Anticoagulation in Pregnant Women With Prosthetic Heart Valves

Thrombosis of mechanical mitral valve prosthesis during pregnancy: An ongoing "saga" in need of comprehensive solutions

Emergency treatment for thrombosed mechanical valve prothesis during pregnancy is not uncommon in low- and middle-income countries. The presence of a mechanical valve continues to be an important cause of maternal morbidity and mortality. There is a pressing need for increasing awareness and feasible solutions for this huge problem. We here describe four patients who needed emergency treatment for thrombosis of mechanical valve prothesis during pregnancy and review the evolving comprehensive strategies for dealing with this issue.

Valvular Heart Disease in Pregnancy: Anticoagulation and the Role of Percutaneous Treatment

Valvular heart disease is present in about 1% of pregnancies, and it poses a management challenge as both fetal and maternal lives are at risk of complications. Pregnancy is associated with significant hemodynamic changes, which can compromise the cardiac status in women with underlying valvular disorders. Management of valvular heart diseases has undergone considerable innovation and advancement with newer techniques, approaches and devices being employed. The decision regarding the management of anticoagulation, especially in patients with prosthetic valves, raises distinct questions and challenges. In this review, we describe the management of common valvular heart diseases encountered during pregnancy, role of percutaneous catheter based therapeutic interventions, the importance of a team-based approach, and the challenges given existing gaps in the literature.

Maternal mortality due to cardiac disease in low- and middle-income countries

Objectives

To assess the frequency of maternal death (MD) due to cardiac disease in low‐ and middle‐income countries (LMIC).

Methods

Systematic review searching Medline, EMBASE, Web of Science, Cochrane Library, Emcare, LILACS, African Index Medicus, IMEMR, IndMED, WPRIM, IMSEAR up to 01/Nov/2017. Maternal mortality reports from LMIC reviewing all MD in a given geographical area were included. Hospital‐based reports or those solely based on verbal autopsies were excluded. Numbers of MD and cardiac‐related deaths were extracted. We calculated cardiac disease MMR (cMMR, cardiac‐related MD/100 000 live births) and proportion of cardiac‐related MDs among all MDs. Frequency of cardiac MD was compared with the MMR of the country.

Results

Forty‐seven reports were included, which reported on 38,486 maternal deaths in LMIC. Reported cMMR ranged from 0/100 000 live births (Moldova, Ghana) to 31.9/100 000 (Zimbabwe). The proportion of cardiac‐related MD ranged from 0% (Moldova, Ghana) to 24.8% (Sri Lanka). In countries with a higher MMR, cMMR was also higher. However, the proportion of cardiac‐related MD was higher in countries with a lower MMR.

Conclusions

The burden of cardiac‐related mortality is difficult to assess due limited availability of mortality reports. The proportion of cardiac deaths among all MD appeared to be higher in countries with a lower MMR. This is in line with what has been called ‘obstetric transition’: pre‐existing medical diseases including cardiac disease are becoming relatively more important where the MMR falls.

Heart disease and pregnancy: State of the art

The association between heart disease and pregnancy is increasingly prevalent. Although most women with heart disease tolerate the physiological changes of pregnancy, there are heart conditions that manifest for the first time during pregnancy and others that totally contraindicate a pregnancy. It is therefore important to establish multidisciplinary teams dedicated to the management of women with heart disease who intend to become, or who already are, pregnant. The aim of this article is to systematically review current knowledge on the approach to women with high-risk cardiovascular disease during pregnancy.

Postpartum anticoagulation in women with mechanical heart valves

Background

Women with mechanical heart valves (MHV) requiring anticoagulation (AC) are at high risk for hemorrhagic complications. Despite guidelines to manage antenatal and peripartum AC, there are few evidence-based recommendations to guide the initiation of postpartum AC. We reviewed our institutional experience of pregnant women with MHV to lay the groundwork for recommendations of immediate postpartum AC therapy.

Study design

This descriptive retrospective cohort used ICD-9 and -10 codes to identify pregnant women with MHV on AC at the Yale-New Haven Hospital from 2007 to 2018. All identified patients were confirmed by chart review. Delivery hospitalization and the immediate postpartum AC management were reviewed. Maternal complications recorded were postpartum hemorrhage, transfusion, wound hematoma, intra-abdominal bleeding, stroke, valve thrombosis, and death. Further, immediate neonatal outcomes were detailed.

