Pregnancy and Reproductive Health in Adult Congenital Heart Disease

Evan F. Shalen

Abigail D. Khan

INTRODUCTION

Innovations in the treatment of congenital heart disease (CHD) have greatly improved survival, leading to a dramatic increase in the size of the population of adults with CHD (ACHD).¹ CHD is now the most prevalent type of heart disease in pregnant women worldwide.² Reproductive health issues are of paramount importance as the CHD population ages into adulthood, and counseling about contraception and pregnancy is the cornerstone of ACHD care.³

ACHD comprises a diverse group of disorders with a wide range of expected clinical outcomes. The diversity of the underlying conditions and the changing nature of the surgical approach to ACHD have resulted in significant heterogeneity in pregnancy risk. Similarly, the risks associated with contraception and assisted reproductive strategies vary, presenting a challenge to those delivering care to this population. In this chapter, we provide an overview of ACHD pregnancy risk and address reproductive-related care for both men and women with ACHD.

PATHOGENESIS

An understanding of the hemodynamic changes of pregnancy is critical to the management of pregnant ACHD patients. The major cardiovascular changes associated with normal pregnancy are as follows:

An increase in the circulating plasma volume that begins by 6 weeks of gestation and peaks at 50% of baseline by 32 weeks.
A decrease in systemic vascular resistance and blood pressure.
An approximately 20% increase in heart rate.
Ventricular remodeling, leading to increased left ventricular (LV) end-diastolic volume with preserved LV ejection fraction (LVEF) and increased stroke volume, resulting in a 30% to 50% increase in cardiac output.
In active labor, 300 to 500 mL of blood is returned to the central circulation with each contraction, and cardiac output increases by 50%.
The decreased preload associated with the performance of the Valsalva maneuver during pushing results in a decrease in cardiac output in some patients.

CLINICAL PRESENTATION

Most cases of CHD are known prior to pregnancy. In rare cases, the physiologic changes of pregnancy and/or the increased intensity of medical care yields a new diagnosis of CHD. The clinical presentation is variable; however, women can present with murmurs, arrhythmias, or dyspnea and peripheral edema.

DIAGNOSIS

Echocardiography

Echocardiography is the first-line diagnostic tool in pregnancy, carrying a high sensitivity and specificity with no documented adverse fetal effects. It provides both anatomic and hemodynamic information. It is generally possible to obtain adequate transthoracic images in pregnant patients. If not, transesophageal echocardiography can usually be safely performed, but the risks of the associated sedation should be discussed with the patient and obstetric and anesthesia teams. Noncontrast magnetic resonance imaging (MRI) is an option for those with poor acoustic echocardiographic windows. Ultrasound-enhancing agents are not typically used in pregnancy, because their risk is unknown. Saline contrast is assumed to be safe in pregnancy, but it has not been systematically studied.

Computed Tomography

The elevated heart rate associated with pregnancy can be a limiting factor in the acquisition of gated cardiac imaging. Consideration of cardiac Computed Tomography (CT) in pregnancy should include discussion with a radiologist about the expected radiation dose to the fetus and also with an obstetrician to help define the fetal risk. The typical fetal radiation dose from maternal chest imaging is low, although there is known association between in utero radiation exposure and childhood malignancy at higher levels of exposure.⁴ Assessment of the blood-tissue interface and intravascular and vascular structures is enhanced with intravenous contrast. Low osmolar agents cross the placenta but have not been associated with fetal injury.⁴

Magnetic Resonance Imaging

MRI provides detailed imaging of the heart and central vasculature and is considered safe in pregnancy.⁴ There appears to be
no appreciable effect on offspring after first trimester maternal MRI exposure.⁵ Gadolinium contrast agents are generally avoided as they are classified as category C (ie, animal reproduction studies have shown an adverse effect on the fetus, and there are no adequate and well-controlled studies in humans) by the Food and Drug Administration (FDA).⁴

Cardiac Catheterization

Invasive angiography and hemodynamic assessment are essential in the evaluation of some pregnant patients. Radiation exposure to the fetus should be minimized.⁴

Exercise Testing

Abnormal chronotropic response to stress testing either before pregnancy or in the first trimester is a predictor of adverse pregnancy events in women with CHD.⁶ Stress testing to assess expected maternal response to pregnancy or to rule out cardiac ischemia is appropriate in selected patients, but the anticipated diagnostic benefits need to be weighed against the risks of the test. In general, submaximal exercise stress testing is safe in pregnancy.

