessels the mechanical effects of angiotensin I and II were investigated in organ bath experiments. Endothelium-intact and endothelium-denuded arteries were used, and the integrity of the endothelium was examined by histologic studies.

RESULTS

The activity of angiotensin-converting enzyme ranked the intramyometrial arteries from pregnant women >> intramyometrial arteries from nonpregnant women > fetal stem villous arteries. Angiotensin-converting enzyme activity was unaffected by removal of the endothelium. Angiotensin II 10(-5) mol/L produced contractile responses in the intramyometrial arteries without significant differences between arteries from nonpregnant and pregnant women. In fetal stem villous arteries the effects of angiotensin II 10(-5) mol/L were less pronounced. As for angiotensin II, the contractile responses to angiotensin I 10(-5) mol/L showed marked development of tachyphylaxis. In the endothelium-denuded preparations the contractile responses to angiotensin I 10(-5) mol/L were significantly enhanced in intramyometrial arteries from nonpregnant women but remained unchanged in intramyometrial arteries from pregnant women and in fetal stem villous arteries. In all preparations pretreatment with captopril or perindopril (10(-5) mol/L) markedly reduced angiotensin-converting enzyme activity, whereas no effects were observed on the contractile responses to angiotensin I. Saralasin 10(-5) mol/L completely abolished the contractile responses to angiotensin I and II.

CONCLUSION

Local angiotensin-converting enzyme activity in human intramyometrial arteries seems to be markedly increased during pregnancy and shows marked differences between maternal and fetal uteroplacental arteries. High concentrations of angiotensin I may imply direct effects on the angiotensin II receptor independent of the local angiotensin-converting enzyme activity.

Teratogen update: angiotensin-converting enzyme inhibitors

Occasionally there is a drug whose record in pregnancy is so frequently associated with adverse outcome of so specific a pattern that it becomes clear that its use must be restricted before scientific proof from epidemiological studies is obtained. I believe this to be the case with the drug class of ACEIs. There are mammalian models suggesting substantial fetotoxicity in a dose-related fashion. There is a strong and consistent pattern to the reported cases of ACEI-related adverse outcomes: the syndrome of oligohydramnios-anuria, neonatal hypotension, renal dysplasia, and hypocalvaria is too specific in association with the use of these drugs to be ignored. There is a very plausible biologic mechanism to explain the relationship. The features of ACEI fetopathy suggest that the underlying pathogenetic mechanism is fetal hypotension, which may also result from other exposures. Thus, while the fetopathy may not be truly specific to ACEIs, they are particularly liable to produce adverse fetal renal effects with their sequels (anuria-oligohydramnios, pulmonary hypoplasia, growth restriction) and hypocalvaria.

Risks of angiotensin-converting enzyme inhibition during pregnancy: experimental and clinical evidence, potential mechanisms, and recommendations for use

OBJECTIVE

To review reports on the use of angiotensin-converting enzyme inhibitors (ACE-I) during pregnancy in order to determine the incidence, nature, and potential mechanisms of fetal complications in an attempt to establish recommendations related to the use of these drugs during gestation.

DATA SOURCES

Relevant English-language articles identified through a Medline search and bibliographies found in recent articles.

STUDY SELECTION

Large number of reports both on animals and on humans have consistently shown a high degree of morbidity and even mortality in fetuses or newborns exposed to ACE-I during pregnancy. The reported complications include oligohydramnios, intrauterine growth retardation, premature labor, fetal and neonatal renal failure, bony malformations, limb contractures, persistent patent ductus arteriosus, pulmonary hypoplasia, respiratory distress syndrome, prolonged hypotension, and neonatal death. A high incidence of fetal complications was related to the use of ACE-I at all trimesters of pregnancy.

CONCLUSION

The gestational use of ACE-I may be associated with a high degree of fetal and newborn morbidity and even mortality. The use of these drugs should be avoided at all trimesters of pregnancy.