Results

Forty-two pregnant women with nonnative heart valves were identified during the study period. From those pregnant women, nine had an MHV and were anticoagulated throughout gestation. Of 19 total pregnancies, 14 met the inclusion criteria. The median gestational age of the delivered pregnancies was early term (37w2d). Nine deliveries were via cesarean (64%). The median time to restart AC after birth was 6 hours. After six deliveries (43%), AC was initiated ≤6 hours postpartum. Hemorrhagic complications occurred in six cases (43%), including wound and intra-abdominal hematomas. Four cases (29%) required blood transfusion. No maternal strokes, thrombotic events, or deaths were recorded. Five (38.5%) neonates required admission to the neonatal intensive care unit.

Conclusion

MHV in pregnancy was rare but was associated with significant maternal morbidity, particularly postpartum hemorrhagic complications. We noted significant variability in the timing of restarting postpartum AC and in the selected agents. Pooled institutional data and an interdisciplinary approach are recommended to minimize competing risks and sequelae of valve thrombosis and obstetrical hemorrhage and, thereby, to optimize maternal outcomes and develop evidence-based guidelines for postpartum AC management.

Prosthetic heart valve selection in women of childbearing age with acquired heart disease: a case report

Background

The problem of prosthetic heart valve selection in fertile women with acquired heart defects remains crucial in modern cardiology. Mechanical heart valves require lifelong indirect anticoagulant therapy, which has significant fetal toxicity and is unacceptable for women planning pregnancy. Bioprosthetic heart valves are the best choice for fertile women; however, their durability is limited, and reoperations are required.

Case presentation

We describe the clinical case of a 21-year-old Russian woman with infectious endocarditis who underwent heart valve replacement with an epoxy-treated mitral valve prosthesis.

Conclusions

Epoxy-treated bioprosthetic heart valves can be used without long-term anticoagulant therapy because of their optimal hemodynamic functional parameters. Moreover, their high thromboresistance and resistance to infection improve patients’ quality of life in their late postoperative period. We recommend these valves both in older persons and in young patients including women who are planning pregnancy.

Early postpartum mitral valve thrombosis requiring extra corporeal membrane oxygenation before successful valve replacement

Pregnancy is associated with an increased risk of thrombosis in women with mechanical prosthetic heart valves. We present the case of a 29-year-old woman who developed early postpartum mitral valve thrombus after an elective cesarean delivery. The patient had a mechanical mitral valve and was treated with warfarin in the second trimester, which was replaced with high-dose dalteparin during late pregnancy. Elective cesarean delivery was performed under general anesthesia at 37weeks of gestation. The patient was admitted to the intensive care unit for postoperative care and within 30min she developed dyspnea and hypoxia requiring mechanical ventilation. She deteriorated rapidly and developed pulmonary edema, worsening hypoxia and severe acidosis. Urgent extra corporeal membrane oxygenation was initiated. Transesophageal echocardiography revealed a mitral valve thrombus. The patient underwent a successful mitral valve replacement after three days on extra corporeal membrane oxygenation. This case highlights the importance of multidisciplinary care and frequent monitoring of anticoagulation during care of pregnant women with prosthetic heart valves.

Mechanical Prosthetic Valves and Pregnancy: A therapeutic dilemma of anticoagulation

Choosing the best anticoagulant therapy for a pregnant patient with a mechanical prosthetic valve is controversial and the published international guidelines contain no clear-cut consensus on the best approach. This is due to the fact that there is presently no anticoagulant which can reliably decrease thromboembolic events while avoiding damage to the fetus. Current treatments include either continuing oral warfarin or substituting warfarin for subcutaneous unfractionated heparin or low-molecular-weight heparin (LMWH) in the first trimester (6-12 weeks) or at any point throughout the pregnancy. However, LMWH, while widely-prescribed, requires close monitoring of the blood anti-factor Xa levels. Unfortunately, facilities for such monitoring are not universally available, such as within hospitals in developing countries. This review evaluates the leading international guidelines concerning anticoagulant therapy in pregnant patients with mechanical prosthetic valves as well as proposing a simplified guideline which may be more relevant to hospitals in this region.

