An Interesting Case
Management Of A Pregnant Patient With Fontan Physiology And Coarctation Of The Aorta
Authors: Olga Pawelek MD†, Poyee Tung MD††, Nischal Gautam MD†
† Department of Anesthesiology
†† Department of Cardiology
McGovern Medical School, UT Health, Houston
A 20-year-old female with a history of tricuspid atresia, d-transposition of the great arteries (d-TGA), and aortic arch coarctation status post palliation with an extracardiac Fontan now presents with a 32-week gestation pregnancy. Her pregnancy is complicated by gestational hypertension and oligohydramnios.
She had an extracardiac Fontan palliation at three years of age and a balloon dilatation nine years ago for residual aortic coarctation. The distal aortic coarctation gradient was 40 mmHg last year. However, she refused balloon angioplasty at that time and became pregnant shortly thereafter.
She is currently on enoxaparin 40 mg once daily and was recently started on nocturnal oxygen supplementation at 5 liters (L) per minute via nasal cannula to maintain an oxygen saturation of 95%. She has a reassuring airway exam and is otherwise in good health. Her cardiologist referred her to a high-risk obstetrician who plans to admit her for optimization before delivery.
Vital signs on admission:
Weight = 66 kg, HR= 96 bpm, BP 122/75 mmHg, SpO2 = 94% on 5L per minute.
Imaging on the day of admission:
Transthoracic echocardiography performed at admission:
- Systemic ventricle (anatomic left ventricle (LV)) is normal in size and systolic function.
- Anatomic right ventricle (RV) is small and hypoplastic.
- Trivial aortic regurgitation.
- No mitral regurgitation.
- Right pulmonary artery measures 14 mm and left pulmonary artery measures 16mm. Laminar flow is seen in both branch pulmonary arteries. Glenn is not well visualized. Fontan fenestration is not seen.
- The left ventricular outflow tract (LVOT) and ascending aorta have normal dimensions (LVOT 2.2cm, sinus of Valsalva 3.2 mm, ST junction 2.2) and there is normal flow across the LVOT and aorta.
- Turbulent flow is seen in the distal arch and proximal thoracic descending aorta with a peak gradient of 50 mmHg.
Fetal echocardiography demonstrates a structurally normal heart.
Audience Question 1: At the multidisciplinary case conference, how would you suggest managing this patient’s delivery?
A. Admit patient, plan for an elective cesarean at 34 weeks under general anesthesia
B. Admit patient, plan for an elective cesarean at 36 weeks under neuraxial anesthesia
C. Admit patient, plan for an elective cesarean at 36 weeks under general anesthesia
D. Admit patient, plan for induction of labor at 36 weeks
E. Discharge patient and admit with rupture of membranes/onset of labor or at 38 weeks
Audience Question 2: What other diagnostic studies or interventions would you recommend?
A. Repeat cardiac catheterization and ballooning of coarctation between 32-36 weeks’ gestation
B. Repeat cardiac catheterization and ballooning of coarctation in the immediate postpartum period
C. No intervention
Audience Question 3: How would you manage anticoagulation in this patient?
A. Stop enoxaparin at 36 weeks and start the patient on subcutaneous unfractionated heparin 5000 Units every 8 hours
B. Stop enoxaparin at 36 weeks and transition the patient to an IV heparin infusion
C. Continue enoxaparin until delivery
D. Continue enoxaparin and discontinue 24 hours prior to neuraxial block placement
Audience Question 4: The patient tolerates an uneventful cesarean section with epidural anesthesia. A baby girl is successfully delivered with APGARS 8/9. There was 2.5L of total blood loss during the case. The patient is comfortable post-operatively. Where would you recover this patient?
A. Cardiac intensive care unit (ICU) with central venous and arterial monitoring
B. Cardiac ICU with no invasive monitoring
C. Cardiac floor with telemetry monitoring
D. Postpartum unit
Audience Question 1:
At the multidisciplinary case conference, how would you suggest managing this patient’s delivery?