MANAGEMENT OF THE PATIENT WITH ADULT CONGENITAL HEART DISEASE

Overview of Risk Stratification of Pregnant Women With Congenital Heart Disease

There are three commonly used risk scoring systems for pregnant women with CHD, each of which has unique strengths and limitations, and the information that they provide should be viewed as complementary to information gleaned from smaller, lesion-specific cohorts.

Cardiac Disease in Pregnancy Study II (CARPREG II) Risk Score

The Cardiac Disease in Pregnancy (CARPREG II) score was developed in a cohort of 1938 women with various types of heart disease⁷ and identified 10 predictors of maternal cardiac events (Table 104.1). This score is easy to calculate, applies to women with and without CHD, and is appealing to clinicians and patients because it yields a user-friendly percentage risk. How the CARPREG II score performs in real-world cohorts has yet to be determined.

ZAHARA (Zwangerschap bij vrouwen met een Aangeboren HARtAfwijking-II [translated as “Pregnancy in Women with CHD II Risk Index”]) Risk Score

The ZAHARA score was developed in a large retrospective European cohort of women with CHD and identified eight factors associated with maternal cardiac complications (Table 104.1).⁸ Like CARPREG, ZAHARA calculates a percentage predicted risk but is less commonly used in the United States. While some risk markers are common to both CARPREG and ZAHARA, there are important differences, likely related to study methodology and the characteristics of the study populations.

TABLE 104.1 Predictors of Pregnancy Risk in the CARPREG II and ZAHARA Studies

CARPREG II	ZAHARA
Prior cardiac events or arrhythmias Higher NYHA class^a or cyanosis Mechanical valve High-risk left-sided valve disease/LVOT obstruction^b
Ventricular dysfunction^c	Cardiac medications before pregnancy
Pulmonary hypertension^d	≥ Moderate systemic atrioventricular valve regurgitation
Coronary artery disease	≥ Moderate pulmonary valve regurgitation
High-risk aortopathy^e	–
No prior cardiac intervention	–
Late pregnancy assessment^f	–
Note: Merged cells indicate risk factors that are common to both scores. LVOT, left ventricular outflow tract obstruction; NYHA, New York Heart Association.
^aCARPREG II: Baseline NYHA III-IV status, ZAHARA= NYHA prior to pregnancy >II. ^bCARPREG II: aortic valve area <1.5 cm², subaortic gradient >30 mm Hg, mitral valve area <2 cm², or moderate to severe mitral regurgitation, ZAHARA: Peak aortic gradient >50 mm Hg or aortic valve area <1.0 cm². ^cLeft ventricular ejection fraction <55%. ^dRight ventricular systolic pressure ≥50 mm Hg in the absence of right ventricular outflow obstruction. ^eMarfan syndrome, bicuspid aortic valve with aortic diameter >45 mm, Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome or prior aortic dissection or pseudoaneurysm. ^fFirst antenatal visit after 20 weeks’ gestation.
Adapted from Silversides CK, Grewal J, Mason J, et al. Pregnancy outcomes in women with heart disease: the CARPREG II study. J Am Coll Cardiol. 2018;71:2419-2430; Drenthen W, Boersma E, Balci A, et al. Predictors of pregnancy complications in women with congenital heart disease. Eur Heart J. 2010;31:2124-2132.

World Health Organization Classification

The World Health Organization (WHO) classification is a qualitative scoring system that incorporates anatomic and physiologic features (Table 104.2).⁹ The WHO score performs well as a predictor of maternal, obstetric, and fetal events and has a higher discriminative ability than the CARPREG or ZAHARA scores.²,¹⁰ The WHO classification is the tool endorsed by major society guidelines.⁹,¹¹

Risk Stratification by Defect Complexity

Simple Defects

Simple defects include small and uncomplicated atrial and ventricular septal defects (ASD, VSD); patent ductus arteriosus; mild pulmonic stenosis; and repaired ASD, VSD, and anomalous pulmonary venous return. These defects are associated with a minimally increased risk in pregnancy (Table 104.2).
Paradoxical embolus is a concern for those with persistent intracardiac shunts, and avoidance of venous stasis with compression stockings and early ambulation after delivery is recommended.