Managing cardiovascular disease during pregnancy: best practice to optimize outcomes

ABSTRACT: 

Cardiac disease is the most common cause of death in pregnancy in the UK. Optimal management requires an understanding of the physiological changes of the cardiovascular system during pregnancy, and their impact on existing or developing heart disease. Pregnancy itself is associated with the onset of cardiomyopathy, and a potential risk factor for ischemic heart disease and aortic dissection. Women with valvular disease and aortopathy require regular follow-up in specialized centers, and those requiring long-term anticoagulation face difficult challenges to balance maternal and fetal risks. In the UK, the Confidential Enquiries into maternal deaths and the UK Obstetric Surveillance system are examples of existing systems for identifying clinical risks and provide examples of potential improvements in care.

Pregnancy in adult congenital heart disease

Cardiac disease in pregnancy is a challenging health care problem. The number of cases and their complexity is increasing, such that heart disease is now the leading cause of maternal mortality in developed countries. Numerically, women with congenital heart disease (CHD) make up the majority of cases and although maternal mortality is infrequent, a good outcome is only achieved though meticulous care, which starts pre-pregnancy and continues for months after the pregnancy has ended. All women with CHD should be assessed and counseled before pregnancy and carefully monitored during pregnancy, the delivery and in the puerperium. In most cases, pregnancy is well tolerated but in some conditions, such as pulmonary hypertension or severe dilatation of the aorta, pregnancy is extremely high risk and should be advised against.

Monitoring of Anti-Xa in Pregnant Patients With Mechanical Prosthetic Valves Receiving Low-Molecular-Weight Heparin

Objectives:

We hypothesized that the guideline-recommended peak anti-Xa levels for pregnant women with mechanical prosthetic heart valves (MPHVs) receiving adjusted dose low-molecular-weight heparin (LMWH) are associated with subtherapeutic trough levels and consequently with an inadequate level of anticoagulation.

Background:

Low-molecular-weight heparin is often used for anticoagulation in pregnant women including those with MPHV. American College of Cardiology/American Heart Association guidelines recommend monitoring of plasma anti-Xa factor peak levels and adjustment of the dose to achieve peak levels of 0.7 to 1.2 U/mL. In spite of these recommendations, cases of valve thrombosis during pregnancy continue to occur.

Methods and Results:

We studied 30 pregnant patients receiving anticoagulation for various indications with adjusted dose LMWH given subcutaneously twice a day which had both trough and peak anti-Xa levels throughout pregnancy for a total of 187 paired determinations. The recommended peak anti-Xa levels (0.7-1.2 U/mL) were obtained in 123 (66%) of the measurements but in 80% of them, the trough levels were found to be subtherapeutic (<0.6 U/mL). Subtherapeutic trough levels were found in 8 (73%) of the 11 measurements with peak levels of 0.7 to 0.79 U/mL, 17 (74%) of the 23 of 0.8 to 0.89 U/mL, 21 (72%) of the 29 of 0.9 to 0.99 U/mL, and 28 (44%) of the 63 of 1.0 to 1.2 U/mL. There were 42 measurements with peak anti-Xa levels >1.2 U/mL and even in these cases, 13 (31%) of the trough levels were found to be subtherapeutic.

Conclusions:

Anticoagulation with adjusted dose LMWH aimed to achieve guideline-recommended peak levels of anti-Xa for patients with MPHVs is commonly associated with subtherapeutic trough levels. Routine measurement of trough anti-Xa levels is therefore advisable in women with MPHV treated with LMWH during pregnancy to assure adequate level of anticoagulation.

Management of cardiovascular diseases during pregnancy

The prevalence of cardiovascular diseases (CVDs) in women of childbearing age is rising. The successes in medical and surgical treatment of congenital heart disease have led to an increasing number of women at childbearing age presenting with problems of treated congenital heart disease. Furthermore, in developing countries and in immigrants from these countries, rheumatic valvular heart disease still plays a significant role in young women. Increasing age of pregnant women and increasing prevalence of atherosclerotic risk factors have led to an increase in women with coronary artery disease at pregnancy. Successful management of pregnancy in women with CVDs requires early diagnosis, a thorough risk stratification, and appropriate management by a multidisciplinary team of obstetricians, cardiologists, anesthesiologists, and primary care physicians. The following review is based on the recent European guidelines on the management of CVDs during pregnancy, which aim at providing concise and simple recommendations for these challenging problems.

