Losartan and fetal toxic effects

Society for Maternal-Fetal Medicine Consult Series #68: Sickle cell disease in pregnancy

Pregnant individuals with sickle cell disease have an increased risk of maternal and perinatal morbidity and mortality. However, prepregnancy counseling and multidisciplinary care can lead to favorable maternal and neonatal outcomes. In this consult series, we summarize what is known about sickle cell disease and provide guidance for sickle cell disease management during pregnancy. The following are Society for Maternal-Fetal Medicine recommendations.

Metabolomic Profile, Plasmatic Levels of Losartan and EXP3174, Blood Pressure Control in Hypertensive Patients and Their Correlation with COVID-19

Systemic arterial hypertension (SAH) is one of the most prevalent chronic diseases worldwide and is related to serious health complications. It has been pointed out as a major risk factor for COVID-19. This study aimed to determine the impact of COVID-19 on the metabolomic profile, the correlation with the plasmatic levels of losartan and its active metabolite (EXP3174), biochemical markers, and blood pressure (BP) control in hypertensive patients. 1H NMR metabolomic profiles of hypertensive and normotensive patients with and without previous COVID-19 diagnosis were identified. Plasmatic levels of LOS and EXP3174 were correlated with BP, biochemical markers, and the metabolomic fingerprint of the groups. Biomarkers linked to important aspects of SAH and COVID-19 were identified, such as glucose, glutamine, arginine, creatinine, alanine, choline, erythritol, homogentisate, 0-tyrosine, and 2-hydroxybutyrate. Those metabolites are indicative of metabolic alterations, kidney damage, pulmonary dysfunction, and persistent inflammation, which can be found in both diseases. Some hypertensive patients did not reach the therapeutic levels of LOS and EXP3174, while the BP control was also limited among the normotensive patients with previous COVID-19 diagnoses. Metabolomics proved to be an important tool for assessing the effectiveness of losartan pharmacotherapy and the damage caused by SAH and COVID-19 in hypertensive patients.

Metabolomic Profile and Its Correlation with the Plasmatic Levels of Losartan, EXP3174 and Blood Pressure Control in Hypertensive and Chronic Kidney Disease Patients

Systemic arterial hypertension (SAH) is one of the most prevalent chronic diseases worldwide and, when dysregulated, may cause serious complications. Losartan (LOS) blocks relevant physiological aspects of hypertension, acting mainly on the reduction of peripheral vascular resistance. Complications of hypertension include nephropathy, in which diagnosis is based on the observation of functional or structural renal dysfunction. Therefore, blood pressure control is essential to attenuate the progression of chronic kidney disease (CKD). In this study, ¹H NMR metabolomics were used to differentiate hypertensive and chronic renal patients. Plasmatic levels of LOS and EXP3174, obtained by liquid chromatography coupled with mass-mass spectroscopy, were correlated with blood pressure control, biochemical markers and the metabolomic fingerprint of the groups. Some biomarkers have been correlated with key aspects of hypertension and CKD progression. For instance, higher levels of trigonelline, urea and fumaric acid were found as characteristic markers of kidney failure. In the hypertensive group, the urea levels found could indicate the onset of kidney damage when associated with uncontrolled blood pressure. In this sense, the results point to a new approach to identify CKD in early stages and may contribute to improving pharmacotherapy and reducing morbidity and mortality associated with hypertension and CKD.

Obesity-associated cardiometabolic complications in polycystic ovary syndrome: The potential role of sodium-glucose cotransporter-2 inhibitors

Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in reproductive-age women. PCOS is characterized by androgen excess, oligo/anovulation, and polycystic appearance of the ovaries. Women with PCOS have an increased prevalence of multiple cardiovascular risk factors such as insulin resistance, hypertension, renal injury, and obesity. Unfortunately, there is a lack of effective, evidence-based pharmacotherapeutics to target these cardiometabolic complications. Sodium-glucose cotransporter-2 (SGLT2) inhibitors provide cardiovascular protection in patients with and without type 2 diabetes mellitus. Although the exact mechanisms of how SGLT2 inhibitors confer cardiovascular protection remains unclear, numerous mechanistic hypotheses for this protection include modulation of the renin-angiotensin system and/or the sympathetic nervous system and improvement in mitochondrial function. Data from recent clinical trials and basic research show a potential role for SGLT2 inhibitors in treating obesity-associated cardiometabolic complications in PCOS. This narrative review discusses the mechanisms of the beneficial effect of SGLT2 inhibitors in cardiometabolic diseases in PCOS.

Valsartan exposure in pregnancy with resultant anhydramnios and chronic kidney disease in a late preterm infant

In utero exposure to angiotensin II receptor blockers (ARBs) has fetotoxic effects including renal failure, oligohydramnios and lung hypoplasia. We present the case of a 24-year-old woman who presented to the maternity services in the 34th week of her first pregnancy. She was taking valsartan for hypertension. Ultrasound showed a structurally normal fetus with anhydramnios. The patient was admitted and valsartan was discontinued. She had spontaneous preterm delivery at 35 weeks' gestation of a baby girl. The baby's urine output was minimal in the first week of life and she was transferred to a paediatric hospital for specialist nephrology input. At 6 months of age, she requires ongoing nephrology follow-up and she remains on treatment for hypertension and anaemia. This case demonstrates the serious adverse effects resulting from ARB exposure in utero, and highlights the importance of avoiding fetotoxic medications in women of childbearing age.

