What are the management and treatment options for a pregnant woman with pre-existing left-sided heart failure?

Left-Sided Heart Failure in Pregnancy: Management and Treatment

Definition

Left-sided heart failure in pregnancy is characterized by the inability of the left ventricle to adequately pump blood forward, resulting in pulmonary congestion and reduced cardiac output, which can be either pre-existing (dilated cardiomyopathy) or develop during the peripartum period (peripartum cardiomyopathy). 1

How Left-Sided Heart Failure Affects Pregnancy

Increased Cardiac Demand

• Pregnancy increases blood volume by 40-50%, cardiac output by 30-50%, and heart rate by 10-20 beats per minute, placing enormous stress on an already failing left ventricle 2, 3
• The hemodynamic burden peaks during labor, delivery, and immediately postpartum when autotransfusion from the contracted uterus and lower extremities dramatically increases preload 1

Maternal Complications

• Cardiac events occur in 32-60% of pregnant women with left ventricular dysfunction (LVEF <40%) 3
• Acute decompensated heart failure with pulmonary edema is the most common complication, particularly during labor and the first few days postpartum 1
• Arrhythmias including atrial fibrillation and ventricular tachycardia occur frequently and worsen outcomes 3
• Thromboembolic events including stroke and peripheral embolism are increased due to pregnancy-related hypercoagulability combined with low ejection fraction and venous stasis 1
• Maternal mortality ranges from 17-33% in recent studies for women with severe left ventricular dysfunction (LVEF <20-30%) 3

Fetal Complications

• Intrauterine growth restriction occurs due to reduced placental perfusion from decreased maternal cardiac output 2
• Preterm delivery occurs in approximately 17% of cases, often necessitated by maternal hemodynamic deterioration 1
• Fetal mortality is reported at approximately 6% 2

Causes of Left-Sided Heart Failure in Pregnancy

• Peripartum cardiomyopathy (PPCM): develops in the last month of pregnancy or within 5 months postpartum in previously healthy women 1
• Pre-existing dilated cardiomyopathy: familial or idiopathic cardiomyopathy diagnosed before pregnancy 1
• Ischemic cardiomyopathy: from coronary artery disease, increasingly common with advanced maternal age, obesity, diabetes, and smoking 1
• Valvular heart disease: severe mitral or aortic regurgitation causing volume overload 1
• Hypertrophic cardiomyopathy with systolic dysfunction: rare but can decompensate during pregnancy 4

Symptoms

• Progressive dyspnea on exertion or at rest 1
• Orthopnea and paroxysmal nocturnal dyspnea 1
• Peripheral edema (must be distinguished from normal pregnancy-related edema) 1
• Fatigue and exercise intolerance beyond normal pregnancy symptoms 3
• Palpitations from arrhythmias 3
• Chest pain or pressure 1

Nursing Interventions for Left-Sided Heart Failure

Dependent Nursing Interventions (Requiring Physician Orders)

Medication Administration:

• Administer beta-1 selective blockers (metoprolol) as the cornerstone of heart failure therapy during pregnancy 1
• Administer diuretics (furosemide or hydrochlorothiazide) ONLY when pulmonary congestion is present, as they can decrease placental blood flow 1
• Administer hydralazine and nitrates for afterload reduction (ACE inhibitors, ARBs, and renin inhibitors are absolutely contraindicated during pregnancy due to fetotoxicity) 1
• Administer low molecular weight heparin (LMWH) for anticoagulation when ejection fraction is very low, monitoring anti-Xa levels 1
• Administer inotropic support with dopamine or levosimendan if hemodynamic instability develops 1

Monitoring:

• Continuous cardiac monitoring during labor and delivery with invasive hemodynamic monitoring in severe cases 1
• Monitor newborns for 24-48 hours after delivery for hypoglycemia, bradycardia, and respiratory depression if mother received beta-blockers 1
• Monitor fluid balance meticulously with urinary catheter drainage during labor 1

Independent Nursing Interventions

Positioning and Activity:

• Position patient in left lateral position during labor to ensure adequate venous return from the inferior vena cava, or sitting-up position if in active heart failure 1
• Encourage early ambulation postpartum to prevent venous stasis and thromboembolism 1
• Apply compression stockings to prevent paradoxical embolism in patients with intracardiac shunts 1

Patient Education:

• Educate patient to avoid supine position during pregnancy and labor 1
• Teach recognition of worsening heart failure symptoms requiring immediate medical attention 3
• Counsel against breastfeeding in peripartum cardiomyopathy due to postulated negative effects of prolactin subfragments and high metabolic demands of lactation 1

Fluid Management:

• Restrict intravenous fluid administration to prevent pulmonary edema 1
• Eliminate air bubbles from all IV lines meticulously to prevent paradoxical air embolism 1

Delivery Support:

• Advocate for vaginal delivery when patient is hemodynamically stable, as it is preferable to cesarean section 1
• Coordinate epidural analgesia during labor as it stabilizes cardiac output 1
• Discourage prolonged bearing down efforts during second stage; facilitate low forceps or vacuum-assisted delivery to reduce exertion 1

Drugs of Choice in Left-Sided Heart Failure During Pregnancy

During Pregnancy (Antepartum):

First-Line Therapy:

• Beta-1 selective blockers (metoprolol) are indicated for all patients with heart failure if tolerated; atenolol should NOT be used 1
• Hydralazine and nitrates for afterload reduction (replacing ACE inhibitors/ARBs which are contraindicated) 1

Second-Line Therapy:

• Diuretics (furosemide or hydrochlorothiazide) ONLY if pulmonary congestion is present 1
• LMWH for anticoagulation in patients with very low ejection fraction, atrial fibrillation, or intracardiac thrombus 1

Contraindicated Medications:

• ACE inhibitors, ARBs, and renin inhibitors are absolutely contraindicated due to fetotoxicity 1
• Aldosterone antagonists (spironolactone) should be avoided due to antiandrogenic effects in first trimester 1
• Atenolol should not be used 1

Postpartum (After Delivery):

Once baby is delivered and patient is hemodynamically stable, standard heart failure therapy can be applied 1:

• ACE inhibitors: benazepril, captopril, or enalapril are preferred during breastfeeding 1
• Beta-blockers: continue metoprolol 1
• Diuretics: furosemide or hydrochlorothiazide as needed 1
• Anticoagulation: restart LMWH or vitamin K antagonists once postpartum bleeding has stopped 1

Critical Management Considerations:

• Urgent delivery irrespective of gestational age should be considered in women with advanced heart failure and hemodynamic instability 1
• Administer single IV dose of furosemide after delivery to counteract autotransfusion from contracted uterus 1
• Avoid ergometrine for third stage management; use single dose intramuscular oxytocin instead 1
• Monitor children's weight during first 4 weeks as indicator of kidney dysfunction if mother taking ACE inhibitors while breastfeeding 1

Common Pitfalls to Avoid:

• Never use ACE inhibitors, ARBs, or renin inhibitors during pregnancy—they cause fetotoxicity 1
• Do not withhold beta-blockers during pregnancy; they are essential therapy 1
• Do not routinely use diuretics prophylactically—only when pulmonary congestion is present, as they decrease placental blood flow 1
• Do not delay anticoagulation in patients with very low ejection fraction due to high risk of thromboembolism 1
• Do not perform cesarean section routinely—vaginal delivery is preferable when hemodynamically stable 1