Cardiovascular Disease

Executive Summary

This briefing document summarizes key information regarding cardiovascular health during pregnancy, drawing insights from "Pregnancy and Cardiovascular Disease - Cardiovascular Medicine Text - MKSAP 19.pdf". It highlights the increasing maternal mortality in the US due to cardiovascular disorders, the physiological changes during normal pregnancy, and the critical importance of prepregnancy evaluation, multidisciplinary management, and careful consideration of medication and anticoagulation therapies for women with pre-existing or pregnancy-related cardiovascular conditions. Special attention is given to high-risk conditions like peripartum cardiomyopathy and Marfan syndrome.

I. Maternal Mortality Trends and Primary Causes

Maternal mortality in the United States has increased over the past two decades, a trend contrasting with decreasing rates in other Western countries. The leading cause of maternal mortality is acquired cardiovascular disorders, specifically "cardiomyopathy, coronary artery disease, and aortic disorders."

II. Cardiovascular Changes During Normal Pregnancy

Understanding normal physiological changes is crucial for distinguishing between healthy and pathologic signs. Key cardiovascular adaptations during a normal pregnancy include:

• Relative Anemia: Due to a greater increase in plasma volume compared to erythrocyte mass.
• Decreased Mean Arterial Pressure: Resulting from "reduced systemic vascular resistance and increased heart rate and cardiac output."
• Increased Heart Rate and Cardiac Output: Maternal cardiac output "peaks at approximately 40% to 50% above the prepregnancy level by the 32nd week," and can further increase to "as much as 80% above the prepregnancy level" during delivery.
• Common Normal Symptoms/Signs: Mild dyspnea, dyspnea with exertion, atrial and ventricular premature beats, heart rate increased by 20-30%, modest blood pressure decrease (~10 mm Hg), and a "basal systolic murmur grade 1/6 or 2/6 present in 80% of pregnant patients, S3."

Table 45 (Normal Versus Pathologic Signs and Symptoms in Pregnancy) provides a detailed comparison, distinguishing normal physiological changes from symptoms like orthopnea, chest pain, atrial fibrillation, heart rate >100/min, high blood pressure (≥140/90 mm Hg), systolic murmur grade ≥3/6, or any diastolic murmur/S4, which are considered pathologic.

III. Prepregnancy Evaluation and Risk Stratification

Mandatory Prepregnancy Counseling: "All women with cardiovascular disease should receive pregnancy counseling," including genetic counseling and testing if appropriate. Multidisciplinary Approach: A comprehensive evaluation involving a "cardiologist, a maternal-fetal medicine specialist, and an obstetric anesthesiologist" is essential to assess risks and formulate a management plan for labor and postpartum. Risk Assessment Tool: The modified World Health Organization pregnancy risk classification is currently the "most accurate system of risk assessment."

A. Low-Risk Conditions

Women with certain conditions generally experience no increased morbidity or mortality:

• Uncomplicated small patent ductus arteriosus
• Mild pulmonary stenosis
• Mitral valve prolapse
• Successfully repaired simple lesions (atrial or ventricular septal defect, patent ductus arteriosus, anomalous pulmonary venous drainage)
• Isolated atrial or ventricular ectopic beats
• Tetralogy of Fallot, most supraventricular arrhythmias, and Turner syndrome without aortic dilatation. These patients can typically be managed and deliver in a local hospital.

B. Extremely High-Risk Conditions (Require Expert Center Care)

Conditions conferring "extremely high risk for maternal mortality or severe morbidity" necessitate care and delivery at "an expert center for pregnancy and cardiac disease":

• Pulmonary hypertension
• Previous peripartum cardiomyopathy with residual left ventricular dysfunction
• Severe left ventricular dysfunction (ejection fraction <30% or NYHA functional class III-IV symptoms)
• Severe mitral stenosis
• Symptomatic severe aortic stenosis
• Marked ascending aorta dilatation

IV. Management of Cardiovascular Disease During Pregnancy

A. Valvular Lesions

• Obstructive: Symptoms may arise due to increased blood volume/cardiac output; intervention before pregnancy should be considered.
• Regurgitant: Generally well-tolerated during pregnancy.

B. Hypertrophic Cardiomyopathy

• Symptomatic obstructive hypertrophic cardiomyopathy: Treated with "nonvasodilating β-blockers, with monitoring of fetal growth."

C. Arrhythmias

• Most arrhythmias are benign.
• Shared decision-making is crucial for antiarrhythmic drugs, considering maternal and fetal risks/benefits.
• Most β-blockers (except atenolol) are safe for pregnancy and breastfeeding.
• Adenosine is the drug of choice for acute symptomatic supraventricular tachycardia.
• Amiodarone is rarely used due to toxicity.

D. Delivery Method

• Vaginal delivery is generally preferred due to "less blood loss, quicker recovery, and lower risk for thrombosis."
• Cesarean delivery is recommended for:Obstetric reasons in women with severe decompensated cardiovascular disease.
• Some patients with a markedly dilated aorta.
• Women on warfarin therapy to reduce fetal intracranial hemorrhage risk due to fetal anticoagulation.

V. Specific Cardiovascular Disorders

A. Peripartum Cardiomyopathy (PPCM)

• Definition: "New onset of heart failure in the last month of pregnancy or within 5 months of delivery in the absence of an identifiable cause."
• Risk Factors: Multiparity, age >30 years, multifetal pregnancy, gestational hypertension, preeclampsia, previous PPCM, tocolytic therapy.
• Causes of Death: Heart failure, thromboembolic events, or arrhythmias.
• Prognosis: Most women recover fully, but 13% may have major cardiovascular events or persistent severe cardiomyopathy. Recovery timeframe is typically 6 months. Worse outcomes are linked to severe LV dysfunction/dilatation at presentation, older maternal age, and multiparity.
• Management: Prompt medical therapy (β-blockers, digoxin, hydralazine, nitrates, diuretics). ACE inhibitors, ARBs, and aldosterone antagonists are teratogenic and must be avoided until after delivery.
• Anticoagulation: Recommended for LVEF <35% due to high thromboembolism risk. Duration is at least 8 weeks or until ejection fraction normalizes.
• Severe Refractory Cases: Referral to a specialty center for advanced treatments (ventricular assist device, advanced arrhythmia management, heart transplantation).
• Future Pregnancy: Women with a previous PPCM episode and persistent LV dysfunction "should be advised to avoid future pregnancy" due to high risk of recurrence or deterioration.

B. Other Cardiovascular Disorders

• Adverse Pregnancy Outcomes: Linked to the acquisition of cardiovascular risk factors (e.g., hypertensive disorders of pregnancy, preterm delivery).
• Marfan Syndrome: Increased risk for pregnancy-rela...