Pregnancy in patients with prosthetic heart valves: the effects of anticoagulation on mother, fetus, and neonate

A Case Report of Secondary Postpartum Hemorrhage in a Pregnant Woman With a Mechanical Mitral Valve: Challenges of Anticoagulation

A pregnant woman with rheumatic heart disease always runs the risk of developing both thromboembolic and hemorrhagic symptoms, necessitating careful monitoring of her anticoagulation treatments both throughout pregnancy and after delivery. Postpartum haemorrhage, a hemorrhagic manifestation, can be challenging to control and presents a significant challenge when it comes to beginning anticoagulation after delivery. Thus, pregnancy in these patients is an extremely risky endeavour. Given that these women take anticoagulants, managing these women with artificial heart valves throughout pregnancy can be difficult. The diminished clotting ability in these women may be the cause of postpartum haemorrhage, and a multidisciplinary approach is necessary for a successful treatment. To manage this potentially fatal illness, a well-equipped institution with proper support systems is essential. We present a 23-year-old primigravida who was 39 weeks and three days pregnant and had a repaired aortic valve as well as a prosthetic mitral valve. She was taking warfarin to prevent clotting when she was pregnant.

Successful management of postpartum hemorrhage and surgical site infection in a pregnant woman under warfarin for heart valve replacement: A case report

INTRODUCTION AND IMPORTANCE

Pregnant women under warfarin for mechanical heart valves can pose a variety of challenges which requires fine tuning of various anticoagulants throughout the pregnancy and in the postpartum period as hemorrhage can lead to maternal and fetal morbidity and mortality.

CASE PRESENTATION

A 36-year-old woman gravida two, para one at 35 weeks 5 days gestation, with hypothyroidism with mitral valve replacement and tricuspid valve repair due to rheumatic heart disease underwent emergency lower section cesarean section for fetal bradycardia. B-lynch suturing was eventually done to control atonic postpartum hemorrhage. During hospital stay she developed surgical site infection of abdominal skin incision site which was also subsequently managed. Postpartum anticoagulation was started late due to postpartum hemorrhage and finally the patient was discharged on warfarin.

CLINICAL DISCUSSION

There is always a risk of both thromboembolic and hemorrhagic manifestations in a pregnant woman with a prosthetic heart valve which requires fine tuning of anticoagulants throughout the pregnancy and in the postpartum period. Hemorrhagic manifestation in the form of postpartum hemorrhage is common which can be difficult to manage and also poses a great dilemma in restarting the anticoagulation after delivery. Excessive blood loss can itself lead to mortality and morbidity, and also via increased risk of surgical site infection.

CONCLUSION

Appropriate preconception counseling along with meticulous assessment, management and monitoring of pregnant women with prosthetic heart valves is necessary to decrease fetal and maternal morbidity and mortality.

Surgical techniques for aortic valve xenotransplantation

Background

Heart valve replacement in neonates and infants is one of the remaining unsolved problems in cardiac surgery because conventional valve prostheses do not grow with the children. Similarly, heart valve replacement in children and young adults with contraindications to anticoagulation remains an unsolved problem because mechanical valves are thrombogenic and bioprosthetic valves are prone to early degeneration. Therefore, there is an urgent clinical need for growing heart valve replacements that are durable without the need for anticoagulation.

Methods

A human cadaver model was used to develop surgical techniques for aortic valve xenotransplantation.

Results

Aortic valve xenotransplantation is technically feasible. Subcoronary implantation of the valve avoids the need for a root replacement.

Conclusion

Aortic valve xenotransplantation is promising because the development of GTKO.hCD46.hTBM transgenic pigs has brought xenotransplantation within clinical reach.

Determinants of health-related quality of life among warfarin patients in Pakistan

INTRODUCTION

The effect of anticoagulation control on overall Health-Related Quality of Life (HRQoL) in patients taking warfarin in Pakistan has not been explored yet. Therefore, this study aimed to evaluate HRQoL among warfarin patients in Pakistan.

METHODS

This cross-sectional study was conducted among patients on warfarin in Pakistan. By purposive sampling, data were collected using demographic data collection form and the World Health Organization Quality of Life: Brief Version (WHOQOL-BREF). The WHOQOL-BREF is comprised of four domains; physical, psychological, social relationships, and environment. Descriptive and inferential statistical analysis was done using SPSS version 22.

RESULTS

Out of 295 warfarin patients, more females than males (<0.001) were observed (n = 184, 62.4%, and n = 111, 37.6% respectively). One hundred and eighteen (40.0%) patients were less than 30-years of age, whereas one hundred and seventy-seven (60.0%) patients were above 30-years of age. Mean scores for the physical (62.44±15.36), psychological (67.84±15.54), social (64.27±26.28) and environment domains (63.45±17.66) were observed.

CONCLUSION

Patients had overall lower to moderate but satisfactory HRQoL scores in all four domains. Age, gender, employment status, education level, the indication of use and duration of warfarin therapy was associated with one or more domains of HRQoL among warfarin patients. The findings of this study would serve as a primary database for future studies. This study highlights how non-clinical factors could impact HRQoL in studied patients.

Warfarin-associated intracranial haemorrhage in pregnant woman with double mechanical valve replacement: a case presentation

BACKGROUND

Management of warfarin-associated major haemorrhage in prosthetic valve diseases is difficult as there is a fine line between haemorrhage and thrombosis. An individual's propensity towards thrombosis, such as pregnancy, makes this situation even more complicated. Cases like these are very rare in the literature.

