|Year : 2017 | Volume
| Issue : 1 | Page : 60-62
Stuck mitral prosthesis in pregnancy – A challenge
Pankaj K Gupta1, Indira Malik1, AS Tomar1, Vishnu Datt1, Sanjula Virmani1, Vithal K Betigeri2
1 Department of Anaesthesia and Critical Care, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi, India
2 Department of Cardiothoracic and Vascular Surgery, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi, India
|Date of Web Publication||1-Jun-2017|
Pankaj K Gupta
House No 1069, Sector 28, Faridabad, Haryana - 121 008, India
Source of Support: None, Conflict of Interest: None
Pregnancy with prosthetic valve is a challenging situation since this is a hypercoagulable state and maintenance of anticoagulation for prosthetic valves becomes difficult due to the teratogenic effects and altered pharmacokinetics of anticoagulant drugs. This may result in prosthetic valve thrombosis which is an emergency and requires multidisciplinary approach for management. We present a case of a patient who presented with thrombosed mitral prosthesis at 34 wks of gestation; after a multispeciality consultation, she eventually underwent caesarean section followed by mitral valve replacement.
Keywords: Caesarean, pregnancy, prosthetic valve thrombosis, redo mitral valve replacement
|How to cite this article:|
Gupta PK, Malik I, Tomar A S, Datt V, Virmani S, Betigeri VK. Stuck mitral prosthesis in pregnancy – A challenge. J Obstet Anaesth Crit Care 2017;7:60-2
|How to cite this URL:|
Gupta PK, Malik I, Tomar A S, Datt V, Virmani S, Betigeri VK. Stuck mitral prosthesis in pregnancy – A challenge. J Obstet Anaesth Crit Care [serial online] 2017 [cited 2019 Dec 11];7:60-2. Available from: http://www.joacc.com/text.asp?2017/7/1/60/207394
| Introduction|| |
Rheumatic heart disease (RHD) has a high prevalence of 0.9/1000 in India among school children. Young females having undergone valve replacement when become pregnant face an uphill task of maintaining anti-coagulation required for prosthetic heart valve (PHV). Pregnancy being a hypercoagulable state, teratogenic effects of anticoagulant drugs and altered pharmacokinetics increase predisposition for PHV thrombosis, which, in the presence of physiological changes of pregnancy, may lead to life threatening situations, followed by a dilemma regarding the timing of delivery, replacement of the thrombosed PHV and risk of postpartum haemorrhage (PPH). We report the case of a patient who presented with stuck mitral prosthesis at 34 weeks of gestation, for which she underwent caesarean section (CS) followed by mitral valve replacement (MVR).
| Case Report|| |
A 28-year-old, female was referred to our hospital at 34 weeks of gestation. She had undergone balloon mitral valvuloplasty (BMV) 5 years back and MVR 1.5 years back with mechanical, bi-leaflet prosthesis. She had been receiving tablet warfarin 5 mg, which she continued throughout pregnancy except during the 6–12th week when she received low molecular weight heparin (LMWH), as advised by a cardiologist.
Her antenatal course was uneventful until after the 30th week of pregnancy when she started having increased breathlessness on exertion and lying supine with pedal oedema. She was admitted to a hospital at 33 weeks. On physical examination, blood pressure was 114/70 mmHg and heart rate was 84/minute, however, prosthetic valve clicks were absent and diastolic murmur was heard. Foetal heart rate (FHR) was 140/min. Her INR on admission was 2, which was sub-therapeutic. Echocardiography showed that one leaflet of PHV was stuck, severe tricuspid regurgitation (TR) and severe PAH with ejection fraction (EF) of 60%. She received digoxin, furosemide and LMWH (40 mg) twice daily, as well as warfarin 5 mg, metoprolol, iron, calcium, folic acid and dexamethasone for lung maturity of the foetus. Her symptoms worsened from New York Heart Association (NYHA) II to NYHA IV, and was advised surgical intervention by cardiologist. Because cardiac surgery was unavailable at that centre, she was referred to our hospital at 34 weeks. After a multispecialty consultation, decision to perform CS followed by MVR was taken. Warfarin was stopped by the previous centre in view of need for surgery. LMWH was discontinued 12 h prior to surgery and routine investigations were normal. In the operating room (OR), routine monitors were attached and a radial arterial line was inserted under local anaesthesia. Because the patient was dyspnoeic in supine position, insertion of central venous catheter (CVC) was deferred till after induction and delivery. A 15-cm wedge was introduced under the right hip and thiopentone 200 mg with rocuronium 50 mg were given, followed by rapid sequence intubation (RSI) with 7.0 Fr cuffed endotracheal tube; anaesthesia was maintained with oxygen (O2) and nitrous oxide (N2O). CS was performed with induction to delivery time of 5 minutes; the baby had Apgar scores of 8 and 9 at 1 and 5 minutes, respectively. Oxytocin infusion (10 units/h) was started post delivery to improve uterine contraction and facilitate placental delivery; fentanyl 5 μg/kg and midazolam 2 mg were given. Uterine contraction was assured and abdomen was closed after meticulous haemostasis.
