The pregnant woman with heart disease: management of pregnancy and delivery

A 28-year-old woman presented with a pregnancy wish. She had a history of subvalvular membranous aortic stenosis. At 7 and at 14 years of age surgical resection of the membrane was performed. As a young adult, she developed recurrent severe subvalvular stenosis which became symptomatic. When she was 21 years old, the membrane was radically resected through a Morrow procedure and the left ventricular (LV) outflow tract was widened with a Konno procedure. After this operation she was symptom-free and needed no medication. Her echocardiogram demonstrated septal akinesia with an LV diastolic diameter of 57 mm at the basal level but a normal midventricular diameter of 52 mm. LV ejection fraction was 50%. The aortic valve was abnormal with grade I regurgitation and valvular aortic stenosis with peak and mean gradients of 27 and 15 mmHg. It was concluded that she had a slightly elevated risk of heart failure and arrhythmias during pregnancy because of her mild aortic valve dysfunction and local wall motion abnormality of the LV. She was graded as pregnancy risk WHO class II [5‐7] (low-moderate risk). She became pregnant in 2007 and was followed in the cardiac service at 20, 26 and 34 weeks. Her LV diameters and ejection fraction as well as the aortic stenosis and regurgitation were stable. She developed dyspnoea on exertion during the second trimester without signs of heart failure, which was attributed to the pregnancy in combination with moderate overweight. During the last weeks of pregnancy she started to gain weight, a total of 8 kg in 2 weeks time, and she felt more dyspnoeic. The patient, a medical doctor herself, suggested that she had fluid retention due to heart failure, but the junior gynaecologist assured her that this weight gain was normal and the cardiologist was not consulted. Delivery was induced at 39 weeks and a healthy daughter was delivered by secondary caesarean section. Two months after delivery she was admitted because of bradycardia due to 2nd degree AV block and a DDDR pacemaker was inserted. Unfortunately, at the first echocardiogram after delivery her LV diameters were significantly larger than pre-pregnancy, 65 and 58 mm at basal and midventricular levels, respectively, with preserved ejection fraction of 50%. She remained in NYHA class II post-pregnancy. It was considered that she may have had an unrecognised period of heart failure in the weeks before delivery which was a likely explanation for the LV dilatation. Alternatively, ventricular pacing may have caused the dilatation post-pregnancy.

It can be concluded that the care of this woman was suboptimal in the last weeks of her pregnancy. Her pregnancy risk was adequately assessed as low to moderate, therefore routine cardiac supervision was not planned after the 34th week. However, the cardiologist should have been consulted both when she complained of excessive weight gain and increasing dyspnoea and when the delivery started. We can only speculate if this would have made any difference in outcome. Nevertheless, if she had been diagnosed with heart failure, medication and/or early delivery might have prevented damage. In the CEMACH (Confidential Enquiry on Maternal Death) report [8], it appeared that substandard care was an important contributing factor to the death of many mothers. Substandard care included insufficient communication between team members and inappropriate delegation of tasks to junior doctors. Though outcome was more favourable than in the CEMACH report, these factors may have also played a role in our case. Adequate organisation of care with skilled multidisciplinary teams working according to standard operating procedures is important to prevent unnecessary complications.

It is advisable that all women with cardiac disease have one consultation in a specialised centre for counselling, risk estimation and formulation of a management plan. This should preferably take place before pregnancy, or otherwise as early in pregnancy as possible. It should be decided where the woman will receive cardiology and obstetric care during pregnancy. Three levels of care can be distinguished. These levels of care are comparable with the care recommended in the ESC guidelines for the management of grown-up congenital heart disease and are modified for pregnant women with heart disease according to disease complexity and pregnancy risk [9]. Level 1 represents care for highly complex and high-risk (WHO class III or IV) lesions, for which exclusive care in a specialist unit is advisable, usually monthly or bimonthly. Level 2 represents care for moderately complex lesions and low to moderate risk of pregnancy (WHO II); these women can be managed in a shared care model by collaboration of a specialist and a regional cardiac and obstetric service and usually need cardiac follow-up once per trimester. Women with simple lesions and low pregnancy risk (WHO class I) are classified for level 3 care which means that they can be managed entirely in a regional hospital. For these women, cardiac follow-up can be limited to once or twice during the pregnancy. Examples are provided in Table 1.

When a woman uses medication, she needs to be advised about the continuation, cessation or change of her medication before she gets pregnant. ACE inhibitors, angiotensin II receptor blockers and statins are contraindicated throughout pregnancy and must be discontinued, preferably before pregnancy. Amiodarone should also be discontinued. Vitamin K antagonists should be avoided in the first trimester and be replaced by unfractionated heparin or low-molecular-weight heparin. However, in women with mechanical valves, continuation of vitamin K antagonists can be considered, especially when daily dose requirements are low, because of the higher risk of valve thrombosis with heparins. Most β-blockers can be continued if necessary, except atenolol. Also calcium antagonists appear to be well tolerated and can be used during pregnancy when necessary, though experience is limited [6, 10]. In all women with a pregnancy wish or who are pregnant, thromboembolic risk should be assessed according to the schedules presented in the ESC guidelines for the management of cardiovascular diseases during pregnancy [6], and when applicable thromboprophylaxis and/or compression stockings can be implemented when pregnancy occurs.

During pregnancy, standard cardiac follow-up for most women will consist of clinical assessment and echocardiography. Additionally depending on the underlying lesion and on symptoms, 24-hour ECG monitoring can be performed. Exercise testing should preferably be performed pre-pregnancy to assist in risk estimation, but can be performed in asymptomatic pregnant women to a heart rate of 80% of the maximal predicted heart rate [6]. It is evident that radiation must be avoided if possible, but for vital indications procedures involving radiation may be performed, if no other possibilities are available. Radiation exposure of the foetus is limited for most procedures and acute foetal risk does not usually exist. Few data are available to judge the safety of magnetic resonance imaging during pregnancy, but it is probably safe at least after the first trimester and provided gadolinium is avoided [11].

A multidisciplinary team should be involved in the management of the pregnancy. The core members of this team are the cardiologist and the gynaecologist, and when delivery approaches the anaesthetist and neonatologist. For some women a haematologist or a cardiac surgeon need to be involved. It should never be forgotten that the general practitioner is an important member of the team who should be well informed about the course of the pregnancy, since he may get involved at any stage of the pregnancy and especially in emergency situations occurring outside the hospital. A nurse practitioner can be a very useful member of the team and can serve as the coordinator. Adequate communication between team members is of paramount importance. The cardiologist should formulate the cardiac risks of the pregnancy and both cardiologist and gynaecologist must readily inform all team members about the results of examinations and about complications that occur.

At the end of the second trimester the multidisciplinary team should formulate a plan for the delivery. This plan should include:

After delivery, haemodynamic changes occur due to caval decompression and volume loading through autotransfusion of blood from the contracting uterus. Therefore, the risk of complications is increased. Discharge from hospital should routinely be delayed until at least 24–72 h after delivery, depending on underlying heart disease and risk estimation.