An audit of pregnant women with prosthetic heart valves at a tertiary hospital in South Africa: a five-year experience

BACKGROUND

Cardiac disease in pregnancy is a common problem in under-resourced countries and a significant cause of maternal morbidity and mortality. A large proportion of patients with cardiac disease have prosthetic mechanical heart valve replacements, warranting prophylactic anticoagulation.

AIM

To evaluate obstetric outcomes in women with prosthetic heart valves in an under-resourced country.

METHODS

A retrospective chart review was performed of 61 pregnant patients with prosthetic valve prostheses referred to our tertiary hospital over a five-year period.

RESULTS

Sixty-one (6%) of 1 021 pregnant women with A diagnosis of cardiac disease had prosthetic heart valves. Fifty-nine had mechanical valves and were on prophylactic anticoagulation therapy, three had stopped their medication prior to pregnancy and two had bioprosthetic valves. There were forty-one (67%) live births, two (3%) early neonatal deaths, 12 (20%) miscarriages and six (10%) stillbirths. Maternal complications included mitral valve thrombosis (n = 4), atrial fibrillation (n = 8), infective endocarditis (n = 6), caesarean section wound haematomas (n = 7), broad ligament haematoma (n = 1) and warfarin embryopathy (n = 4). Haemorrhagic complications occurred in five patients and all five required blood transfusions.

CONCLUSION

Prophylactic anticoagulation with warfarin in patients with mechanical heart valve prostheses was associated with high rates of maternal and neonatal complications, including significant foetal wastage in the first and early second trimesters of pregnancy. Health professionals providing care for pregnant women with prosthetic heart valves must consistently advise on family planning matters, adherence to anticoagulation regimes and consider the use of prophylactic anticoagulant regimens other than warfarin, particularly during the first trimester of pregnancy.

Use of low molecular weight heparin in pregnant women with mechanical heart valves

There are a number of different anticoagulation options for pregnant women with mechanical heart valves. The purpose of this study was to examine maternal thromboembolic complications in women with mechanical valves treated with low-molecular weight heparin (LMWH) throughout pregnancy. This was a substudy of a larger prospective cohort study of pregnant women with heart disease followed from 1998 to 2008. All pregnant women with mechanical left-sided valves who were treated with LMWH throughout pregnancy were included. Maternal thromboembolic events were defined as valve thrombosis, need for valve replacement, or stroke during pregnancy or postpartum (up to 6 months). Twenty-three pregnancies (17 women) occurred in women treated with LMWH and low-dose aspirin: 15 in women with mechanical mitral valves, 9 in women with mechanical aortic valves, and 1 in a woman with both. There was 1 maternal thromboembolic event (4%), which resulted in maternal and fetal death. Five women (22%) developed other adverse cardiac events during pregnancy. Nine pregnancies (43%) had fetal or neonatal adverse events, 5 of which had favorable outcomes. Three pregnancies were complicated by postpartum hemorrhage. In conclusion, carefully monitored LMWH may be a suitable anticoagulation strategy in pregnant women with mechanical heart valves who are unwilling to use warfarin. However, this group of women remains at risk for maternal cardiac and fetal complications. The occurrence of valve thrombosis resulting in maternal death despite therapeutic anti-Xa levels highlights current limitations with anticoagulation in this population.