Expert Opinion #1: OB considerations
Is there a benefit to admitting the patient before delivery?
What resources should be available at the facility where delivery is planned?
What is this patient’s risk according to the ZAHARA1 and CARPREG2 and modified WHO?
Are there any advantages for a cesarean section versus labor and a vaginal delivery?
Should the uterus be exteriorized?
What is the plan for hemostasis?
Would you plan for extracorporeal membrane oxygenation (ECMO) back up?
The decision to admit the patient prior to delivery depends on the ease of coordination of services within the hospital and the ability of the patient to be assessed in an outpatient setting. The center for delivery should have experience treating patients with Fontan physiology and have obstetricians, cardiologists, cardiac anesthesiologists, cardiologists, cardiac surgeons, and critical care physicians familiar with congenital heart disease (CHD) who are capable of coordinating management for high-risk CHD patients3. The plan for anticoagulation management may also warrant an admission.
A review in 2018 by Kim et al. compared the three scales and found that the modified WHO score is the best scale to predict adverse cardiac outcomes4,5. Risk stratification allows for optimal planning and management of patients with Fontan physiology. The goal in taking care of patients with a Fontan physiology is to maintain cardiac output and to keep the transpulmonary gradient between the systemic veins and the pulmonary veins at a minimum. Pregnancy alters the cardiopulmonary profile and these changes plateau between 28 and 32 weeks of pregnancy6. During normal pregnancy, there is an increase in preload, a decrease in afterload, increased circulating volume, and increased cardiac output (40-50%) via increase in stroke volume and heart rate. Most of these changes might assist in maintaining forward flow in the pregnant woman with a “healthy” Fontan physiology. In addition, pregnancy decreases pulmonary vascular resistance (34%), again adding a favorable effect in patients with a “healthy” Fontan physiology. However, risk stratification is based on the single ventricle’s ability to handle and keep up with these changes. If the systemic ventricle is unable to handle the increase in preload or in the presence of poor ventricular function, obstruction to forward flow, or increased pulmonary vascular resistance, the WHO classification changes from healthy Fontan (class III) to a complicated Fontan (class IV) categorizing these patients at the highest risk.
The decision for planned trial of labor versus planned caesarean section should be discussed at the multidisciplinary meeting and the team should provide advice to the parturient on the management of birth. The plan should include a discussion about the ability to quickly mobilize all teams involved in care. Planned trial of labor confers advantages of reduced blood loss, and fewer postpartum complications7,8. However, the unpredictability of progress of labor, increased incidence of labor emergencies in this subset of patients6, and fetal distress resulting in emergency caesarean sections requiring general anesthesia are known complications of this approach. Planned caesarean delivery is often indicated for known obstetrical indications8.
The existing data currently does not show a definite benefit of vaginal delivery versus cesarean section in Fontan patients for maternal outcomes9. The experience from reported case series shows that about a quarter to half of the pregnancies in Fontan parturients are delivered by cesarean section6,9. However, recent data suggests that in patients with cardiac diseases, planned caesarean section has no additional advantage over vaginal delivery in terms of maternal outcomes but is associated with adverse fetal outcomes10. This review recommends planned vaginal birth when no obstetrical contraindications exists in patients with significant cardiac disease10.
Neuraxial techniques for labor analgesia decrease preload and raise concerns of impeding cardiac output11. However, a review of recent literature suggests that when used with close hemodynamic monitoring, neuraxial catheter technique of anesthesia in the form of epidural was the most common choice for labor or caesarian section in patients with Fontan physiology6. If a general anesthetic has to be used in an emergency setting or due to obstetrical indications, then anesthetic maneuvers to augment cardiac output (avoid aortocaval compression, maintain preload, etc.) and minimize pulmonary vascular resistance (avoid high peak airway and plateau pressures, hypoxia, hypercarbia, etc.) should be incorporated in the anesthetic plan. A rapid sequence induction is often necessary in this setting and the use of positive pressure ventilation has been shown to be successful when used in these patients6.
