In the 2018 Confidential Enquiries into Maternal Deaths (CEMD), cardiac disease remained the leading overall cause of maternal death in the UK between 2014 and 2016, accounting for nearly a quarter of maternal deaths. Over three-quarters of these women were not known to have pre-existing cardiac disease, so the possibility of undiagnosed cardiac disease must be remembered. The spectrum of pre-existing cardiac disease affecting pregnant women has changed in the UK as rheumatic heart disease has become less common (though it is still a major problem in other parts of the world) and congenital heart disease more common, partly related to the improved survival of girls with congenital heart disease who undergo surgery during infancy and childhood.
The most common acquired cardiac disease in the UK is ischaemic heart disease. Possible epidemiological factors include an increased prevalence of risk factors such as smoking among younger women, increased age and obesity.
Problems and special considerations
Although different sorts of cardiac disease require different management, there are general principles that are applicable to this heterogeneous group. Many of these have been highlighted in recent CEMD reports, which have found the following:
• There is a general failure fully to understand the impact of the normal physiological changes of pregnancy on pre-existing cardiovascular pathology (see Chapter 11, Physiology of pregnancy).
• Symptoms such as a raised respiratory rate, chest pain, persistent tachycardia or breathlessness, or orthopnoea may indicate exacerbation of known or undiagnosed cardiac disease.
• Management of women with cardiac disease is often undertaken by inappropriately experienced medical staff. Consultants from all relevant specialties should be involved in management from early pregnancy onward, with review in a joint obstetric cardiac clinic. If necessary, patients should be referred onwards to specialist cardiological units.
• There may be failure to carry out essential investigations such as chest radiography, where the radiation risks to the fetus are minimal but the information gained from the investigation may be life-saving. Equally, necessary medications such as angiotensinconverting enzyme inhibitors should not be withheld because of breastfeeding.
• There may be failure to communicate with other specialties involved in a woman’s care and failure to organise clear written plans for management of labour and delivery. Anaesthetic review should occur in the second or third trimester (bearing in mind that many cardiac patients will have a preterm delivery), and critical care staff consulted and/ or involved early as appropriate.
• The severity of the mother’s condition may be underestimated, either because of the above or because symptoms are mild or absent, or because they are mistaken for those of pregnancy.
Management options
The pregnant woman with cardiac disease, whether congenital or acquired, should be seen as early as possible in her pregnancy. Ideally, she should be seen for preconception counselling when her risks (Table 91.1) and those of her baby can be fully discussed.
A full history and examination should be performed during the first trimester of pregnancy, and baseline cardiological investigations should be arranged. These may include electrocardiography, chest x-ray, echocardiography and possibly cardiac catheterisation. Severity of cardiac disease is frequently assessed by using the New York Heart Association (NYHA) classification, which although originally described for heart failure is a useful overall measure of severity (Table 91.2)
Women with cardiovascular disease graded NYHA I and II usually tolerate the physiological changes of pregnancy well, though it should be remembered that certain conditions (e.g. mitral and aortic stenosis, pulmonary hypertension and complex lesions) may be dangerous even in the absence of symptoms.
Studies suggest that cardiac complications (pulmonary oedema, arrhythmia, stroke or cardiac death) are more likely in women who have the following predictors: a history of previous cardiac events or arrhythmia; NYHA class IV or cyanosis; left heart obstruction; or left ventricular systolic dysfunction - with complications occurring in around a quarter of women with one predictor and three-quarters of women with more than one predictor.
Table 91.1 Risk of death or severe morbidity resulting from certain cardiac lesions in pregnancy
|
Low risk (mortality 0.1-1%) |
Most repaired lesions Uncomplicated left-to-right shunts Mitral valve prolapse; bicuspid aortic valve; aortic regurgitation; mitral regurgitation; pulmonary stenosis; pulmonary regurgitation |
|
Intermediate risk (mortality 1-5%) |
Metal valves Single ventricle Systemic right ventricle; switch procedure Unrepaired cyanotic lesions Mitral stenosis; aortic stenosis; severe pulmonary stenosis |
|
High risk (mortality 5-30%) |
NYHA III or IV Severe systemic ventricular dysfunction Severe aortic stenosis Marfan’s syndrome with aortic valve lesion or aortic dilatation Pulmonary hypertension (mortality 30-50%) |
Table 91.2 New York Heart Association (NYHA) classification of cardiovascular disease, adapted version
|
NYHA I |
No limitation of physical activity and no objective evidence of cardiovascular disease |
|
NYHA II |
Slight limitation of normal physical activity and objective evidence of minimal disease |
|
NYHA III |
Marked limitation of physical activity and objective evidence of moderately severe disease |
|
NYHA IV |
Severe limitation of activity including symptoms at rest and objective evidence of severe disease |
Further risk stratification tools may be used, such as the CARPREG risk score which looks at pre-pregnancy symptoms and signs, or the modified WHO classification of maternal cardiovascular risk which looks at cardiac lesions and their surgical repair. Such stratification may help plan antenatal follow-up and labour care.
