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

Anticoagulant therapy in pregnant women with mechanical and bioprosthetic heart valves

OBJECTIVE

The aim of the present study was to review maternal and fetal outcomes in pregnant women with prosthetic heart valves.

METHODS

A retrospective record review of pregnant women with prosthetic heart valves on anticoagulation was performed at the Specialist Cardiac Antenatal Clinic, Johannesburg South Africa from 2015 to 2023.

RESULTS

Fifty pregnancies with mechanical heart valves and three with tissue valves, on anticoagulation for comorbid atrial fibrillation were identified. The majority were of African ethnicity at a mean age of 33 ± 6 years. Anti-Xa adjusted enoxaparin was commenced at 10.5 ± 5.6 weeks' gestation until delivery in 48 (90.6%) pregnancies and warfarin was continued in five (9.4%) pregnancies. The live birth rates on enoxaparin and warfarin were 56.3% (95% confidence interval [CI]: 42.3-69.3) and 20.0% (95% CI: 2.0-64.0), respectively. There were 12 (22.6%) miscarriages at a mean of 11.3 ± 3.7 weeks' gestation, four (7.5%) intrauterine fetal deaths on warfarin and two (3.8%) warfarin embryopathy/fetopathy. The rates of antepartum/secondary postpartum bleeding and primary postpartum bleeding were 29.4% (95% CI: 18.6-43.1) and 5.9% (95% CI: 1.4-16.9), respectively. Maternal complications included anemia (n = 11, 20.8%), arrhythmia (n = 2, 3.8%), heart failure (n = 2, 3.8%) and paravalvular leak (n = 2, 3.8%). There was one (1.9%) mitral valve thrombosis and one (1.9%) stuck valve in pregnancies who defaulted warfarin prior to pregnancy. There were no maternal deaths.

CONCLUSION

Multidisciplinary management of pregnant women with prosthetic heart valves with anti-Xa adjusted low molecular weight heparin throughout pregnancy represents an effective anticoagulation option for low-middle-income countries.

Pregnant Woman in Outcomes with Prosthetic Heart Valves

We here sought to assess thrombotic and hemorrhagic complications and associated risk factors during pregnancy, delivery, and postpartum in women with prosthetic heart valves (PHV).

METHODS

The retrospective cohort study covered January 2011 to December 2022. The objective of the study was to assess the risk factors and frequency of thrombotic and hemorrhagic complications during pregnancy, delivery, and the postpartum period in women with PHV based on the experience of one perinatal center. We included 88 pregnancies with 77 prosthetic heart valves (PHV), which were divided into two groups, mechanical valve prostheses (MVP) (n = 64) and biological valve prosthesis (BVP) (n = 24). In the study we analyzed pregnancy outcomes, as well as thrombotic and hemorrhagic complication frequencies.

RESULTS

Of 88 pregnancies, 79 resulted in live births. In the MVP group, there were six miscarriages (9.4%) and two medical abortions (3.1%), including one due to Warfarin's teratogenic effects. No miscarriages were reported in the BVP group, but one fetal mortality case (4.2%) occurred. During pregnancy, 11 MVP cases (17.2%) experienced thrombotic complications. In the BVP group, one patient (4.2%) had transient ischemic attack (TIA). Two MVP cases required surgical valve repair during pregnancy, and one in the post-delivery stage was caused by thrombotic complications. Postpartum, two MVP cases had strokes, and in one MVP patient, pulmonary embolism was registered, while no thrombotic complications occurred in the BVP group. Hemorrhagic complications affected 15 MVP cases (17.9%) in the postpartum period. There were no registered cases of maternal mortality.

CONCLUSIONS

The effective control of anti-factor Xa activity reduced thrombotic events. However, the persistently high incidence of postpartum hemorrhagic complications suggests a need to reassess anticoagulant therapy regimens, lower target levels of anti-Xa, and reduce INR levels for discontinuing heparin bridge therapy. Despite the heightened mortality risk in MVP patients, our study cohort did not have any mortality cases, which contrasts with findings from other registries.

Pregnancy outcomes in women with a mitral valve prosthesis: A systematic review and meta-analysis

Objectives

To evaluate the ongoing debate concerning the choice of valve prosthesis for women requiring mitral valve replacement (MVR) and who wish to conceive. Bioprostheses are associated with risk of early structural valve deterioration. Mechanical prostheses require lifelong anticoagulation and carry maternal and fetal risks. Also, the optimal anticoagulation regimen during pregnancy after MVR remains unclear.

Methods

A systematic review and meta-analysis was conducted of studies reporting on pregnancy after MVR. Valve- and anticoagulation-related maternal and fetal risks during pregnancy and 30 days' postpartum were analyzed.

