Cardiovascular disease (CVD) is one of the leading causes of morbidity and mortality during pregnancy.1 This review will give an overview of the types of CVD seen in pregnancy, present a risk stratification scheme to assess cardiovascular risk during pregnancy, and address the importance of coordinated care.
Physiologic changes in pregnancy
Pregnancy places an increased workload on the heart, including increases in circulating blood volume, plasma volume, heart rate, and cardiac output.2 This is usually well tolerated by healthy mothers but may not be by women with preexisting CVD who have inadequate cardiovascular reserve. During labor and delivery, additional hemodynamic changes including increased heart rate, arterial pressure, central venous pressure, and cardiac output place additional stress on the maternal heart. Pregnancy may also lower the threshold for rhythm disturbances.3 Pregnancy is also a prothrombotic state with hypercoagulable changes occurring early in pregnancy and persisting well into the postpartum period, thus increasing the risk of intracardiac thrombus and cardioembolic events.4 For these reasons, preconceptual counseling is necessary for women with preexisting CVD to clearly define both maternal and fetal risks of pregnancy.5
Congenital heart disease
In developed countries, congenital heart disease (CHD) has become the most common type of maternal CVD complicating pregnancy.6-8 CHD is the most common form of birth defect and, due to advances in congenital heart surgery and interventional catheterization procedures, most patients with CHD now survive well into adulthood. Many patients with CHD (as well as many physicians) mistakenly assume that if one or more surgeries were performed during childhood, CHD is repaired or “cured.” However, for many of these patients, there are significant residual anatomic abnormalities or sequelae from the original surgery that may affect cardiovascular function. Some surgical procedures are considered palliative whereas others restore more normal or nearly normal intracardiac anatomy. Many patients are unaware or have only limited knowledge of their specific CHD diagnosis or their specific surgical repair. Likewise, many women with CHD are not aware of their specific risks for pregnancy due to their heart disease. Thus, a patient’s stated history of CHD “repair” is often inaccurate and her knowledge of her specific pregnancy risk is often inadequate. Therefore, preconceptual counseling and risk stratification are very important for the CHD population.
Approximately 50% of all patients with CHD have a simple defect such as a secundum atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), isolated mild aortic or pulmonary valve disease, or a repaired simple ASD, VSD, or PDA. For women with these simple defects, pregnancy is usually well-tolerated with no significant increase in morbidity or mortality.
The remaining nearly 50% of all patients with CHD are those with either moderate or complex defects, including individuals with a single ventricle, a systemic right ventricle, pulmonary hypertension, persistent cyanosis, valvular disease, and other complicated issues. Pregnancy in women with moderate or complex defects may or may not be well-tolerated and the risk of fetal and maternal complications (including both morbidity and mortality) is significantly increased. The most common maternal complications are arrhythmias and heart failure, but stroke, cardioembolic events and infection may also occur.5-7 Fetal complications include spontaneous abortion, intrauterine fetal demise, preterm birth, small for gestational age, and neonatal and perinatal death.6-8
For mothers with moderate or complex CHD, maternal cardiovascular complications are more frequent, and involvement of a cardiologist specializing in adult congenital heart disease is critical for the optimal management of these patients. Several specific types of CHD are associated with particular risks.5-9