Women with acquired or congenital heart disease have a higher risk of cardiac complications during pregnancy than the general population. In general, a full evaluation including history, physical examination, echocardiogram, and electrocardiogram should be considered in the patient maternla patient with underlying heart disease. Further risk stratification and monitoring are dictated by a number of factors, including the presence of prior cardiac events, heart failure, valvular heart disease, and systolic or diastolic dysfunction.

A prospective study performed by Siu and colleagues identified four predictors of maternal cardiac events.^[1] These include:

• A prior cardiac event (e.g., heart failure, transient ischemic attack, arrhythmia or stroke) before pregnancy
• A baseline New York Heart Association (NYHA) class higher than Class II heart failure or cyanosis
• A left-sided heart obstruction (mitral valve area smaller than 2 cm², aortic valve area less than 1.5 cm², or peak left ventricular outflow tract gradient more than 30 mm Hg by echocardiography
• Reduced left (or systemic) ventricular systolic function (ejection fraction) less than 40%

Based on this study of approximately 600 patients, the estimated risk of a cardiac event in pregnancies with 0, 1, and more than 1 point was 5%, 27%, and 75%, respectively. The authors recommended that those with a low cardiac risk of 0 could safely be delivered in a community hospital, but those at intermediate or high cardiac risk (risk score of 1 or more) should be delivered at a regional center.

It should be noted that severe pulmonary hypertension is associated with a 30-50% risk of maternal mortality.

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines designate the following valvular lesions as high risk during pregnancy^[2]:

• Severe aortic stenosis
• Symptomatic mitral stenosis
• Aortic regurgitation or mitral regurgitation with NYHA class III to IV symptoms
• Aortic and/or mitral valve disease with left ventricular dysfunction (left ventricular ejection fraction < 40%)
• Aortic and/or mitral valve disease with severe pulmonary hypertension (pulmonary artery (PA) pressure > 75% of systemic pressure)
• Marfan syndrome
• Mechanical prosthetic valve requiring anticoagulation

Cardiology