Results

Fifteen studies reporting 722 pregnancies were included. In total, 87.2% of pregnant women had a mechanical prosthesis and 12.5% a bioprosthesis. Maternal mortality risk was 1.33% (95% confidence interval [CI], 0.69-2.56), any hemorrhage risk 6.90% (95% CI, 3.70-12.88). Valve thrombosis risk was 4.71% (95% CI, 3.06-7.26) in patients with mechanical prostheses. 3.23% (95% CI, 1.34-7.75) of the patients with bioprostheses experienced early structural valve deterioration. Of these, the mortality was 40%. Pregnancy loss risk was 29.29% (95% CI, 19.74-43.47) with mechanical prostheses versus 13.50% (95% CI, 4.31-42.30) for bioprostheses. Switching to heparin during the first trimester demonstrated a bleeding risk of 7.78% (95% CI, 3.71-16.31) versus 4.08% (95% CI, 1.17-14.28) for women on oral anticoagulants throughout pregnancy and a valve thrombosis risk of 6.99% (95% CI, 2.08-23.51) versus 2.89% (95% CI, 1.40-5.94). Administration of anticoagulant dosages greater than 5 mg resulted in a risk of fetal adverse events of 74.24% (95% CI, 56.11-98.23) versus 8.85% (95% CI, 2.70-28.99) in ≤5 mg.

Conclusions

A bioprosthesis seems the best option for women of childbearing age who are interested in future pregnancy after MVR. If mechanical valve replacement is preferred, the favorable anticoagulation regimen is continuous low-dose oral anticoagulants. Shared decision-making remains priority when choosing a prosthetic valve for young women.

Maternal and Fetal Outcomes in Pregnant Patients With Mechanical and Bioprosthetic Heart Valves

Background Guidelines for choice of prosthetic heart valve in people of reproductive age are not well established. Although biologic heart valves (BHVs) have risk of deterioration, mechanical heart valves (MHVs) require lifelong anticoagulation. This study aimed to characterize the association of prosthetic valve type with maternal and fetal outcomes in pregnant patients. Methods and Results Using the 2008 to 2019 National Inpatient Sample, we identified all adult patients hospitalized for delivery with prior heart valve implantation. Multivariable regressions were used to analyze the primary outcome, major adverse cardiovascular events, and secondary outcomes, including maternal and fetal complications, length of stay, and costs. Among 39 871 862 birth hospitalizations, 4152 had MHVs and 874 had BHVs. Age, comorbidities, and cesarean birth rates were similar between patients with MHVs and BHVs. The presence of a prosthetic valve was associated with over 22-fold increase in likelihood of major adverse cardiovascular events (MHV: adjusted odds ratio, 22.1 [95% CI, 17.3-28.2]; BHV: adjusted odds ratio, 22.5 [95% CI, 13.9-36.5]) as well as increased duration of stay and hospitalization costs. However, patients with MHVs and BHVs had no significant difference in the odds of any maternal outcome, including major adverse cardiovascular events, hypertensive disease of pregnancy, and ante/postpartum hemorrhage. Similarly, fetal complications were more likely in patients with valve prostheses, including a 4-fold increase in odds of stillbirth, but remained comparable between MHVs and BHVs. Conclusions Patients hospitalized for delivery with prior valve replacement carry substantial risk of adverse maternal and fetal events, regardless of valve type. Our findings reveal comparable outcomes between MHVs and BHVs.

Assessing the cost and utilization of SMS printers by primary health care facilities: lessons learned from South Africa

Background

Historically, paper-based laboratory reports were delivered by couriers to health facilities resulting in post-analytical delays. As a result, short message service (SMS) printers were deployed to fill this gap, with the global data service platform (GDSP) being primarily used to facilitate deployment. In addition, these printers generate binary and quantitative information that can be used to assess utilization.

Objective

The objective of this study was to determine the costs and utilization of the SMS printer program in South Africa.

Methods

A cost analysis for 2020 was undertaken. We determined annual equivalent costs (AEC) for staffing, printers, fixed costs related to the national coordinator, consumables, travel costs, database support/hosting/dashboard development, printer repairs, and results transmission. The main outcome of interest was the cost per SMS printer result delivered. Data were extracted to assess utilization as follows: i) months active (based on internet protocol data); ii) signal; iii) battery strength.

Results

There were 4,450,116 results delivered to printers that were situated at 2232 primary health care facilities. An AEC of $687,727 was reported, with a cost per result delivered of $0.1618. The SMS printers contributed 73.52% to the total AEC. Overall, 90% of the printers were GDSP based, of which only 69.5% were determined to be active. The majority of active printers reported a signal strength of ≥60% and a battery strength of ≥6 volts.

Conclusion

Although the SMS printer program has the potential to reduce post-analytical delays, pathology services should migrate to an end-to-end electronic interface to improve patient care.

Outcomes in Pregnant Women with Valvular Heart Disease from Portuguese-Speaking African Countries Treated in Portugal through an International Agreement of Health Cooperation

Aims

We performed a clinical audit of maternal and fetal outcomes in pregnant women with valvular heart disease (VHD) from Portuguese-speaking African countries who were transferred for their care, during a twenty-year period, through a memorandum of agreement of international cooperation.