CASE PRESENTATION

A 26 weeks pregnant, gravida two, para one, 35-year-old patient with prosthetic aortic and mitral valves presented to an external emergency clinic with clouding of consciousness. Her international normalised ratio(INR) was 8.9 at presentation. Brain MRI revealed a left subdural haematoma with no significant mass effect. Warfarin treatment was discontinued. On the second day of follow-up, she was referred to our centre for further evaluation of her clinical deterioration. She was haemodynamically stable on admission to the intensive care unit and followed up with a stable condition until the fourth day when she developed right eye drop and subsequent loss of consciousness. Her haematoma was surgically evacuated, and her condition improved. Eventually, she and a healthy newborn were discharged.

CONCLUSION

Intracranial haemorrhage during pregnancy is a relatively rare complication that requires a multidisciplinary management plan. Although the thrombogenic risk is high, it is vital to complete a reversal of warfarin anticoagulation in pregnant women with major bleeding.

Ectopic mineralization in heart valves: new insights from in vivo and in vitro procalcific models and promising perspectives on noncalcifiable bioengineered valves

Ectopic calcification of native and bioprosthetic heart valves represents a major public health problem causing severe morbidity and mortality worldwide. Valve procalcific degeneration is known to be caused mainly by calcium salt precipitation onto membranes of suffering non-scavenged cells and dead-cell-derived products acting as major hydroxyapatite nucleators. Although etiopathogenesis of calcification in native valves is still far from being exhaustively elucidated, it is well known that bioprosthesis mineralization may be primed by glutaraldehyde-mediated toxicity for xenografts, cryopreservation-related damage for allografts and graft immune rejection for both. Instead, mechanical valves, which are free from calcification, are extremely thrombogenic, requiring chronic anticoagulation therapies for transplanted patients. Since surgical substitution of failed valves is still the leading therapeutic option, progressive improvements in tissue engineering techniques are crucial to attain readily available valve implants with good biocompatibility, proper functionality and long-term durability in order to meet the considerable clinical demand for valve substitutes. Bioengineered valves obtained from acellular non-valvular scaffolds or decellularized native valves are proving to be a compelling alternative to mechanical and bioprosthetic valve implants, as they appear to permit repopulation by the host's own cells with associated tissue remodelling, growth and repair, besides showing less propensity to calcification and adequate hemodynamic performances. In this review, insights into valve calcification onset as revealed by in vivo and in vitro procalcific models are updated as well as advances in the field of valve bioengineering.

[Anticoagulation's problematic during pregnancy in carriers of mechanical heart prosthesis]

INTRODUCTION

The heart prosthesis pregnant women are becoming more frequent due to the persistence of rheumatic fever in the country sends developments.

OBJECTIVE

To propose management strategies from preconception to pregnancy and postpartum.

MATERIALS AND METHODS

Prospective study from 2009-2014 about parturientes followed in cardiology and maternity on center Hospitalo University Oran.

RESULTS

Thirty patients were followed, ejection fraction was equal to 60% in 29 cases. A single case of stenosis of the aortic prosthesis. Sixteen received low molecular weight heparins (LMWH) enoxaparine kind between 6 and 12 weeks, 13 received l'acenocoumarol (AVK) in the first quarter. One patient had been insufficient dose enoxaparine to 1/day and complicate ischemic stroke, abortion of a fetus of 16 weeks malformed in a mother who received acenoucoumarol (AVK) in the first quarter. Maternal mortality was null.

DISCUSSION

LMWHs were 100% effective in sufficient doses, the VKA and LMWH relay period was critical and should be done in a hospital setting.

CONCLUSION

Wearing a prosthetic valve is compatible with supervised pregnancy LMWHs were 100% effective, provided they were used in sufficient doses between 6-12 weeks of amenorrhea.

Biological versus mechanical heart valve prosthesis during pregnancy in women with congenital heart disease

BACKGROUND

We evaluate pregnancy outcome and anticoagulation regimes in women with mechanical and biological prosthetic heart valves (PHV) for congenital heart disease.

METHODS

Retrospective multicenter cohort studying pregnancy outcomes in an existing cohort of patients with PHV.

RESULTS

52 women had 102 pregnancies of which 78 pregnancies (46 women) ≥20 weeks duration (59 biological, 19 mechanical PHV). Miscarriages (n = 19, ≤20 weeks) occurred more frequently in women using anticoagulation (P < .05). During 42% of pregnancies of women with mechanical PHV a combined low molecular weight heparin (LMWH) vitamin-K-antagonist anticoagulation regime was used (n = 8). Overall, cardiovascular, obstetric and fetal/neonatal complications occurred in 17% (n = 13), 68% (n = 42) and 42% (n = 27) of the pregnancies. Women with mechanical PHV had significantly higher cardiovascular (12% vs 32%, P < .05), obstetric (59% vs 85%, P = .02) and fetal/neonatal (34% vs 61%, P < .05) complication rates than women with biological PHV. This was related to PHV thrombosis (n = 3, P < .02), post-partum hemorrhage (P < .02), cesarean section (P < .02), low birth weight and small for gestational age (both P < .05). PHV thrombosis occurred in 3 pregnancies, including 2/5 pregnancies with pulmonary mechanical PHV. PHV thrombosis was related to necessary cessation of anticoagulation therapy or insufficient monitoring of LMWH. Other cardiovascular complications occurred equally frequent in both groups.

CONCLUSION

Complications occur more often in pregnancies of women with a mechanical PHV than in women with a biological PHV, mainly caused by PHV thrombosis and bleeding complications. Meticulous monitoring of anticoagulation in pregnant women is necessary. Women with a pulmonary mechanical PHV are at high risk of complications.

