DESCRIPTION

• Maternal blood volume and cardiac output increase up to 50% by 32 wk of pregnancy and continue at that level until delivery.
• These changes put unique stress on the patient with underlying heart disease and may contribute to the development of certain heart diseases (peripartum cardiomyopathy).
• There are 3 general patient presentations:
  • Uncorrected congenital heart disease, which can be divided into:
    • Predominant volume loads such as atrial septal defects, patent ductus arteriosus
    • Pressure loads such as pulmonic valve stenosis, coarctation of the aorta, aortic valve disease
    • Complex often cyanotic congenital heart disease such as tetralogy of Fallot
  • Acquired heart disease:
    • Most common are rheumatic heart disease, coronary heart disease, and peripartum cardiomyopathy.
  • Corrected congenital or acquired heart disease:
    • Common issues here are the patient with a prosthetic valve or partially corrected defects.
• System(s) affected: Cardiovascular, pulmonary
• Fluid retention, excessive weight gain, and infections should be avoided if possible.
• Antibiotic prophylaxis to prevent bacterial endocarditis should be considered in those at highest cardiac risk (prosthetic valves, conduits).

EPIDEMIOLOGY

• Predominant age: Young adults
  • Prognosis worsens with heart disease and advancing age of the mother.
• Predominant sex: Female

Incidence

Maternal heart disease occurs in 1–4% of pregnancies.

RISK FACTORS

Prior pregnancy-associated heart disease increases risk of subsequent pregnancies.

Genetics

Women with congenital heart disease have an increased risk of having children with congenital heart disease.

GENERAL PREVENTION

• Pregnancy should be avoided with certain heart diseases.
• Fluid retention, excessive weight gain, and infections should be avoided if possible.
• Antibiotic prophylaxis to prevent bacterial endocarditis should be considered in those at highest cardiac risk (prosthetic valves, conduits).

PATHOPHYSIOLOGY

Increased volume load on the heart

ETIOLOGY

Congenital or acquired

COMMONLY ASSOCIATED CONDITIONS

• Anemia of pregnancy
• Pregnancy-associated HTN

Outline

• Description
• Epidemiology
  • Incidence
• Risk Factors
  • Genetics
• General Prevention
• Pathophysiology
• Etiology
• Commonly Associated Conditions

Clinical presentation of pregnancy complicated by heart disease depends on the underlying disease, its severity, and the stage of pregnancy.

History

• Fatigue and dyspnea, common symptoms of heart disease, are common with normal pregnancies.
• Chest pain from gastroesophageal reflux must be distinguished from angina.
• Palpitations are common during pregnancy (often sinus tachycardia).
• Fever and night sweats are common during normal pregnancy.

Physical Exam

• Alterations in the cardiovascular physical exam due to the normal hemodynamic changes of pregnancy must be distinguished from pathologic changes due to heart disease.
• Normal pregnancy may be associated with:
  • Heart rate in the upper range of normal
  • Systolic BP increases as pregnancy progresses to levels largely determined by the patient’s age and parity (increases with both).
  • Higher values for BP are recorded upright or in the left lateral position and the lowest levels in the supine position when the gravid uterus compresses the inferior vena cava and reduces venous return to the heart.
  • An enlarged apical impulse and 3rd heart sound are often present.
  • The 1st and 2nd heart sounds are often loud and exhibit increased splitting. 4th heart sounds are rare and suggest the presence of heart disease.
  • Systolic heart murmurs are common in pregnancy and result from the increased stroke volume and hyperkinetic state of pregnancy.
  • A continuous murmur may be heard due to increased blood flow to the breasts (mammary soufflé), and venous hums heard in the aortic area may mimic aortic regurgitation.
  • True diastolic murmurs are rare in pregnancy and suggest heart disease.

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• Confirmation of pregnancy
• Blood count often shows anemia.
• Oxygen saturation reduced in cyanotic congenital heart disease

Follow-up & special considerations

With heart failure or diuretic treatment serum electrolytes, creatinine, BUN appropriate

Imaging

Initial approach

• Use of CXR is of limited value in pregnancy because of the potential hazards of exposing the fetus to radiation. Also, the cardiac silhouette is altered by the elevation of the diaphragm, making specific chamber enlargement difficult to diagnose accurately.
• Echo is the diagnostic test of choice.

Follow-up & special considerations

MRI/A best for suspected aortic dissection

Diagnostic Procedures/Surgery

• EKG can be very useful, but a leftward shift in the axis and ST-T wave changes can occur normally in pregnancy.
• Pulmonary artery catheterization can be performed with a flow-directed catheter without the use of fluoroscopy.
• Left heart catheterization can be performed with abdominal shielding and use of a brachial approach to minimize exposure of the fetus to radiation, but should only be performed if the diagnostic information cannot be obtained by other less invasive methods.

Pathological Findings

Depends on specific heart disease

DIFFERENTIAL DIAGNOSIS

Heart disease vs. normal hemodynamic changes of pregnancy

Outline

• Information
• History
• Physical Exam
• Diagnostic Tests & Interpretation
  • Lab
  • Imaging
  • Diagnostic Procedures/Surgery
  • Pathological Findings
• Differential Diagnosis

First Line

• For heart failure:
  • Digoxin is safe, but blood levels need to be monitored.
  • Furosemide or other diuretics are safe, but potassium levels need to be monitored.
  • Hydralazine is safe in those patients who do not respond to digoxin and diuretics.
• For arrhythmias:
  • Digoxin is useful for controlling the heart rate in supraventricular arrhythmias.
  • -Blockers can be added if digoxin does not control the heart rate.
  • Verapamil is relatively safe unless heart failure is present.
  • Procainamide is relatively safe.
  • Lidocaine for ventricular tachyarrhythmias is relatively safe.
• For anticoagulation:
  • Heparin is preferred because it is not teratogenic, but there is risk of hemorrhage.
• Contraindications:
  • ACE inhibitors increase the incidence of stillbirths and should be avoided.
  • Amiodarone causes fetal hypothyroidism and premature births.
  • Warfarin causes birth defects and fetal death, especially if used in the 1st trimester.
• Precautions:
  • See manufacturer’s literature on each product.
• Significant possible interactions:
  • Digoxin levels can be increased by concomitant use of calcium channel blockers.
  • Many drugs increase warfarin levels.

