Pregnancy and Heart Disease:Congenital Heart Disease
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Overview
Given that more patients with congenital heart disease are living into adulthood, congenital heart disease is now rapidly becoming the most common cardiac problem among pregnant patients. There are also improved diagnostic techniques to aid in the management of these patients. Outcomes are clearly linked to functional status pre-pregnancy. Children of affected mothers at increased risk of having similar lesions.
I. General Principles of Managing the Pregnant Patient with Congenital Heart Disease
There are five major maternal risk factors for maternal and fetal complications of pregnancy:
1. Pulmonary Hypertension
The maternal presence of pulmonary hypertension is the poorest prognostic factor. The presence of Eisenmenger syndrome carries a particularly poor prognosis and is a contraindication to pregnancy. Mortality is up to 50% in patients with Eisenmenger syndrome, and only 15% to 20% of pregnancies reach term. Patients with pulmonary hypertension cannot accomodate the rapid hemodynamic shifts that occur during pregancy particularly at the time of delivery and if complications such as bleeding occur. If systemic vascular resistance is lowered, blood flow can be shunted away from the pulmonary circulation and fatal hypoxemia can rapidly ensue. Most fatalities occur at the time of delivery or in the week following pregnancy.
2. Cyanosis
The pre-partum (before pregnancy) arterial oxygen saturation is another important predictor of poor outcomes in both the mother and the fetus. If the oxygen saturation is < 85%, the odds of live birth are low at 12% whereas the odds are 63% if the oxygen saturation is > 85%. The hypoxemia associated with congeniial heart disease can cause secondary erythrocytosis. Phlebotomy is indicated if both of the following are present:
Given the sensitivity of these patients to hemodynamic perturbations, rapid reductions in the hematocrit should be avoided. While hypoxemia is a risk factor for poor outcomes, treatment with oxygen prior to pregnancy has no documented benefits and is not recommended.
3. Maternal functional class
New York Heart Association (NYHA) functional classificationv III or IV is associated with maternal morbidity and mortality. It is very important to note that it is very difficult to assign a NYHA classification in women with cyanotic disease due to venoarteriolar disease because the dyspnea can be due to a fall in systemic vascular resistance that in turn causes an increase in right-to-left shunting. In contrast, the presence of pulmonary edema due to left ventricular disease or valvular disease which results in NYHA class III or IV heart failure is a poor prognostic sign.
4. Arrhythmias
Conservative management is indicated if the incidence is infrequent and if clinical sequela of the arrhythmia is benign. If on the other hand there is hemodynamic compromise associated with the arrhythmia, then treatment is indicated. The risk of most antiarrhythmic agents during pregnancy is low (consult the package insert for details). If medical therapy fails, then radiofrequency ablation can be considered. Cardioversion is relatively safe during pregnancy. Because of the shifts in volume of distribution with pregnancy, drug concentrations and pharmacodynamcc responses and changes in QT intervals may be less predictable than usual and should be monitored closely.
II. Management of the Pregnant Patient with Congenital Heart Disease Based Upon Their Hemodynamic Status
Classification of Congenital Heart Disease Into Three Classes
Volume Overload (L-->R shunt)
- ASD, VSD, and PDA well tolerated if pulmonary hypertension not present
- PVR and SVR falls to same degree
- Degree of shunting does not change
- Eisenmenger’s Syndrome
- Maternal and fetal mortality ≥50%
- Consider termination if detected early
- Careful medical management
- -Supplemental O2 during pregnancy
- -Hospitalization at 20 weeks gestation
- -Prompt treatment of CHF
- -Avoid shifts in preload/afterload
- Atrial Septal Defect (ASD): Arrhythmias, thromboembolism may develop among pregnant women with an ASD. However, there is no available evidence to suggest that pregnant patients should be managed differently from nonpregnant patients with respect to the indications for ASD closure are no different in pregnant women compared to non-pregnant women.
Pressure Overload
- AS, MS
- Pulmonic Stenosis
- Degree of obstruction determines outcome
- Gradient >80 mm Hg mandates correction
- Coarctation of the aorta
- Accounts for 9% of all congenital disease in adults
- Class I or II patients usually do well
- Overall 3.5% mortality in unoperated patients (aortic dissection/rupture, CVA, CHF, endocarditis)
- HTN needs careful management
- HOCM
- Early to mid pregnancy, C.O. and end-diastolic dimension ↓ outflow tract obstruction (counteracted by SVR)
- Avoid Valsalva
- Encourage left lateral decubitus position
- Maximum risk period during delivery when blood loss can result in increased gradient + systemic hypotension
- Keep well hydrated
- Avoid digoxin, simpathomimetics and excessive diuretics
Cyanotic Heart Disease (R-->L shunt)[1]
- Poor prognosticators:
- Hematocrit > 60%
- O2 sat<85%
- Livebirth 12% vs. 92% is sat >90%
- Systemic RV pressures
- h/o recurrent syncope
- Tetralogy of Fallot most common unrepaired defect
- Drop in SVR leads to increased shunting, deeper cyanosis and rising HCT
- Need to avoid Valsava during delivery
- Maternal mortality more than 4%
III. Management of the Patient with Specific Congenital Heart Disease States
Aortic Stenosis
- Most commonly bicuspid valve
- Fixed cardiac output in response to stress
- Patients with mild to moderate severity do very well
- Severe cases have maternal mortality up to 17% and fetal mortality up to 32%
- Critical cases need surgery / valvuloplasty
- Any reduction in preload can lead to cardiac / cerebral ischemia and compromised uterine flow
Marfan's Syndrome
- Autosomal dominant inheritance pattern (counseling is essential)
- Major risk is aortic dissection
- Most common in 3rd trimester or 1st stage of labor
- Increases with enlarging aortic root diameter
- Surgery recommended pre-conception if root diameter >40 mm
- Surgery recommend during gestation if > 55 mm
- Prophylactic Beta-blockers appear to be helpful
- Close follow-up with serial echo
Mitral Stenosis
Overview
- Most hemodynamically important valvular problem during pregnancy
- Physiologic changes result in increased pulse and C.O. with augmentation of diastolic gradient
- Atrial fibrillation can lead to rapid deterioration
- Volume shifts during delivery can result in pulmonary hypertension or pulmonary edema
Management of MS in Pregnancy
- Restriction of physical activity and salt intake. Avoid supine position
- Beta-blockade to lengthen disatolic filling period
- Diuretics if necessary (gentle)
- Consideration of invasive monitoring
- Replace blood losses during delivery carefully
- Percutaneous Balloon Mitral Valvuloplasty can be performed during pregnancy if necessary (Class III,IV)
- ↑ Presbitero P. et al. Circulation 1994;89:2673-6.