Methods and results

A retrospective analysis of 81 pregnancies in 45 patients with VHD (median age 24, interquartile range 22-29 years) from 2000 to 2020 was performed. The main outcome measures were maternal cardiovascular and fetal outcomes. History of rheumatic heart disease was present in 60 (74.1%) pregnancies. Most were in New York Heart Association (NYHA) functional class I or II; at the first evaluation, 35 (43.2%) were on cardiac medication and 49 (60.5%) were anticoagulated. Forty-eight pregnancies had at least one valvular prosthesis, including 38 mechanical heart valves. During pregnancy, deterioration in NYHA functional class occurred in 35 (42.0%), and eight (9.9%) patients required initiation or intensified cardiac medication. Mechanical valve thrombosis complicated four (4.9%) pregnancies, all cases on heparin, and resulted in one maternal death. Haemorrhagic complications happened in 7 (8.6%) anticoagulated patients, in the immediate postpartum or puerperal period. The 81 pregnancies resulted in 56 (69.1%) live births, while miscarriage and fetal malformations occurred in 19 (23.5%) and 12 (14.8%) pregnancies, respectively. In multivariate analysis, vitamin K antagonist therapy was the only independent predictor of an unsuccessful pregnancy (p = 0.048).

Conclusion

In a high-income country, successful pregnancy was possible with low rate of maternal events in women with VHD transferred from five low-middle income countries in Africa. The use of anticoagulation with a vitamin K antagonist was associated with an unsuccessful pregnancy.

Anticoagulation for mechanical heart valves during pregnancy: A case report and a literature review

RATIONALE

Most previous treatment guidelines for pregnant women with mechanical heart valves recommend that low molecular weight heparin (LMWH) should be applied once every 12 hours and only as required to reach peak anti-Xa levels of approximately 1.0 to 1.2 IU/mL, but it is commonly associated with subtherapeutic trough levels, consequently with an inadequate level of anticoagulation. Our case report here together with a literature review suggests that dose-adjusted (Target trough anti-Xa levels of 0.6 to 0.7 IU/mL and with peak anti-Xa levels of around 1.0 to 1.2 IU/mL or < 1.5 IU/mL) LMWH should be given thrice daily throughout pregnancy. In addition, the findings of this rare case indicate that a combination of LMWH and warfarin is effective in the treatment of small thromboses in pregnancy.

PATIENT CONCERNS

In the 1st trimester of pregnancy, a 28-year old pregnant female with a mechanical valve had a significant increase in the aortic valve flow rate and suspected mechanical valve thrombosis.

DIAGNOSES

The peak velocity of the pregnant female aortic mechanical valve increased, and mechanical valve thrombosis was suspected.

INTERVENTIONS

We adjusted the enoxaparin sodium dose every 12 hours to 1 injection every 8 hours, with a total daily dose of 160 mL. Based on the original application of LMWH, warfarin (3 mg/day) was recommended.

OUTCOMES

The pregnant woman delivered a live baby by cesarean section, and the peak flow velocity of the mechanical valve in the aortic position was reduced to nearly equivalent to the patient's pre-pregnancy status. The mother and the baby were in good health at the time of discharge.

LESSONS

LMWH is administered twice daily, and anti-Xa trough levels are mostly in a subtherapeutic state, which may lead to insufficient anticoagulation and thrombosis. Dose-adjusted LMWH thrice daily throughout pregnancy is the recommended treatment for pregnant women with mechanical heart valves. The combination of LMWH and warfarin exhibited good efficacy for the treatment of small thromboses.

Mechanical Heart Valves, Pregnancy, and Bleeding: A Systematic Review and Meta-Analysis

Anticoagulant therapy is essential in pregnant women with mechanical heart valves to prevent valve thrombosis. The risk of bleeding complications in these patients has not gained much attention. This systematic review and meta-analysis investigate the prevalence of bleeding peri-partum and post-partum in women with mechanical heart valves and also investigate whether bleeding risk differed across anticoagulant regimens or according to delivery mode. The present study was conducted according to The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Studies reporting bleeding prevalence in pregnant women with mechanical heart valves receiving anticoagulant therapy were identified through PubMed and Embase on December 08, 2021. Data on bleeding complications, delivery mode, and anticoagulation therapy were extracted. A total of 37 studies were included, reporting 423 bleeding complications in 2,508 pregnancies. A meta-analysis calculated a pooled prevalence of 0.13 (95% confidence interval [CI]: 0.09-0.18) bleeding episodes per pregnancy across anticoagulant regimens. The combination of unfractionated heparin (UFH) and vitamin K antagonist (VKA) and single VKA therapy showed the lowest risk of bleeding (8 and 12%). Unexpectedly, the highest risk of bleeding was found in women receiving a combination of low-molecular-weight-heparin (LMWH) and VKA (33%) or mono-therapy with LMWH (22%). However, this could be dose related. No difference in bleeding was found between caesarean section versus vaginal delivery (p = 0.08). In conclusion, bleeding episodes are common during pregnancy in women with mechanical heart valves receiving anticoagulant therapy. A combination of UFH and VKA or VKA monotherapy showed the lowest risk of bleeding.

Continued use of Warfarin in lower dose has safe maternal and neonatal outcomes in pregnant women with Prosthetic Heart Valves

Background and Objective:

There has been concerns regarding the safety of Warfarin in pregnant females due to its teratogenic potential. At the same time warfarin provides best anticoagulation in patients with prosthetic valves. Various dosage regimes have been tried to strike a balance between safety of mother and the avoidance of congenital anomalies in the newborn. This study was conducted to observe the effect of Warfarin in pregnant mothers taking different doses of warfarin, and their neonatal outcome, in our outdoor patients.