Treatment of pregnancy related venous thromboembolism

Introduction. Prevention and treatment of venous thromboembolism during pregnancy are complicated since the use of antithrombotic drugs carries a certain risk to the mother, the fetus or both. Coumarins cross the placental barrier and may be responsible for bleeding, teratogenicity and central nervous system abnormalities. The risk of embriopathy is particularly high between 6 and 12 weeks of gestation. Treatement. Heparin is the treatment of choice for thrombosis during pregnancy because it is entirely safe for the fetus, unlike oral anticoagulants. The frequency of heparin-induced thrombocytopenia and osteoporosis is significantly lower if LMWH is applied, so this heparin type is preferable to UFH during pregnancy. Treatment of women with VTE during pregnancy, especially those with thrombophilia, requires individualized dosing and duration of antithrombotic thrapy. Peripartal management. In order to avoid the peripartum anticoagulant heparin effect and possible bleeding, heparin should be discontinued prior to the delivery and reintroduced after the parturition. PROPHYLACTIC REGIMEn. Prophylactic antithrombotic regimen during subsequent pregnancies should also be individualized. The use of low molecular weight heparins is becoming more widespread. They have reliable pharmacokinetics, require less frequent injections than unfractionated heparin and carry a lower risk of treatment complications. LMW heparins are safe and effective and they are replacing UFH as the anticoagulant of choice during pregnancy. Both UFH and LMWH are not secreted into breast milk and can be safely given to nursing mothers. Warfarin does not induce an anticoagulant effect in the breast-fed infant, so it can be safely used in women who require postpartum anticoagulant therapy.

Pregnancy in women with prosthetic heart valves

Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis and death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than un-fractionated and low-molecular-weight heparin, but carry the risk of embryopathy, which is probably dose-dependent. The different anticoagulation regimens are discussed in this review. When valve thrombosis occurs during pregnancy, thrombolysis is the preferable therapeutic option. Bioprostheses have a more favourable pregnancy outcome than mechanical prostheses but due to the high re-operation rate in young women they do not constitute the ideal alternative. When women with native valve stenosis need pre-pregnancy intervention, mitral balloon valvuloplasty is the best option in mitral stenosis, while the Ross operation or homograft implantation may be the preferable surgical regimen in aortic stenosis. (Neth Heart J 2008;16:406-11.).

[Anticoagulation and thrombophilia in pregnancy]

A review of coagulation disturbances during pregnancy and the current management of the anticoagulated patient with heart valve prostheses, atrial fibrillation, and thromboembolic events is presented. All patients with mechanical heart valve prostheses require life-long oral anticoagulation with coumarin or one of its derivatives. Recommendations for the treatment and prevention of thromboembolic events are discussed. The advantages and disadvantages of three different treatment approaches to anticoagulation during pregnancy are discussed and recommendations for the management in different situations are outlined with delineation of specific risks for the mother and the fetus.

Congenital heart disease in pregnancy

INTRODUCTION

Pregnancy, birth, and the puerperium are associated with significant physiological changes and adaptations in the cardiovascular system, which pose a significant risk to pregnant women with congenital heart disease (CHD). Thanks to advances in pediatric cardiac surgery and cardiology the majority of children with CHD survive to adulthood, and an increasing number eventually become pregnant. In fact, cardiac disease - mostly congenital - is now a leading cause of maternal death in western industrialized countries.

METHODS

Selective literature review.

RESULTS AND DISCUSSION

Optimal care of women with CHD before, during, and after pregnancy requires a multidisciplinary team including obstetricians, cardiologists, and anaesthetists. Successful pregnancy at a minimum risk is feasible for most women with CHD when appropriate counseling and optimal care are provided.

Pregnancy and adult congenital heart disease

Increasing numbers of women with complex congenital heart disease are reaching childbearing age. Pregnancy is a major issue in the management of adult congenital heart disease. Cardiac disease is one of the most common causes of maternal morbidity and mortality. Complications, such as growth retardation, preterm and premature birth and even fetal and neonatal mortality, are more frequent among children of women with congenital heart disease. The risk of complications is determined by the severity of the cardiac lesion, the presence of cyanosis, the maternal functional class and the use of anticoagulation. However, the pathophysiology of these complications is not completely understood and may be related to a diminished increase in cardiac output and/or endothelial dysfunction. The management of pregnant cardiac patients is based on limited clinical information. This article reviews pre-pregnancy counseling and management during pregnancy in patients with congenital heart disease.

MECHANICAL HEART VALVES AND PREGNANCY

Mechanical heart valves pose a particular challenge in pregnancy, as the primary agent used to prevent valve thrombosis, coumadin (warfarin), is a known teratogen. Alternatives to coumadin, such as unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are safer for the fetus, particularly during the first trimester of pregnancy, but expose the mother to potential valve failure. This review will examine these controversies and the complex literature regarding management in pregnancy.