Echocardiography in Pregnancy: Part 2

The prevalence of pregnant women with cardiovascular heart disease is increasing. Transthoracic echocardiography is safe during pregnancy, and it is an important diagnostic tool in pregnant women with established heart disease in order to monitor ventricular and valvular anatomy and function. In addition, it can be used to delineate cardiac anatomy in complex congenital heart disease and help stratify maternal risk during pregnancy. This review will focus on the use of echocardiography in the diagnosis and management of pregnant women with common congenital lesions and with prosthetic valves.

Anesthesia in pregnancy with heart disease

Management of pregnant women with heart disease remains challenging due to the advancement of innovations in cardiac surgery and correction of complex cardiac anomalies, and more recently, with the successful performance of heart transplants, cardiac diseases are not only likely to coexist with pregnancy, but will also increase in frequency over the years to come. In developing countries with a higher prevalence of rheumatic fever, cardiac disease may complicate as many as 5.9% of pregnancies with a high incidence of maternal death. Since many of these deaths occur during or immediately following parturition, heart disease is of special importance to the anesthesiologist. This importance arises from the fact that drugs used for preventing or relieving pain during labor and delivery exert a major influence - for better or for worse - on the prognosis of the mother and newborn. Properly administered anesthesia and analgesia can contribute to the reduction of maternal and neonatal mortality and morbidity.

Pregnancy Outcome in Women with Mechanical Prosthetic Heart Valves Treated with Unfractionated Heparin (UFH) or Enoxaparin

OBJECTIVE

This study was carried out to determine the maternal (including thromboembolic and hemorrhagic complications) and fetal outcomes (including miscarriage, stillbirth, baby death, and live birth) in women with mechanical heart valves managed with therapeutic doses of unfractionated heparin (UFH) versus enoxaparin during pregnancy.

METHODS

This is a prospective comparative, nonrandomized study. Pregnant women with mechanical heart valves presenting to high-risk pregnancy unit of Benha University Hospital, Egypt were treated with UFH 15,000 U/12 h versus enoxaparin (Clexane) 1 mg/kg SC/12 h during pregnancy and the results were analyzed.

RESULTS

40 pregnant women were included in the study. In 20 pregnant women, anticoagulation was with UFH, and 20 pregnant women received enoxaparin. One (3 %) thrombotic complication occurred with enoxaparin treatment. Noncompliance or subtherapeutic levels contributed to this outcome in this case. Antenatal hemorrhage occurred in 4 (10 %) and postpartum hemorrhagic complications in 5 (12.5 %) pregnancies. Of the 32 pregnant women who continued after 20 weeks' gestation, 100 % (17/17) of the women taking predominantly UFH had a surviving infant compared with 93 % (14/15) of the women taking primarily enoxaparin (p = 0.25). One intrauterine fetal death occurred in the enoxaparin group. There was no significant difference in the live birth rates between the two groups (p = 0.31).

CONCLUSIONS

Compliance with therapeutic dose of UFH during pregnancy in women with mechanical heart valves is associated with a low risk of valve thrombosis and good fetal outcomes, but meticulous monitoring is essential.

Anticoagulation in Pregnant Women With Prosthetic Heart Valves

Background: Pregnancy is associated with an increased risk of thrombosis in women with mechanical prosthetic heart valves. Effective anticoagulation is therefore critical in such patients but remains problematic, since oral anticoagulation and both unfractionated and low-molecular-weight heparin may be associated with important fetal and maternal side effects.

Purpose: To review information related to the use of anticoagulation with both warfarin and heparin and reassess the safety and efficacy of these therapies in pregnant women with mechanical prosthetic heart valves.

Data source and selection: A MEDLINE search from 1966 to October 2003 for English and non-English language articles that reported the use of anticoagulation in pregnancy was conducted. Articles were included if they reported use of anticoagulation in pregnancy with emphasis on those that included women with mechanical prosthetic heart valves.

Conclusions: Anticoagulation prophylaxis with both warfarin and heparin (unfractionated heparin and low-molecular-weight heparin) may be associated with important fetal and maternal side effects. Optional regimens for the treatment of low-risk and high-risk patients are proposed to minimize potential complications.

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.

Pregnancy outcomes in women with aortic valve substitutes

Young women who require aortic valve replacement need information on the potential cardiac and obstetric complications of pregnancy for the different valve substitutes available. We, therefore, assessed the pregnancy outcomes in women who had received an autograft, homograft, or mechanical valve in the aortic position. Women who were pregnant after surviving aortic valve replacement at our institution from 1987 to 2011 were included. Information on cardiac status and pregnancy outcome was obtained through the hospital medical records and by an extensive patient questionnaire. A total of 40 women experienced 67 pregnancies, of which 55 (82%) were completed pregnancies, 6 (9%) were miscarriages, and 6 (9%) were terminated. Of the 40 women, 18 (45%) had a pulmonary autograft, 13 (32%) a homograft, and 9 (23%) a mechanical valve. The mean age at the first pregnancy was 30.0 ± 5.7 years. No maternal mortality but 1 fetal death (1.8%) and 1 neonatal death (1.8%) occurred. Maternal cardiac complications developed in 13% and obstetric complications in 38% of the completed pregnancies. Heart failure (9%), arrhythmias (7%), hypertension-related disorders (7%), preterm delivery (24%), and small-for-gestational-age infants (15%) were most often encountered. Mechanical valve recipients had the greatest incidence of both cardiac and obstetric complications. In conclusion, pregnancy-associated complications after aortic valve replacement were common, and human tissue valves should be considered in the discussion for the optimal aortic valve substitute in a young woman. However, careful obstetric monitoring is mandatory.

