patent ductus arteriosus
mitral valve prolapse
LVEF = left ventricular ejection fraction; NYHA = New York Heart Association; WHO = World Health Organization
It is known that complicated maternal heart disease increases fetal risks (see Chapter 10). The best-documented factors are summarized in Table 6.5. Unsurprisingly, some of these are the same factors that can complicate maternal outcome.
|Baseline NYHA class >II or cyanosis|
|Maternal left heart obstruction|
|Smoking during pregnancy|
|Use of oral anticoagulants during pregnancy|
|Mechanical valve prosthesis|
FGR = fetal growth restriction; NYHA = New York Heart Association; RDS = respiratory distress syndrome
The risk of a child being born with CHD in the general population is estimated to be 0.8%. The risk of a structural cardiac lesion in the offspring of a parent with CHD ranges from 2% to 50% (e.g. for 22q11 deletion or Marfan syndrome). This requires a detailed discussion with the woman and her partner. The woman’s own experience with her heart disease may affect how she views the risk of her child being born with a congenital heart defect.
The long-term prognosis for the woman should be discussed as well. She may have a significantly increased risk of premature death or disability, even without the pregnancy. This will be relevant to planning future childcare if she decides to go ahead with a pregnancy. There are also concerns about whether this pregnancy will worsen her long-term prognosis. This is certainly the case with peripartum cardiomyopathy and possibly with systemic right ventricle and tetralogy of Fallot.[12,13] Data on the effect of pregnancy on long-term outcome in these women are still very preliminary (Chapters 23 and 24).
After these risks are understood and have been discussed, the focus will next be placed on what needs to be done to reduce these risks. This may involve some invasive intervention (Chapter 8), preferably prior to conception, and/or initiation of medication (e.g. severe aortic stenosis or a patient with atrial septal defect) and lifestyle changes (e.g. careful attention to salt intake for a patient with decreased systolic function). For some patients, termination of pregnancy needs to be seriously considered and the related discussion sensitively handled.
Once the maternal and fetal risk assessment has been completed and the decision has been made to continue with the pregnancy, arrangements can be made for their ongoing follow-up.
Women who fall into the low-risk group of WHO I and II can reasonably be cared for by their local obstetrician and local cardiologist (Table 6.4). This group would include women with normal left ventricular systolic function, small left-to-right shunts, valvar regurgitation without ventricular dysfunction, or repaired defects without significant sequelae. This assumes that they have been fully evaluated and that the risk assessment is accurate. At times, it may be reasonable to refer even these individuals to a specialized center for an initial assessment and confirmation of their low-risk status.
Patients in WHO class III and WHO class II–III are best managed by experienced and expert teams and specialized centers. Such centers should be able to provide the full range of medical and perinatal care. The team should consist of an obstetrician and a cardiologist, as well as an anesthetist and later a neonatologist, as well as providing midwife support and social support as necessary. Care will be easier if the obstetrician and the cardiologist can see the woman together at the same location. Such an arrangement enhances communication among all members of the team. Careful planning and communication are essential in the management of the higher risk pregnancy.
The frequency of the antenatal visits will depend significantly on the severity of the woman’s underlying cardiac problem and will have to be adjusted to deal with changes in her status. It cannot be emphasized enough that careful documentation of findings and plan of management should be discussed with the patient and all members of the team, and should be available for review by the on-call cardiologist. Decisions about endocarditis prophylaxis, as well as plans for anesthesia, labor and delivery, and pediatric care need to be clearly spelled out. Some women will require increased postpartum monitoring and prolonged postpartum hospital stay because of their particular lesion. The availability of the plans for management and delivery is critical because the patient may present at any time, and not necessarily when the usual members of her team are on duty. This is also important for the woman who is being cared for by a specialized unit but who may live some distance away. She may well present to her local hospital and it will be important that all her information is freely available to the local physician as well as to the specialized unit cardiologist who is being called about her. The use of electronic medical records can facilitate such availability; however, an acceptable alternative is the UK system, whereby women carry their own clinical records and a copy of the key data is kept in the hospital. Many years’ experience of this approach shows that it is very rare for women to lose their own notes (after all, their proper care depends upon the notes being readily available when needed, so they have a major incentive to keep them safe), whereas lost or unavailable notes within the hospital system is a common phenomenon.