Anticoagulation management is important because there is a high risk of arrhythmia and thromboembolism in Fontan patients9. Pregnancy is also a hypercoagulable state, putting the low-flow Fontan circuit at risk for thrombo-embolism5. Gouton et al.9 recommend that all women with Fontan palliation should receive at least prophylactic anticoagulation during pregnancy and into the postpartum period. Half to all of the cesarean section patients underwent a form of neuraxial analgesia12. A common contraindication to neuraxial analgesia was a rapid onset of labor and use of LMWH12.
Blood loss for vaginal delivery is reported as more than 500 mL and double that for cesarean section (at more than 1 L). Bonner et al. report an overall cesarean section rate of 60% with the majority performed for pre-term labor and fetal growth restriction13. Almost all women in that series underwent combined spinal epidural anesthesia for labor and only two women had general anesthesia due to inadequate spinal block. Cesarean section may offer the benefit of having all the team assembled in case there is a need for further interventions and possible ECMO support. Since the Fontan patient is receiving anticoagulation medication, bleeding from the cesarean section needs to be anticipated. If all of the team members are readily available, a vaginal delivery may be decided upon with input from the obstetrical service.
Exteriorizing the uterus during a cesarean section may introduce air into the circulation resulting in a stroke and an increase in pulmonary vascular resistance (PVR), which has severe consequences for patients with similar anatomy and cardiac condition to the patient described in this scenario. The discussion for ECMO back-up during delivery should include assessment of the femoral vessels for patency and whether an ECMO circuit should be primed and immediately available.
The ZAHARA1, CARPREG2 and WHO scores are useful tools to stratify patient risk.
- Poor functional class (NYHA functional class III or IV) or cyanosis
- Systemic ventricular ejection fraction <40%
- Left heart obstruction
Cardiac event prior to pregnancy
- History of arrhythmias (weighted score 1.5)
- Cardiac medications before pregnancy (weighted score 1.5)
- NYHA functional class prior to pregnancy ≥II, left heart obstruction (weighted score 0.75)
- Left heart obstruction (weighted score 2.5)
- Systemic atrioventricular valve regurgitation (weighted score 0.75)
- Pulmonary atrioventricular valve regurgitation (weighted score 0.75)
- Mechanical valve prosthesis (weighted score 4.25)
Cyanotic heart disease (weighted score 1.0)
Modified WHO classification
WHO classification I
- Uncomplicated small or mild pulmonary stenosis
- Patent ductus arteriosus
- Mitral valve prolapse
- Successfully repaired simple lesions (atrial or ventricular septal defect, patent ductus arteriosus, anomalous pulmonary venous connection)
WHO classification II (if otherwise well and uncomplicated)
- Unrepaired atrial or ventricular septal defect
- Unrepaired Tetralogy of Fallot
WHO classification II–III (depending on individual)
- Mild left ventricular impairment
- Native or tissue valvular heart disease not considered WHO I or IV
- Marfan syndrome without aortic dilation
- Aorta <45 mm in association with bicuspid aortic valve disease
- Repaired coarctation
WHO classification III
- Mechanical valve
- Systemic right ventricle
- Fontan circulation
- Unrepaired cyanotic heart disease
- Other complex congenital heart disease
- Aortic dilation 40–45 mm in Marfan syndrome
- Aortic dilation 45–50 mm in bicuspid aortic valve disease
WHO classification IV (pregnancy contraindicated)
- Pulmonary arterial hypertension from any cause
- Severe systemic ventricular dysfunction (LVEF <30%, NYHA functional class III–IV)
- Severe mitral stenosis; severe symptomatic aortic stenosis
- Marfan syndrome with aorta dilated >45 mm
- Aortic dilation >50 mm in aortic disease associated with bicuspid aortic valve
- Native severe coarctation of the aorta
Risk stratification in pregnancy
a. CARPREG (Cardiac Disease in Pregnancy): Each risk factor is worth 1 point. Women with risk scores of 0, 1, or >1 had event rates during pregnancy of 5%, 25%, or 75%, respectively.
b. ZAHARA (Zwangerschap bij vrouwen met een Aangeboren HARtAfwijking-II): Weighted risk score. Weights shown in parenthesis. Women with risk scores of 0–0.50, 0.51–1.5, 1.51–2.5, 2.51–3.5, and >3.51 had event rates of 2.9%, 7.5%, 17.5%, 43.1%, and 70.0%, respectively.
c. World Health Organization (WHO) classification:
- WHO classification I: no detectable increased risk of maternal mortality and no/mild increase in morbidity.
