Cardiac valve prostheses, anticoagulation, and pregnancy

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.

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).

Neurological sequelae of intrauterine warfarin exposure

Warfarin embryopathy is a well-defined manifestation of intrauterine warfarin exposure. The embryopathy phenotype as it relates to the nervous system is broad and poorly recognised. We describe an adult with neurological sequelae of fetal warfarin exposure. We review previous cases with neurological sequelae and discuss the pathogenetic mechanism in light of recent research.

Anticoagulation therapy during pregnancy of patients with artificial heart valves: fetomaternal outcome

OBJECTIVES

The major problem is the need for anticoagulant therapy in patient with mechanical heart valves.

STUDY DESIGN

The aim of the study was to analyze the course and outcome of pregnancies of patients with artificial mechanical heart valves with anticoagulant therapy. Study included 43 pregnancies leaded and terminated at the Institute of Gynecology and Obstetrics Clinical Center of Serbia in 20 years. We divided the patients in two groups depending on the type of anticoagulation therapy. Group I included 21 patients who were under Ethylbiscumacetate (Pelenthan) during the first 36 weeks of gestation, and intravenous Heparin in the last 4 weeks and after the delivery. Group II included 22 patients who received oral anticoagulant therapy all the time.

RESULTS

Worsening of the heart functional status happened in 6 patients (13.9%). The incidence of heart failure during the pregnancy was 13.9% and after the delivery 9.3%. The incidence of hemorrhagic complications was 11.6% during pregnancy and 14% after the delivery. Four patients had thromboembolic events before the pregnancy. The incidence of postpartal thromboembolic complications was 6.9% in group I. Two patients died due to the heart failure 3-7 days after the vaginal delivery. Maternal mortality was 4.6%. One neonatus died of hydrocephalus (2.5%) in group II. In our study there were no fetuses with congenital heart disease.

CONCLUSIONS

Pregnancies of patients with mechanical heart valves should be planned. We suggest ethylbiscumacetate in combination with Heparin as anticoagulation therapy during the pregnancy.

Anticoagulation in patients with mechanical valves during pregnancy

Mechanical valve thrombosis is a life-threatening event, while pregnancy is associated with a hypercoagulable state. Thus, in pregnant women with mechanical valves, adequate anticoagulation becomes even more critical. This prospective study was conducted to establish a uniform anticoagulation regimen for these women. A total of 250 pregnancies in 245 women with mechanical heart valves were evaluated. The patients were divided into 2 groups: group 1 (n = 150) took oral warfarin throughout pregnancy and group 2 (n = 100) received subcutaneous heparin in the 1(st) trimester and oral warfarin for the other trimesters. Both groups received heparin at the time of delivery. There were no coumarin-induced fetal malformations. Minor thromboembolic episodes took place in 5 women in group 1 and 3 in group 2. Valve thrombosis occurred in 1 woman in group 2 and led to 1 maternal death in this series. The incidence of spontaneous abortion was similar between the groups. We conclude that warfarin is safe and convenient to use during pregnancy. The teratogenic effects of warfarin during the 1(st) trimester are overstated, and switching to heparin is not mandatory.

Effect of oral anticoagulant during pregnancy with prosthetic heart valve

This retrospective study aimed to evaluate the risks and outcome of oral anticoagulant use during pregnancy in women with prosthetic heart valves. Between December 1989 and November 1998, 192 females of childbearing age underwent heart valve replacement with a mechanical prosthesis. There were 37 pregnancies in 30 patients during follow-up. Pregnancy was terminated on medical grounds in 5 cases, there were 2 (6%) spontaneous abortions, and 1 (3%) premature birth of a normal baby who died 24 hours later due to asphyxia. The other 29 pregnancies (91%) went to full term and the mothers continued taking oral anticoagulants until a week before the expected date of delivery, then switched to heparin. There was no thromboembolism, valve thrombosis, or maternal mortality. Three babies (10%) had a skeletal deformity: nasal hypoplasia in all 3, with cleft pinna in 1. Continuation of oral anticoagulants during pregnancy provided adequate protection against thromboembolism and valve thrombosis, but the risks of fetal abnormalities and premature delivery should be explained to women of childbearing age with a mechanical valve prosthesis.

Pregnancy and mechanical heart valves replacement; dilemma of anticoagulation

OBJECTIVES

To establish a uniform anticoagulation regimen for pregnant patients with mechanical heart valves taking into account the socio-economic background and to evaluate the incidence of anticoagulant related complications.