CVC was inserted after delivery for monitoring changes in fluid status and loading conditions of the heart. Anaesthesia was maintained with O2 + N2O, fentanyl 2–4 μg/kg hourly, 0.5 MAC sevoflurane and rocuronium 0.6 mg/kg/h. After sternotomy and dissection, 3 mg/kg of heparin was given and cardiopulmonary bypass (CPB) was instituted. Tranexamic acid (10 mg/kg) at induction followed by 2 mg/kg/h was started to reduce bleeding. Intraoperatively, one PHV leaflet was found stuck [Figure 1]. The thrombus and clot around the valve was removed and the valve was replaced by a 25 size Onyx valve. CPB and cross clamp time were 145 min and 87 min, respectively. On CPB, anaesthesia was maintained with fentanyl (2 μg/kg), rocuronium (0.2 mg/kg) and midazolam (0.02 mg/kg) hourly. Patient was weaned off CPB with adrenaline (0.04 μg/kg), milrinone (0.5 μg/kg) and dobutamine (5 μg/kg). An obstetrician checked for PPH intermittently after heparin administration, both intra and postoperatively. Post CPB anaesthesia was maintained with fentanyl, rocuronium and sevoflurane. After heparin reversal and adequate haemostasis, sternum was closed and the patient was shifted to the intensive care unit (ICU).
|Figure 1: Intraoperative picture with arrow showing stuck leaflet of prosthetic valve|
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Oxytocin infusion was continued for 24 h; heparin and warfarin were started on the first postoperative day. The patient required ventilation for 72 h due to severe PAH preoperatively and CPB-induced lung injury. She was gradually weaned off the ventilator, and both the baby and mother were in good health after 1 week.
| Discussion|| |
The incidence of thromboembolic complications in pregnancy with PHV in a large review has been reported to be 3.9% with warfarin, 9.2% with unfractionated heparin in the first trimester followed by warfarin and 33% with unfractionated heparin throughout. With LMWH, incidence has been reported to be 3.6% with use only in the first trimester and 9% with use throughout pregnancy. ACC/AHA guidelines recommend warfarin continuation throughout pregnancy if dosage <5 mg. LMWH administration necessitates anti-Xa monitoring, which is not freely available in many centres.,
PHV thrombosis leads to a state similar to untreated mitral stenosis, with clinical features depending on the degree of thrombosis and narrowing of orifice. Physiologically, in pregnancy, an increased heart rate (25%), blood volume (45%) and cardiac output (50%) significantly increase the gradient across the stenosed orifice and cause pulmonary congestion, due to high left atrial pressure, and low CO, due to decreased forward flow into left ventricle, and decreased venous return due to aortocaval compression.
PHV thrombosis can be treated medically by thrombolysis or surgically. Thrombolysis is not recommended in pregnancy, specifically for left-sided valve thrombosis due to limited experience, risk of embolization and subplacental bleeding.
Timing of surgical valve replacement depends upon the severity of symptoms, irrespective of foetal maturity. In a case series of 23 patients, 17 needed urgent surgery due to PHV thrombosis, combined CS and MVR were performed at >28 weeks of gestation; if gestational age was <28 weeks only valve replacement was done. Two separate reports have described similar cases where concomitant CS and MVR were done., High maternal (1.5–5%) and foetal (16–33%) mortality in pregnant patients undergoing cardiac surgery necessitates delivery of the viable foetus prior to cardiac surgery.
Preoperatively, prosthetic valve status, gestational age, anticoagulants and medications should be recorded, and bridging therapy with unfractionated heparin or LMWH should be considered, which can be stopped 4–12 h before surgery.
Intraoperative concerns depend upon the clinical status of the patient and surgical plan, whether isolated valve surgery or combined with CS. Routine monitors along with invasive arterial and CVC are desirable. Poor oxygen reserve, pulmonary congestion, full stomach and difficulty in intubation are challenges to be considered. Haemodynamic goals include maintaining an acceptable slow heartbeat, sinus rhythm, avoiding aorto-caval compression, normovolemia, normotension and pain relief, with an eye on avoiding exaggeration of PAH. If CS is planned, avoid opioids till delivery and minimise incision to delivery time. Risk of pulmonary oedema is high due to auto-transfusion of uterine blood after delivery. PPH is a major concern in this case due to heparinization; hence, oxytocin infusion should be considered (10U/h). Prostaglandins and hot mops are recommended to improve uterine tone. Because anticoagulants are started postoperatively, the risk of delayed PPH is high. Use of anti-fibrinolyics, adequate heparin reversal and avoidance of hypothermia are some of the measures that can be taken by the anaesthesiologist to minimise blood loss keeping in view that it is a repeat surgery and adhesions are encountered.
Postoperatively, risk of PPH and thrombosis due to hypercoagulability require cautious balancing. In our case, oxytocin infusion was continued till 24 h, while heparin was started to prevent thrombosis; however, there are no recommended guidelines for the duration of oxytocin infusion after concomitant CS and cardiac surgery. Elective ventilation is desirable owing to preoperative PAH and pulmonary congestion.
| Conclusion|| |
Our case highlights the need to review anticoagulation in pregnancy with care and after a multidisciplinary consultation regarding treatment modalities. As anaesthesiologists we must be well-versed with the challenges involved in PHV thrombosis and its appropriate perioperative management in these patients.
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Conflicts of interest
There are no conflicts of interest.
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