Cardiopulmonary bypass:
Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman
Carnero-Alcazar et al. (12 October 2009)
[Abstract]
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Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman
eComment. Re: Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman |
19 November 2009 |
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Leo A. Bockeria
Bakoulev Scientific Center for Cardiovascular Surgery , Roublevskoye Sh. 135, 121552 Russia,
Olga L. Bockeria, Irina A. Goustova, Anna S. Mordvinova.
Send ecomment to journal:
Re: eComment. Re: Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman
leoan{at}heart-house.ru Leo A. Bockeria, et al.
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Interactive CardioVascular and Thoracic Surgery 2009, doi:10.1510/icvts.2009.220806C
© 2009 European Association of Cardio-Thoracic Surgery
Pregnancy in women with mechanical prosthesic valves is associated
with a high risk of maternal mortality as the outcome of prosthetic-valve
thrombosis. One of the actual goals of modern cardiology is an adequate
anticoagulation therapy for such category of patients. It’s well known
that clinical recommendations concerning valvular heart disease during
pregnancy are dependant on the period of gestation.
In this report [1], Carnero-Alcazar M. and colleagues describe their
experience of the mitral valve replacement due to mechanical prosthetic
valve thrombosis which occurred during first trimester of pregnancy. The
cardiopulmonary bypass has many potential adverse effects that can
compromise uteroplacental perfusion and fetal development. The authors have
performed the surgical procedure using high perfusion pressure and mild
hypothermia during cardiopulmonary bypass. The maintenance of acidbase
balance during open heart, the use of high flow rate, high perfusion
pressure and normothermia or mild hypothermia during cardiopulmonary
bypass, minimization of the duration of the aortic cross-clamp time has a
significant importance in successful outcomes of operation.
Administration of warfarin during pregnancy in women with mechanical
valves [2] diminishes the risk of development of prosthetic valve
thrombosis. But it is associated with a high level of fetal loss
(approximately 30 percent including spontaneous abortions, stillbirths,
and neonatal deaths). The rate of adverse events during warfarin therapy is
considered to be 6%. Administration of warfarin is associated with “fetal
warfarin syndrome” characterized by nasal hypoplasia,
stippled epiphyses, limb deformities, and respiratory distress. Warfarin
therapy in period between 6 and 12 weeks of gestation doubles in fetal
mortality compared to administration of heparin. Injection of heparin
during the first trimester reduces by half the risk of maternal
thromboembolism and death (9.2% and 4.2%, respectively) [3]. Nevertheless,
long-term heparin administration is associated with a higher risk of
heparin-induced thrombocytopenia and osteopenia in women [1]. A strategy of
substituting warfarin for low molecular weight heparin during the period of organogenesis
(6–12 weeks of gestation) reduces the risk of warfarin embryopathy but
increases twice the maternal thromboembolism (9%).
In the Bakoulev Center for Cardiovascular Surgery, the management of pregnant women with
mechanical valves has been investigated. Only preliminary data have been
accumulated.
According to the data presented in overviews and case reports, usually
the caesarian section is applied in most of the cases before radical
correction of cardiac pathology. Based on cite data it is recommended to
administer warfarin with target level of INR 2,0-3,0. It’s
inadmissible to use warfarin therapy during two periods: between 6 and 12
weeks of pregnancy and after 36 weeks of pregnancy [2]. Within these
periods an unfractionated heparin should be applicated under monitoring of
coagulation.
In spite of the existence of well-tested cardiopulmonary bypass protocol,
complications are still observed. The problem is insufficiently known
because of limited quantity of studies. Further investigation should be
carried out.
References
[1] Carnero-Alcazar M, Reguillo-Lacruz F, Montes-Villalobos L,
Rodriguez-Hernandez JE. Mechanical prosthetic mitral valve thrombosis in
a first trimester pregnant woman. Interact CardioVasc Thorac
Surg, doi:10.1510/icvts.2009.220806.
[2] Bockeria L.A., Bockeria O.L, Orjonikidze N.V., Lobacheva G.V.,
Bespalova E.D., Nechai Y.A., Volkovskaya I.V., Trofimova E.R., Mordvinova
A.S. The management and delivery in pregnant women with severe
cardiovascular pathology. The Bulletin of Bakoulev Center for Cardiovasc
Surg. 2009.