Methods:

This is a cross sectional observational study conducted at the Faisalabad Institute of Cardiology. The pregnant mothers taking warfarin for prosthetic valve replacement who presented to our specialized clinic between November 2016 to April 2017 were included in the study. These included a total of 75 females between the age of 20-35 years. To compare the dose related effect of warfarin, two groups of the patients were formed. One group comprised of patients taking warfarin ≤5mg while the other group consisted of those who were taking >5mg of warfarin daily. These patients were followed till their delivery. The information was collected about the maternal and fetal outcomes. The maternal outcomes including mode of delivery/miscarriage, peripartum bleeding and any valve related thromboembolic complications. The fetal outcomes included birth weight, maturity, embryopathy and congenital anomaly in the baby.

Results:

Patient’s mean age was 29.25±3.75 years. The mitral valve replacement was present in 60% patients (n=45) while 25.3% patients (n=19) had aortic valve replacement and 14.7% patients (n=11) had double valve replacement. In this group 30 patients (40%) had taken <5 mg warfarin and 45 patients (60%) had received >5 mg warfarin medicine. Miscarriages, cesarean sections, low birth weight and prematurity were more common in patients receiving warfarin >5 mg with p-values 0.005, 0.046, 0.01 and 0.033 respectively. No case of fetal embryopathy was found in both groups.

Conclusion:

No case of embryopathy was found in each group which signifies that warfarin in lower doses is safe anticoagulant in patients with prosthetic valve replacements.

Anticoagulation in sub-Saharan Africa: Are direct oral anticoagulants the answer? A review of lessons learnt from warfarin

Warfarin has existed for >7 decades and has been the anticoagulant of choice for many thromboembolic disorders. The recent introduction of direct-acting oral anticoagulants (DOACs) has, however, caused a shift in preference by healthcare professionals all over the world. DOACs have been found to be at least as effective as warfarin in prevention of stroke in patients with atrial fibrillation and in treatment of venous thromboembolism. In sub-Saharan Africa, however, the widespread use of DOACs has been hampered mainly by their higher acquisition costs. As the drugs come off patent, their use in sub-Saharan Africa is likely to increase. However, very few trials have been conducted in African settings, and safety concerns will need to be addressed with further study before widespread adoption into clinical practice.

A review of the epidemiology of atrial fibrillation in sub-Saharan Africa

This systematic review summarizes the data on the prevalence, risk factors, complications, and management of atrial fibrillation (AF) in sub-Saharan Africa (SSA). Bibliographic databases were searched from inception to 31 May 2019, to identify all published studies providing data on AF in populations living in SSA. A total of 72 studies were included. The community-based prevalence of AF was 4.3% and 0.7% in individuals aged ≥40 years and aged ≥70 years, respectively. The prevalence of AF ranged between 6.7% and 34.8% in patients with ischemic stroke, between 9.5% and 46.8% in those with rheumatic heart disease (RHD), between 5% and 31.5% in patients with dilated cardiomyopathy. The main risk factors for AF were hypertension, affecting at least one-third of patients with AF, and valvular heart disease (12.3%-44.4%) and cardiomyopathy (~20%). Complications of AF included heart failure in about two thirds and stroke in 10% to 15% of cases. The use of anticoagulation for stroke prevention was suboptimal. Rate control was the most frequent therapeutic strategy, used in approximately 65% to 95% of AF patients, with approximately 80% of them achieving rate control. The management of AF was associated with exorbitant cost. In conclusion, AF seems to have a higher prevalence in the general population than previously thought and is mostly associated with hypertension, cardiomyopathy, and RHD in SSA. It is associated with a high incidence of heart failure and stroke. The management of AF is suboptimal in SSA, especially with a low uptake of oral anticoagulation.

High-Versus Low-Dose Warfarin-Related Teratogenicity: A Case Report and Systematic Review

OBJECTIVE

The optimal anticoagulant therapy during pregnancy in women with mechanical heart valves remains controversial. This study highlights a case of high-dose warfarin ingestion throughout pregnancy and performed a systematic review to assess rates of teratogenicity with high versus low warfarin dosing (≤5 mg daily).

METHODS

A literature search for all case reports and available literature was conducted in PubMed, Medline, and EMBASE up to December 2016 using medical subject heading terms "mechanical prosthetic valves," "pregnancy," "oral anticoagulants," "warfarin," "coumarins," "heparin, low-molecular-weight," and "thromboembolism." To be included, warfarin had to be administered anytime between 6 and 12 weeks of gestation with the dose being specified. The Newcastle-Ottawa Scale was used to assess quality of the cohort data.

RESULTS

The woman in the studied case received the highest reported warfarin doses throughout pregnancy (14.5-16.5 mg daily) and delivered a baby with no evidence of teratogenicity to the current age of 5 years. The study identified 23 case reports, with all demonstrating warfarin teratogenicity regardless of high-dose (n = 12) or low-dose (n = 11) warfarin. Twelve cohort studies identified a warfarin teratogenicity rate of 5.0%, with rates of 2.4% and 10.5% with low- and high-dose warfarin, respectively. Risk of bias was moderate (median Newcastle-Ottawa Scale score of 6) for all of the cohort studies.

