Cardiovascular Drugs in Pregnancy

Review of Cardiovascular Drugs in Pregnancy

Cardiovascular disease is now the leading cause of pregnancy-related deaths in the United States. Increasing maternal mortality in the United States underscores the importance of proper cardiovascular management. Significant physiological changes during pregnancy affect the heart's ability to respond to pathological processes such as hypertension and heart failure. These physiological changes further affect the pharmacokinetic and pharmacodynamic properties of cardiac medications. During pregnancy, these changes can significantly alter medication efficacy and metabolism. This article systematically reviews the literature on safety, efficacy, pharmacokinetics, and pharmacodynamics of cardiovascular drugs used for hypertension and heart failure during pregnancy and lactation. The 2017 American College of Cardiology/American Heart Association hypertension guidelines recommend transitioning pregnant patients to methyldopa, nifedipine, or labetalol. Heart failure medications, including beta-blockers, furosemide, and digoxin, are relatively safe and can be used effectively. Medications that block the renin angiotensin-aldosterone system have been shown to be beneficial in the general population; however, they are teratogenic and, therefore, contraindicated in pregnancy. Cardiovascular medications can also enter breast milk and, therefore, care must be taken when selecting drugs during the lactation period. A summary of the safety of drugs during pregnancy and lactation from an online resource, LactMed by the National Library of Medicine's TOXNET database, is included. High-risk pregnant patients with cardiovascular disease require a multispecialty team of doctors, including health care providers from obstetrics and gynecology, maternal fetal medicine, internal medicine, cardiovascular disease specialists, and specialized pharmacology expertise.

Peripartum cardiomyopathy-diagnosis, management, and long term implications

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening pregnancy-associated disease that typically arises in the peripartum period. While the disease is relatively uncommon, its incidence is rising. It is a form of idiopathic dilated cardiomyopathy, defined as pregnancy-related left ventricular dysfunction, diagnosed either towards the end of pregnancy or in the months following delivery, in women without any other identifiable cause. The clinical presentation, diagnostic assessment and treatment usually mirror that of other forms of cardiomyopathy. Timing of delivery and management require a multidisciplinary approach and individualization. Subsequent pregnancies generally carry risk, but individualization is required depending on the pre-pregnancy left ventricular function. Recovery occurs in most women on standard medical therapy for heart failure with reduced ejection fraction, more frequently than in other forms of nonischemic cardiomyopathy. The purpose of this review is to summarize the current state of knowledge with regard to diagnosis, treatment and management, with a focus on long term implications.

Management of pregnancy in cardiomyopathies and heart failure

Pregnancy exposes women with inherited cardiomyopathies to increased risk for arrhythmias and heart failure. In asymptomatic patients with inherited cardiomyopathies, pregnancy is generally well tolerated. Preconception evaluation, risk assessment and proper counseling by a team of experienced physicians are mandatory in managing women with inherited cardiomyopathies planning pregnancy. In this paper, we reviewed the clinical course, risk assessment and management during pregnancy of women with cardiomyopathies.

Pharmacotherapy in pregnancy; effect of ABC and SLC transporters on drug transport across the placenta and fetal drug exposure

Pharmacotherapy during pregnancy is often inevitable for medical treatment of the mother, the fetus or both. The knowledge of drug transport across placenta is, therefore, an important topic to bear in mind when deciding treatment in pregnant women. Several drug transporters of the ABC and SLC families have been discovered in the placenta, such as P-glycoprotein, breast cancer resistance protein, or organic anion/cation transporters. It is thus evident that the passage of drugs across the placenta can no longer be predicted simply on the basis of their physical-chemical properties. Functional expression of placental drug transporters in the trophoblast and the possibility of drug-drug interactions must be considered to optimize pharmacotherapy during pregnancy. In this review we summarize current knowledge on the expression and function of ABC and SLC transporters in the trophoblast. Furthermore, we put this data into context with medical conditions that require maternal and/or fetal treatment during pregnancy, such as gestational diabetes, HIV infection, fetal arrhythmias and epilepsy. Proper understanding of the role of placental transporters should be of great interest not only to clinicians but also to pharmaceutical industry for future drug design and development to control the degree of fetal exposure.

Cocaine and aortic dissection

Aortic dissection is a rare, potentially catastrophic vascular emergency. Early recognition of the clinical manifestations, rapid confirmation using imaging modalities, urgent administration of appropriate medication and expedient selection of definitive long-term therapy are key to preserving life and reducing morbidity. In recent years it has become increasingly clear that there is a relation between cocaine and aortic dissection. Cocaine serves as both a predisposing factor to aortic dissection due to its effect on aortic connective tissue and as a precipitating factor due to its propensity to produce abrupt and severe hypertension. While similarities exist in the clinical features and diagnostic methods between cocaine-related aortic dissection and aortic dissection unrelated to cocaine use, there are important differences in management between these two syndromes which are rooted in the pharmacology and physiology of cocaine. An understanding of these differences is key to effective early and long-term management of cocaine-related aortic dissection.