Intracranial hemorrhage in pregnancy

A pregnant woman with a mechanical prosthetic mitral valve was anticoagulated with low-molecular-weight heparin in the first trimester followed by warfarin until 36 weeks' gestation. She was then switched to intravenous unfractionated heparin infusion to allow for regional anesthesia in anticipation of vaginal delivery. She developed severe headache on hospital day 2 that was refractory to pain medications. Cranial imaging demonstrated a large subdural hematoma with midline shift. She delivered a healthy baby girl by cesarean section. Eventually, symptoms and intracranial abnormalities resolved over time. In conclusion, subdural hematoma is a relatively rare complication that requires multidisciplinary management plan.

VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The use of anticoagulant therapy during pregnancy is challenging because of the potential for both fetal and maternal complications. This guideline focuses on the management of VTE and thrombophilia as well as the use of antithrombotic agents during pregnancy.

METHODS

The methods of this guideline follow the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We recommend low-molecular-weight heparin for the prevention and treatment of VTE in pregnant women instead of unfractionated heparin (Grade 1B). For pregnant women with acute VTE, we suggest that anticoagulants be continued for at least 6 weeks postpartum (for a minimum duration of therapy of 3 months) compared with shorter durations of treatment (Grade 2C). For women who fulfill the laboratory criteria for antiphospholipid antibody (APLA) syndrome and meet the clinical APLA criteria based on a history of three or more pregnancy losses, we recommend antepartum administration of prophylactic or intermediate-dose unfractionated heparin or prophylactic low-molecular-weight heparin combined with low-dose aspirin (75-100 mg/d) over no treatment (Grade 1B). For women with inherited thrombophilia and a history of pregnancy complications, we suggest not to use antithrombotic prophylaxis (Grade 2C). For women with two or more miscarriages but without APLA or thrombophilia, we recommend against antithrombotic prophylaxis (Grade 1B).

CONCLUSIONS

Most recommendations in this guideline are based on observational studies and extrapolation from other populations. There is an urgent need for appropriately designed studies in this population.

Venous thromboembolism, thrombophilia, antithrombotic therapy, and pregnancy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This article discusses the management of venous thromboembolism (VTE) and thrombophilia, as well as the use of antithrombotic agents, during pregnancy and is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that benefits do, or do not, outweigh risks, burden, and costs. Grade 2 recommendations are weaker and imply that the magnitude of the benefits and risks, burden, and costs are less certain. Support for recommendations may come from high-quality, moderate-quality or low-quality studies; labeled, respectively, A, B, and C. Among the key recommendations in this chapter are the following: for pregnant women, in general, we recommend that vitamin K antagonists should be substituted with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1A], except perhaps in women with mechanical heart valves. For pregnant patients, we suggest LMWH over UFH for the prevention and treatment of VTE (Grade 2C). For pregnant women with acute VTE, we recommend that subcutaneous LMWH or UFH should be continued throughout pregnancy (Grade 1B) and suggest that anticoagulants should be continued for at least 6 weeks postpartum (for a total minimum duration of therapy of 6 months) [Grade 2C]. For pregnant patients with a single prior episode of VTE associated with a transient risk factor that is no longer present and no thrombophilia, we recommend clinical surveillance antepartum and anticoagulant prophylaxis postpartum (Grade 1C). For other pregnant women with a history of a single prior episode of VTE who are not receiving long-term anticoagulant therapy, we recommend one of the following, rather than routine care or full-dose anticoagulation: antepartum prophylactic LMWH/UFH or intermediate-dose LMWH/UFH or clinical surveillance throughout pregnancy plus postpartum anticoagulants (Grade 1C). For such patients with a higher risk thrombophilia, in addition to postpartum prophylaxis, we suggest antepartum prophylactic or intermediate-dose LMWH or prophylactic or intermediate-dose UFH, rather than clinical surveillance (Grade 2C). We suggest that pregnant women with multiple episodes of VTE who are not receiving long-term anticoagulants receive antepartum prophylactic, intermediate-dose, or adjusted-dose LMWH or intermediate or adjusted-dose UFH, followed by postpartum anticoagulants (Grade 2C). For those pregnant women with prior VTE who are receiving long-term anticoagulants, we recommend LMWH or UFH throughout pregnancy (either adjusted-dose LMWH or UFH, 75% of adjusted-dose LMWH, or intermediate-dose LMWH) followed by resumption of long-term anticoagulants postpartum (Grade 1C). We suggest both antepartum and postpartum prophylaxis for pregnant women with no prior history of VTE but antithrombin deficiency (Grade 2C). For all other pregnant women with thrombophilia but no prior VTE, we suggest antepartum clinical surveillance or prophylactic LMWH or UFH, plus postpartum anticoagulants, rather than routine care (Grade 2C). For women with recurrent early pregnancy loss or unexplained late pregnancy loss, we recommend screening for antiphospholipid antibodies (APLAs) [Grade 1A]. For women with these pregnancy complications who test positive for APLAs and have no history of venous or arterial thrombosis, we recommend antepartum administration of prophylactic or intermediate-dose UFH or prophylactic LMWH combined with aspirin (Grade 1B). We recommend that the decision about anticoagulant management during pregnancy for pregnant women with mechanical heart valves include an assessment of additional risk factors for thromboembolism including valve type, position, and history of thromboembolism (Grade 1C). While patient values and preferences are important for all decisions regarding antithrombotic therapy in pregnancy, this is particularly so for women with mechanical heart valves. For these women, we recommend either adjusted-dose bid LMWH throughout pregnancy (Grade 1C), adjusted-dose UFH throughout pregnancy (Grade 1C), or one of these two regimens until the thirteenth week with warfarin substitution until close to delivery before restarting LMWH or UFH) [Grade 1C]. However, if a pregnant woman with a mechanical heart valve is judged to be at very high risk of thromboembolism and there are concerns about the efficacy and safety of LMWH or UFH as dosed above, we suggest vitamin K antagonists throughout pregnancy with replacement by UFH or LMWH close to delivery, after a thorough discussion of the potential risks and benefits of this approach (Grade 2C).