[3] Ginsberg JS, Greer I, Hirsh J. Use of antithrombotic agents during
pregnancy. Chest 2001;119:Suppl:122S-131S. |
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Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman
eComment. Are LWMH effective in mechanical valve prosthesis anticoagulation during pregnancy? |
18 November 2009 |
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Yolanda Carrascal
University Hospital Valladolid, Ramón y Cajal 3, 47005 Valladolid, Spain
Send ecomment to journal:
Re: eComment. Are LWMH effective in mechanical valve prosthesis anticoagulation during pregnancy?
ycarrascal{at}hotmail.com Yolanda Carrascal
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Interactive CardioVascular and Thoracic Surgery 2009, doi:10.1510/icvts.2009.220806B
© 2009 European Association of Cardio-Thoracic Surgery
I have read with interest the case reported by Carnero-Alcazar et
al in which referred to surgical treatment of mitral valve thrombosis
in a pregnant patient [1]. In reference to the presented case, I would like to
comment that this report adds to others referring low weight molecular
heparin (LWMH) inefficiency to prevent thrombosis of mechanical valve
prosthesis during pregnancy [2]. Although the American College of Chest
Physicians Evidence-Based Clinical Practice Guidelines (8th Edition) [3]
include its use as a type IC recommendation, in order to anticoagulate
mechanical valve prosthesis in pregnant patients, it seems necessary to evaluate
its harmlessness with caution.
Up to now, aetiology of mechanical valve thrombosis is related to low
therapeutic levels of LWMH motivated by increasing of plasmatic volume
distribution during pregnancy. In consequence, monitoring levels of anti
Xa was considered adequate in order to evaluate its therapeutic efficiency
[3]. Thrombotic events described up to date, were associated with decreasing
of anti Xa levels below the recommended by LMWH manufacturers (0.6-1.2
U/ml).
The difficulty in determining efficacy of LMWH usage in these cases is
due to absence of prospective studies. Recently, Yinon et al [4] have
reported, in a prospective study (including 23 patients with aortic or mitral mechanical valve prosthesis, under LWMH treatment throughout their pregnancies, with 4-hour post-injection anti-Xa levels of 1 to 1.2 IU/ml
and associated with daily administration of 81 mg. of aspirin), the
appearance of a thrombosis in a second generation mechanical aortic valve
prosthesis, as the patient who illustrates the case presented by Carnero-
Alcazar et al [1]. Neither of the patients could be classified, according to the
American College of Chest Physicians Evidence-Based Clinical Practice
Guidelines criteria, as high risk thrombosis patients.
In conclusion, both cases suggest that safety of isolated anti Xa
monitoring cannot be adequate to prevent thrombotic events in pregnant
patients with mechanical valve prosthesis. Complementary clinical and
echocardiographic periodic controls and evaluation of efficacy of
monitoring pre dose of anti Xa [5] seem to be necessary to prevent this
type of event.
References
[1] Carnero-Alcazar M, Reguillo-Lacruz F, Montes-Villalobos L,
Rodríguez-Hernández JE. Mechanical prosthetic mitral valve thrombosis in a
first trimester pregnant woman. Interact CardioVasc Thorac Surg doi:10.1510/icvts.2009.220806.
[2] Roberts N, Ross D, Flint SK, Arya R, Blott M. Thromboembolism in
pregnant women with mechanical prosthetic heart valves anticoagulated with
low molecular weight heparin. Br J Obstet Gynaecol 2001; 108:327–329
[3] Bates SM, Greer IA, Pabinger I, Sofaer S, Hirsh J. Venous
thromboembolism. Thrombophilia, antithrombotic therapy, and pregnancy:
American College of Chest Physicians Evidence Based Clinical Practice
Guidelines, 8th edition. Chest 2008; 133: 844S–886S.
[4] Yinon Y, Siu SC, Warshafsky C, Maxwell C, McLeod A, Colman JM,
Sermer M, Silversides CK. Use of low molecular weight Heparin in pregnant
women with mechanical heart valves. Am J Cardiol 2009; 104: 1259-63.