Fetotoxic risk of AT1 blockers exceeds that of angiotensin-converting enzyme inhibitors: an observational study

OBJECTIVE

The fetotoxic potential of prenatal exposure to angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARBs) has been known for many years. Symptoms range from transient oligohydramnios to neonatal anuria and permanent renal damage, joint contractures, hypocalvaria, lung hypoplasia and intrauterine or neonatal death. This study aims to investigate the critical gestational time for renin-angiotensin system inhibitor (RAS-I)-induced fetopathy, to quantify the fetopathy risk and to evaluate factors associated with the occurrence and severity of fetopathy.

METHODS

Prospectively and retrospectively ascertained RAS-I exposed pregnancies from the databases of six teratology information services were analyzed.

RESULTS

Eighty-nine pregnancies with ACE-I and 101 with ARB exposure beyond the first trimester were identified. Fifty-nine of these 190 pregnancies were classified as having evidence of RAS-I fetopathy. All pregnancies affected with fetopathy were exposed after 20 0/7 gestational weeks. Limited to prospectively enrolled cases with exposure at least 20 0/7 gestational weeks, the rate of fetopathy was 3.2% for ACE-I and 29.2% for ARB. The chance of recovery of amniotic fluid volume was higher with RAS-I discontinuation before 30 gestational weeks and with a longer exposure-free interval before delivery.

CONCLUSION

Exposure to ARBs is associated with a higher fetopathy risk than exposure to ACE-Is. RAS-I should ideally be discontinued prior to pregnancy or immediately after recognition of pregnancy. Because symptoms may improve in cases of RAS-I-induced oligohydramnios, pregnancy should be maintained as long as there is fetal well being. Physicians and patients need to be alerted to the fetotoxic risks of RAS-I.

Risk assessment of therapeutic agents under consideration to treat COVID-19 in paediatric patients and pregnant women

AIM

Repurposing strategies to address the COVID-19 pandemic have been accelerated. As both pregnant and paediatric patients are likely to be excluded from most planned investigations, the list of repurposed options and the available data on these drugs and vaccines provide a baseline risk assessment and identify gaps for targeted investigation.

METHODS

Clinical trials have been searched and reviewed; 23 repurposed drugs and drug combinations and nine candidate vaccines have been assessed regarding the availability of relevant data in paediatrics and pregnant women and to evaluate expected or unanticipated risk.

RESULTS

Thirteen of the repurposed drugs or drug combinations are indicated for use in paediatrics in some age category albeit for indications other than COVID-19; 10 of these are indicated for use in pregnant women. Even in cases where these drugs are indicated in the populations, source data from which safety and or dosing could be extrapolated for use in COVID-19 is sparse. Vaccine trials are ongoing and generally exclude pregnant women; only in a few instances have paediatric subgroups been planned for enrolment. Data from individual case studies and RWD may suggest that subpopulations of both paediatric patients and pregnant women may be more at risk, particularly those in an increased inflammatory state.

CONCLUSION

In conjunction with more prospective collaboration, plans are evolving to ensure that we will be better prepared to address similar situations especially in paediatrics and pregnant women where experience is limited and actual practice relies heavily on leveraging data from other populations and indications.

Prenatal Diagnosis of Autosomal Recessive Renal Tubular Dysgenesis with Anhydramnios Caused by a Mutation in the AGT Gene

Autosomal recessive renal tubular dysgenesis (ARRTD) is a rare and lethal disorder that causes stillbirth or early neonatal death. Most of the reported cases are diagnosed postnatally by a histopathological hallmark of the absence or paucity of differentiated proximal tubules in kidneys. Prenatal diagnosis of ARRTD is challenging because only a few fetal features (e.g., oligohydramnios/anhydramnios, anuria) are associated with this condition. In this study, we report a fetus with ARRTD, which showed anhydramnios and invisible urinary bladder since the second trimester, followed by growth restriction and reversed end diastolic flow in the middle cerebral artery (MCA-REDF). No morphological anomaly was detected on the fetal kidneys during an ultrasound scan. The baby died of refractory hypotension the day after their birth. Genetic analysis of genes that are involved in the renin-angiotensin-aldosterone system (RAAS), which are the known genetic causes of ARRTD, identified a novel, biparental-origin homozygous c.857-619_1269+243delinsTTGCCTTGC mutation in the AGT gene. The mutation is considered as pathogenic because it is cosegregated with ARRTD and detected in other unrelated ARRTD families. Our findings link the fetal ultrasound manifestations to the ARRTD, highlighting clues that are useful for prenatal diagnosis, which warrants confirmatory genotyping of the RAAS genes including oligohydramnios/anhydramnios, anuria (absent filling of a fetal urinary bladder), MCA-REDF, and a morphologically normal kidney.

The Role of Agonistic Autoantibodies to the Angiotensin II Type 1 Receptor (AT1-AA) in Pathophysiology of Preeclampsia

Preeclampsia is the leading cause of death and morbidity worldwide for the mother and fetus during pregnancy. Preeclampsia does not only affect the mother and the baby during pregnancy, but can also have long-term effects, such as the increased risk of hypertension and cardiovascular disease on the offspring and the postpartum mother later in life. The exact cause of preeclampsia is unknown, but women with preeclampsia have elevated concentrations of agonistic autoantibodies against the angiotensin II type 1 receptor (AT1-AA). These AT1-AA's through multiple studies have shown to play a significant role in the pathology and possible genesis of preeclampsia. This review will discuss the discovery of AT1-AAs and the role of AT1-AAs in the pathophysiology of preeclampsia. This review will also discuss future therapeutic approaches towards the AT1-AA to prevent adverse pregnancy outcomes. Furthermore, we will examine the relationship between AT1-AA induced hypertension associated with increased oxidative stress, antiangiogenic factors (such as soluble fms-related tyrosine kinase-1 (sFlt-1), endothelin-1 (ET-1), inflammation, endothelial dysfunction, and reduced renal function. Understanding the pathological role of AT1-AAs in hypertensive pregnancies is important as we search for novel therapies to manage preeclampsia.

Prenatal hypocalvaria after prolonged intrauterine exposure to angiotensin II receptor antagonists

We report a case of prenatal exposure to angiotensin II receptor antagonists (ARA II) from the beginning of pregnancy in a patient with a hypokinetic dilated cardiomyopathy. This case report emphasizes the fetal renal impact of prolonged intrauterine exposure to renin-angiotensin system (RAS) blockers, and highlights that this exposure can cause severe prenatal hypocalvaria. This delayed ossification can be reversible after birth, but the presence of anhydramnios indicates an early and irreversible block of RAS blockers in the fetus that is responsible for fetal kidney development abnormalities. This association carries a high risk of neonatal death. Prolonged exposure to ARA II or other RAS blockers remains prohibited throughout pregnancy.

Pregestational Diabetes in Pregnancy

Diabetes is a common chronic condition in women of reproductive age. Preconception care is crucial to reducing the risk of adverse maternal and fetal outcomes, such as hypertensive disorders, abnormal fetal growth, traumatic delivery and stillbirth, associated with poor glycemic control. Insulin is the preferred medication to optimize glucose control in women with pregestational diabetes. Frequent dose adjustments are needed during pregnancy to achieve glycemic goals, and team-based multidisciplinary care may help. Postpartum care should include lactation support, counseling on contraceptive options, and transition to primary care.

Uncoupling proteins as a therapeutic target to protect the diabetic heart

Myocardial remodeling and dysfunction caused by accelerated oxidative damage is a widely reported phenomenon within a diabetic state. Altered myocardial substrate preference appears to be the major cause of enhanced oxidative stress-mediated cell injury within a diabetic heart. During this process, exacerbated free fatty acid flux causes an abnormal increase in mitochondrial membrane potential leading to the overproduction of free radical species and subsequent cell damage. Uncoupling proteins (UCPs) are expressed within the myocardium and can protect against free radical damage by modulating mitochondrial respiration, leading to reduced production of reactive oxygen species. Moreover, transgenic animals lacking UCPs have been shown to be more susceptible to oxidative damage and display reduced cardiac function when compared to wild type animals. This suggests that tight regulation of UCPs is necessary for normal cardiac function and in the prevention of diabetes-induced oxidative damage. This review aims to enhance our understanding of the pathophysiological mechanisms relating to the role of UCPs in a diabetic heart, and further discuss known pharmacological compounds and hormones that can protect a diabetic heart through the modulation of UCPs.

Important considerations in pregnant patients with lupus nephritis

INTRODUCTION

In the last few decades, identification of predictors of pregnancy outcome and appropriate pregnancy planning have significantly reduced the maternal and fetal risks in pregnant women with lupus nephritis. Areas covered: Successful pregnancies have been reported even in women with chronic renal disease and renal insufficiency. However, refractory hypertension and severe renal or cardiac chronic dysfunction are still considered contraindications to pregnancy. Pre-term delivery and fetal growth restriction may still occur in SLE patients more frequently than in healthy women, even in pregnancies regularly planned and monitored by a team of nephrologists and gynaecologists. Expert commentary: Stable disease remission is the most important factor for a successful pregnancy. In case of flare-ups of lupus, timely diagnosis and appropriate management may ensure a successful outcome in the majority of pregnant women. The negative role of anti-phospholipid antibodies and of chronic arterial hypertension may be countered with appropriate anticoagulation and anti-hypertensive therapy. Further studies are needed to better assess the possible impact of pregnancy on the long-term outcome of lupus nephritis.

Postnatal acute renal failure after fetal exposure to angiotensin receptor blockers

Maternal hypertensive treatment with angiotensin receptor blockers (ARBs) during the second and third trimester of pregnancy is associated with several fetal and neonatal complications, and potential adverse outcomes. We report a neonate presenting with transient renal acute failure during the first days of life after maternal treatment with ARBs. Women who became pregnant while taking one of these drugs must modify antihypertensive therapy with a different class drug as soon as pregnancy is recognised.