METHODS

A retrospective study on 63 pregnancies in 21 women with mechanical heart valves was evaluated. These pregnancies were divided into two groups: Group I (n=42) received oral anticoagulants throughout pregnancy and Group II (n=21) received subcutaneous heparin in the 1st trimester and oral anticoagulants for the rest of pregnancy period. Both groups received heparin at time of delivery.

RESULTS

There was no case of coumarin embryopathy seen and there was no maternal death. Life threatening valve thrombosis occurred in two patients who were both from Group II and needed emergency re-replacement. Group I had a higher incidence of spontaneous abortion than Group II although this was not statistically significant.

CONCLUSIONS

The role of coumarin embryopathy has been overstated. We recommend the use of oral anticoagulants throughout pregnancy especially in countries with similar socio-economic background.

Feto-maternal morbidity and mortality after cardiac valve replacement

BACKGROUND

The aim of this study is to evaluate the fetomaternal morbidity and mortality of the pregnancies of women who conceived after cardiac valve replacement.

METHODS

A consecutive series of one hundred and thirty-six pregnancies of one hundred and one patients who conceived after cardiac valve replacement were retrospectively analyzed. Regarding the anticoagulation therapy, 101 patients were classified into three groups: A: patients on oral anticoagulants (n=68), B: patients on heparin (n=16) and C: patients who received no anticoagulation (n=17).

RESULTS

Three groups (patients on oral anticoagulants (A), on heparin (B), patients who received no anticoagulation (C)) were compared in terms of spontaneous abortion (19%, 11%, 5.6%), preterm delivery (14%, 22.3%, 16.6%), maternal mortality (3%, 11.1%, 0%), thromboembolic events (4%, 11.1%, 0%), cardiac failure (6%, 11.1%, 11.1%), atrial fibrillation (9%, 11.1%, 5.6%), antenatal bleeding (9%, 11.1%, 5.6%), delivery route and fetal malformation (5%, 0%, 0%) and no statistically significant differences were detected. In group B, hematoma formation rate (22.2%) (p=0.011) and transfusion rate (27.8%) (p=0.005) were significantly higher. Five cases of congenital anomalies were detected, all belonging to group A, but this tendency was not found to be statistically significant.

CONCLUSIONS

Management of pregnancies with prosthetic heart valves require closely monitored anticoagulation, and an obstetrician should be familiar with the potential fetal and maternal adverse effects of any anticoagulant therapy during the course of pregnancy.

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.

Pregnancy with St. Jude Medical Mitral Valve Prosthesis

From 1986 to 1995, 513 young women of childbearing age (11 to 45 years) underwent mitral valve replacement with a bileaflet St. Jude Medical prosthesis. Twenty-one patients became pregnant within 3 years postoperatively. The mean age of these patients at the onset of pregnancy was 27 ± 8 years (range, 16 to 43 years). Follow-up was complete for all pregnant patients. Of 11 who continued to take warfarin during pregnancy, one had a premature delivery, 2 had spontaneous abortions, and 8 had therapeutic abortions. Five patients who ceased oral anticoagulant therapy had normal deliveries but 4 underwent reoperation for valve thrombosis postnatally, with concurrent left hemiplegia in one case. The other 5 patients adhered to an anticoagulation protocol for pregnancy; there were 3 normal deliveries, 1 premature birth, and 1 abortion. There is a high risk of thromboembolism in patients with mechanical heart valves whose anticoagulants are interrupted during pregnancy. We believe that careful supervision can reduce maternal morbidity and mortality.

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.

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.

Recombinant tissue type plasminogen activator treatment of thrombosed mitral valve prosthesis during pregnancy

PURPOSE

Prosthetic heart valve thrombosis occurring during pregnancy is a life-threatening complication. Surgical treatment requires clot removal under cardiopulmonary bypass (CPB) and carries a high mortality. We describe the successful use of thrombolytic therapy for recurrent thrombosed valve prosthesis in a pregnant patient.