Anticoagulation for prosthetic heart valves in pregnancy. Is there an answer?

The aim of this retrospective study was to compare the different anticoagulation regimens used in pregnant women with prosthetic heart valves. We reviewed 196 pregnancies in 110 women from 1974 to 2000. The patients were divided into two groups: group 1 (142 pregnancies) had warfarin throughout pregnancy; and in group 2 (54 pregnancies), warfarin was replaced by subcutaneous heparin during the first trimester and last two weeks of pregnancy. There were no maternal complications in 129 pregnancies in group 1 and 44 in group 2. There were significantly fewer normal births in group 1 (56; 39.4%) compared to group 2 (39; 72.2%). Group 1 had a significantly higher rate of spontaneous abortion (46.5% vs 14.8%), but group 2 had a higher rate of valve thrombosis. In group 1, women with a warfarin requirement < 5 mg had a lower rate of spontaneous abortion. Warfarin is an effective anticoagulant in pregnant women with mechanical valves but it results in significant fetal loss when the dose is > 5 mg. Heparin is a less effective anticoagulant resulting in more maternal complications, but it is more protective of the fetus.

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.

Prosthetic Heart Valves and Arrhythmias in Pregnancy

The majority of women with bioprosthetic valves do not require anticoagulation during pregnancy. In women with mechanical valves, a detailed discussion of the advantages and disadvantages of the three anticoagulant options (warfarin, unfractionated heparin and low molecular weight heparin) is indicated. The majority of women with arrhythmias during pregnancy have a benign increased rate of atrial or ventricular premature beats. Those women who are hemodynamically stable can be reassured and do not usually require treatment. Women with more ominous arrhythmias should be managed in collaboration with a cardiologist, usually using the same agents that would be chosen in the non-pregnant patient, including electrical cardioversion when necessary. This is the fifth and final article in a series reviewing in detail the assessment and management of specific cardiac disorders in pregnancy.

Pregnancy in patients with heart disease: experience with 1,000 cases

BACKGROUND

Previously, the high maternal mortality in cardiac patients who became pregnant prompted the assertion: Women with an abnormal heart should not become pregnant. This long-standing notion needs to be revised today.

HYPOTHESIS

The study was undertaken to ascertain the experience with a large series of pregnant women with cardiac disease cared for in the same referral center.

METHODS

From 1989 to 1999, 1,000 pregnant women with heart disease were followed by the same clinical and obstetric team. The cardiac diseases included rheumatic heart disease (55.7%), congenital heart disease (19.1%), Chagas' disease (8.5%), cardiac arrhythmias (5.1%), cardiomyopathies (4.3%), and others (7.3%).

RESULTS

Of the pregnant women studied, 765 (76.5%) experienced no cardiovascular events during the study; 235 (23.5%) patients had the following cardiovascular complications: congestive heart failure (12.3%), cardiac arrhythmias (6%), thromboembolism (1.9%), angina (1.4%), hypoxemia (0.7%), infective endocarditis (0.5%), and other complications (0.7%). Clinical treatment allowed adequate management in 161 (68.8%) patients; however, 46 (19.6%) patients underwent interventional procedures because of refractory complications. The general maternal mortality rate was 2.7%. Of the 915 (91.5%) infants who were discharged, 119 (13%) were premature.

CONCLUSION

Pregnancy in women with heart disease is still associated with considerable morbidity and mortality rates, which strongly correlate to maternal underlying disease. Strict prenatal care and early risk stratification during gestation are fundamental measures to improve the prognosis of pregnancy in women with heart disease.

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.

Low-molecular-weight heparin for thromboprophylaxis in pregnant women with mechanical heart valves

BACKGROUND

Pregnancy in a woman with a mechanical heart valve is a life-threatening situation. Due to the inability of unfractionated heparin to prevent valvular thromboses, warfarin or other vitamin K antagonists have been the preferred anticoagulants for the mother. They are, however, potentially harmful to the fetus. With the advent of low-molecular-weight heparins, clinicians were hopeful for an alternative that was safe for the fetus, but more effective than unfractionated heparin, which carries a 29-33% risk of life-threatening thromboses and a 7-15% chance of mortality. Unfortunately, fatal thromboses have occurred with low-molecular-weight heparin as well.

METHODS

We searched the MEDLINE database and other sources to identify cases of the use of low-molecular-weight heparin for thromboprophylaxis in women with mechanical heart valves.

RESULTS

We found 73 cases and added three of our own for a total of 76. There were 17 thrombotic events (22%). Thirteen were valve thromboses, two were strokes, and two were myocardial infarctions. There were three deaths (4%).

CONCLUSIONS

While pregnant women with mechanical heart valves who receive low-molecular-weight heparin for thromboprophylaxis are at extremely high risk of life-threatening thromboses, there is no evidence that low-molecular-weight heparin is inferior to unfractionated heparin.