CONCLUSION

Although a lower prevalence of warfarin-induced teratogenicity is reported with low-dose warfarin, a safe "cut-off" dose is misleading. Teratogenic risk with warfarin is unpredictable, mandating individual decisions regardless of the dose.

Impact of prosthetic heart valves on pregnancy in Bangladeshi women

Background:

This study evaluated pregnancy outcome in women with a prosthetic heart valve, especially with the oral anticoagulation therapy that must be weighed against the risk of intracardiac thrombosis.

Methods:

This multicenter, retrospective, cohort study was undertaken between January 2012 and June 2017. The principal maternal outcome variables included bleeding and thromboembolic complications, infective endocarditis, prosthetic valve thrombosis and heart failure. However, the main foetal outcome variables included miscarriage, mortality, preterm baby, warfarin embryopathy, low birthweight and the mode of delivery.

Results:

A total of 265 pregnancies in women with prosthetic heart valves were evaluated in two groups: Group I (n = 182) covers a mechanical valve, while Group II (n = 82) covers a bioprosthetic valve. The mean age of the patients was 25.2 ± 2.5 years and 24.5 ± 5.2 years in Group I and Group II, respectively. Approximately 80% of the patients had normal echocardiography findings. However, Group I (mechanical prostheses) has a higher incidence (11.54%) of thrombus formation in comparison with the bioprostheses. Hemorrhagic complications and spontaneous miscarriage were statistically significant (p⩽0.05) between the study groups. However, normal pregnancy outcome (91.57%) was significantly higher (p⩽0.05) in Group II compared to Group I (61.54%). Mean birthweight and mean APGAR score were found normal in both study groups. Only 2.75% of patients have warfarin embryopathy in Group I. Furthermore, comparison of SF-36 scores for HRQOL (Health-Related Quality of Life) before and after pregnancy were statistically insignificant among the study population.

Conclusion:

Proper antenatal care and early risk stratification are the fundamental measures to improve the maternal and foetal outcomes in a patient with a prosthetic heart valve.

Impact of prosthetic heart valves on pregnancy in Bangladeshi women

Background:

This study evaluated pregnancy outcome in women with a prosthetic heart valve, especially with the oral anticoagulation therapy that must be weighed against the risk of intracardiac thrombosis.

Methods:

This multicenter, retrospective, cohort study was undertaken between January 2012 and June 2017. The principal maternal outcome variables included bleeding and thromboembolic complications, infective endocarditis, prosthetic valve thrombosis and heart failure. However, the main foetal outcome variables included miscarriage, mortality, preterm baby, warfarin embryopathy, low birthweight and the mode of delivery.

Results:

A total of 265 pregnancies in women with prosthetic heart valves were evaluated in two groups: Group I (n = 182) covers a mechanical valve, while Group II (n = 82) covers a bioprosthetic valve. The mean age of the patients was 25.2 ± 2.5 years and 24.5 ± 5.2 years in Group I and Group II, respectively. Approximately 80% of the patients had normal echocardiography findings. However, Group I (mechanical prostheses) has a higher incidence (11.54%) of thrombus formation in comparison with the bioprostheses. Hemorrhagic complications and spontaneous miscarriage were statistically significant (p⩽0.05) between the study groups. However, normal pregnancy outcome (91.57%) was significantly higher (p⩽0.05) in Group II compared to Group I (61.54%). Mean birthweight and mean APGAR score were found normal in both study groups. Only 2.75% of patients have warfarin embryopathy in Group I. Furthermore, comparison of SF-36 scores for HRQOL (Health-Related Quality of Life) before and after pregnancy were statistically insignificant among the study population.

Conclusion:

Proper antenatal care and early risk stratification are the fundamental measures to improve the maternal and foetal outcomes in a patient with a prosthetic heart valve.

Low-dose warfarin maternal anticoagulation and fetal warfarin syndrome

Fetuses exposed to warfarin during pregnancy are at an increased risk of developing an embryopathy known as fetal warfarin syndrome or warfarin embryopathy. The most consistent anomalies are nasal hypoplasia and stippling of vertebrae or bony epiphyses. Management of pregnant patients on anticoagulation is challenging. Current guidelines suggest the use of warfarin if the therapeutic dose is ≤5 mg/day. We report the case of a newborn with signs of warfarin embryopathy born from a mother anticoagulated with warfarin due to mechanical mitral and aortic heart valves. Warfarin was required at the dose of 5 mg/day and was withheld without medical advice between weeks 8 and 10 with no other anticoagulation. The newborn presented with skeletal abnormalities and a ventricular septal defect that have not required specific treatment during the first year of life. Low-dose warfarin is associated with a lower risk of warfarin-related fetopathy but the risk of embryopathy seems unchanged.