Enalapril. A reappraisal of its pharmacology and therapeutic use in hypertension

Enalapril, an angiotensin converting enzyme (ACE) inhibitor usually administered orally once daily, decreases blood pressure by lowering peripheral vascular resistance without increasing heart rate or output. It is effective in lowering blood pressure in all grades of essential and renovascular hypertension. Patients not responding adequately to enalapril monotherapy usually respond with the addition of a thiazide diuretic (or a calcium antagonist or beta-blocker), and rarely require a third antihypertensive agent. Enalapril is at least as effective as other established and newer ACE inhibitors, and members of other antihypertensive drug classes including diuretics, beta-blockers, calcium antagonists and alpha-blockers, but therapy with enalapril may be less frequently limited by serious adverse effects or treatment contraindications than with other drug classes. The most frequent adverse effect limiting all ACE inhibitor therapy in clinical practice is cough. This favourable profile of efficacy and tolerability, and the substantial weight of clinical experience, explain the increasing acceptance of enalapril as a major antihypertensive treatment and supports its use as logical first-line therapeutic option.

Adverse effects of angiotensin converting enzyme (ACE) inhibitors. An update

The angiotensin converting enzyme (ACE) inhibitors are a group of effective drugs with a unique mechanism of action. These drugs have proven to be useful for hypertension and congestive heart failure. Early clinical trials of captopril used doses that are now known to be inappropriately high, and dose-related adverse effects were observed frequently. The recognition that lower doses are effective has reduced the incidence of adverse reactions and resulted in improved patient tolerance. When patients are properly selected and correctable risk factors are removed, serious side effects are uncommon. Unfortunately, the early reputation of nephrotoxicity persists, as does the belief that significant blood dyscrasias, endocrine effects and rash are serious risks for the average patient. After wide use of captopril, enalapril and lisinopril, and investigational trials of nearly a dozen newer agents, a sufficiency of clinical observation, experimental evidence and accurate postmarketing recording of events is accumulating to allow insight into the major toxicities with regard to more intelligent patient selection, more rational dosing and proper identification of risk factors. The most common adverse reactions are cough and skin rash. It appears that the agents are generally not cross-reactive with regard to skin rash, although it is not clear whether this effect is drug-specific or class-specific with regard to cough. Statistically but not clinically significant lowering of haemoglobin and hematocrit is common; these effects are inconsequential in most patients. Neutropenia, once thought to be prevalent, now appears to be so only in patients with autoimmune or collagen-vascular disease; the majority of patients outside these groups are at low risk. Hyperkalaemia is a frequent occurrence. This should not be surprising in view of the effect of the ACE inhibitors on plasma aldosterone. When dietary potassium intake is regulated and sources of altered potassium excretion are identified, hyperkalaemia is seldom a serious problem. Identification of sodium and water deficits allows correction before the drugs are started, and the frequency of hypotension and hyperkalaemia caused by the drugs is quite low if these factors are properly managed. An unexpected finding emerging in recent years is the dry cough associated with ACE inhibitor therapy. Its mechanism is not definitely known. Nonsteroidal anti-inflammatory drugs may control this symptom in some patients. The frequent observation of proteinuria in patients taking ACE inhibitors has gained notice and sometimes caused undue alarm. It is difficult to separate disease effects in diabetes and hypertension from true drug effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevention and treatment of pregnancy-associated hypertension: what have we learned in the last 10 years?