Resolution of refractory hypotension and anuria in a premature newborn with loss-of-function of ACE

We present the investigation and management of a premature, hypotensive neonate born after a pregnancy complicated by anhydramnios to highlight the impact of early and informed management for rare kidney disease. Vasopressin was used to successfully treat refractory hypotension and anuria in the neonate born at 27 weeks of gestation. Next generation sequencing of a targeted panel of genes was then performed in the neonate and parents. Subsequently, two compound heterozygous deletions leading to frameshift mutations were identified in the angiotensin 1-converting enzyme gene ACE; exon 5:c.820_821delAG (p.Arg274Glyfs*117) and exon24: c.3521delG (p.Gly1174Alafs*12), consistent with a diagnosis of renal tubular dysgenesis. In light of the molecular diagnosis, identification, and treatment of associated low aldosterone level resulted in further improvement in renal function and only mild residual chronic renal failure is present at 14 months of age. Truncating alterations in ACE most often result in fetal demise during gestation or in the first days of life and typically as a result of the Potter sequence. The premature delivery, and serendipitous early treatment with vasopressin, and then later fludrocortisone, resulted in an optimal outcome in an otherwise lethal condition.

Transdermal contraception and the renin-angiotensin-aldosterone system in premenopausal women

The oral contraceptive pill (OCP) activates the renin-angiotensin-aldosterone system (RAAS) through first-pass hepatic metabolism. Although usually benign, RAAS activation may have detrimental effects on renal and hemodynamic function in some women. Since combined hormonal contraception with the transdermal patch (EVRA) does not undergo first-pass hepatic metabolism, we hypothesized that the RAAS response would be different from that of OCP subjects. Thirty-five nonsmoking, premenopausal women (15 control subjects, 10 OCP subjects, and 10 contraceptive patch subjects) without evidence of cardiovascular disease, renal disease, or diabetes were studied. Baseline angiotensinogen, renin, angiotensin II, aldosterone, and plasma renin activity were assessed along with hormonal and hemodynamic responses to simulated orthostatic stress using incremental lower body negative pressure (LBNP; −15, −25, and −40 mmHg). Baseline levels of angiotensinogen, angiotensin II, and plasma renin activity were significantly higher in OCP subjects compared with normotensive control and contraceptive patch subjects ( P < 0.05), whereas aldosterone was significantly higher in OCP versus control subjects only ( P < 0.05). Plasma renin levels were significantly lower at baseline in contraceptive patch subjects compared with normotensive control and OCP subjects ( P < 0.05). In response to LBNP, increases in renin, angiotensin II, and aldosterone were attenuated in contraceptive patch subjects in conjunction with an exaggerated decline in mean arterial pressure ( P < 0.05 vs. control and OCP subjects). The contraceptive patch in healthy premenopausal women is associated with an impaired ability to maintain blood pressure in response to LBNP, possibly due to insensitivity of the endogenous RAAS. Further evaluation may be beneficial in women with kidney disease.

Angiotensin-II receptor 1 antagonist fetopathy--risk assessment, critical time period and vena cava thrombosis as a possible new feature

AIMS

Angiotensin-II receptor 1 antagonists (AT₁-antagonists) may cause severe and even lethal fetopathy in late pregnancy. However, exposure still occurs in spite of warnings in package leaflets. This study aimed to assess the risk of fetopathy, the sensitive time window, and possible new symptoms in prospective as well as retrospective cases with AT₁-antagonist treatment during the second or third trimester of pregnancy.

METHODS

Patients were enrolled by the Berlin Institute for Clinical Teratology and Drug Risk Assessment in Pregnancy between 1999 and 2011 through risk consultation. Symptoms defined as indicative of AT₁-antagonist fetopathy were: oligo-/anhydramnios, renal insufficiency, lung hypoplasia, joint contractures, skull hypoplasia and fetal/neonatal death.

RESULTS

In 5/29 (17%) prospectively enrolled cases with AT₁-antagonist exposure beyond the first trimester oligo-/anhydramnios was diagnosed. Two infants showed additional symptoms of fetopathy. The risk is more than 30% if treatment continues beyond the 20th week of pregnancy. Oligo-/anhydramnios was reversible after AT₁-antagonist withdrawal. Among 16 retrospective case reports, three infants presented with a thrombosis of the inferior vena cava in the vicinity of the renal veins. Four out of 13 live births did not survive.

CONCLUSIONS

Our survey suggests that the risk increases with duration of AT₁-antagonist treatment into late pregnancy and oligo-/anhydramnios may be reversible after AT₁-antagonist discontinuation. Thrombosis of inferior vena cava may be a new feature of AT₁-antagonist fetopathy. AT₁-antagonist medication during pregnancy constitutes a considerable risk and must be discontinued immediately. In case of indicative diagnostic findings in either the fetus or newborn, previous maternal AT₁-antagonist exposure should be considered.