Consideration should be given to the appropriate place for both subsequent antenatal management and delivery. Referral to a local teaching hospital with facilities for cardiac surgery may be indicated, and in some cases it may be in the woman’s best interests to be referred to a supra-regional unit.
Routine antenatal care is not adequate for women with cardiac disease. Antenatal appointments need to be more frequent; there must be clear communication with the general practitioner and the community midwife and also with the woman herself, who should receive instructions about symptoms that demand immediate medical attention. Serial investigations and careful documentation of symptoms should alert medical staff to any deterioration in cardiac health, and it may be useful to admit women with cardiac disease for 24-48 hours towards the end of the second trimester of pregnancy in order to repeat investigations and arrange multidisciplinary review. These women require careful monitoring for development of pre-eclampsia, since it may be poorly tolerated in the presence of cardiac disease.
Elective admission to hospital in the third or even second trimester may be useful to ensure the mother can rest, with due attention to antithrombotic prophylaxis and regular assessments. Continuous oxygen therapy may also be given if required.
As a general rule, operative delivery should only be carried out if indicated for obstetric reasons or deteriorating maternal condition, and not just because the mother has cardiac disease; caesarean delivery has not been shown to confer benefit to women with cardiac disease if they are stable. Regional analgesia and anaesthesia can be safely provided for the majority of women with cardiac disease, even in those with fixed cardiac output (though this is more controversial), although this may be precluded by anticoagulation in certain cases. Epidural anaesthesia may be advisable to reduce the pain-related cardiovascular stresses of labour, or to facilitate delivery with minimal active pushing with the associated Valsalva manoeuvre, which may be detrimental to cardiac output. Analgesia and anaesthesia should only be carried out in units familiar with the management of such high-risk patients.
Cardiac monitoring for arrhythmias/ischaemia and invasive blood pressure monitoring may be useful during labour and delivery, so long as there are appropriate personnel to manage and interpret these monitors. The risk of endocarditis should be remembered;
although recent UK guidance suggests that prophylactic antibiotics may not be indicated, many clinicians with experience of managing such patients still elect to give them, because the consequences of endocarditis can be so devastating. Cardiovascular side effects of oxytocics should be considered and weighed against the risk of postpartum haemorrhage and decreased venous return. Depending on cardiac pathology, reduced bolus doses or infusions alone may be given. Non-pharmacological methods of haemostasis should be considered early if the consequences of haemorrhage are a particular risk.
The puerperium is a time of high risk for many women with cardiac disease, and vigilance should be maintained. The mother with cardiac disease should be nursed on the delivery suite or high-dependency unit until all medical staff involved in her care agree that she can be safely returned to the general postnatal ward. Haemodynamic parameters have usually returned to normal within 3-5 days but may take longer in severe cases, and rarely may never return to pre-pregnancy values.
Key points
• Women with cardiovascular disease should be identified and assessed early in pregnancy, and referred to specialist units when necessary. Coordinated multiprofessional care should occur during and after the pregnancy.
• Good communication between specialties is mandatory.
• Clear management plans should be written.
• Vigilance should be maintained into the puerperium.
Further reading
Curry R, Swan L, Steer PJ. Cardiac disease in pregnancy. Curr Opin Obstet Gynecol 2009; 21: 508-13.
European Society of Cardiology. ESC guidelines on the management of cardiovascular diseases during pregnancy: the Task Force on the Management of Cardiovascular Diseases during Pregnancy of the European Society of Cardiology (ESC). Eur Heart J 2011; 32: 3147-97.
Royal College of Obstetricians and Gynaecologists. Cardiac disease and pregnancy. Good Practice 13.
London: RCOG, 2011. www.rcog.org.uk/en/guidelines-research-services/guidelines/good-prac tice-13 (accessed December 2018).
Ruys TPE, Roos-Hesselink JW, Hall R, et al. Heart failure in pregnant women with cardiac disease: data from the ROPAC. Heart 2014; 100: 231-8.
Turnbull J, Bell R. Obstetric anaesthesia and peripartum management. Best Pract Res Clin Obstet Gynaecol 2014; 28: 593-605.
Vause S, Clarke B, Thorne S, James R, on behalf of the MBRRACE-UK cardiovascular chapter writing group. Lessons on cardiovascular disease. In Knight M, Nair M, Tuffnell D, et al.; MBRRACE-UK. Saving Lives, Improving Mothers’ Care: Surveillance of maternal deaths in the UK 2012-14 and lessons learned to inform maternity care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2009-14. Oxford: National Perinatal Epidemiology Unit, University of Oxford, 2016, pp. 33-68.