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.

Risk of drug-induced congenital defects

Defects attributable to drug therapy represent about 1% of congenital defects of known aetiology. This means that a precautionary attitude and correct use of drugs in fertile, and especially pregnant, women is a feasible form of prevention. Drugs currently in use with proven teratogenic effect number approximately 25, but new pharmaceutical drugs are constantly in preparation. Recognition of a drug-induced teratogenic effect is a complex procedure taking into account not only experimental animal data but also experience in humans. Considering that 40% of pregnancies are not planned, it follows that any drug with known or suspected teratogenic potential must be used only under strict medical control. Also, adequate knowledge on potential teratogenicity of a drug permits modification of therapy before conception. It goes without saying that any drug should be used during pregnancy only if it is essential, and it would be prudent to use only those where adequate information is provided and prior clinical experience is available. Teratology Information Services can assist both physicians and patients when any doubt exists.

Stroke in pregnancy

Stroke in pregnancy and the puerperium is a rare but serious cause of maternal and fetal mortality. Pregnancy-associated maternal changes should remain additional considerations in the evaluation and treatment of the pregnant patient who has stroke and not preclude a comprehensive stroke evaluation. Instead, the approach to the pregnant patient who has stroke should include the evaluation of general causes of stroke in the young, with the additional consideration of the rare pregnancy-specific causes. Understanding the potential maternal and fetal risks of diagnostic testing and treatment is crucial to appropriate decision making when caring for the pregnant patient who has stroke.

Successful Pregnancy in a Patient With Double Outlet Left Ventricle After a Rastelli Operation Using a Prosthetic Valve

A woman with double outlet left ventricle (DOLV) had undergone a Rastelli operation using a prosthetic Björk Shiley valve and who was receiving anticoagulant drug delivered a healthy male infant. Oral warfarin was replaced by heparin from the 5th to the 13th week of gestation and for the last 5 weeks of gestation. Successful pregnancy in patients with DOLV after a Rastelli operation using a prosthetic valve is possible with careful maintenance.

The risk of fetal loss associated with Warfarin anticoagulation

OBJECTIVES

To examine if fetal risks associated with Warfarin anticoagulation during pregnancy may have been over-estimated at the time the drug was contraindicated during pregnancy.

METHODS

Seven case series with the same therapeutic objective for Warfarin anticoagulation published after 1980 were identified. The frequencies of fetal complications were calculated and compared with those of the 1980 compilation.

RESULTS

The frequencies of embryopathy, stillbirths, and neonatal deaths were similar to the 1980 database, but higher with respect to spontaneous abortions (24.1 vs. 8.6%) and premature deliveries (13.9 vs. 4.6%), and lower regarding live births (73.3 vs. 83.7%).

CONCLUSIONS

Fetal risks associated with Warfarin anticoagulation during pregnancy have not been overestimated. Warfarin should not be given in cases where other anticoagulants do not increase the risk for the expecting mother.

Emergency redo mitral valve replacement in a 27-year-old pregnant female with a clotted prosthetic mitral valve, preoperative fetal demise and postoperative ventricular assist device: a case report

A 27-year-old Laotian woman with a St Jude mechanical mitral valve became pregnant, requiring a change in her anticoagulant after the first trimester when her warfarin sodium (coumadin) was replaced with enoxaparin sodium (lovenox). Her prosthetic valve clotted and became dysfunctional. She was 16 weeks pregnant and was taken to the operating room for emergency surgery for replacement of the valve. The fetus had not been viable for 1-2 weeks, but still remained in utero. The clotted valve was replaced with another St Jude valve of a slightly smaller diameter (27 mm). The patient could not be weaned from bypass so a right ventricular assist device (RVAD) was inserted. The patient was weaned from the RVAD after 2 days of support. Two days following removal of the RVAD the fetus spontaneously aborted. The patient had a long, complicated hospital course and was discharged 3 months later. She subsequently died 4 months after discharge of a cerebral hemorrhage from excessive anticoagulation.

Malformations Due to Warfarin: A Case Report

We report a 5-month-old infant with severe growth retardation who was exposed to in utero warfarin for the first 4 months. She had a dysmorphic face with depressed nasal hypoplasia and low-set ears. Cranial computerized tomography revealed bifrontal atrophy, agenesis of corpus callosum, and dilation of lateral ventricles. In addition she had patent ductus arteriosus with pulmonary hypertension, which had to be ligated.

Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves

OBJECTIVES

Firstly, to compare pregnancy outcomes and cardiac complications in women with: 1) either mechanical or bioprosthetic valves at the mitral site; 2) mechanical valves treated with warfarin or subcutaneous heparin. Secondly, to determine pregnancy and cardiac outcomes in women with aortic homograft valves.

DESIGN

Historical cohort study.

SETTING

Greenlane Hospital, Auckland, New Zealand.

POPULATION

Young women (n = 255) who had valve replacements between 1972 and 1992. Seventy-nine women underwent 147 pregnancies.

MAIN OUTCOME MEASURES

Pregnancy loss, cardiac complications.