Hypertensive disorders of pregnancy: preventative-, immediate- and long-term management

The hypertensive disorders of pregnancy are common and continue to be significant contributors to maternal and perinatal mortality and morbidity, both globally and in the UK. This review aims to describe the recent developments in the understanding of the pathophysiology of the disease processes, potential strategies for identification of women at high risk, and current and future therapeutic strategies for the treatment and prevention of hypertension in pregnancy. Women who experience adverse pregnancy outcomes are also at increased risk of premature cardiovascular disease, and potential therapeutic strategies to minimize their risk profile are discussed.

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.

Spectrum of mutations in the renin-angiotensin system genes in autosomal recessive renal tubular dysgenesis

Autosomal recessive renal tubular dysgenesis (RTD) is a severe disorder of renal tubular development characterized by early onset and persistent fetal anuria leading to oligohydramnios and the Potter sequence, associated with skull ossification defects. Early death occurs in most cases from anuria, pulmonary hypoplasia, and refractory arterial hypotension. The disease is linked to mutations in the genes encoding several components of the renin-angiotensin system (RAS): AGT (angiotensinogen), REN (renin), ACE (angiotensin-converting enzyme), and AGTR1 (angiotensin II receptor type 1). Here, we review the series of 54 distinct mutations identified in 48 unrelated families. Most of them are novel and ACE mutations are the most frequent, observed in two-thirds of families (64.6%). The severity of the clinical course was similar whatever the mutated gene, which underlines the importance of a functional RAS in the maintenance of blood pressure and renal blood flow during the life of a human fetus. Renal hypoperfusion, whether genetic or secondary to a variety of diseases, precludes the normal development/ differentiation of proximal tubules. The identification of the disease on the basis of precise clinical and histological analyses and the characterization of the genetic defects allow genetic counseling and early prenatal diagnosis.

Azilsartan medoxomil: a new angiotensin II receptor antagonist for treatment of hypertension

OBJECTIVE

To evaluate the efficacy, safety, and clinical role of azilsartan medoxomil, an angiotensin II receptor blocker (ARB) that recently gained Food and Drug Administration approval for lowering of blood pressure (BP) in patients with hypertension.

DATA SOURCES

A systematic review of the literature was performed through August 2011 using MEDLINE, Web of Science, and International Pharmaceutical Abstracts and the key words and MeSH terms azilsartan, azilsartan medoxomil, TAK-491, TAK-536, and Edarbi. Abstracts presented in the last 2 years from the annual meetings of appropriate medical societies were reviewed in addition to a search of clinicaltrials.gov.

STUDY SELECTION AND DATA EXTRACTION

Studies eligible for inclusion were in vitro or in vivo evaluations of azilsartan medoxomil, with no restrictions on patient population or indication. Data related to the patient populations and outcomes of interest were extracted from each publication.

DATA SYNTHESIS

Three trials are available in full publication form with others available only as abstracts. Azilsartan medoxomil 40 mg and 80 mg daily significantly improves both systolic and diastolic BP from baseline compared with placebo, and the 80-mg dose has greater efficacy than other ARBs, including olmesartan 40 mg daily and valsartan 320 mg daily. Improvements in both 24-hour BP using ambulatory monitoring and clinic monitoring have been seen with azilsartan medoxomil as well as a higher proportion of patients reaching the goal level. Additional information shows added BP lowering when azilsartan medoxomil is combined with chlorthalidone. Adverse events are similar with azilsartan medoxomil versus other ARBs and include headache, dizziness, urinary tract infections, and fatigue.

CONCLUSIONS

Azilsartan medoxomil is a safe and effective ARB with a unique pharmacologic profile versus other agents, including slowed angiotensin II type 1 receptor dissociation rates and improved receptor specificity. Studies have shown azilsartan medoxomil 80 mg once daily to reduce BP to a greater extent than valsartan and olmesartan, with similar safety and tolerability.

Teratogenic exposures

A consideration of teratogenic exposures includes not only an agent (chemical, radiation, biologic) but an exposure level and timing of exposure. There are criteria by which exposures are evaluated for a causal connection with an abnormal outcome. We here review some teratogenic exposures and discuss how they were initially described and confirmed. We have limited our discussion to some of the exposures for which a connection to structural malformations has been accepted in some quarters, and we indicate some exposures for which a causal association awaits confirmation. We recommend that counselors find a reliable and updatable source of information on exposures during pregnancy.

Antihypertensive drugs in pregnancy

Blood pressure targets and medications that are safe differ in pregnant women compared with nonpregnant individuals. The principles of treatment for mild, moderate, and severe hypertension in pregnancy, chronic versus gestational versus preeclampsia, and women hypertensive at term versus remote from term are reviewed. The choice of antihypertensive drugs also is discussed; methyldopa, labetalol, and nifedipine, among others, appear safe for use in pregnancy, whereas angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be avoided. The management of increased blood pressure in the postpartum period, and agents to use in lactation, are also discussed.

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.