Anticoagulation for the Pregnant Patient with a Mechanical Heart Valve, No Perfect Therapy: Review of Guidelines for Anticoagulation in the Pregnant Patient

Heart valve replacement with a mechanical valve requires lifelong anticoagulation. Guidelines currently recommend using a vitamin K antagonist (VKA) such as warfarin. Given the teratogenic effects of VKAs, it is often favorable to switch to heparin-derived therapies in pregnant patients since they do not cross the placenta. However, these therapies are known to be less effective anticoagulants subjecting the pregnant patient to a higher chance of a thrombotic event. Guidelines currently recommend pregnant women requiring more than 5 mg a day of warfarin be switched to alternative therapy during the first trimester. This case report highlights a patient who was switched to alternative therapy during her first pregnancy and suffered a devastating cerebrovascular accident (CVA). Further complicating her situation was during a subsequent pregnancy; this patient continued warfarin use during the first trimester and experienced multiple transient ischemic attacks (TIAs). This case highlights the increased risk of thrombotic events in pregnant patients with mechanical valves. It also highlights the difficulty of providing appropriate anticoagulation for the pregnant patient who has experienced thrombotic events on multiple anticoagulants.

Valvular heart disease in pregnancy

Valvular heart disease may be a pre-existing complication of pregnancy or it may be diagnosed for the first time during pregnancy. Accurate diagnosis, tailored therapy and an understanding of the physiology and pathophysiology of pregnancy are necessary components of management, best achieved through the use of multidisciplinary clinics. This review outlines the management of specific lesions, with particular reference to post-rheumatic valvular heart disease.

Maternal and Fetal Outcomes in Pregnant Women with a Prosthetic Mechanical Heart Valve

BACKGROUND

Pregnancy is associated with several cardiocirculatory changes that can significantly impact underlying cardiac disease. These changes include an increase in cardiac output, sodium, and water retention leading to blood volume expansion, and reductions in systemic vascular resistance and systemic blood pressure. In addition, pregnancy results in a hypercoagulable state that increases the risk of thromboembolic complications.

OBJECTIVES

The aim of this study is to assess the maternal and fetal outcomes of pregnant women with mechanical prosthetic heart valves (PHVs).

METHODS

This is a prospective observational study that included 100 pregnant patients with cardiac mechanical valve prostheses on anticoagulant therapy. The main maternal outcomes included thromboembolic or hemorrhagic complications, prosthetic valve thrombosis, and acute decompensated heart failure. Fetal outcomes included miscarriage, fetal death, live birth, small-for-gestational age, and warfarin embryopathy. The relationship between the following were observed:

– Maternal and fetal complications and the site of the replaced valve (mitral, aortic, or double)

– Maternal and fetal complications and warfarin dosage (≤5 mg, >5 mg)

– Maternal and fetal complications and the type of anticoagulation administered during the first trimester

RESULTS

This study included 60 patients (60%) with mitral valve replacement (MVR), 22 patients (22%) with aortic valve replacement (AVR), and 18 patients (18%) with double valve replacement (DVR). A total of 65 patients (65%) received >5 mg of oral anticoagulant (warfarin), 33 patients (33%) received ≤5 mg of warfarin, and 2 patients (2%) received low-molecular-weight heparin (LMWH; enoxaparin sodium) throughout the pregnancy. A total of 17 patients (17%) received oral anticoagulant (warfarin) during the first trimester: 9 patients received a daily warfarin dose of >5 mg while the remaining 8 patients received a daily dose of ≤5 mg. Twenty-eight patients (28%) received subcutaneous (SC) heparin calcium and 53 patients (53%) received SC LMWH (enoxaparin sodium). Prosthetic valve thrombosis occurred more frequently in patients with MVR (P = 0.008). Postpartum hemorrhage was more common in patients with aortic valve prostheses than in patients with mitral valve prostheses (P = 0.005). The incidence of perinatal death was higher in patients with AVR (P = 0.014). The incidence of live birth was higher in patients with DVR (P = 0.012). The incidence of postpartum hemorrhage was higher in patients who received a daily dose of >5 mg of warfarin than in patients who received ≤5 mg of warfarin (P = 0.05). The incidence of spontaneous abortion was also higher in patients receiving >5 mg of warfarin (P ≤ 0.001), while the incidence of live births was higher in patients receiving ≤5 mg of warfarin (P = 0.008). There was a statistically significant difference between the anticoagulant received during the first trimester and cardiac outcomes. Specifically, patients on heparin developed more heart failure (P = 0.008), arrhythmias (P = 0.008), and endocarditis (P = 0.016). There was a statistically significant relationship between heparin shifts during the first trimester and spontaneous abortion (P = 0.003).

CONCLUSION

Warfarin use during the first trimester is safer for the mother but is associated with more fetal loss, especially in doses that exceed 5 mg. The incidence of maternal complications is greater in women who receive LMWH or unfractionated heparin during the first trimester, especially prosthetic valve thrombosis, although the fetal outcome is better because heparin does not cross the placenta.

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.

Low-dose maternal warfarin intake resulting in fetal warfarin syndrome: In search for a safe anticoagulant regimen during pregnancy

BACKGROUND

Fetal exposure to maternal ingestion of warfarin is known to produce certain dysmorphic features in the neonate, known as fetal warfarin syndrome (FWS). There is a general consensus that maternal intake of warfarin at a daily dose of 5 mg or less is safe both for the infant and the mother.

