Pregnancy in non-palliated functionally single ventricle: challenges of management in resource-poor settings

Women with complex functionally univentricular hearts rarely survive into adulthood without corrective or palliative surgery. Reports of pregnancy outcome in this group of patients in resource-poor settings are sparse. We report a case of unrepaired pulmonary atresia ventricular septal defect (VSD) with major aorto-pulmonary collateral arteries (MAPCA) who survived into adulthood and was able to complete a successful pregnancy in a resource-poor country.


Introduction
The term functionally single ventricle refers to a spectrum of congenital heart defects in which the ventricular mass, which may be anatomically single or double, does not lend itself to safe partitioning in a way that commits one ventricular pump to the systemic circulation, and the other to the pulmonary circulation [1]. Pulmonary atresia with VSD and major aorto-pulmonary collateral arteries (MAPCA) is the most extreme form of tetralogy of Fallot (TOF) representing 5% to 10% of TOF patients [2]. The survival rate without surgical repair is reported to be 50% at 1 year of age and 8% at 10 years [3]. Survival into adulthood without palliation is rare; successful pregnancy in such patients is even rarer. Pregnancy is accompanied by dramatic changes in systemic vascular resistance and venous return from the late second trimester onwards. Pregnancy in patients with uncorrected PA VSD MAPCA is fraught with many challenges which are magnified in resource-poor settings. These challenges and their management are not usually encountered in routine clinical practice in developing countries. Current available guidelines are in reference to specialized adult congenital heart disease (ACHD) centers, largely unavailable in resource-poor settings. We report our experience in successfully managing pregnancy in a patient with uncorrected PA VSD MAPCAs in Accra, Ghana.

Patient and observation
Ghana's National Cardiothoracic Centre was officially inaugurated in April of 1992. In 1983 when the patient was four years of age, she was part of a selected group of children who received philanthropic support to travel to Europe for treatment of cyanotic CHD. She was prepared for surgery with a preoperative diagnosis of truncus arteriosus (common arterial trunk). At surgery, a solitary systemic arterial trunk arising from the ventricular mass was found. The pulmonary blood flow was derived from large collateral vessels arising from the descending aorta. Because the patient's saturation was satisfactory (above 80% most times) no intraoperative intervention was deemed necessary. The patient returned home after an uneventful recovery to be followed up locally. She maintained satisfactory saturations and fairly adequate exercise tolerance throughout childhood. She underwent phlebotomy on three occasions on account of hyperviscosity. Although counselled about the risks of pregnancy, she was insistent on having a child. At age 32 years, she became pregnant but miscarried in the first trimester. One year later, she presented to our clinic with a seven week pregnancy.
At the time of the pregnancy, she was not on any medication and had only mild effort intolerance (NYHA II). The oxygen saturations ranged between 86%-89%. Her blood pressure was 101/69mmHg with a pulse rate of 86 per minute. Her hemoglobin was 18.3g/dl (hematocrit of 54.9%). The transthoracic echocardiography was in keeping with her intraoperative findings in childhood: usual veno-atrial and atrioventricular connections, diminutive outlet portion of the right ventricle without continuity with an arterial segment, both ventricles connected to a 40mm solitary arterial trunk through a 27mm subarterial VSD. No intra-pericardial pulmonary artery was found. Large collateral vessels (MAPCAs) arising from the descending aorta appeared to be the source of pulmonary blood flow, with origin stenosis of the left-sided MAPCA. The ventricular function was good with ejection fraction of 76%. There were echocardiographic signs of pulmonary hypertension. The risks of pregnancy to mother and fetus were once again emphasized and termination discussed as an option but the patient preferred to continue with the pregnancy.
A multidisciplinary specialist team consisting of a cardiologist, obstetrician/gynecologist, and cardiac anesthetist as the core team members was formed to draw a management plan for the pregnancy, deliver, and puerperium. The patient, being a house wife, was advised to reduce her chores at home in keeping with her comfort. The patient tolerated the pregnancy relatively well, maintaining oxygen saturations between 84% and 88% until the 28 th week. At 28 weeks gestation, her effort tolerance worsened, her oxygen saturation dropped to 80% and the hemoglobin rose to 19.9g/dl. She was hospitalized and placed on bed rest, close surveillance, and regular fetal monitoring. She was given elastic compression stockings and anticoagulated with warfarin (target INR between 2 and 3) to counter the risk of thromboembolism. The initial pelvic scan demonstrated no obvious fetal abnormalities but subsequent scans showed signs of oligohydramnios. The findings suggested slow amniotic fluid loss. The decision was thus taken at 34 weeks to deliver the fetus. An elective Caesarean Section was performed at 34 weeks of gestation under general anesthesia. A female infant, weighing 1.2 kg was delivered with APGAR scores of 6 and 7 (first and fifth minutes).
On the second postpartum day the patient developed congestive heart failure. She was treated with diuretics (furosemide and spironolactone) with good response and was discharged a week later.
The baby was initially nursed in the neonatal intensive care unit.
Echocardiography on the baby prior to discharge showed no CHD.
Post-delivery evaluation of the mother showed good ventricular function on echocardiogram. A computed tomographic angiography was performed a year after delivery to evaluate the sources of pulmonary blood flow ( Figure 1A). The ascending aorta measured 45mm with usual branching pattern. The right lung was supplied by an 18mm MAPCA from the descending aorta ( Figure 1B). The left lung was supplied by another MAPCA measuring 20mm with origin stenosis ( Figure 1C). After six years post-delivery follow up, both mother and child are doing well. The mother's effort tolerance has diminished moderately but she is still able to care for the child and perform her usual daily chores reasonably well.

