Ann Thorac Surg 2003;75:1317-1318
© 2003 The Society of Thoracic Surgeons
Case report
Successful thrombectomy for thrombosis of aortic composite valve graft in pregnancy
Francesco Alessandrini, MDa,
Elisabetta Lapenna, MD*a,
Giuseppe Nasso, MDa,
Michele De Bonis, MDa,
Gian Federico Possati, MDa
a Department of Cardiac Surgery, "Policlinico Gemelli" University Hospital, Catholic University of The Sacred Heart, Rome, Italy
Accepted for publication October 8, 2002.
* Address reprint requests to Dr Lapenna, Via Don Milani 23 E–20063 Cernusco Sul Naviglio, Milan, Italy
e-mail: elisabettalapenna{at}tiscalinet.it
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Abstract
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Prosthetic heart valve thrombosis in pregnancy is a life-threatening complication whose management remains controversial and particularly difficult because of the additional challenge to save the fetus. Thrombolysis, thrombectomy, or prosthetic replacement are the currently available options. We report the case of a 17-week pregnant patient who was successfully treated by emergency open-heart thrombectomy for thrombosis of an aortic composite valve graft. Pregnancy was carried to term and a healthy baby was vaginally delivered 5 months later.
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Introduction
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Prosthetic heart valve thrombosis is a life-threatening complication requiring emergency treatment. Thrombolysis, thrombectomy, or prosthetic replacement are the currently available options. However the choice of the most appropriate strategy to adopt remains controversial and becomes even more difficult in pregnancy because of the additional challenge to save the fetus.
We report the case of a 17-week pregnant patient who was successfully treated by emergency open-heart thrombectomy for thrombosis of an aortic composite valve graft.
A 33-year-old woman with Marfan’s syndrome, in the 17th week of her first pregnancy, was admitted to our department because of marked dyspnea. She had previously undergone a redo-Bentall procedure implanting a 25-mm St. Jude Medical composite valve graft (St. Jude Medical, St. Paul, MN). Since then she had followed thromboembolic prophylaxis with sodium warfarin. Three years later, when a pregnancy of 6 weeks had been noticed, she was switched to subcutaneous calcium heparin (Calciparine 12500 IU three times a day) to maintain a partial thromboplastin time (PTT) twice the basal value. On admission to our institution, PTT was 32 seconds and two-dimensional echocardiography documented reduced leaflets motion, thrombi covering both sides of the hemidiscs and a transprosthetic pressure gradient of 80 mm Hg. Intravenous heparin infusion was started at 1500 IU/h, to maintain a PTT twice the normal value. Because of fast deterioration in the patient’s conditions, thrombolysis could not be an option and the woman, despite advanced pregnancy, was taken to the operating room for emergency surgery. An upper 3- to 4-cm median resternotomy was performed. Right femoral artery and vein were used for cannulation. Normothermic cardiopulmonary bypass (CPB) was established with a perfusion rate of 2.6 L/m/m2 and a mean blood pressure of 70 to 80 mm Hg. The distal end of the prosthetic tube was cross-clamped and a longitudinal incision of the graft was performed exposing the mechanical valve. Intermittent normothermic blood antegrade cardioplegia was administered in the coronary ostia. The prosthesis appeared almost completely occluded by recent thrombus formation sparing the coronary ostia. Thrombi were carefully removed from both the aortic and ventricular sides. A big size surgical needle was used for cleaning the ventricular surface of the prosthesis. The left ventricular cavity was inspected through the aortic orifice and irrigated with saline solution to eliminate any thrombotic material left in place. The appropriate valve tester was then used to confirm proper and free movements of both leaflets and unobstructed flow. Aortic cross-clamp time was 20 minutes and total CPB time was 30 minutes including the slow weaning to avoid hypotension or low cardiac output. During the operation fetal heart tones were monitored and no fetal heart rate disturbances were noticed. An obstetric ultrasonography, performed after surgery, revealed normal fetal movements. Patient’s anticoagulation with subcutaneous calcium heparin was restarted 24-hours later and warfarin was readministered on the third postoperative day, when chest drains were removed. The postoperative course was uneventful. A predischarge transesophageal echocardiography revealed normal valve motion and a normal gradient across the prosthesis. The woman was discharged home on the tenth day. The further course of pregnancy was uneventful and fetal growth remained normal. The patient received warfarin therapy until the 36th gestational week, when it was replaced by intravenous heparin. At the 39th week of pregnancy a healthy baby (3.1 kg) was delivered vaginally. Both mother and child were discharged home in excellent condition 5 days later. At a 10-month follow-up, the patient and her child are doing well.