Efficacy and safety of angiotensin II receptor type 1 antagonists in children and adolescents

Our purpose was to evaluate the effects of angiotensin II receptor type 1 antagonists (ARAs) in children and adolescents with hypertension or/and several kinds of nephropathies on blood pressure (BP) and proteinuria and to evaluate related safety issues. Data sources were Medline, Embase, The Cochrane Library, BIOSIS Previews, contact with investigators and manufacturers, personal bibliography of the lead author, and manual searches. We selected randomized controlled trials (RCTs), uncontrolled trials, and case series investigating ARAs in children and adolescents, as well as case reports about adverse events and the embryotoxic effects of ARAs in children. In four RCTs with 698 individuals, mean systolic blood pressure (BP) decreased by 10.5 mmHg [95% confidence interval (CI) 9.8-11.2] and mean diastolic BP by 6.4 mmHg (95% CI 5.8-7.0). Proteinuria decreased by 30-64% (range) in two RCTs and four case series. Safety data were comparable with adult safety data. ARAs can be considered effective and safe in lowering BP and proteinuria in the pediatric age group. The correlation between the surrogate parameters BP and proteinuria with clinical endpoints is documented to a large degree. The evidence is based on RCTs and also on lower evidence levels, such as case series. In some conditions, RCTs in children are not feasible. Registers could provide more evidence in the future.

The detrimental role of angiotensin receptor agonistic autoantibodies in intrauterine growth restriction seen in preeclampsia

Growth-restricted fetuses are at risk for a variety of lifelong medical conditions. Preeclampsia, a life-threatening hypertensive disorder of pregnancy, is associated with fetuses who suffer from intrauterine growth restriction (IUGR). Recently, emerging evidence indicates that preeclamptic women harbor AT₁ receptor agonistic autoantibodies (AT₁-AAs) that contribute to the disease features. However, the exact role of AT₁-AAs in IUGR and the underlying mechanisms have not been identified. We report that these autoantibodies are present in the cord blood of women with preeclampsia and retain the ability to activate AT₁ receptors. Using an autoantibody-induced animal model of preeclampsia, we show that AT₁-AAs cross the mouse placenta, enter fetal circulation, and lead to small fetuses with organ growth retardation. AT₁-AAs also induce apoptosis in the placentas of pregnant mice, human villous explants, and human trophoblast cells. Finally, autoantibody-induced IUGR and placental apoptosis are diminished by either losartan or an autoantibody-neutralizing peptide. Thus, these studies identify AT₁-AA as a novel causative factor of preeclampsia-associated IUGR and offer two possible underlying mechanisms: a direct detrimental effect on fetal development by crossing the placenta and entering fetal circulation, and indirectly through AT₁-AA–induced placental damage. Our findings highlight AT₁-AAs as important therapeutic targets.

Fetal and neonatal consequences of antenatal exposure to type 1 angiotensin II receptor-antagonists

Sartans are selective type 1 angiotensin II receptor-antagonists that are used in the treatment of arterial hypertension. Few reports are available concerning the use of sartans during pregnancy. We report two cases of adverse fetal outcome in hypertensive pregnancies exposed to sartans. In the first case, anamnios and fetal renal failure due to severe tubular dysgenesia led to termination of pregnancy in the 27th week. The second patient presented with hypocalvaria and developed fetal renal failure. The use of sartans during the two last trimesters of pregnancy should be strictly avoided.

Angiotensin II Receptor Blockers in Pregnancy: A Case Report and Systematic Review of the Literature

OBJECTIVE

To describe the case of a woman exposed to angiotensin-II receptor blockers (ARBs) in the preconceptional period and to systematically review the literature on the safety of these drugs when used by pregnant women.

METHODS

The case was identified at the Korean Motherisk Program (Seoul). For the systematic review, we searched the PubMed for case reports, case series, and post-marketing surveys.

RESULTS

A hypertensive woman was exposed to irbesartan prior to conception. The embryo had delayed development of upper and lower extremities and decreased digital groove. A karyotype identified a 45,XO Turner syndrome. The patient had a spontaneous abortion. Including the case reported here, 64 published cases were identified in total; 57.8% had favorable and 42.2% had unfavorable outcomes. Duration of treatment during pregnancy among women who had adverse fetal outcomes was 26.3 +/- 10.5 weeks (mean +/- SD), compared with 17.3 +/- 11.6 weeks in those who had favorable outcomes (p = 0.04).

CONCLUSIONS

Exposure to ARBs for a period longer than the first trimester of pregnancy appears to be associated with a high risk for adverse fetal outcomes.

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.

Congenital unilateral renal tubular dysgenesis and severe neonatal hypertension

Severe arterial hypertension rarely occurs in the neonatal period but may have life-threatening consequences. It is most often caused by renal parenchymal or vascular abnormality, which, to be accurately diagnosed, may require a combination of imaging modalities. We report on a case of neonatal hypertension presenting as cardiac failure. Initial imaging suggested unilateral renal artery stenosis, but this was not corroborated by magnetic resonance angiography. Surgical nephrectomy was curative for the hypertension and also allowed diagnosis of renal tubular dysgenesis. Unilateral congenital tubular dysgenesis without renal infarction has not been previously reported. We speculate that the condition was secondary to a period of localised hypoperfusion during early foetal life.