- WHO classification II: small increase in maternal risk mortality or moderate increase in morbidity.
- WHO classification III: significantly increased risk of maternal mortality or severe morbidity. Expert counseling required. If pregnancy is decided upon, intensive specialist cardiac and obstetric monitoring needed throughout pregnancy, childbirth and the puerperium.
- WHO classification IV: extremely high risk of maternal mortality or severe morbidity; pregnancy contraindicated. If pregnancy occurs, termination should be discussed. If pregnancy continues, care as for WHO class III.
Audience Question 2
What other diagnostic studies or interventions would you recommend?
Expert Opinion #2: Cardiology considerations
If the patient chooses balloon dilatation of the aortic arch, when would you plan to perform the intervention?
If the cardiac function is depressed, would you recommend an urgent cardiac intervention?
Would recommendations change if the patient developed worsening atrio-ventricular valve regurgitation due to the volume load of pregnancy?
Do you want to know what the PVR is? Does it matter?
How would your management change if the aorta is dilated?
Despite the residual aortic coarctation, our patient had no signs or symptoms of cardiac decompensation nor issues related to poor fetal growth secondary to placental hypoperfusion. Cardiac interventions should be avoided during pregnancy unless necessary due to possible maternal decompensation. Should cardiac catheterization interventions be required, the best time is after the fourth month during the second trimester. During this time, organogenesis is complete and the fetal thyroid is still inactive. Uterine volume at this time is relatively small, which minimizes fetal radiation exposure due to the greater distance between the chest and abdomen. The possibility of emergent cardiac surgery needs to be considered if a cardiac catheterization intervention fails or there is a complication. Cardiopulmonary bypass during pregnancy carries a 20% risk of fetal mortality. Hence, the decision to proceed with cardiac catheterization interventions with cardiac surgery as a backup needs to be carefully considered.
If the patient had cardiac dysfunction with the coarctation of aorta in the setting of Fontan physiology, this would certainly put her in WHO class IV in terms of cardiac risk. Management during pregnancy depends on whether the parturient has refractory heart failure symptoms despite medical therapy. If the patient is in heart failure and the baby is at a viable gestational age, such as greater than 26-28 weeks, an earlier delivery can be considered versus performing a percutaneous intervention for aortic coarctation. This decision needs to be discussed among the cardiologist, neonatologist, maternal fetal medicine specialist, and, of course, the patient and her family. Worsening atrioventricular regurgitation may occur during pregnancy as a result of volume overload. This can usually be managed medically and rarely requires earlier delivery.
If a Fontan patient had significantly elevated PVR then she would present with symptoms related to low cardiac output and hypoxia. The WHO definition of pulmonary hypertension during pregnancy is greater than 3 Wood units. A Fontan patient with pulmonary hypertension during pregnancy is at risk for poor cardiac outcome. If there are concerns for elevated PVR based on physical exam and clinical data, then cardiac catheterization for hemodynamic evaluation would help guide management and the potential use of vasodilator therapy. Also, pulmonary hypertension carries a significant risk of maternal mortality and consideration for termination should also be discussed.
If there is significant aortic root dilation (i.e.,> 45 mm in Marfan, > 50 mm in a bicuspid valve, > 25 mm/m2 in Turner), then the parturient is WHO class IV status for maternal cardiac risk. Patients with significant aortic root dilatation are at risk for aortic dissection and progression of aortic root dilation during pregnancy. These patients should be treated with a beta-blocker and be monitored closely for progression of aortic dilation during pregnancy and after delivery.
