PATIENT STORY 1

A 29-year-old woman with complete transposition of the great arteries (TGA) repaired with a Mustard atrial switch surgery presented with heart failure symptoms 7 days postpartum. TGA is a form of cyanotic congenital heart disease (CHD) in which the aorta originates from the right ventricle (RV) pumping deoxygenated blood to the body and the pulmonary artery (PA) originates from the left ventricle (LV) pumping oxygenated blood to the lungs. This lesion is often incompatible with life and many adults currently living with TGA have undergone atrial switch surgeries as infants to direct deoxygenated blood to the LV to be pumped to the lungs and oxygenated blood to the RV to be pumped to the body (Figure 11-1A). The RV in patients who have undergone the atrial switch procedure is the systemic ventricle and becomes hypertrophied, dilated, and often dysfunctional.

This woman had an uncomplicated pregnancy and underwent a cesarean section for obstetrical reasons during which time she received several liters of intravenous fluids. On presentation, one week postpartum, she presented with dyspnea and edema. She underwent an echocardiogram that did not reveal any changes in systemic ventricular function and tricuspid valve regurgitation (Figure 11-1B). She was treated with intravenous furosemide and her symptoms dramatically improved. The increased volume load of pregnancy is not tolerated well in some women with CHD, particularly those with underlying ventricular dysfunction. Symptoms may be exacerbated in the postpartum period when afterload increases and dramatic changes in volume loading may occur.

CASE EXPLANATION

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  The presence of cardiovascular disease in pregnant women poses a difficult clinical scenario in which the responsibility of the treating physician extends not only to the mother but also to the unborn fetus.

  
  
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  Pregnancy has a profound effect on the circulatory system. Most of these hemodynamic changes start in the first trimester, peak during the second trimester, and plateau during the third trimester.

  
  
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  The delivery and immediate postpartum period is associated with further profound and rapid changes in the circulatory system. During delivery, cardiac output, heart rate, blood pressure, and systemic vascular resistance increase with each uterine contraction.¹

  
  
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  Immediately postpartum, the delivery of the placenta increases afterload by removing the low-resistance circulation and increases the preload by returning placental blood to the maternal circulation. This increase in preload is accentuated by the elimination of the mechanical compression of the inferior vena cava (IVC). Blood loss is typically 300 to 400 mL during vaginal delivery and 500 to 800 mL during cesarean delivery. These changes can place an intolerable strain on an abnormal heart necessitating aggressive medical management, such as in the case of this patient, and very occasionally, invasive hemodynamic monitoring.²

DIAGNOSIS

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  In the United States, CHD is now the most common form of heart disease complicating pregnancy.

  
  
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  Women with complete transposition of the great arteries are reaching reproductive age because of operative interventions, which in the earlier days of surgical repair involved atrial switch repairs, such as the Mustard or Senning procedures.

  
  
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  Gestational risks after Mustard or Senning repairs are related chiefly to the functional status of the subaortic morphologic right ventricle, the presence of pulmonary hypertension, and to conduction and rhythm abnormalities.

  
  
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  Patients with known or suspected systemic ventricular dysfunction should have an echocardiogram before conception, or as soon as possible after pregnancy is confirmed, to determine baseline ventricular function. Pregnancy should be discouraged if there is a significant reduction in ventricular function (ejection fraction <40%).³

  
  
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  There are several modalities that may be utilized to follow women with CHD throughout pregnancy and the postpartum period at risk of congestive heart failure. These include laboratory testing including B-type natriuretic peptide (BNP), exercise testing, and imaging studies.

  
  
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  Vaginal delivery is preferred because it causes smaller shifts in blood volume, less hemorrhage, fewer clots, and fewer infections. Cesarean delivery is generally indicated only for obstetric reasons.⁴

B-Type Natriuretic Peptide

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  Plasma brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels are well-recognized markers of heart failure and these markers may also be helpful in monitoring women with cardiovascular disease during pregnancy.

  
  
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  The BNP increases in response to increased volume loading and predicts adverse outcomes in women with congenital heart disease during pregnancy.

  
  
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  Tanous et al reported that a BNP value of less than or equal to 100 pg/mL during pregnancy had a negative predictive value of 100% for identifying cardiac events in women with CHD⁵ (Figure 11-2).

  
  
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  In patients with repaired tetralogy of Fallot, Kamiya reported that the peak BNP after the second trimester was most useful in predicting adverse maternal cardiac events in women with repaired tetralogy of Fallot.⁶

Exercise Testing

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  Another useful tool in risk stratification is objective exercise testing.