A complete history and physical examination should be documented at the initial assessment. The cardiologist will need to make a careful repeat assessment at each visit, looking for changes of significance. It is common for pregnant women even without heart disease to complain of fatigue, dyspnea, palpitation, or pedal edema. It can be challenging to distinguish the symptoms of a normal pregnancy from those of early heart failure. On examination, pregnancy can frequently be associated with a systolic ejection murmur as well as a physiological third heart sound. It is important to decide under which circumstances a third heart sound becomes a concern. Blood pressure deserves special attention. Pre-existing cardiac disease does not protect the woman from preeclampsia, and preeclampsia can be particularly troublesome in the setting of complex cardiac disease. Oxygen saturation should be measured regularly and may be of special concern in women with open shunts. The usual decrease in peripheral vascular resistance may facilitate right to left shunting and will need to be carefully followed.
Regular fetal assessment is very important and will have implications regarding the cardiac management of the woman. Evidence of fetal growth restriction may indicate inadequate cardiac output and may prompt a change in treatment or constitute sufficient grounds for invasive intervention.
For the patient on medication, it is important to establish their usual level of compliance. This is especially true of the pregnant patient with PH who is receiving advanced therapies. Careful monitoring of anticoagulation is critical and the patient needs to understand how important it is for her to have ongoing blood investigations for optimal anticoagulation. Patients on diuretics and those with decreased systolic function should have regular assessment of electrolytes and renal function. The urine should be checked for protein.
Patient monitoring in hospital and postpartum will depend on the complexity and the severity of the heart disease, and the progression of the pregnancy. The previously formulated plans will provide guidance on the degree of monitoring required, keeping in mind that the clinical situation may change and warrant reconsideration of the degree of monitoring. Usually, close attention to blood pressure, heart rate, and rhythm is sufficient, with oxygen saturation monitoring needed for those with heart failure and cyanotic lesions. Invasive monitoring is usually only considered for patients with symptomatic aortic stenosis or mitral stenosis, worsening hypotension, Eisenmenger syndrome, or PH. Invasive monitoring with an arterial line and a central venous catheter is recommended for patients with Eisenmenger syndrome or PH. The use of a pulmonary artery catheter in this setting remains controversial.
Some women, such as those with Marfan syndrome or PH, may require more prolonged monitoring in hospital after delivery, as well as closer attention for weeks and months postpartum. In general, a follow-up assessment at 6–8 weeks is advisable and plans are necessary regarding long-term cardiology follow-up because the woman still has her underlying cardiac disease that continues to require ongoing assessment and management. Repeat imaging is frequently undertaken at 6–9 months, after the majority of the cardiovascular remodeling effects of pregnancy have worn off. There have been concerns that the pregnancy itself may contribute to worsening of the underlying cardiac lesion but there are insufficient data to provide good guidance (Chapters 23 and 24).
Echocardiography is central to the management of the pregnant woman with heart disease. It is readily available, can be performed safely throughout gestation, and allows a more precise definition of the presence and severity of cardiac lesions and serial assessment of ventricular function compared with clinical assessment alone. A detailed description of physiological changes and cardiac remodeling related to pregnancy is given in Chapter 3. Understanding these changes is crucial to anticipating and recognizing the effects of these changes on various cardiac lesions. The added hemodynamic burden of pregnancy may unmask a previously well-compensated or undiagnosed lesion. The frequency of echocardiography surveillance required is related to the cardiac condition and the clinical assessment. In our practice, echocardiography is usually performed at the initial assessment during pregnancy and then repeated (in all except the low-risk patients) toward the end of the second trimester when the hemodynamic changes have almost reached a maximum. In high-risk conditions, for example cardiomyopathy, PH, or aortopathy, more frequent echocardiographic studies are recommended.[1,2]
Congenital and structural heart disease encompasses a broad spectrum of lesions and each patient is potentially unique. Therefore, an exhaustive approach to their echocardiographic assessment is outside the scope of this chapter. However, for all heart disease and pregnancy the essential information provided should include: