The Fontan operation was first introduced in 1971 as a palliative procedure for patients with tricuspid atresia, and since then it has been used to provide palliation for patients with various forms of CHDs where biventricular repair is not feasible. With evolving modifications, the outcome has markedly improved, and thus increasing number of females having undergone Fontan surgery in childhood are now reaching childbearing age and are contemplating pregnancy. On the other hand, the haemodynamic changes of pregnancy impose significant maternal and fetal risk. Although successful pregnancies have been reported in Fontan patients with strict perinatal care, in developing countries with limited healthcare facilities, financial constraints, and poor awareness, the outcome of such patients can get compromised.
We report a case of a Fontan-palliated patient with an unplanned and unsupervised twin pregnancy complicated by pre-eclampsia and significant hypoalbuminaemia who delivered twin babies at 34 weeks of gestation and was successfully managed in the postpartum period.
Case report
A 29-year-old primigravida patient presented at 33 weeks of gestation with a twin pregnancy after a spontaneous conception. She was diagnosed as a case of complex cyanotic CHD – with tricuspid atresia, ventricular septal defect, and ventriculo-arterial concordance with pulmonary stenosis – at 6 months of age and underwent classical left Blalock–Taussig shunt. Subsequently, she was palliated with a bidirectional Glenn shunt at the age of 4 years after which she was lost to follow-up. Finally, she underwent an extracardiac Fontan completion at the age of 19 years. At the time of discharge, her cardiac function was reported as normal; however, she was again lost to follow-up until she presented with complaints of dyspnoea on exertion (NYHA II/IV) and oedema of feet and legs, along with a twin pregnancy at 33 weeks of gestation. According to the patient, she was asymptomatic during these 10 years and could do all the household work without any difficulty, but never underwent a cardiac evaluation. This was her first pregnancy, which was unplanned, and she was under the care of a local obstetrician throughout the pregnancy, but again no cardiac assessment was performed. Her blood pressure was reported as normal in the first trimester. She became symptomatic in the latter half of the second trimester, and as the symptoms deteriorated she was referred for cardiac evaluation by the treating obstetrician. At 33 weeks of gestation, echocardiography revealed a patent Fontan circuit with a left ventricular ejection fraction of 45% and mild mitral regurgitation. Clinically, she had pitting oedema of her legs without hepatomegaly. Laboratory investigations revealed a serum albumin level of 1.5 g/dl and mild anaemia with haemoglobin of 10 g/dl. Brain natriuretic peptide was not measured. She was started on diuretics and was advised to maintain close follow-up and delivery at a tertiary-care centre; however, 1 week later, she was admitted under the obstetrician with premature onset of labour. On evaluation, she was diagnosed as having systemic hypertension (blood pressure 140/96 mmHg) along with rupture of membranes and meconium staining of the liquor. Her preoperative investigations revealed anaemia (haemoglobin 10.6 g/dl), renal dysfunction (blood urea 32 mg/dl, creatinine 1.6 mg/dl), deranged coagulation (international normalised ratio 2.3), and significant hypoalbuminaemia (serum albumin 1.5 g/dl). Her electrocardiogram showed normal sinus rhythm. She was then transferred to a tertiary-care hospital for acute management and underwent emergency caesarean section, delivering two male babies weighing 1.5 and 1.4 kg with normal Apgar scores and no evidence of any congenital abnormalities. After delivery, the babies were transferred to the neonatal unit and the mother was transferred to the cardiac ICU.
Postoperatively, she had acidosis (pH 7.13, base deficit −12) and severe hypertension (blood pressure160/120 mmHg); her central venous pressure was 8–10 mmHg, with significant hypoalbuminaemia with marked proteinuria. Although a 24-hour urinary protein measurement was not obtained, a spot urinalysis had revealed 3+proteins, suggestive of pre-eclampsia. Initial fluid therapy was guided by central venous pressure monitoring that was targeted between 12 and 14 mmHg. Sodium nitroprusside infusion was started to control blood pressure and was titrated according to invasive blood pressure monitoring. Echocardiography at this point of time revealed a left ventricular ejection fraction of 25% with moderate mitral regurgitation, and therefore milrinone infusion was added for systemic vascular resistance reduction. In addition, low-dose Lasix infusion was added, packed red cell transfusion was given to correct anaemia, and fresh, frozen plasma was administered to improve coagulation, as well as for volume augmentation.
On the 1st postoperative day, haemodynamic stability improved with normalisation of pH and reduction of blood pressure; however, she developed fever, with deteriorating renal function (blood urea 32 mg/dl, creatinine 2.0 mg/dl), whereas the total leucocyte count increased to 23,900/cumm with neutrophilia (84%) and serum albumin levels remained low (1.5 g/dl). Thus, antibiotics were upgraded, given the possibility of early sepsis. She also had hyponatraemia that was corrected. Nephrologist consultation was sought for the renal dysfunction, who advised conservative management.
On the 2nd postoperative day, she showed marked improvement in her clinical status. Her blood pressure was controlled, and hence oral antihypertensives were added and nitropruside infusion was tapered off. Serum creatinine levels reduced to 1.6 mg/dl, whereas serum albumin levels slightly improved (1.6 g/dl). Echocardiography revealed an improvement in left ventricular ejection fraction (40%). Over next 4–5 days, she showed progressive improvement, such that the milrinone infusion and antihypertensive medications were stopped. By the 6th postoperative day, her renal function normalised (blood urea16 mg/dl, creatinine 0.9 mg/dl), serum albumin levels increased to 2.0 g/dl associated with subsidence of pedal oedema. Urinalysis revealed no proteinuria.
Finally she was discharged on the 8th postoperative day in a clinically stable state (NYHA-I/IV), with no oedema and the echo showing a left ventricular ejection fraction of 45% with mild mitral regurgitation. Both the babies required minimal respiratory support in the form of non-invasive continuous positive airway pressure support for 1 day, and thereafter they did well.
Discussion
The number of females reaching childbearing age after having undergone a Fontan procedure in childhood is steadily increasing. This case describes a common scenario in developing countries with such patients presenting with unplanned and unsupervised pregnancy often associated with numerous complications.
Pregnancy is known to be associated with various haemodynamic changes, which include an increase in plasma volume by 30–40% and cardiac output by 50% above non-pregnant levels. In addition, there is a 25% increase in heart rate, whereas myocardial oxygen consumption increases by 20%. In a twin pregnancy, the haemodynamic changes are more marked with a 20% greater rise in cardiac output and stroke volume compared with a singleton pregnancy.Reference Kuleva, Youssef and Maroni 1 These changes are well tolerated in normal women; however, a Fontan-palliated patient is dependent on venous return and the capability to increase the stroke volume is limited. This imposes an increased risk of heart failure, arrhythmia, ascites, or even death.Reference Inoue, Masuyama, Akagi and Hiramatsu 2 The haemodynamic compromise of the Fontan circulation therefore has the potential to be more serious with multiple pregnancies owing to the massive circulatory changes. Moreover, pregnancy is a prothrombotic state, and this tendency is further increased in Fontan patients, leading to significant risk of thrombosis. This should be prevented using appropriate anticoagulationReference Gouton, Nizard and Patel 10 , use of compression stockings, and maintaining regular mobility.
Various complications known to occur during pregnancy in a Fontan-palliated patient can be divided into cardiac, obstetric, and neonatal complications.
Cardiac complications
The additional haemodynamic burden of pregnancy is less well tolerated by a Fontan-palliated patient compared with a normal female. It often leads to cardiac complications such as deterioration in functional class, arrhythmias, heart failure, protein-losing enteropathy, myocardial infarction, and occasionally death. Our patient had a deterioration of her functional status (NYHA I to II). Canobbio et alReference Canobbio, Cetta, Silversides, Warnes, Aboulhosn and Colman 3 in their series of 71 Fontan pregnancies found that 33% (n=17) of pregnancies were complicated by an adverse maternal cardiac event including heart failure (n=5) and arrhythmias (n=12). The incidence of arrhythmias has come down significantly after the introduction of the total cavopulmonary connection technique.Reference Lee, Kwak and Kim 4 Fortunately, our patient did not have an episode of arrhythmia during her entire hospital stay, nor had a history of palpitations before admission.