Second Line

Newer drugs such as ARBs, type I-C and III antiarrhythmic drugs, and low-molecular-weight heparin have not been used extensively in pregnancy, but may be of use in selected patients.

Outline

• First Line
• Second Line

ADDITIONAL TREATMENT

General Measures

• Outpatient evaluation and treatment unless the fetus or the mother’s life is threatened
• Prompt treatment of infections
• Prevention and treatment of anemia with iron supplements
• Vaginal delivery is generally preferred, with pain control to avoid tachycardia and hemodynamic monitoring in selected patients to guide therapy during delivery.

Referral

Patients with suspected heart disease should be referred to a cardiologist.

SURGERY

• When decompensation threatens the mother’s life and aggressive pharmacologic therapy is insufficient, surgical correction of any correctable lesions should be considered.
• Risk to the mother is not particularly higher when pregnant, but fetal loss is not uncommon.
• In the case of mitral stenosis, percutaneous balloon valvotomy may be accomplished with less risk to the fetus.
• Cesarean delivery should be reserved for obstetrical reasons because it puts more stress on the heart.

IN-PATIENT CONSIDERATIONS

Initial Stabilization

Depends on reason for admission

Admission Criteria

• Heart failure
• Syncope
• Chest pain

IV Fluids

May be useful in vaso-vagal syncope

Nursing

• Monitor EKG
• Frequent vital signs
• Monitor fetal heart beat

Discharge Criteria

Resolution of problem

Outline

• Additional Treatment
  • General Measures
  • Referral
• Surgery
• In-Patient Considerations
  • Initial Stabilization
  • Admission Criteria
  • IV Fluids
  • Nursing
  • Discharge Criteria

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

• Depends on the heart condition
• Coordinate delivery plans with cardiologist and anesthesiologist

DIET

• Low-salt for heart failure
• Low-fat if coronary atherosclerosis suspected

PATIENT EDUCATION

• Depends on cardiac condition
• Prenatal care is critical in heart disease patients

PROGNOSIS

• Maternal mortality rates depend on the underlying cardiac condition.
• <1%:
  • Left-to-right shunts at the atrial, ventricular, and ductal levels
  • Pulmonary valve disease
  • Corrected congenital heart disease
  • Bioprosthetic valves
  • Mild to moderate mitral stenosis
• 5–10%:
  • Moderate to severe mitral stenosis
  • Mechanical prosthetic valves
  • Aortic stenosis
  • Coarctation of the aorta
  • Uncorrected congenital heart disease
  • Marfan syndrome with normal aorta
• 25–50%:
  • Pulmonary HTN
  • Complicated coarctation of the aorta (aortic stenosis or severe HTN)
  • Marfan syndrome with dilated aorta

COMPLICATIONS

Fetal abnormalities, fetal death, maternal death, heart failure, infective endocarditis, arrhythmias, thromboembolism, and arterial thrombosis

Outline

• Follow-Up Recommendations
  • Patient Monitoring
• Diet
• Patient Education
• Prognosis
• Complications

CODES

ICD9

• 648.60 Other cardiovascular diseases of mother complicating pregnancy, childbirth, or the puerperium, unspecified as to episode of care
• 674.50 Peripartum cardiomyopathy, unspecified as to episode of care or not applicable
• 674.53 Peripartum cardiomyopathy, antepartum condition or complication
• 648.63 Other cardiovascular diseases of mother, antepartum

SNOMED

• 16253001 dilated cardiomyopathy secondary to peripartum heart disease (disorder)
• 78381004 heart disease in mother complicating pregnancy, childbirth AND/OR puerperium (disorder)

CLINICAL PEARLS

• The vasodilation associated with pregnancy reduces the intensity of the murmurs of aortic and mitral regurgitation, and hypertrophic obstructive cardiomyopathy.
• Fetal arrhythmias can be treated by giving antiarrhythmic drugs such as sotalol to the mother.
• Maternal hemodynamics may not return completely to normal until after lactation ceases.

Outline

• Codes
  • ICD9
  • SNOMED
• Clinical Pearls

ADDITIONAL READING

• Drenthen W, et al. Outcome of pregnancy in women with congenital heart disease: A literature review. J Am Coll Cardiol. 2007;49:2303–2311.
• Elkayam U, et al. Maternal and fetal outcomes of subsequent pregnancies in women with peripartum cardiomyopathy. N Engl J Med. 2001;344:1567.
• Elkayam U, et al. Valvular heart disease and pregnancy: Part I: Native valves. J Am Coll Cardiol. 2005;46:223–230.
• James Att, et al. Acute MI in pregnancy: A United States population based study. Circulation. 2006;113:1564–1571.
• Immer FF, et al. Aortic dissection in pregnancy: Analysis of risk factors and outcome. Ann Thorac Surg. 2003;76:309–314.

Michael H. Crawford