Every woman with acquired or congenital heart disease considering pregnancy should undergo preconceptual cardiac counseling by a cardiologist with expertise in pregnancy and heart disease. If pregnancy has already occurred, a comprehensive assessment by a cardiologist with experience in pregnancy should be organized early in pregnancy.
Questions to Consider During Preconceptual Counseling of Women with Heart Disease
What are the risks of pregnancy for the mother?
In a large prospective study of women with heart disease, adverse maternal cardiac events occurred in 13% of pregnancies. (1) The probability of an adverse event in women with congenital heart disease varies from 7.6% (3) to 19.4%. (2)
The most common complications that occur during pregnancy in women with heart disease are:
1. Arrhythmias
2. Heart failure
3. Stroke
4. Other embolic complications
5. Endocarditis
6. Myocardial infarction
7. Death –cardiac and noncardiac
Probability of a maternal complication varies according to the underlying cardiac lesion. (see lesion specific sections on website) (4)
In addition, there are general (or global) cardiac factors that are predictors of increased risk of cardiac complications during pregnancy. These include: (1,2,3)
1. Poor functional status (NYHA functional class > II)
2. Cyanosis (oxygen saturation at rest < 90%)
3. Left ventricular systolic dysfunction (ejection fraction < 40%)
4. Right ventricular systolic dysfunction and/or severe pulmonary regurgitation
5. Moderate or severe systemic atrioventricular valve regurgitation
6. Moderate or severe pulmonary atrioventricular valve regurgitation
7. Left heart obstruction
8. Mechanical valve prosthesis
9. History of cardiac events prior to pregnancy (arrhythmia, pulmonary edema or stroke)
Risk scores have been proposed to quantitate global cardiac risk of pregnancy. The original risk score from a Canadian consortium (CARPREG risk score) (1) is based on 4 risk predictors: 1) poor functional status (NYHA class > II) or cyanosis, 2) systemic (left) ventricular systolic dysfunction, 3) left heart obstruction, and 4) history of prior cardiac events (arrhythmia, stroke, heart failure). Each predictor is assigned one point. Patients with 0 predictors were at low risk (5%), patients with 1 predictor were at intermediate risk (25%) and those with >1 predictor was at high risk (75%) of adverse cardiac events during pregnancy. The risk score by Khairy et at (3) incorporated right ventricular systolic dysfunction and/or severe pulmonary regurgitation into the CARPREG risk score. The most recent risk score from the ZAHARA investigators, (3) is a weighted scoring system and incorporates a number of new variables into the risk prediction model including: a) cardiac medications before pregnancy, b) systemic atrioventricular regurgitation, and c) mechanical valve prosthesis.
In addition to the above global risk predictors, lesion specific risks should be incorporated into risk assessment. Some conditions known to have high pregnancy risk may not have been adequately represented in the large cohort studies from which the global risk predictors were derived. Women at high risk for complications but not identified by the risk predictors above include those with Marfan syndrome and dilated aortic roots, Fontan operations, or peripartum cardiomyopathy.
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