Siu and associates (2001 b) expanded the NYHA classification and developed a scoring system for predicting cardiac complications during pregnancy. The system derives from a Canadian prospective analysis of 562 pregnant women with heart disease during 617 pregnancies. Predictors of cardiac complications included: (1) prior heart failure, transient ischemic attack, arrhythmia, or stroke; (2) baseline NYHA class III or IV or cyanosis; (3) left-sided obstruction defined as mitral valve area <2 cmr, aortic valve area < 1.5 cmr, or peak left tion fraction <40 percent. The risk of pulmonary edema, sus tained arrhythmia, stroke, cardiac arrest, or cardiac death was substantially elevated with one of these factors and even more so with two or more. Khairy and colleagues (2006) reported similar indings.
An even more comprehensive risk stratification system is the tion of Cardiovascular Disease and Pregnancy (Table 49-3). It ceptional counseling. Lu (2015) and Pijuan-Domenech (2015) and their associates in their analyses concluded that the modi ied WHO classification provides the greatest predictive accu racy for cardiac complications during pregnancy.
Women with severe heart disease will beneit immensely from counseling before pregnancy, and they usually are referred for maternal-fetal medicine or cardiology consultation (Clark, 2012; Seshadri, 2012). Maternal mortality rates generally correlate directly with functional classification, and this relationship may change as pregnancy progresses. From the previously described Canadian study, Siu and colleagues (2001 b) observed signiicant worsening of NHA class in 4.4 percent of 579 pregnancies in which the baseline class was I or II. As described later, some women have life-threatening cardiac abnormalities that can be reversed by corrective surgery, and subsequent pregnancy becomes less dangerous. In other cases, such as women with mechanical valves taking warfarin, fetal teratogenic concerns predominate. Last, many congenital heart lesions are inherited as polygenic characteristics (Chap. 13, p. 268). Because of this, some women with congenital heart lesions give birth to similarly afected neonates, and the risk varies widely (Table 49-4).
In most instances, management involves a team approach with an obstetrician, cardiologist, anesthesiologist, and other specialists as needed. With complex lesions or other high-risk cases, evaluation by a multidisciplinary team is recommended early in pregnancy. Within this framework, both prognosis and management are influenced by the type and severity of the speciic lesion and by the maternal functional classiication. In some, pregnancy termination may be advisable.
With rare exceptions, women in NYHA class I and most in class II negotiate pregnancy without morbidity. Special
TABLE 49-3. World Health Organization (WHO) Risk Classification of Cardiovascular Disease and Pregnancy with Management Recommendations
WHO l-Risk no higher than general population Uncomplicated, small, or mild:
Mitral valve prolapse with no more than trivial mitral regurgitation
Successfully repaired simple lesions:
WHO 2-Small increase in risk of maternal mortality If otherwise uncomplicated: • Individualized care similar to WHO categories 2 or 3 depending on lesion and disease severity
WHO 3-Significantly increased risk of maternal Mechanical valve mortality or expert cardiac and obstetrical care Systemic right ventricle-congenitally corrected transposition, required simple transposition post Mustard or Senning repair
WHO 4-Very high risk of maternal mortality or Pulmonary arterial hypertension termination discussed Previous peripartum cardiomyopathy with any residual impairment
Marfan syndrome with aorta dilated >40 mm
Pregnancy contraindicated.
If pregnancy occurs, monthly or bimonthly cardiac and obstetrical monitoring