Treatment of mechanical valve thrombosis during pregnancy

Pregnant patients with mechanical valves require anticoagulation. The risk of bleeding and embryopathy associated with oral anticoagulation must be weighed against the risk of valve thrombosis. In the presence of a mechanical valve thrombosis, an appropriate treatment modality must be selected, as it is critical for the health of mother and fetus. In this review, we present a pregnant patient with mechanical valve thrombosis (MVT) who underwent thrombolytic therapy, subsequent anticoagulation according to available guidelines, and delivered a healthy baby at full term.

The obstetrical patient with a prosthetic heart valve

Definitive recommendations on anticoagulation strategy in pregnant women who have prosthetic heart valves are lacking because of the paucity of prospectively collected data. The use of warfarin, UFH, LMWH, or any combination of these choices has potentially adverse outcomes for the mother and fetus. Although there is no treatment option that has proven to be completely satisfactory, there is agreement that failures are most often due to underdosing and the lack of intensive monitoring of anticoagulation. A careful discussion with the patient must be undertaken so that she and the clinician can come to a decision about the most appropriate protocol.

Pregnancy in women with valvular heart disease

Patients with valvular disease who desire pregnancy or are already pregnant require specialised care. Ideally, women undergo preconceptual counselling that addresses any procedures needed to decrease the risks of pregnancy, including valve replacement, if the patient has symptoms at baseline. Management during pregnancy includes replacing any contraindicated medications with safer alternatives, optimising loading conditions, careful monitoring and aggressive treatment of any exacerbating factors. Rarely, percutaneous or surgical intervention is required during pregnancy. Labour and delivery often require invasive haemodynamic monitoring and a multi-disciplinary team for optimal maternal and fetal outcomes.

Periprocedural bridging therapy in patients receiving chronic oral anticoagulation therapy

BACKGROUND

In patients receiving chronic oral anticoagulation with vitamin K antagonists (VKAs) it may be necessary to temporarily discontinue VKA therapy to allow surgery or other invasive procedures to be performed, as maintaining treatment may increase the risk of bleeding during the procedure. This, however, creates a clinical dilemma, since discontinuing VKAs may place the patient at risk of thromboembolism.

SCOPE

We undertook a systematic narrative review of patients on chronic oral anticoagulation, requiring a periprocedural bridging therapy with heparin during invasive procedures.

FINDINGS AND RECOMMENDATIONS

For patients requiring temporary discontinuation of VKA, current guidelines recommend the use of 'bridging' therapy with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) in patients considered to be at intermediate-to-high risk of thromboembolism, such as those with prosthetic heart valves or atrial fibrillation. Recent studies show that LMWHs are associated with low rates of thromboembolism and, when compared with UFH, are as effective and safe as UFH when used as periprocedural bridging therapy in such patients. LMWHs also offer advantages such as ease of administration and predictable anticoagulant effects. Moreover, outpatient-based periprocedural bridging therapy with LMWH has been shown to result in significant cost savings compared with in-hospital UFH.

CONCLUSIONS

The decision to provide bridging therapy requires careful consideration of the relative risks of thromboembolism and bleeding in each patient. Based upon the studies reviewed we recommend a therapeutic dose of UFH or LMWH for patients at intermediate-to-high thromboembolic risk requiring interruption of VKA, especially for low bleeding risk procedures. We would like to propose upgrading the American College of Chest Physicians (ACCP) guideline recommendations from 2C to 1C. However, there is still a need for a randomized controlled trial on the efficacy and safety of the available bridging strategies, including heparin and placebo comparators, in preventing thromboembolism for specific patients and procedures.

Valvular Heart Disease and Pregnancy

A large number of prosthetic heart valves (PHV) are being implanted in patients with both congenital and acquired valvular disease. Many of the recipients of such valves are women of childbearing age who desire to have children. The main issues involved with pregnancy in a patient with PHV include the selection of PHV in women during their childbearing age, risks to both the mother and the fetus associated with pregnancy and the management of the patients with PHV during gestation.