METHODS

We report four cases of FWS born to mothers with rheumatic heart disease on warfarin prophylaxis during pregnancy at a dose less than 5 mg/day.

RESULTS

Along with typical facial features of FWS and multiple epiphyseal stippling in skeletal x-ray, Case 1 had Dandy-Walker malformation and Case 2 had laryngo-tracheomalacia and patent ductus arteriosus.

CONCLUSION

We emphasize the need for optimizing the choice and dosage schedule of anticoagulants during pregnancy, least harmful for the mother and her developing fetus.

Prosthetic heart valves in pregnancy, outcomes for women and their babies: a systematic review and meta-analysis

BACKGROUND

Historically, pregnancies among women with prosthetic heart valves have been associated with an increased incidence of adverse outcomes.

OBJECTIVES

Systematic review to assess risk of adverse pregnancy outcomes among women with a prosthetic heart valve(s) over the last 20 years.

SEARCH STRATEGY

Electronic literature search of Medline, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature and Embase to find recent studies.

SELECTION CRITERIA

Studies of pregnant women with heart valve prostheses including trials, cohort studies and unselected case series.

DATA COLLECTION AND ANALYSIS

Primary analysis calculated absolute risks and 95% confidence intervals (CI) for pregnancy outcomes using a random effects model. The Freeman-Tukey transformation was utilised in secondary analysis due to the large number of individual study outcomes with zero events.

MAIN RESULTS

Eleven studies capturing 499 pregnancies among women with heart valve prostheses, including 256 mechanical and 59 bioprosthetic, were eligible for inclusion. Pooled estimate of maternal mortality was 1.2/100 pregnancies (95% CI 0.5-2.2), for mechanical valves subgroup 1.8/100 (95% CI 0.5-3.7) and bioprosthetic subgroup 0.7/100 (95% CI 0.1-4.5), overall pregnancy loss 20.8/100 pregnancies (95% CI 9.5-35.1), perinatal mortality 5.0/100 births (95%CI 1.8-9.8) and thromboembolism 9.3/100 pregnancies (95% CI 4.0-16.5).

CONCLUSIONS

Women with heart valve prostheses experienced higher rates of adverse outcomes than expected in a general obstetric population; however, lower than previously reported. Women with bioprostheses had significantly fewer thromboembolic events compared to women with mechanical valves. Women should be counselled pre-pregnancy about risk of maternal death and pregnancy loss. Vigilant surveillance by a multidisciplinary team throughout the perinatal period remains warranted for these women and their infants.

TWEETABLE ABSTRACT

Metaanalysis suggests improvement in #pregnancy outcomes among women with #heartvalveprostheses.

Pregnancy in Women With a Mechanical Heart Valve: Data of the European Society of Cardiology Registry of Pregnancy and Cardiac Disease (ROPAC)

BACKGROUND

Pregnant women with a mechanical heart valve (MHV) are at a heightened risk of a thrombotic event, and their absolute need for adequate anticoagulation puts them at considerable risk of bleeding and, with some anticoagulants, fetotoxicity.

METHODS AND RESULTS

Within the prospective, observational, contemporary, worldwide Registry of Pregnancy and Cardiac disease (ROPAC), we describe the pregnancy outcome of 212 patients with an MHV. We compare them with 134 patients with a tissue heart valve and 2620 other patients without a prosthetic valve. Maternal mortality occurred in 1.4% of the patients with an MHV, in 1.5% of patients with a tissue heart valve (P=1.000), and in 0.2% of patients without a prosthetic valve (P=0.025). Mechanical valve thrombosis complicated pregnancy in 10 patients with an MHV (4.7%). In 5 of these patients, the valve thrombosis occurred in the first trimester, and all 5 patients had been switched to some form of heparin. Hemorrhagic events occurred in 23.1% of patients with an MHV, in 5.1% of patients with a tissue heart valve (P<0.001), and in 4.9% of patients without a prosthetic valve (P<0.001). Only 58% of the patients with an MHV had a pregnancy free of serious adverse events compared with 79% of patients with a tissue heart valve (P<0.001) and 78% of patients without a prosthetic valve (P<0.001). Vitamin K antagonist use in the first trimester compared with heparin was associated with a higher rate of miscarriage (28.6% versus 9.2%; P<0.001) and late fetal death (7.1% versus 0.7%; P=0.016).

CONCLUSIONS

Women with an MHV have only a 58% chance of experiencing an uncomplicated pregnancy with a live birth. The markedly increased mortality and morbidity warrant extensive prepregnancy counseling and centralization of care.