TABLE 104.2 Modified WHO Classification of Maternal Cardiovascular Risk

WHO Class	Associated Risk	Lesion
I	No detectable increased risk of maternal mortality and no/mild increase in morbidity.	Uncomplicated, small, or mild: Pulmonary stenosis PDA Mitral valve prolapse Repaired simple lesions ASD or VSD PDA Anomalous pulmonary venous drainage Isolated ectopic beats
II	Small increased risk of maternal mortality or moderate increase in morbidity.	Unoperated ASD or VSD Repaired tetralogy of Fallot Most arrhythmias
II or III	May fall into higher or lower risk classification based on additional patient factors.	Mild left ventricular impairment Hypertrophic cardiomyopathy Native or tissue valvular heart disease not considered class I or IV Marfan syndrome without aortic dilation Bicuspid aortic valve aortopathy with aorta diameter < 45 mm Repaired coarctation
III	Significantly increased risk of maternal mortality or severe morbidity.	Mechanical valve Systemic right ventricle Fontan circulation Unrepaired cyanotic heart disease Other complex CHD Marfan syndrome with aortic diameter 40-45 mm Bicuspid aortopathy with aortic diameter 45-50 mm
IV	Extremely high risk of maternal mortality or severe morbidity; pregnancy contraindicated.	Pulmonary arterial hypertension Severe systemic ventricular dysfunction Peripartum cardiomyopathy with any residual left ventricular dysfunction Severe mitral stenosis Severe symptomatic aortic stenosis Marfan syndrome with aortic diameter >45 mm Bicuspid aortopathy with aortic diameter >50 mm Severe native aortic coarctation
ASD, atrial septal defect; CHD, congenital heart disease; PDA, patent ductus arteriosus VSD, ventricular septal defect.
Data from Regitz-Zagrosek V, Blomstrom Lundqvist C, Borghi C, et al. ESC Guidelines on the management of cardiovascular diseases during pregnancy: The task force on the management of cardiovascular diseases during pregnancy of the European Society of Cardiology (ESC). Eur Heart J. 2011;32(24):3147-3197 and Jastrow N, Meyer P, Khairy P, et al. Prediction of complications in pregnant women with cardiac diseases referred to a tertiary center. Int J Cardiol. 2011;151(2):209-213.

Moderate Complexity Congenital Heart Disease

Preconception counseling is strongly recommended for patients with moderate complexity CHD, and pregnant patients need to be followed by a cardiologist with CHD experience and a high-risk obstetrician. Preconception imaging is useful for risk stratification and hemodynamic optimization, whereas those at elevated risk of arrhythmias should have ambulatory rhythm monitoring. In some cases, exercise testing is helpful to predict cardiac events.⁶

Vaginal delivery is preferred unless there is an obstetric indication for cesarean section. Rare exceptions include those with decompensated heart failure or significantly impaired LV function, severe aortic enlargement, and/or ongoing poorly tolerated arrhythmias. A multidisciplinary delivery plan, including a discussion of the location and mode of delivery and the need for cardiac monitoring, is recommended.

Moderate and Large Unrepaired Atrial Septal Defects. Most moderate and large unrepaired ASD are WHO Class II (Table 104.2), although pregnancy is contraindicated if there is severe pulmonary arterial hypertension (WHO Class IV). Preconception cardiac MRI can be helpful to accurately size the right ventricle (RV), define the shunt fraction, and determine whether there is partial anomalous pulmonary venous return. Hemodynamically significant ASDs should be closed prior to pregnancy.³

Unrepaired ASD is associated with an increased risk of arterial thromboembolism, and strategies to reduce the risk of venous stasis are recommended. Women with unrepaired ASD can also develop atrial arrhythmias. Whereas those with large shunts and associated RV enlargement and/or dysfunction are theoretically at higher risk of volume overload, clinical heart failure is rare.¹²

Tetralogy of Fallot. Most women with repaired Tetralogy of Fallot (TOF) tolerate pregnancy well, with a reported maternal cardiac event rate of 7% or less.¹³,¹⁴ Heart failure and arrhythmias occur more frequently in women with RV dysfunction and/or moderate to severe pulmonary regurgitation.¹⁵ Overall complication rates are low, even in those with significant pulmonary stenosis or regurgitation.¹⁶,¹⁷

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Tags: Cardiovascular Medicine and Surgery

May 8, 2022 | Posted by drzezo in CARDIOLOGY | Comments Off

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