CLINICAL FEATURES

A 32-yr-old patient whose pregnancy was complicated by two episodes of a thrombosed St Jude mitral prosthesis is reported. The first episode occurred at 20 wk of pregnancy during the change of oral anticoagulant therapy (acenocoumarol 4 mg a day) to sc heparin. As the patient was in cardiogenic shock, the valve thrombus was treated by clot removal under CPB., with a cross clamp time of 32 min, a perfusion pressure above 70 mmHG. There was no fetal cardiac rhythm during CPB which lasted < 45 min. The second episode occurred at the 28th gestational week in a patient in cardiogenic shock and because reoperation was thought to carry too high a risk, the thrombus was successfully treated with 50 mg recombinant tissue plasminogen activators (rtPA) i.v. Following this, the course of pregnancy was uneventful and carried to term and the patient delivered vaginally. Pain relief was achieved with intravenous patient-controlled analgesia with alfentanil (bolus 100 mug; lock out = five minutes). Although rtPA has been used before, this is the first report in which pregnancy was carried to term and standard vaginal delivery performed.

CONCLUSION

This case provides evidence for the efficacy and relative safety of rtPA as thrombolytic therapy in the treatment of haemodynamically compromised valve heart thrombosis in pregnancy.

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.

[Thrombolytic therapy with rt-PA of recurrent thrombosis in tricuspid valve prosthesis during pregnancy]

The authors report a case of a woman who had two episodes of a tricuspid Saint-Jude prosthesis thrombosis treated with fibrinolysis using rt-PA, during the fourth month of pregnancy. A first course of thrombolytic therapy was successful with normal valve function despite threatening abortion and uterine bleeding. An early rethrombosis of the prosthetic valve and a failure of a second course of thrombolysis required the interruption of pregnancy with a replacement of the tricuspid valve prosthesis.

Valvular heart surgery during pregnancy

The pathophysiology of mitral and valvular heart disease is presented with an emphasis on the relationship of these conditions to pregnancy. Management options are discussed. Special attention is directed to patients who have prosthetic valves in place and who become pregnant. The care of this group of patients may be difficult, and treatment strategies are presented.

Pregnancy outcome in women with cardiac valve prosthesis

Twenty-one pregnancies in 16 women who conceived after cardiac valve replacement were reviewed. Oral anticoagulants were discontinued before conception or as soon as possible for subcutaneous heparin treatment (8000-14,000 IU every 8-12 h) and resumed in the second trimester until the last period of pregnancy when oral anticoagulants were replaced again by heparin. No therapeutic abortion was performed. The spontaneous abortion rate was found to be 14.3% (3/21). Preterm delivery (< or = 37 weeks) and low birth weight babies (< 2500 g) were 29.4% (5/17) and 35.3% (6/17), respectively, significantly more frequent than those of the control group (P < 0.02 and P < 0.0005). No significant statistical difference was found when the rate of spontaneous abortion [14.3% (3/21)] and the rate of fetal growth retardation [11.8% (2/17)] were compared with the control group. The majority of thromboembolic events (6/7) occurred during heparin regimen in three mothers; one of them subsequently died. No coumarin embryopathy was observed and the physical and mental development in the 16 surviving children was good. This study confirms: (1) the increased rate of preterm delivery and infants weighing < 2500 g; (2) the increased risk of maternal thrombosis related to heparin use; and (3) the good follow-up in the surviving children.

Outcome of pregnancy in women with valve prostheses

OBJECTIVE

To study the outcome of pregnancy in women with artificial heart valves treated in major European centres, and to compare the safety and efficacy of different anticoagulant regimens and of mechanical and bioprosthetic valves.

DESIGN

Retrospective study.

METHOD

The information was obtained by questionnaire sent to all major cardiac centres in Europe sending one cardiologist from each centre a covering letter suggesting that the questionnaire be handed on where appropriate to the most relevant colleague.

RESULTS

214 pregnancies were reported in 182 women; 151 pregnancies in 133 women with mechanical valves, and 63 pregnancies in 45 women with bioprostheses. Most women were in New York Heart Association class I or II and in sinus rhythm. 150 women with mechanical valves and 11 (17%) with bioprostheses received anticoagulants during pregnancy. One patient with an aortic valve prosthesis refused to take anticoagulants. Including the spontaneous abortions reported as well as the therapeutic abortions 83% of the pregnancies in women with bioprostheses and 73% in those with mechanical valves resulted in a healthy baby, full term or premature, who did well (NS). The incidence of stillbirths (3% and 6%) and of reported spontaneous abortions are excluded (because they are unlikely to have been fully reported), the success rate was 91% for women with bioprosthetic valves and 84% for women with mechanical valves (NS). 114 (53%) of the women had taken warfarin for some part of the pregnancy (46 (40%) of these during the first trimester) but there were no embryopathies. There were 13 valve thromboses (four fatal), eight embolic events (two fatal), and seven bleeds in women with mechanical valves. Most of these complications occurred with heparin but fatal aortic valve thrombosis occurred in the one woman who refused anticoagulant treatment out of the 151 women with mechanical valves. There were no maternal deaths in the bioprosthesis group but in 17/49 (35%) of these valves functional deterioration led to urgent replacement during pregnancy (two) or soon after.