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Comment
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Prosthetic heart valve thrombosis may complicate more than 6% of pregnancies in women with mechanical prostheses [1]. It is mainly due to the hormones-related hypercoagulability and the poor anticoagulation achieved during the first 3 months and the last 2 weeks of pregnancy when warfarin is replaced by heparin [1, 2]. To treat this emergency condition heparin infusion might be sufficient if the thrombus is small or relatively unobstructive [3], but when thrombosis is associated with a complicated course, as in our patient, fibrinolysis or surgery are the only available options. During pregnancy the further challenge to save the fetus has to be taken into consideration. Thrombolytic therapy has been successfully carried out in two pregnant patients [3]. However, its use in pregnancy is limited by the potential bleeding complications besides incomplete or absent lysis of the thrombus, systemic embolism, and late rethrombosis [4]. Furthermore, fibrinolysis cannot be performed when the patient, as in our case, is too sick to undergo a 1-day to 4-day trial of medical therapy [2]. The two alternatives are thrombectomy or prosthesis replacement, both requiring CPB, which carries a risk of fetal mortality as high as 30% [1]. Because CPB time is mainly related to fetal loss, it should be as short as possible maintaining high flow, high pressure, normothermic perfusion. Redo-replacement of the thrombosed prosthesis implies long ischemic and CPB times, therefore it should be restricted to cases of extensive pannus underlying the thrombuslike material or if a prosthesis mechanical damage is found. On the other hand, when the event is related to an inadequate level of anticoagulation, such as in our case, thrombectomy could be an excellent approach. It does not damage the prosthesis by surface trauma and does not increase the risk of rethrombosis [5]. Inspection of the ventricular side of the prosthesis should be carried out carefully to be certain that no thrombi are left in place. So far, three reports of prosthetic valve thrombectomy during pregnancy have been described [1, 2, 6]. In our patient, replacing the composite valve graft would have been too risky and a caesarean section before surgery could not be an option due to the early time of pregnancy. Therefore we preferred to perform a thrombectomy, restoring normal valve function with short CPB time and relatively low risk to the mother and the fetus.
Given the high mortality and complication rate associated with replacement of a thrombosed aortic valve graft conduit in pregnancy, we believe that thrombectomy should be preferred when there is no mechanical damage of the prosthesis, all thrombotic material can be removed and the free movement of the leaflets resumed.
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References
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- Gonzales-Santos J.M., Vallejo J.L., Rico M.J., Gonzales-Santos M.L., Horno R., Garcia-Dorado D. Thrombosis of mechanical valve prosthesis late in pregnancy: case report and review of the literature. Thorac Cardiovasc Surg 1986;34:335-337.[Medline]
- Massad M., Fahl M., Slim M., et al. Thrombosed Bjork-Shiley standard disc mitral valve prosthesis. J Cardiovasc Surg 1989;30:976-980.[Medline]
- Fleyfel M., Bourzoufi K., Huin G., Subtil D., Puech F. Recombinant tissue type plasminogen activator treatment of thrombosed mitral valve prosthesis during pregnancy. Can J Anaesth 1997;44:735-738.[Medline]
- Di Roio C., Perrot D., Vedrinne J.M., Mellier G., Robin J., Motin J. Thrombolytic therapy with rt-PA of recurrent thrombosis in tricuspid valve prosthesis during pregnancy. Ann Fr Anesth Reanim 1996;15:666-668.[Medline]
- Venugopal P., Kaul U., Iyer K.S., et al. Fate of thrombectomized Bjork-Shiley valves. A long-term cinefluoroscopic, echocardiographic, and hemodynamic evaluation. J Thorac Cardiovasc Surg 1986;91:168-173.[Abstract]
- Donzeau Gouge P., N’Guyen A., Touchot B., et al. Acute thrombosis of a St. Jude Medical aortic prosthesis in a pregnant woman. Thorac Cardiovasc Surg 1985;33:248-249.[Medline]
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Abstract
Introduction