RESULTS

Pregnancy loss occurred in 59% of pregnancies with mitral mechanical valves (n = 50) and 7% with mitral bioprosthetic valves (n = 33) (RR 8 x 20, 95% CI 2 x 10-31 x 93). Pregnancy loss rate was 70% in pregnancies treated with warfarin, compared with 25% for those switched from warfarin to heparin (RR 2 x 81, 95% CI 1 x 03-7 x 73). All heparin-associated losses occurred in the first trimester, whereas there were four stillbirths with warfarin. Cardiac complications occurred in 10 pregnancies (20%) in the women with mitral mechanical valves and four (13%) with mitral bioprosthetic valves (RR 1 x 55, 95% CI 0 x 53-4 x 52). All four thromboembolic complications with mechanical valves occurred in the 14 women treated with heparin throughout pregnancy. Structural valve deterioration occurred in four pregnancies (10%) with mitral bioprosthetic valves. No cardiac complications or known pregnancy losses occurred with aortic homograft valves (n = 41).

CONCLUSION

The high pregnancy loss rate in women with mitral mechanical valves was associated with warfarin throughout pregnancy, whereas the thromboembolic cardiac complications were associated with heparin. Pregnancy outcome was very good in women with bioprosthetic and homograft valves.

Anticoagulation in pregnant women with mechanical heart valve prostheses

OBJECTIVE

To evaluate the outcome of pregnancy in women with mechanical heart valve prostheses in relation to the anticoagulant treatment used in the first trimester and the incidence of thrombotic and bleeding complications.

METHODS

92 pregnancies in 59 women were followed between 1986 and 1997. In 31 pregnancies, oral anticoagulants were discontinued when pregnancy was diagnosed and subcutaneous heparin was started (12 500 U every 12 hours) adjusted to prolong the adjusted partial thromboplastin time to twice the control level. In the second trimester oral anticoagulants were resumed but changed to heparin again 15 days before the expected delivery date. In 61 pregnancies oral anticoagulants were continued during the first trimester. The same regimen of heparin was used for delivery.

RESULTS

Abortion or fetal losses were similar (p = 0. 5717) in women exposed to oral anticoagulants in the first trimester (13/61; 25%) compared with those who received adjusted subcutaneous heparin (6/31; 19%). Embolic episodes were more common (p = 0.0029) in women who received heparin (4.92%) compared with those on oral anticoagulants (0.33%). Embolic episodes were cerebral and transient. No valve thromboses were observed. No malformations appeared in the 71 newborns, except for one case of hydrocephalus. There were no maternal deaths secondary to thrombotic complications. The only death was the result of major bleeding after the delivery of a premature stillborn.

CONCLUSIONS

Oral anticoagulants seem to be safer for the mother than adjusted subcutaneous heparin. Heparin does not offer a clear advantage over oral anticoagulation in the pregnancy outcome.

Dose-dependent fetal complications of warfarin in pregnant women with mechanical heart valves

OBJECTIVES

The purpose of this study was to assess the incidence of warfarin fetal complications and whether they are dose-dependent.

BACKGROUND

Gravid patients with mechanical heart valves require long-term anticoagulant therapy. Controversy exists concerning the appropriate treatment of these patients.

METHODS

Forty-three women on warfarin carrying out 58 pregnancies were studied. For each patient with full-term pregnancy a caesarian section was scheduled for the 38th week during brief warfarin discontinuation. Maternal and fetal complications were evaluated. Fetal complications were divided according to the warfarin dosage < or = 5 mg and > 5 mg necessary to keep an international normalized ratio (INR) of 2.5 to 3.5, and analyzed subsequently.

RESULTS

A total of 58 pregnancies were observed: 31 healthy babies (30 full term, 1 premature) and 27 fetal complications (22 spontaneous abortions, 2 warfarin embryopathies, 1 stillbirth, 1 ventricular septal defect, 1 growth retardation) were recorded. Two maternal valve thromboses occurred. No fetal or maternal bleeding was observed during caesarian sections or premature vaginal delivery. Patients whose warfarin doses during pregnancy were > 5 mg had 22 fetal complications, whereas those taking a dose < or = 5 mg had only five fetal complications (p = 0.0001). For an increase of the warfarin dose there was a substantially increased probability of fetal complications (p < 0.0001; p < 0.7316).

CONCLUSIONS

There is a close dependency between warfarin dosage and fetal complications. Patients on warfarin anticoagulation may be delivered by planned caesarian section at the 38th week while briefly interrupting anticoagulation.

Effect of pregnancy on the duration of bovine pericardial bioprostheses

BACKGROUND

This study sought to evaluate the effect of pregnancy on the rate of deterioration of bovine pericardial bioprostheses. To avoid the fetal and maternal risks associated with anticoagulant therapy during pregnancy, the use of bioprostheses has been advocated for young women with cardiac valve disease who may later wish to bear children. Several reports have suggested the probability of pregnancy-related accelerated deterioration of these valves.

METHODS AND RESULTS

The incidence of prosthetic dysfunction and the freedom from deterioration were investigated in 48 women who had 58 pregnancies and in a control group of 167 patients in the same age range. There were 39 cases of prosthetic dysfunction (deaths plus reoperations resulting from valve failure): 12 in the pregnant group for a linearized rate of 3.5% +/- 0.99% (SE) per patient-year and 27 in the control group or 3.4% +/- 0.65% per patient-year (P = not significant). The actuarial freedom from dysfunction was 90.4% (95% confidence interval 77.9 to 96.2) at 5 years and 77.0% (59.7 to 88.3) at 8 years for the pregnancy group and 86.3% (77.3 to 92.0) and 73.4% (56.6 to 84.8), respectively, for the control group ( P = not significant). In the Cox proportional hazard regression analysis, pregnancy did not influence dysfunction. A direct correlation was found between freedom from dysfunction and the patient's age at surgery.