Audience Question 3
How would you manage anticoagulation in this patient?
Expert Opinion #3: Intraoperative considerations
How would you manage her peripartum anticoagulation?
Discuss what factors would favor general anesthesia versus neuraxial technique.
What is the backup plan for intraoperative deterioration? Would you consider cannulating the femoral vessels before cesarean section?
How would you manage hemostasis?
Which monitors would you choose for this patient during the delivery?
Is there a plan for uterine compression suture, uterine vessel balloon occlusion or hysterectomy? Discuss the risks and benefits of oxytocin, methylergonovine, and carboprost in this patient.
Anticoagulation can be managed with once daily enoxaparin dosing if the plan is to do a scheduled cesarean section. If the decision is made to do a trial of labor, the patient can be transitioned on a heparin infusion, which can be held prior to epidural placement. General anesthesia and neuraxial anesthesia have been used successfully for cesarean sections in Fontan patients. The risks and benefits to perform general anesthesia or neuraxial anesthesia should be discussed with the team. Low dose epidural anesthesia or combined spinal-epidural anesthesia have the benefits of preserving negative inspiratory pressure and cardiac preload, which is beneficial for Fontan physiology3. General anesthesia provides the benefit of afterload reduction but the downside of positive pressure ventilation and the negative inotropic effects of anesthetic agents and dilation of uterine vasculature that may worsen the risk of bleeding. The patient may also prefer to witness the birth of her child if it can be done safely to enhance the maternal-infant bonding.
Given this patient’s aortic coarctation and supplemental oxygen, arterial blood pressure and central pressure monitors should be placed to help guide the infusion of oxytocin and postoperative management. The obstetrical team should be prepared for increased postpartum bleeding given the patient’s anticoagulation. The anesthesiologist needs to consider whether the patient will tolerate oxytocin as a slow infusion with invasive blood pressure monitoring for guidance. Other options for minimizing postpartum bleeding are methylergonovine, which has a risk of vasoconstriction and hypertension, or prostaglandin, which has a risk of bronchospasm and V/Q mismatch. Misoprostol may be less effective but does not carry the risks of hypertension and bronchospasm. Uterine compression sutures, intrauterine balloon tamponade, embolization or ligation of arteries supplying uterus and hysterectomy are obstetrical options. If the patient decompensates, ECMO should be available and hence, the requirement to deliver this patient in an ECMO capable facility.
Audience Question 4:
Where would you recover this patient?
Postoperative monitoring is essential given the risks of arrhythmia, thromboembolic events, or bleeding. The duration of monitoring will depend on the patient’s status. It is advisable to have access to critical care physicians, nurses, and obstetricians who are familiar with congenital cardiac patients. Patients who are stable after the immediate postpartum period can be transitioned from the ICU to the postpartum unit and continue to be followed by the cardiology service.
The patient was admitted at 32 weeks with the above diagnosis requiring oxygen supplementation and inpatient monitoring. Based on the recommendations of the multidisciplinary team, the patient was scheduled for delivery at 36 weeks via cesarean section. However, the patient had premature rupture of membranes at 35 weeks and thus underwent a semi-elective cesarean section. Arterial and central venous catheters were placed for monitoring. A femoral artery sheath and venous access sheaths were placed subsequently. Following this, the patient underwent combined spinal-epidural anesthesia with intrathecal fentanyl and 2% lidocaine in the epidural space. After ensuring an adequate anesthetic level, a low transverse cesarean section was performed, and a healthy newborn with good APGAR scores was delivered. The uterus was then exteriorized, the hysterotomy was closed, and hemostasis was achieved. The patient tolerated the procedure well and was discharged on postoperative day 4. The patient was subsequently followed up and was seen one week post-partum for lower extremity edema related to fluid shift but was not in clinical heart failure. At six weeks, post-partum, the patient had recovered to baseline and was scheduled for an elective angioplasty of the coarctation.
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