Peripartum cardiomyopathy: Causes, diagnosis, and treatment
ABSTRACTPeripartum cardiomyopathy is a life-threatening condition of unknown cause that occurs in previously healthy women during the peripartum period. It is characterized by left ventricular dysfunction and symptoms of heart failure that can arise in the last trimester of pregnancy or up to 5 months after delivery. We review its possible causes and how to recognize and manage it.
KEY POINTS
- Heightened suspicion is important when a pregnant woman presents with signs of heart failure, because early diagnosis allows proven treatment to be started.
- Standard heart failure therapy should be started in postpartum patients with this disease, using available local protocols.
- Pregnant women should not receive angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or warfarin because of potential teratogenic effects.
- An initial left ventricular end-systolic dimension less than 5.5 cm, a left ventricular ejection fraction greater than 30%, and a low cardiac troponin level may predict a better outcome.
- Subsequent pregnancies carry a high risk of relapse, even in women who have fully recovered left ventricular function.
WHO IS AT RISK?
Demakis and colleagues2 suggest the following risk factors for peripartum cardiomyopathy:
- Multiparity
- Advanced maternal age (although the disease can occur at any age, the incidence is higher in women over age 3036)
- Multifetal pregnancy
- Preeclampsia
- Gestational hypertension
- African American race.
CLINICAL FEATURES
Peripartum cardiomyopathy involves left ventricular systolic dysfunction in women with no history of heart disease. It can be diagnosed only if other causes of cardiomyopathy are absent.2
Diagnostic criteria for peripartum cardiomyopathy (all must be present) are37:
- Cardiac failure developing in the last month of pregnancy or within 5 months of delivery
- No identifiable cause of the cardiac failure
- No recognizable heart disease before the last month of pregnancy
- An ejection fraction of less than 45%, or the combination of an M-mode fractional shortening of less than 30% and an end-diastolic dimension greater than 2.7 cm/m2.
Symptoms of heart failure such as dyspnea, dizziness, pedal edema, and orthopnea can occur even in normal pregnancies. Therefore, a pregnant woman in whom peripartum cardiomyopathy is developing may consider her symptoms to be normal. The dyspnea during normal pregnancy is thought to be due to hyperventilation caused by the effects of progesterone, and also due to pressure on the diaphragm from the growing uterus.38 Peripheral edema occurs in approximately two-thirds of healthy pregnant women.39 Nevertheless, if swelling and other heart failure symptoms develop suddenly in an otherwise normal pregnancy, this should prompt further investigation.40
Pulmonary edema was a presenting symptom in all 106 patients in a 2007 study in China. 41 The clinical presentation was similar to that of congestive heart failure but was highly variable; 17% of cases were diagnosed antepartum and 83% postpartum. The mean age at diagnosis was 28 ± 6 years. Left ventricular function almost completely normalized in 51% of surviving patients. These findings were similar to those in earlier studies.2,36 Interestingly, the left ventricular ejection fraction normalized only in 23% of an African cohort.23
Thromboembolism can be a presentation of peripartum cardiomyopathy. Hemoptysis and pleuritic chest pain may be presenting symptoms of pulmonary embolism.42
Cardiac arrhythmias and sudden cardiac arrest have also been reported.43
A latent form of peripartum cardiomyopathy without significant clinical signs and symptoms has been reported.8
Preeclampsia should be excluded on the basis of history and physical examination, as its management is different. Preeclampsia occurs after 20 weeks of gestation and is characterized by high blood pressure, protein in the urine, swelling, sudden weight gain, headaches, and changes in vision.
Delayed diagnosis may be associated with higher rates of illness and death; therefore, physicians should consider peripartum cardiomyopathy in any peripartum patient with unexplained symptoms. Although the symptoms of heart failure can be difficult to differentiate from those of late pregnancy, a heightened suspicion can help.44
The aims during the diagnosis are to exclude other causes of cardiomyopathy and to confirm left ventricular systolic dysfunction by echocardiography. Whether endomyocardial biopsy should be done in this setting is still controversial, and recent guidelines do not recommend it.45,46
Role of cardiac MRI
Magnetic resonance imaging (MRI) may be used as a complementary tool to diagnose peripartum cardiomyopathy, and it may prove to be important in identifying the mechanisms involved. It can measure global and segmental myocardial contraction, and it can characterize the myocardium.47
Furthermore, delayed contrast enhancement (with gadolinium) can help differentiate the type of myocyte necrosis, ie, myocarditis vs ischemia. Myocarditis has a nonvascular distribution in the subepicardium with a nodular or band-like pattern, whereas ischemia has a vascular distribution in a subendocardial or transmural location.48
Kawano et al49 described a patient with peripartum cardiomyopathy whose myocardial damage was demonstrated by delayed contrast enhancement of the left ventricle. This measure improved after she was treated with a beta-blocker, an angiotensin receptor blocker (ARB), and spironolactone (Aldactone), and her cardiac function recovered.
Leurent et al50 advocate using cardiac MRI to guide biopsy to the abnormal area, which may be much more useful than blind biopsy.
Questions remaining about MRI include the pathologic and prognostic implications of late gadolinium enhancement.