Discussion
Current guidelines recommend that women with CHD should consult an ACHD specialist before becoming pregnant. Also, the management of pregnant patients with cyanotic CHD should be undertaken in an ACHD center by a multidisciplinary team that includes ACHD specialists and maternal-fetal medicine obstetricians with expertise in caring for women with heart disease [4]. In resource-poor settings, these ideals are not attainable due to infrastructure and manpower constraints.
Management of such patients in these settings is often accomplished by drawing upon the expertise of practitioners across various departments in a tertiary facility who must work together to achieve optimal outcomes for the patient. During childhood, this patient's diagnosis was truncus arteriosus type IV. The original categorization of truncus arteriosus by Collett and Edwards [5] included a type IV variant characterized by the complete absence of the intra-pericardial pulmonary arteries. Type IV truncus arteriosus is now recognized to be a form of PA VSD [6].
Pregnancy in patients with PA VSD MAPCA carries substantial maternal and fetal risks [7] as well as a risk of CHD in the newborn of 13.4% [8]. Surgical intervention in the form of anatomical repair or palliation that eliminates or significantly ameliorates cyanosis and secondary erythrocytosis has a modifying influence on the pattern of risk observed in pregnant patients with PA VSD MAPCA. In unrepaired patients like ours, maternal mortality and morbidity tends to be low while complications occur mainly in the fetus [7]. A high rate of fetal loss is common as occurred with this patient in the first pregnancy.
Maternal cyanosis carries substantial risk to the fetus with a higher chance of fetal loss in the first trimester, prematurity, and small-forgestational-age neonates. Successful pregnancy is more likely if cyanosis is minimal or absent, and erythrocytosis is moderate or less before pregnancy. Both of these are uncommon findings in the unrepaired patient with PA VSD MAPCA. In one study, the live birth rate was just 8% if the pre-pregnancy hemoglobin exceeded 20g/dl whereas it was 71%, if the hemoglobin was 16g/dl or less, if the maternal oxygen saturation was 85% or less before pregnancy and only 12% of infants were born alive [9]. In this regard, our patient had a borderline fetal risk. and anticoagulation were deemed necessary. Though anticoagulation is considered useful in pregnant cyanotic patients on bed rest, there is no consensus on this issue [4].
Between the 28 th and 34 th weeks, there was concern for the mothers worsening hypoxemia, increasing hematocrit and deteriorating effort

Competing interests
The authors declare no competing interests.