Cardiovascular pharmacotherapeutic considerations during pregnancy and lactation

Cardiovascular drugs are often used in pregnancy for the treatment of maternal and fetal conditions. Mothers could also require continued postpartum drug therapy. Most cardiovascular drugs taken by pregnant women can cross the placenta and therefore expose the developing embryo and fetus to their pharmacologic and teratogenic effects. These effects are influenced by the intrinsic pharmacokinetic properties of a given drug as well as by the complex physiological changes occurring during pregnancy. Many drugs are also transferred into human milk and therefore can potentially have adverse effects on the nursing infant. This 2-part article summarizes some of the available literature concerning the risks and benefits of using various cardiovascular drugs and drug classes during pregnancy and lactation. Included in the discussion are cardiac glycosides, antiarrhythmic drugs, drugs used to treat both acute and chronic hypertension, cholesterol-lowering agents, anticoagulants, thrombolytics, and antiplatelet drugs.

Percutaneous balloon mitral commissurotomy during pregnancy

Percutaneous balloon mitral commissurotomy was performed in 16 pregnant women aged 23 +/- 3 years (range, 16-39 years) who had severe mitral stenosis at pregnancies of mean gestational age 25 +/- 6 weeks. Ten patients were in New York Heart Association functional class III, and six patients were in functional class IV at the time of the procedure. All patients were symptomatic despite maximal medical therapy. The procedure was performed with the Inoue balloon. The mitral valve area increased from 0.9 +/- 0.3 to 1.8 +/- 0.3 cm2 (p < 0.05). The mitral valve pressure gradient decreased from 23 +/- 7 to 6 +/- 3 mm Hg (p < 0.05). The left atrial pressure decreased from 28 +/- 8 to 10 +/- 4 mm Hg (p < 0.05). The pulmonary artery pressure decreased from 59 +/- 18 to 33 +/- 12 mm Hg (p < 0.05). Fourteen patients continued their pregnancies to mean gestational age 37 +/- 2 weeks; all infants were healthy. Two patients had premature deliveries more than 1 month after the procedure due to obstetrical reasons. The two newborns died at day 2 of respiratory distress. Eleven women had vaginal deliveries and five had cesarean sections. All clinically improved to New York Heart Association functional class I or II. Excessive blood loss from the femoral puncture site that required transfusion occurred in one patient. Mitral regurgitation increased one degree in four patients, from 0 to 1+. Patients were observed until delivery. None had restenosis. The degree of mitral regurgitation remained unchanged. Percutaneous balloon mitral commissurotomy can be performed safely during pregnancy. It will effectively improve hemodynamics and symptoms in pregnant patients who have severe mitral stenosis and persistent congestive heart failure symptoms despite conventional medical treatment. There are no immediate detrimental effects of radiation on the fetus. Risks are lower than previously reported when surgical commissurotomy was performed.

Fetal hepatic drug elimination

The majority of studies of fetal hepatic elimination have concentrated on the expression and activity of the metabolizing enzymes, but the unique physiologic milieu of the fetal liver should also be considered. The basic structure of the liver is formed by the end of the first trimester. The fetal hepatic circulation differs substantially from that of the adult in that there is an extra input vessel, the umbilical vein, and there is shunting of 30-70% of hepatic blood flow via the ductus venosus. The left and right lobes of the fetal liver seem to function independently with respect to a variety of biochemical parameters, due at least in part to the lower oxygen supply to the right lobe. The zonation of drug-metabolizing enzymes along the hepatic acinus, which is prominent in the adult liver, is absent in the fetal liver. Unlike rodent species, the human fetal liver has a significant capacity for drug metabolism. Of the oxidative enzymes, CYP3A7 accounts for up to 50% of total fetal hepatic cytochrome P450 content. Expression of this enzyme decreases dramatically after birth. CYP1A1 and CYP2D6 have also been detected in human fetal liver, but whether CYP2E1 is expressed remains controversial. Several other cytochrome P450s have been identified and await characterization. Fetal hepatic drug conjugation may prolong fetal exposure to the metabolites produced, which, being more water soluble, do not readily cross the placenta back to the mother and, if excreted in fetal urine, can be recycled in the fetus via amniotic fluid and fetal swallowing. Limited activity of glucuronidation enzymes has been demonstrated in human fetal liver in contrast to the activity of sulfation enzymes, which is significant. Limited in vivo studies in fetal sheep have demonstrated significant fetal hepatic drug elimination, and this has been confirmed in studies of the isolated perfused fetal sheep liver. Our understanding of fetal hepatic elimination processes has advanced steadily over the years. Future developments, however, should consider more fully the influence of the unique physiological milieu of the fetal liver, in addition to the expression and activity of drug metabolizing enzymes.

Effects of hydralazine on pregnant rats and their fetuses

OBJECTIVE

We conducted this study to assess potential teratogenic or fetotoxic effects of in utero hydralazine exposure in the rat.

STUDY DESIGN

Pregnant rats were treated with hydralazine (0, 15, or 30 mg/kg/day) by either gavage or subcutaneous injection during gestation days 8 through 19, inclusively. Surviving animals were killed, uterine contents examined, and fetuses evaluated by Wilson's method for teratologic examination.

RESULTS

Oral administration did not affect maternal weight gain or fetal or placental weights. Subcutaneous administration decreased fetal and placental weights but only in dams given the highest dose subcutaneously; significantly increased maternal mortality and reduced maternal weight gain were also observed. There was no increased incidence of fetal anomalies in any group.

CONCLUSION

Hydralazine does not have teratogenic or fetopathic effects when given to rats in dosages that are nontoxic to the mother.