Peripartum cardiomyopathy

Did You Know?

• Genetic testing is indicated in mothers with PPCM to possibly identify pathogenic genetic variants that predispose to heart failure in pregnancy.
• The 16 kilodalton N-terminal fragment of prolactin has been implicated in a causal role in genetically susceptible individuals.
• A screening tool for diagnosis includes blood work to rule out anemia, electrolyte abnormalities, thyroid dysfunction, and renal or liver dysfunction.

Signs and symptoms

Symptoms include orthopnea, dyspnea on exertion, pitting edema, cough, frequent night-time urination, excessive weight gain in the last month of pregnancy (1–2+ kg/week), palpitations, chest pain or tightness, fatigue, and light-headedness. Shortness of breath is often described as an inability to take a deep or full breath, and patients may need to prop themselves up with pillows to breathe. These symptoms, along with swelling or cough, may indicate pulmonary edema from acute heart failure. Physical examination can reveal jugular venous distention, displaced apical impulse, a third heart sound, murmur consistent with mitral regurgitation, tachypnea, tachycardia, pulmonary rales, and peripheral edema. Diagnosis may be delayed because early symptoms resemble normal pregnancy; such delays increase morbidity and mortality. Women may also present with embolic complications such as stroke, limb ischemia, or myocardial infarction. PPCM is a leading cause of maternal death in many parts of the United States and worldwide, and accounts for about 60% of cardiogenic shock cases during pregnancy or early postpartum. Clinicians should maintain a high suspicion for PPCM in any peri- or postpartum patient with unusual or unexplained symptoms.

Treatment

Early detection and treatment improve recovery rates and reduce morbidity and mortality. Treatment follows that for congestive heart failure, including diuretics (preferably furosemide), beta blockers, and angiotensin-converting enzyme inhibitors (ACE-I) after delivery. Diuretics help eliminate excess water and lower blood pressure; fluid restriction is also used. During pregnancy, diuretics must be used cautiously as they can impair placental blood flow; hydrochlorothiazide and furosemide are safe during pregnancy and breastfeeding. ACE-I and beta blockers improve circulation and may reverse immune dysfunction; if ACE-I is not tolerated, angiotensin receptor blockers (ARB) may be used, but ACE-I and ARBs are contraindicated during pregnancy and breastfeeding. Hydralazine with nitrates can replace ACE-I in breastfeeding mothers or before delivery, though it may be less effective. Anticoagulation is indicated if ejection fraction is below 35% due to risk of left ventricular thrombi. Left ventricular assist device implantation or heart transplant may become necessary. Regular follow-up with frequent echocardiograms is important, especially after treatment changes. Patients not responding to initial treatment (EF below 20% at two months or below 40% at three months) may require cardiac MRI, catheterization, and endomyocardial biopsy for viral PCR analysis; antiviral, immunoabsorption, intravenous gamma globulin, or other immunomodulation therapy may be considered under controlled research protocols.

Prognosis

With newer conventional heart failure treatment (diuretics, ACE inhibitors, beta blockers), survival rate is very high at 98% or better, and almost all patients improve. In the United States, over 50% of patients experience complete recovery of heart function (EF 55% or greater). Most recovered patients eventually discontinue medications without relapse and have normal life expectancy. Improvement or recovery can continue for years after diagnosis with continued treatment. Once fully recovered, if there is no subsequent pregnancy, the risk of relapse is minimal. Subsequent pregnancy should be avoided if left ventricular function has not recovered and EF is below 55%; however, many fully recovered women have had successful subsequent pregnancies. A significant study reports the risk of recurrence of heart failure in recovered PPCM patients due to subsequent pregnancy is approximately 21% or better; the chance may be smaller for those with normal contractile reserve on stress echocardiography. Careful monitoring is needed in any subsequent pregnancy, with a stress test or echocardiogram completed beforehand. If relapse occurs, conventional treatment should be resumed. Factors associated with better prognosis include small left ventricle diastolic dimension, LVEF greater than 30–35% at diagnosis, absence of troponin elevation, absence of LV thrombus, and non-African American ethnicity. Poor prognosis factors include QRS greater than 120 milliseconds, delay in diagnosis, high NYHA class, multiparity, and African descent. Mortality estimates vary by racial group, geography, and follow-up length; at 1 year in the United States, mortality ranges from 4% to 11%.

Epidemiology

The incidence of PPCM in the United States is estimated between 1 in 1300 and 1 in 4000 live births. It affects women of all races but is more prevalent in some regions, such as South African Bantus (1 in 1000 live births) and Haiti (1 in 300). Some studies suggest it may be slightly more common among older women with higher numbers of liveborn children and among women at the extremes of childbearing age, yet a quarter to a third of patients are young women giving birth for the first time. The use of tocolytic agents or development of preeclampsia or pregnancy-induced hypertension may worsen heart failure but do not cause PPCM; most women with PPCM have not received tocolytics nor had preeclampsia or PIH. Worldwide, the incidence of PPCM correlates well with maternal mortality rates, suggesting that the level of perinatal care may influence incidence. PPCM can occur in any woman of any racial background, at any age during reproductive years, and in any pregnancy.