[5] Elkayam U, Bitar F. Valvular heart disease and pregnancy: part
II: prosthetic valves. J Am Coll Cardiol 2005; 46: 403– 410. |
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Mechanical prosthetic mitral valve thrombosis in a first trimester pregnant woman
eComment. Cardiac operation during pregnancy: What is the appropriate management? |
8 November 2009 |
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Rafet Gunay
Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Center, Istanbul, Turkey
Send ecomment to journal:
Re: eComment. Cardiac operation during pregnancy: What is the appropriate management?
rafetgunay{at}hotmail.com Rafet Gunay
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Interactive CardioVascular and Thoracic Surgery 2009, doi:10.1510/icvts.2009.220806A
© 2009 European Association of Cardio-Thoracic Surgery
We read with great interest the report by Carnero-Alcazar and
coworkers regarding the successful mechanical mitral valve replacement due
to prosthetic valve thrombosis in a first trimester pregnant woman [1].
Two percent of all pregnant women suffer from some kind of cardiac
pathology. Although this incidence varies in different countries, cardiac
disease is the leading cause of death in pregnancy [2]. Many factors are
associated with pregnancy in cardiopathic patient such as social, ethical
and maternal desire for decision whether the pregnancy will be terminated
or maintained. When a cardiac problem requires an operation during
pregnancy the risks are inevitably increased and substantial efforts must
be made to reduce the risk. There are several cases reported in the
literature of CPB used on pregnant women at various stages of pregnancy
[2,3,4]. Many factors associated with cardiac operations requiring
cardiopulmonary bypass can adversely affect both the mother and the fetus,
but the embryo-fetal mortality is found that highly increased under
hypothermic conditions than the normothermic conditions although maternal
mortality did not differ at different temperatures [2]. Younger
gestational age and a greater degree of hypothermia are known to increase
fetal morbidity during CPB [3].
Cardiophatic pregnant patients can be separated into two groups. One of
them is pregnant women who have cardiac pathologies and the other is pregnant women
who require emergent surgical interventions. The cardiopathic patient,
even if well compensated, can easily sustain acute heart failure caused by
the increase of cardiorespiratory requirements during pregnancy. Ideally,
valve disease should be evaluated before pregnancy and treated if
necessary. However, pregnancy is often already present when the patient
presents. In such cases, if possible, it is always preferable to delay
surgery until the time the fetus is viable and a caesarean section can be
performed as part of a concomitant procedure [4]. On the other hand,
medical therapy is not always sufficient to drive a heart with a reduced
functional reserve and acute complications, such as the thrombosis of a
valvular prosthesis, endocarditis or acute aortic dissection, which can
seriously compromise the heart functions of the pregnant woman. When the
open heart operation is necessary to save the patient's life in such
situations, the fetus could be seriously compromised after exposure to
cardiopulmonary bypass. High-flow, high-pressure, normothermic bypass
offers the least risk to the fetus. Fetal heart and uterine monitoring is
essential to allow adjustments to the flow to ensure adequate placental
perfusion and early control of contractions as they are associated with
significant fetal loss [4].
Pregnancy is associated with a hypercoagulable state due to relative
decreases in protein S activity, stasis, and venous hypertension and
predisposition to dissection with or without an underlying connective
tissue disorder due to decrease in collagen synthesis. Hence, the
appropriate anticoagulation management is important in pregnancy. Fetal
mortality due to operation is considerably less than 100% mortality
incurred by therapeutic abortion. This case report has shown once again
that open heart operation is not a contraindication to pregnancy
prolongation and it has been reported to be undertaken at any gestational
age but it should be kept in mind that is best between 24 and 28 weeks’
gestation, after the completion of organogenesis. Pump flow and mean
arterial pressure during cardiopulmonary bypass seem to be the most
important parameters that influence fetal oxygenation.
References
[1] Carnero-Alcazar M, Reguillo-Lacruz F, Montes-Villalobos L,
Rodriguez-Hernandez JE. Mechanical prosthetic mitral valve thrombosis in a
first trimester pregnant woman. Interact CardioVasc Thorac Surg
doi:10.1510/icvts.2009.220806
[2] Pomini F, Mercogliano D, Cavalletti C, Caruso A, Pomini P.
Cardiopulmonary bypass in pregnancy. Ann Thorac Surg 1996; 61: 259-68.
[3]Mahli A, Izdes S, Coskun D. Cardiac Operations during pregnancy:
Review of factors influencing fetal outcome. Ann Thorac Surg 2000; 69:
1622-6.
[4]Parry AJ, Westaby S. Cardiopulmonary bypass during pregnancy. Ann
Thorac Surg 1996; 61: 1865-1869 |
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