CONCLUSIONS

Pregnancy does not accelerate the rate of deterioration of bovine pericardial bioprostheses. It is more likely that biological valves deteriorate more rapidly in these patients because of their young age.

Anticoagulant therapy of pregnant patients with prosthetic heart valves: rationale for a clinical trial of low molecular weight heparin

The management of anticoagulant therapy for the prevention of thromboembolism from prosthetic heart valves in the pregnant patient is far from ideal and deserves more clinical research. Warfarin therapy given alone throughout pregnancy poses high risks to the fetus because it crosses the placental barrier. Heparin alone throughout pregnancy poses high risks to the mother, which might be lessened somewhat by more intensive therapeutic regimens and careful monitoring of the heparin level or anticoagulated state of the blood. Because of the major risk of embryopathy in the fetus during the first trimester and latter half of the third trimester, heparin therapy during those times has been recommended. In the opinion of some experts, high-risk cases may benefit from low-dose aspirin in addition to anticoagulant therapy. The fact that warfarin is contraindicated during pregnancy (according to the pharmaceutical company that markets it) poses some problems for the physician who prescribes it. For the above reason, alternative drugs are worthy of consideration and should be given clinical trials. Low molecular weight heparin has the potential for greatly reducing drug-related risk for the fetus while providing greater safety for the mother.

Modern management of prosthetic valve anticoagulation

Prosthetic heart valves have been effectively used for many years. Nonetheless, they are associated with risks of thrombosis and thromboembolic events, as well as anticoagulation-induced bleeding. Substantial changes in anticoagulation measurement and dosing have occurred during the past several years. In this review, the rationale for anticoagulation in patients with prosthetic heart valves, the changes in monitoring and dosing, and the comparison of relevant anticoagulation trials are discussed. On the basis of the existing data, new recommendations regarding lower anticoagulation levels are offered, utilizing a single value goal rather than the traditional therapeutic range. Perioperative management of anticoagulation is discussed in light of the available literature, and major drug interactions are reviewed.

[Arrhythmias and pregnancy]

Although arrhythmias are one of the most frequent consultations during pregnancy, fortunately the majority are benign. Usually, they are well tolerated assuming they occur in patients with structurally normal hearts. However, pregnancy adds a new aspect to the so called "arrhythmia tolerance", because arrhythmia and therapy may jeopardize the fetus. For acute treatment of narrow and wide tachycardias, with few exceptions, antiarrhythmic medications appear to be safe. In addition to the relative security of drugs such as adenosine, digoxin, propranolol, procainamide and flecainide, we could use direct current countershock with no evidence of significant complications. Because no drug is absolutely safe, chronic pharmacologic therapy is best avoided during pregnancy. Finally, radiofrequency ablation could be recommended as an alternative in women with previous tachycardias who would like to become pregnant.

Current concepts of anticoagulant therapy in pregnancy

The optimal use of anticoagulants during pregnancy will continue to be controversial until appropriate randomized controlled and prospective trials with adequate sample sizes are completed. The relative low frequency of thromboembolic events, the concerns about maternal and fetal safety of both treatment and withholding treatment, and the reservations about prospectively enrolling pregnant women in treatment trials has sadly dissuaded the appropriate study of this life-threatening condition. North American trials that enroll pregnant women to evaluate the efficacy of LMWH are of preeminent importance owing to their superior bioavailability, ease in dosing, longer half-life, and side effect profile. Similarly, trials evaluating the optimal management of women of childbearing age with valvular disease are critical to reduce the considerable maternal and fetal morbidity and mortality associated with these pregnancies. Such definitive studies will need to be multicenter in design and it is hoped that the National Institutes of Health initiative to enroll pregnant women in clinical trials will at last be realized in the near future.

Failure of adjusted doses of subcutaneous heparin to prevent thromboembolic phenomena in pregnant patients with mechanical cardiac valve prostheses

OBJECTIVES

This report describes our experience with the use of an anticoagulant regimen of adjusted doses of subcutaneous heparin during pregnancy in women with cardiac valve prostheses.

BACKGROUND

Gravid patients with prosthetic heart valves require long-term anticoagulant therapy. To avoid the increased incidence of fetal morbidity and mortality associated with the use of coumarin agents in such patients during pregnancy, anticoagulation with subcutaneous heparin has been suggested. Controversy exists concerning the appropriate treatment of these patients.

METHODS

Forty pregnancies in 37 women with prosthetic heart valves were prospectively followed up. Subcutaneous heparin was administered from the 6th until the end of the 12th week and in the last 2 weeks of gestation. Heparin was given every 8 h in the first 36 cases and every 6 h in the last 4 cases, and the dose adjusted to maintain the activated partial thromboplastin time at 1.5 to 2.5 times the control level. Acenocoumarol was used at other times.

RESULTS

The incidence rate of spontaneous abortions was 37.5%; there was one neonatal death (2.5%) due to cerebral hemorrhage. No signs of coumarin-induced embryopathy were found in any of the 16 live-born infants studied by the geneticist. One mother died of gastrointestinal bleeding while receiving oral anticoagulant agents. There were two cases of fatal massive thrombosis of a mitral tilting-disk prosthesis during heparin therapy. The study was interrupted after the last of these two cases.

CONCLUSIONS

The regimen of adjusted doses of subcutaneous heparin used in this study is not effective to prevent thrombosis of mechanical valve prostheses during pregnancy. The use of heparin from the 6th to the 12th week of gestation does not decrease the high incidence of fetal wastage associated with anticoagulant therapy. Coumarin agents provide adequate protection against thromboembolism during pregnancy in patients with mechanical valve prostheses.