CONCLUSIONS

The outcome of pregnancy was similar for women with mechanical valves or bioprostheses. Warfarin treatment was safe and effective and was not associated with embryopathy. Heparin treatment was associated with more thromboembolic complications and more bleeding complications. Bioprostheses deteriorate rapidly during pregnancy.

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

Maternal and fetal complications in a consecutive series of 60 pregnancies in 49 patients with prosthetic heart valves were prospectively evaluated. Group 1 consisted of 40 pregnancies in 31 patients who were taking oral anticoagulants. No oral anticoagulation was used in 20 pregnancies in 19 patients (group 2). In group 1 there were three instances of acute valvular thrombosis during the 35 pregnancies in patients with mechanical prostheses, with two maternal deaths. There were two episodes of cerebral embolism, one in group 1 and one in group 2. Patients with isolated aortic valve replacement had fewer maternal complications (2 of 13) than patients with isolated mitral valve replacement (15 of 42) without statistical significance. Severe bioprosthesis dysfunction occurred in 4 of 25 pregnancies (one rupture and three stenosis) with two maternal deaths, one in the puerperium and the other in the postoperative period of cardiac surgery during pregnancy. When analyzing obstetric events we observed seven spontaneous abortions and one hydatidiform mole. All spontaneous abortions occurred in group 1. The incidences of prematurity and low birth weight were significantly higher in group 1 than in group 2 (46.6% vs 10.5%, p less than 0.05, and 50% vs 10.5%, p less than 0.05, respectively). Moreover, there was a significant association between prematurity and the mother's New York Heart Association functional class (61.5% in classes III and IV vs 22.2% in classes I and II, p less than 0.05). There were five neonatal deaths, all in group 1 (p = NS vs group 2). Three infants had warfarin-related congenital defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Pregnancy and its complications after cardiac valve replacement

The outcome of 64 pregnancies in 40 women who conceived after cardiac valve replacement were reviewed. Fetal wastage was 53.2% (25/47) in coumarin administered pregnancies, 36.4% (4/11) using heparin and 16.7% (1/6) without anticoagulants. Two fetal malformations were noted in coumarin administered pregnancies. There were two maternal deaths. Maternal morbidity due to antenatal bleeding, atrial fibrillation, thromboembolic episodes and cardiac failure were found to be 20.0% (8/40), 17.5% (7/40), 10.0% (4/40) and 10.0% (4/40), respectively.

Anesthesia, cardiopulmonary bypass, and the pregnant patient

For the perioperative management of pregnant patients with severe cardiac or aortic disease who require a cardiac surgical procedure and cardiopulmonary bypass, a close, cohesive, working relationship must exist among several medical and surgical specialties. For appropriate management, the well-being of both the mother and the fetus must be considered. The best interests of the mother and the fetus may not coincide, and optimal therapy for one may be inappropriate for the other. We present 10 cases of severe cardiac or aortic disease in pregnant women who required surgical intervention. Eight patients underwent cardiopulmonary bypass during pregnancy, and two patients had cesarean section performed immediately before cardiopulmonary bypass. We also discuss the pertinent pharmacologic aspects related to the perioperative period and the management of cardiopulmonary bypass for the pregnant patient.