High blood pressure (BP) complicates approximately 10% of all pregnancies. Hypertension in pregnancy falls into four categories: (1) preeclampsia-eclampsia, (2) chronic hypertension of whatever cause, (3) preeclampsia-eclampsia superimposed to chronic hypertension or renal disease, and (4) transient or late hypertension (gestational hypertension). Preeclampsia, the association of hypertension, proteinuria, and edema, accounts for more than 50% of all the hypertensive disorders of pregnancy and is a major cause of fetal and maternal morbidity and mortality. Unfortunately, distinguishing between preeclampsia and other causes of hypertension on clinical grounds can be difficult because of the lack of specific tests for differential diagnosis. Increased vascular resistance has been claimed as the primary cause of preeclampsia; however, a variable hemodynamic profile with relatively high cardiac outputs, normal filling pressures, and inappropriately high systemic vascular resistances is now reported by most investigators. Imbalance between vasodilator and vasoconstrictor eicosanoids may account for platelet activation and increased responsiveness to pressor peptides. Altered prostacyclin (PGI2) to thromboxane A2 (TxA2) ratio in maternal uteroplacental vascular bed may favor local platelet activation and vasoconstriction contributing to placental insufficiency and fetal distress. Alternatively, recent evidence seems to suggest that fetal umbilical placental circulation may be the site of the primary vascular injury. Whether low-dose aspirin prevents preeclampsia because it inhibits the excessive maternal TxA2 or whether the partial inhibition of fetal TxA2 is also of therapeutic value remains to be established. Treatment of severe hypertension in pregnancy is probably important to prevent cardiac failure or cerebrovascular accidents in the mother. The need for pharmacological therapy of mild to moderate hypertension is still debated, since no formal studies are available to clarify whether pharmacological treatment in such instances effectively reduces maternal or fetal risk. For the treatment of preeclampsia, hydralazine and nifedipine may be used when delivery is not applicable. Labetalol and diazoxide are effective for hypertensive emergencies. Life-threatening hypertension that does not respond to more conventional therapy is an indication for the use of sodium nitroprusside. For chronic hypertension, alpha-methyldopa remains the treatment of choice; if ineffective, hydralazine or beta-blockers are suitable. Effectiveness and safety of other molecules remain elusive.

Maternal and uteroplacental hemodynamic effects of chronic captopril in the hypertensive, term-pregnant rat

The chronic effects of captopril on maternal hemodynamics and organ perfusion were investigated in 10 untreated and 10 captopril-treated pregnant spontaneously hypertensive rats by means of the radioactive-labeled microsphere technique. The normal decrease in blood pressure during gestation was prevented by reduction of litter size to two conceptuses on day 7 of gestation. Captopril (approximately 10 mg/kg/day) or drug vehicle (50% ethyl alcohol) was administered intraperitoneally by an osmotic pump from day 7 to 21. At term mean arterial pressure was 23% lower in the captopril-treated group as the result of a 29% decrease in total peripheral resistance without a significant change in cardiac output. The decrease in total peripheral resistance was primarily caused by a decline in splanchnic and skin resistances. Maternal organ and uteroplacental perfusion were not significantly altered. We conclude that administration of captopril during the last 2 weeks of pregnancy in the hypertensive rat effectively lowers maternal blood pressure without adverse effects on organ and uteroplacental perfusion.

Managing the pregnant patient with heart disease

Pregnancy and its associated hemodynamic challenge presents potential risks to the patient with cardiac disease, whether acquired or congenital. The hematologic changes which occur during pregnancy include alterations in blood volume, hematocrit, and blood viscosity. There are also alterations in cardiac output and regional blood flow patterns. These hemodynamic alterations are associated with signs and symptoms which can be impressive yet benign, or can suggest poor outcome, depending on the underlying cardiovascular disorder. The clinician is faced with the sometimes difficult task of differentiating the benign from the dangerous while making appropriate management decisions. In this article, diagnosis and current management of many of the more common acquired and congenital cardiac abnormalities are discussed as they pertain to the gravid female. The effects of common cardiovascular medications in pregnancy are also briefly reviewed.

Oligohydramnios sequence and renal tubular malformation associated with maternal enalapril use

We present the case of a child who died of pulmonary hypoplasia as a result of the oligohydramnios sequence. The mother was taking enalapril, as well as propranolol and hydrochlorothiazide, for treatment of hypertension associated with systemic lupus erythematosus. Autopsy examination revealed severe renal tubular malformation. Correlation of animal data with previous case reports of neonatal anuria in association with maternal angiotensin converting enzyme inhibitors suggests that these agents may have a deleterious effect on fetal renal development and general well-being.