Obstetric complications
Obstetric events reported in these patients include spontaneous abortion, the need for assisted delivery using forceps, vacuum, or caesarean section, premature labour (labour onset <37 completed weeks), premature rupture of membranes,Reference Parry and Strauss 5 prolonged second stage of labour, and postpartum haemorrhage. Canobbio et al,Reference Canobbio, Cetta, Silversides, Warnes, Aboulhosn and Colman 3 with a series of 71 pregnancies in Fontan patients reported a spontaneous abortion rate of 17%, a live birth rate of 73%, and overall obstetric complications of 52%. In our patient, although the rupture of membranes had occurred after the onset of labour, it was complicated by meconium staining of the liquor suggestive of fetal distress, and subsequently emergency caesarean section delivery.
Pregnant Fontan patients can develop pregnancy-induced hypertension, defined as a systolic BP>140 mmHg or diastolic BP>90 mmHg without proteinuria, pre-eclampsia, defined as pregnancy-induced hypertension associated with proteinuria >0.3 g/day, eclampsia, defined as pre-eclampsia complicated by grandmal seizures, thrombo-embolic events, low platelet syndrome, renal and hepatic dysfunction, gestational diabetes, and stroke. Although the incidence of pre-eclampsia is similar in Fontan patients, the increased stress of elevated afterload may be poorly tolerated by the functionally single ventricle in a Fontan circulation. The incidence of pre-eclampsia is two to three times higher in twin compared with singleton pregnancy.Reference Bdolah, Lam and Rajakumar 6 Pre-eclampsia is associated with a marked rise in systemic vascular resistance, reduced venous reserve, reduced intravascular volume, and left ventricular concentric hypertrophy with diastolic and later systolic dysfunction.Reference Melchiorre, Sharma and Thilaganathan 7 All these changes can be very detrimental to the Fontan circulation. Our patient developed pregnancy-induced hypertension, which had progressed to pre-eclampsia and also caused marked hypoalbuminaemia.
Neonatal complications
Fetuses of mothers with a Fontan circulation are often compromised and can have complications such as preterm delivery, small for dates, fetal or neonatal death, and recurrence of a congenital heart malformation. The incidence of prematurity in the general population is usually quoted as 10–15%, although reported to be 39% by Drenthen et al.Reference Drenthen, Pieper and Roos-Hessenlink 8 Canobbio et alReference Canobbio, Cetta, Silversides, Warnes, Aboulhosn and Colman 3 reported a mean gestational age of 34 weeks for all live births. Our patient delivered twin babies, who were both preterm as well as small for dates.
With improving survival after Fontan surgery, a greater number of females will reach childbearing age and contemplate pregnancy. Thus, a programmed approach is needed to manage such patients, which includes multidisciplinary teamwork involving several specialists. Counselling related to pregnancy should be started very early after surgery, and initially parents should be informed about the need for regular follow-up, the risks of pregnancy, and the need for pre-pregnancy planning, as certain drugs such as angiotensin converting inhibitors often used in Fontan patients need to be stopped before conception.Reference McRae 9 As these patients approach childbearing age, they should be counselled about contraception, the risk of pregnancy with Fontan circulation, and the need for thorough planning and monitoring if pregnancy is desired. Each Fontan patient should have detailed pre-conception counselling regarding the high miscarriage rates with expected psychological consequences, and the frequent occurrence of other clinically significant complications during pregnancy, especially maternal haemodynamic disturbances, the high incidence of premature labour and delivery, as well as the risks of neonatal death. They should have strict perinatal care with regular follow-up, and a planned delivery at a tertiary cardiac care centre is essential.
Acknowledgements
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Conflict of Interest
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