Eight years' experience with the Medtronic-Hall valve prosthesis

During the period January 1981 to September 1986, 444 Medtronic-Hall heart valve prostheses were implanted in 351 patients (mean age, 45 +/- 10 years) mainly for rheumatic valve disease (63.2%). Most of the patients were in New York Heart Association functional class III. Concomitant surgical procedures, mainly conservative tricuspid or mitral procedures or coronary artery bypass grafting, were performed in 101 patients (28.7%). Single-valve replacement was performed in 262 patients (74.6%) (aortic in 117 patients, mitral in 143, and tricuspid in 2), double-valve replacement in 85 (24.2%) (mitral and aortic in 83 and mitral and tricuspid in 2), and triple-valve replacement in 4 (1.1%). Hospital mortality was 6.2%. Follow-up was 97.7% complete. The overall actuarial 8-year survival rate was 77.2%. The linearized incidence of valve-related complications was as follows: thromboembolism, 1.5%/patient-year; reoperation, 1.5%/patient-year; endocarditis, 1.25%/patient-year; hemolysis, 0.52%/patient-year; anticoagulant-related hemorrhage, 0.39%/patient-year; and noninfection-related paraprosthetic leak, 0.33%/patient-year. There were no instances of structural failure. We conclude that after 8 years of follow-up, the Medtronic-Hall valve prosthesis has an excellent clinical performance and a low range of valve-related complications.

Clinical problems in patients with prosthetic heart valves

Information from the UK Heart Valve Registry, which was established in 1986 and receives data from all centres in the National Health Service, shows that more than 5,000 artificial heart valves are implanted each year in Britain and that almost two-thirds of these are mechanical. This article is intended as a practical outline of the clinical problems and complications which may occur.

Valve replacement in children under 15 years with rheumatic heart disease

From 1967 through 1984, single- or double-valve replacement for rheumatic heart disease (RHD) was undertaken in 184 children (aged 4 to 15 years) in Tunis. At the time of operation most patients were in an advanced state of cardiac disability, but most of them were still in sinus rhythm. A total of 222 valves were inserted. The most commonly used replacement valve was the Starr-Edwards caged-ball prosthesis, with 12 hospital deaths (6.5%). There were no hospital deaths among 19 children who had a (glutaraldehyde-treated porcine) xenograft replacement valve; however, a much higher rate of valve failure occurred later, owing to valve calcification (14 of 19 replacements, 11 requiring reoperation). There were 24 episodes of clinical thrombo-embolism in 21 children after insertion of a prosthetic valve, but only one in a child with a xenograft valve. Two thirds of the patients with prosthetic valves were on anticoagulants, but fewer than half of them had effective levels because of low compliance. For the group with prosthetic valves, the 10-year survival rate was 70%.

Thrombotic and bleeding complications of prosthetic heart valves

A review of articles published since 1979 indicates that thrombotic and bleeding complications account for about 50% of valve-related complications in patients with bioprosthetic aortic and mitral valves and for approximately 75% of the complications in patients with mechanical valves. Although compromised by lack of standard definitions and by variability in reporting and follow-up, the data suggest that the linearized rate of both thrombotic and bleeding complications in patients with aortic bioprostheses is approximately half that for aortic mechanical prostheses (2% versus 4%), but is approximately equal for both bioprostheses and mechanical valves in the mitral position (approximately 4%), and for mechanical and bioprosthetic aortic and mitral valves in combination. However, linearized rates for fatal thrombotic and bleeding events are two to four times higher in patients with mechanical prostheses. The adequacy of warfarin anticoagulation is the most important factor affecting thrombotic and bleeding complications in patients with mechanical valves and over shadows the dubious importance of other phenomena such as atrial fibrillation and left atrial thrombus. Short-term warfarin anticoagulation or the use of long-term platelet inhibitors, or both, do not appear to reduce the incidence of thrombotic complications in patients with aortic bioprostheses but increase bleeding. For mitral bioprostheses, the postoperative use of warfarin for three months or aspirin indefinitely is as effective in preventing thromboembolism as long-term warfarin. Acute prosthetic valve endocarditis is associated with a 13 to 40% incidence of thrombotic complications. Likewise, the recurrence rate of cerebral emboli is high (20-30%) in patients with prosthetic valves who are not anticoagulated. Bioprostheses are strongly preferred for women who wish to bear children; fetal wastage occurs in 25 to 30% of pregnant women with mechanical heart valves who receive either warfarin or heparin, or a combination of the two. Heparin, however, greatly increases the risk of maternal bleeding. In children, the efficacy of platelet inhibitors without warfarin anticoagulation is unproven; nearly all serious strokes occur when warfarin is omitted; and permanent disability from warfarin-related bleeding is rare. All prosthetic cardiac valves initiate coagulation and affect the dynamic equilibrium between activated procoagulants and endogenous anticoagulants. Warfarin is the only available oral exogenous anticoagulant.(ABSTRACT TRUNCATED AT 400 WORDS)