Importance of a multidisciplinary approach and monitoring in fetal warfarin syndrome

Warfarin is a synthetic oral anticoagulant that crosses the placenta and can lead to a number of congenital abnormalities known as fetal warfarin syndrome. Our aim is to report on the follow-up from birth to age 8 years of a patient with fetal warfarin syndrome. He presented significant respiratory dysfunction, as well as dental and speech and language complications. The patient was the second child of a mother who took warfarin during pregnancy due to a metallic heart valve. The patient had respiratory dysfunction at birth. On physical examination, he had a hypoplastic nose, pectus excavatum, and clubbing of the fingers. Nasal fibrobronchoscopy showed upper airway obstruction due to narrowing of the nasal cavities. He underwent surgical correction with Max Pereira graft, zetaplasty, and osteotomies for the piriform aperture. At dental evaluation, he had caries and delayed eruption of the upper incisors. Speech and language assessment revealed high palate, mouth breathing, little nasal patency, and shortened upper lip. Auditory long latency and cognitive-related potential to auditory stimuli demonstrated functional changes in the cortical auditory pathways. We believe that the frequency of certain findings observed in our patient may be higher in fetal warfarin syndrome than is appreciated, since a significant number result in abortions, stillbirths, or children evaluated in the first year of life without a follow-up. Thus, a multidisciplinary approach and long-term monitoring of these patients may be necessary.

Pregnancy and postpartum infective endocarditis: a systematic review

The objective of this review was to describe the clinical characteristics, risk factors, and outcomes of infective endocarditis (IE) in pregnancy and the postpartum period. We conducted a systematic review of Ovid MEDLINE, Ovid Embase, Web of Science, and Scopus from January 1, 1988, through October 31, 2012. Included studies reported on women who met the modified Duke criteria for the diagnosis of IE and were pregnant or postpartum. We included 72 studies that described 90 cases of peripartum IE, mostly affecting native valves (92%). Risk factors associated with IE included intravenous drug use (14%), congenital heart disease (12%), and rheumatic heart disease (12%). The most common pathogens were streptococcal (43%) and staphylococcal (26%) species. Septic pulmonary, central, and other systemic emboli were common complications. Of the 51 pregnancies, there were 41 (80%) deliveries with survival to discharge, 7 (14%) fetal deaths, 1 (2%) medical termination of pregnancy, and 2 (4%) with unknown status. Maternal mortality was 11%. Infective endocarditis is a rare, life-threatening infection in pregnancy. Risk factors are changing with a marked decrease in rheumatic heart disease and an increase in intravenous drug use. The cases reported in the literature were commonly due to streptococcal organisms, involved the right-sided valves, and were associated with intravenous drug use.

Heart valve prostheses in pregnancy: outcomes for women and their infants

BACKGROUND

As the prognosis of women with prosthetic heart valves improves, an increasing number are contemplating and undertaking pregnancy. Accurate knowledge of perinatal outcomes is essential, assisting counseling and guiding care. The aims of this study were to assess outcomes in a contemporary population of women with heart valve prostheses undertaking pregnancy and to compare outcomes for women with mechanical and bioprosthetic prostheses.

METHODS AND RESULTS

Longitudinally linked population health data sets containing birth and hospital admissions data were obtained for all women giving birth in New South Wales, Australia, 2000-2011. This included information identifying presence of maternal prosthetic heart valve. Cardiovascular and birth outcomes were evaluated. Among 1 144 156 pregnancies, 136 involved women with a heart valve prosthesis (1 per 10 000). No maternal mortality was seen among these women, although the relative risk for an adverse event was higher than the general population, including severe maternal morbidity (139 versus 14 per 1000 births, rate ratio [RR]=9.96, 95% CI 6.32 to 15.7), major maternal cardiovascular event (44 versus 1 per 1000, RR 34.6, 95% CI 14.6 to 81.6), preterm birth (183 versus 66 per 1000, RR=2.77, 95% CI 1.88 to 4.07), and small-for-gestational-age infants (193 versus 95 per 1000, RR=2.03, 95% CI 1.40 to 2.96). There was a trend toward increased maternal and perinatal morbidity in women with a mechanical valve compared with those with a bioprosthetic valve.

CONCLUSIONS

Pregnancies in women with a prosthetic heart valve demonstrate an increased risk of an adverse outcome, for both mothers and infants, compared with pregnancies in the absence of heart valve prostheses. In this contemporary population, the risk was lower than previously reported.

Thromboembolism in pregnancy: challenges and controversies in the prevention of pregnancy-associated venous thromboembolism and management of anticoagulation in women with mechanical prosthetic heart valves

Thromboembolism in pregnancy is an important clinical issue. Despite identification of maternal and pregnancy-specific risk factors for development of pregnancy-associated venous thromboembolism, limited data are available to inform on optimal approaches for prevention. The relatively low overall prevalence of pregnancy-associated venous thromboembolism has prompted debate about the validity of recommendations, which are mainly based on expert opinion, and have resulted in an increased use of pharmacological thromboprophylaxis in pregnancy and postpartum. A pragmatic approach is required in the absence of more robust data. Anticoagulation management of pregnant women with mechanical prosthetic heart valves is particularly challenging. Continuation of therapeutic anticoagulation during pregnancy is essential to prevent valve thrombosis. Warfarin, the most effective anticoagulant, is associated with adverse fetal outcomes, including embryopathy and stillbirth. Fetal outcome is improved with therapeutic-dose low-molecular-weight heparin, but there may be more thromboembolic complications. More intensive anticoagulation, targeting higher trough anti-Xa levels, may reduce the risk of valve thrombosis.

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.