  
  
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  Cardiopulmonary exercise testing is often used to evaluate exercise capacity in adults with congenital heart disease including women who are considering pregnancy. A multicenter study including 89 pregnancies in 83 women with CHD identified a low chronotropic index as a risk factor for an adverse maternal cardiac outcome.⁷

Echocardiography

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  Echocardiography may be used to assess cardiac function in the setting of the hemodynamic burden of pregnancy, though the frequency of echocardiographic screening in woman with various forms of congenital heart disease is not well established.

  
  
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  There are normal echocardiographic changes during pregnancy that should not be considered pathologic (Table 11-1).^{8, 9}

PATIENT STORY 2

A 28-year-old woman with truncus arteriosus (Figure 11-3A), born with a single arterial trunk containing the aorta and the pulmonary artery was surgically repaired by removing the pulmonary arteries from the common arterial trunk and attaching them to a conduit from the right ventricle. She had a routine screening fetal echocardiogram given her history of CHD and the fetus was also found to have truncus arteriosus (Figures 11-3B and 11-3C) and a plan to have neonatology present at time of delivery with initiation of intravenous prostaglandins was arranged.

CASE EXPLANATION

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  Women who were born with complex congenital cardiac lesions such as transposition of the great vessels, tricuspid atresia, single ventricle physiology, and truncus arteriosus are now reaching reproductive age due to the success of surgical procedures.

  
  
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  This case outlines the close collaboration between both cardiac and obstetric teams that is needed for optimal care for both women and fetuses with congenital heart disease.

DISCUSSION

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  Current guidelines recommend screening all fetuses of parents with CHD with fetal echocardiography to assess risk to the fetus and to ensure that the parents are properly counseled and post-delivery plans are appropriate.³²

  
  
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  Women with moderate- or high-risk lesions, especially cyanotic lesions, have an increased risk of fetal growth restriction and should be followed with monthly ultrasounds for fetal growth.

  
  
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  Decisions about timing and mode of delivery must be made well in advance of labor.

  
  
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  Continuous electronic fetal heart rate monitoring is recommended to assess fetal well-being during labor and allow timely intervention if non-reassuring fetal heart rate patterns occur.

PATIENT STORY 3

A 38-year-old woman with a bicuspid aortic valve (BAV) with no prior cardiac interventions and only minimal valvar regurgitation presented at 23 weeks’ gestation with myalgias, fevers, chills, and a worsening murmur of aortic regurgitation. She was found to have Streptococcus bacteremia, a vegetation on her aortic valve (Figure 11-4A) and severe aortic regurgitation on echocardiogram (Figure 11-4B). She was treated with intravenous antibiotics with clinical stability; however, at 29 weeks’ gestation she presented with premature labor and signs of heart failure. She underwent an emergent cesarean section, followed by aortic valve and aortic root replacements 1 week later.

CASE EXPLANATION

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  Aortic stenosis (AS) in women of childbearing age is primarily due to a congenital bicuspid aortic valve.

  
  
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  Mild bicuspid aortic stenosis or insufficiency generally is well tolerated during pregnancy because left ventricular ejection fraction (LVEF) is usually above normal.¹⁰

  
  
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  Even though this patient did develop infective endocarditis, a BAV is not a lesion requiring endocarditis prophylaxis unless it has been subjected to valve replacement.

DISCUSSION

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  Common valvular lesions for which antimicrobial prophylaxis is no longer recommended in the 2007 AHA guidelines include bicuspid aortic valve, acquired aortic or mitral valve disease (including mitral valve prolapse with regurgitation), and hypertrophic cardiomyopathy with latent or resting obstruction.¹¹

  
  
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  In addition, uncomplicated vaginal or cesarean delivery is not considered an indication for antibiotic prophylaxis.

  
  
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  Infectious endocarditis (IE) is very rare in pregnancy, with an incidence reported to be 1.7 to 5.5/100,000.

  
  
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  However, the maternal mortality rate is high, with reported rates between 22% and 33%, with the most deaths related to heart failure or an embolic event.

  
  
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  The rate of fetal mortality is equally high and ranges between 15% and 33%.^{12, 13}

PATIENT STORY 4

A 40-year-old woman with Marfan syndrome (MFS) and a dilated aortic root measuring 4.1 cm was treated with atenolol during her pregnancy. She underwent an uncomplicated cesarean section delivery of twins and 6 days later developed neck and back pain. An echocardiogram demonstrated a type 1 aortic dissection (Figure 11-5A) and moderate-to-severe aortic regurgitation (Figure 11-5B). She underwent emergent surgery involving mechanical aortic valve replacement, ascending aortic graft and saphenous vein bypass graft from the aortic graft to the right coronary artery.

CASE EXPLANATION