Emerging therapy-related kidney disease

CONTEXT

Many new therapies have emerged within the last 5 to 10 years to treat a variety of conditions. Several of these have direct or indirect renal toxicities that may go undiagnosed without careful attention of the pathologist to a patient's clinical history, particularly the addition of new medications or treatments.

OBJECTIVE

To discuss patterns of renal injury resulting from medications or therapeutic regimens that have been introduced within the last 10 years. Recognition of these patterns may allow the pathologist to alert the attending clinician to a possible drug-induced renal injury and prevent further deterioration of renal function and possible chronic kidney disease.

DATA SOURCES

A review of recent literature and unpublished observations of case-derived material.

CONCLUSIONS

A number of newer therapies have emerged as agents of renal toxicity, producing a variety of pathologic changes in the kidney. The outcome can be acute or chronic glomerular, tubular, interstitial, and/or vascular injury. Some drugs will result in irreversible changes and end-stage renal disease, whereas many of the alterations can be reversed with removal of the offending agent, avoiding potential long-term kidney injury.

Reversible acute fetal renal failure due to maternal exposure to angiotensin receptor blocker

We report on a case of fetal toxicity due to maternal treatment with olmesartan medoxomil. At 29 weeks' gestation, oligohydramnios was found, although the fetus had normal kidneys on ultrasound evaluation. Withdrawal of olmesartan medoxomil, maternal rehydration, and a single dose of furosemide reversed the renal impairment. After term delivery, the neonate was confirmed to have normal renal function. The case suggested that fetal renal impairment due to olmesartan medoxomil may be reversible.

Toxicité fœtale des antagonistes des récepteurs de l'angiotensine II. À propos d'un cas

The fetal toxicity of angiotensin-converting enzyme inhibitors (ACEI) is now well known. Sartans which are angiotensin II inhibitors, are supposed to have the same side effects on the fetus as ACEI because of their similar mechanism of action. This is supported by experimental and clinical data. Clinical presentation of fetal exposition to sartans varies from transient oligamnios to permanent renal failure, potentially complicated by Potter syndrome. According to previously reported cases, we report a case of transitory fetal oliguria secondary to the exposure to an angiotensin-II-receptor inhibitor (valsartan) between 19 and 21 weeks' gestation. We discuss the management of pregnancies exposed to angiotensin II inhibitors.

In utero losartan withdrawal and subsequent development of fetal inferior vena cava thrombosis

BACKGROUND

Angiotensin receptor blockers are antihypertensive medications prescribed by a wide variety of physicians, especially for patients with coexistent diabetes mellitus. Angiotensin receptor blockers, as well as angiotensin-converting enzyme inhibitors, are contraindicated in pregnancy.

CASE

We describe the reversal of losartan-induced oligohydramnios at 27 weeks of gestation with subsequent development of fetal thrombosis and possible mechanism of action for this extremely rare in utero complication.

CONCLUSION

This theory may help explain the fetal stillbirths in women taking this class of medications during the second and third trimester of pregnancy.

Effects of maternally administered drugs on the fetal and neonatal kidney

The number of pregnant women and women of childbearing age who are receiving drugs is increasing. A variety of drugs are prescribed for either complications of pregnancy or maternal diseases that existed prior to the pregnancy. Such drugs cross the placental barrier, enter the fetal circulation and potentially alter fetal development, particularly the development of the kidneys. Increased incidences of intrauterine growth retardation and adverse renal effects have been reported. The fetus and the newborn infant may thus experience renal failure, varying from transient oligohydramnios to severe neonatal renal insufficiency leading to death. Such adverse effects may particularly occur when fetuses are exposed to NSAIDs, ACE inhibitors and specific angiotensin II receptor type 1 antagonists. In addition to functional adverse effects, in utero exposure to drugs may affect renal structure itself and produce renal congenital abnormalities, including cystic dysplasia, tubular dysgenesis, ischaemic damage and a reduced nephron number. Experimental studies raise the question of potential long-term adverse effects, including renal dysfunction and arterial hypertension in adulthood. Although neonatal data for many drugs are reassuring, such findings stress the importance of long-term follow-up of infants exposed in utero to certain drugs that have been administered to the mother.

Major congenital malformations after first-trimester exposure to ACE inhibitors

BACKGROUND

Use of angiotensin-converting-enzyme (ACE) inhibitors during the second and third trimesters of pregnancy is contraindicated because of their association with an increased risk of fetopathy. In contrast, first-trimester use of ACE inhibitors has not been linked to adverse fetal outcomes. We conducted a study to assess the association between exposure to ACE inhibitors during the first trimester of pregnancy only and the risk of congenital malformations.

METHODS

We studied a cohort of 29,507 infants enrolled in Tennessee Medicaid and born between 1985 and 2000 for whom there was no evidence of maternal diabetes. We identified 209 infants with exposure to ACE inhibitors in the first trimester alone, 202 infants with exposure to other antihypertensive medications in the first trimester alone, and 29,096 infants with no exposure to antihypertensive drugs at any time during gestation. Major congenital malformations were identified from linked vital records and hospitalization claims during the first year of life and confirmed by review of medical records.

RESULTS

Infants with only first-trimester exposure to ACE inhibitors had an increased risk of major congenital malformations (risk ratio, 2.71; 95 percent confidence interval, 1.72 to 4.27) as compared with infants who had no exposure to antihypertensive medications. In contrast, fetal exposure to other antihypertensive medications during only the first trimester did not confer an increased risk (risk ratio, 0.66; 95 percent confidence interval, 0.25 to 1.75). Infants exposed to ACE inhibitors were at increased risk for malformations of the cardiovascular system (risk ratio, 3.72; 95 percent confidence interval, 1.89 to 7.30) and the central nervous system (risk ratio, 4.39; 95 percent confidence interval, 1.37 to 14.02).

CONCLUSIONS

Exposure to ACE inhibitors during the first trimester cannot be considered safe and should be avoided.

Foetal kidney maldevelopment in maternal use of angiotensin II type I receptor antagonists

We report renal lesions observed in a foetus exposed throughout pregnancy to angiotensin II type I (AT 1) receptor antagonists. The mother suffered from essential hypertension and was treated with Cozaar (losartan 50 mg). Autopsy examination of the foetus revealed severe renal lesions, including tubular dysgenesis, hypertrophy of the endothelial and medial cells lining the arterial and arteriolar walls, hyperplasia of the juxtaglomerular apparatus and poorly developed vasa recta. Similar lesions have already been observed in foetuses of women treated with angiotensin-converting enzyme antagonists and also in foetuses and neonates of animals undergoing experimental blockade of the renin-angiotensin system. The purpose of this report is to describe structural lesions observed in the kidneys, and, particularly, vascular lesions. Our results suggest that the use of AT 1 receptor antagonists during pregnancy may have a severe deleterious effect on kidney development in the foetus.

The renin-angiotensin system in the development of the congenital anomalies of the kidney and urinary tract

PURPOSE OF REVIEW

Recognition of the dramatically expanded functional repertoire of the renin-angiotensin system now includes a role in morphogenesis of the kidney and urinary tract. On the basis of published data, the article presents formulations of mechanisms through which the system operates.

RECENT FINDINGS

Studies in humans and animals carrying defective angiotensin-related genes have provided unequivocal evidence that the renin-angiotensin system is involved in the normal development of both the kidney and the urinary tract. Angiotensin exerts its function through at least two different types of receptors, AT1 and AT2. AT1 mediates establishment of the ureteral peristaltic machinery, while AT2 mediates the early kidney and urinary tract morphogenesis. Disruption in receptor functions promotes development of congenital anomalies of the kidney and urinary tract.

SUMMARY

Angiotensin is involved in multiple steps of normal development of the kidney and urinary tract through two types of receptors. This takes place in concert with other functionally overlapping genes.

Clinical pharmacokinetics of losartan

Losartan is the first orally available angiotensin-receptor antagonist without agonist properties. Following oral administration, losartan is rapidly absorbed, reaching maximum concentrations 1-2 hours post-administration. After oral administration approximately 14% of a losartan dose is converted to the pharmacologically active E 3174 metabolite. E 3174 is 10- to 40-fold more potent than its parent compound and its estimated terminal half-life ranges from 6 to 9 hours. The pharmacokinetics of losartan and E 3174 are linear, dose-proportional and do not substantially change with repetitive administration. The recommended dosage of losartan 50 mg/day can be administered without regard to food. There are no clinically significant effects of age, sex or race on the pharmacokinetics of losartan, and no dosage adjustment is necessary in patients with mild hepatic impairment or various degrees of renal insufficiency. Losartan, or its E 3174 metabolite, is not removed during haemodialysis. The major metabolic pathway for losartan is by the cytochrome P450 (CYP) 3A4, 2C9 and 2C10 isoenzymes. Overall, losartan has a favorable drug-drug interaction profile, as evidenced by the lack of clinically relevant interactions between this drug and a range of inhibitors and stimulators of the CYP450 system. Losartan does not have a drug-drug interaction with hydrochlorothiazide, warfarin or digoxin. Losartan should be avoided in pregnancy, as is the case with all other angiotensin-receptor antagonists. When given in the second and third trimester of pregnancy, losartan is often associated with serious fetal toxicity. Losartan is a competitive antagonist that causes a parallel rightward shift of the concentration-contractile response curve to angiotensin-II, while E 3174 is a noncompetitive "insurmountable" antagonist of angiotensin-II. The maximum recommended daily dose of losartan is 100mg, which can be given as a once-daily dose or by splitting the same total daily dose into two doses. Losartan reduces blood pressure comparably to other angiotensin-receptor antagonists. Losartan has been extensively studied relative to end-organ protection, with studies having been conducted in diabetic nephropathy, heart failure, post-myocardial infarction and hypertensive patients with left ventricular hypertrophy. The results of these studies have been sufficiently positive to support a more widespread use of angiotensin-receptor antagonists in the setting of various end-organ diseases. Losartan, like other angiotensin-receptor antagonists, is devoid of significant adverse effects.

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.