I. Peri-partum Cardiomyopathy: What every physician needs to know.
Peri-partum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy presenting with heart failure (HF) secondary to left ventricular (LV) systolic dysfunction toward the end of pregnancy or in the months following delivery where no other cause of HF is found. The left ventricle may not be dilated but the ejection fraction (EF) is nearly always below 45%.
II. Diagnostic Confirmation: Are you sure your patient has Peri-partum Cardiomyopathy?
PPCM is a diagnosis of exclusion, and other causes of cardiac dysfunction should be ruled out.
A. History Part I: Pattern Recognition:
Most patients present with typical signs and symptoms of HF, including weight gain, edema, tachycardia, dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea. In addition, cough, chest pain, and abdominal pain are frequently encountered and tend to confuse the initial clinical evaluation.
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B. History Part 2: Prevalence:
Incidence of PPCM in the U.S. has ranged in different publications from 1:1,149 to 1:4,350 live births with an average of 1:3186. The incidence of PPCM has been found to be higher in women older than 30 years, African Americans, in patients with history of hypertension and preeclampsia, and multifetal pregnancies. In addition recent studies have demonstrated a high incidence of PPCM in families with dilated cardiomyopathies, suggesting that a proportion of patients with PPCM may be due to genetic cause. Compared to the U.S. a much higher incidence has been reported in South Africa (1:1,000), and Haiti (1:300); no information is available regarding the incidence of this condition in Europe.
C. History Part 3: Competing diagnoses that can mimic Peri-partum Cardiomyopathy.
Many of the signs and symptoms of normal pregnancy are similar to those of HF; for this reason, and because of the low incidence of this condition, the diagnosis of PPCM is often missed or delayed, allowing the development of preventable complications.
D. Physical Examination Findings.
Physical examination often reveals tachycardia and tachypnea; blood pressure may be reduced, and patients are often not able to lie down flat because of shortness of breath. There is usually an increased jugular venous pressure, displaced apical impulse and right ventricular heave, murmurs of mitral and tricuspid regurgitation, and a third heart sound, pulmonary rales, and peripheral edema may also be found.
E. What diagnostic tests should be performed?
Electrocardiography usually shows sinus tachycardia with nonspecific ST T-wave changes. LV hypertrophy can be found, as well as left atrial enlargement and, occasionally, conduction abnormalities including left bundle brunch block. Chest radiography usually shows cardiomegaly and pulmonary venous congestion or pulmonary edema, with or without pleural effusion. Echocardiography reveals variable degrees of LV dilatation, with moderate to severe depression of systolic function. Moderate to severe mitral and tricuspid regurgitation are commonly seen, with increased pulmonary pressure and mild pulmonary regurgitation. Cardiac magnetic resonance imaging (MRI) has been used in a limited number of patients for the assessment of cardiac function and the detection of mural thrombi or myocardial fibrosis.
III. Management.
Drug therapy for acute and chronic HF associated with PPCM includes the potential use of diuretic agents, intravenous and oral vasodilators, intravenous inotropes, ACE inhibitors or angiotensin receptor antagonists, beta-blockers, spironolactone, and digoxin. In general, the treatment of HF in patients with PPCM should follow recent guideline recommendations, except during pregnancy and lactation, when drug therapy may need to be altered because of potential detrimental effects on the fetus or the lactating infant.
A. Immediate management.
Experimental therapy: On the basis of the concept of enhanced oxidative stress-mediated cleavage of the nursing hormone prolactin into an antiangiogenic and proapoptotic 16-kDa form that may be responsible for the development of PPCM, there has been limited but promising experience with the use of the prolactin inhibitor bromocriptine in patients with PPCM. In patients demonstrating rapid deterioration and not responding to medical therapy including vasoactive medications, intraaortic balloon pump, extracorporeal membrane oxygenation, and LV assist devices have been used successfully and should be considered.
Because the rate of recovery in patients with PPCM is higher than in patients with other forms of dilated cardiomyopathy, an attempt should be made to use such devices as a bridge to recovery before referral for cardiac transplantation. Cardiac transplantation has been performed in patients with PPCM with favorable results.
B. Physical Examination Tips to Guide Management.
Response to initial heart failure therapy should be assessed by frequent monitoring of vital signs, neck vein pulsation, edema, and the ability of the patient to lie flat. Left ventricular ejection fraction should be followed periodically to assess recovery of cardiac function and the need for continuation of attenuation of anticoagulation, as well as the indication for device therapy such as an implantable defibrillator or resynchronization therapy in patients with persistent LV dysfunction despite appropriate medical therapy (maximally tolerated recommended doses of beta-blockers, ACE inhibitors, or angiotensin receptor antagonists [ARBs] and aldosterone receptor antagonists for 3 to 6 months).
C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.
Monitoring during the initial HF treatment should include daily monitoring of electrolytes and serum creatinine. Measurement of BNP level after stabilization and prior to discharge from the hospital may be useful. Echocardiographic examination should be repeated every month for 3 months after the delivery, at 6 and 12 months, and yearly thereafter.
E. Common Pitfalls and Side-Effects of Management
Drug therapy may need to be altered because of potential detrimental effects on the fetus or the lactating infant. The use of ACE inhibitors or ARBs is contraindicated during pregnancy because of toxic effects, mostly on the developing fetal kidneys.
Other potential side effects include oligohydramnios, intrauterine growth retardation, prematurity, bond malformation, limb contractures, patent ductus arteriosus, pulmonary hypoplasia, respiratory distress syndrome, hypotension, anuria, and neonatal death. During pregnancy, the combination of organic nitrates and hydralazine should be used as a substitute for ACE inhibitors or ARBs.
There is lack of human pregnancy experience with the use of all three beta-blockers approved in the U.S. for the treatment of HF (carvedilol, bisoprolol, and metoprolol succinate, all-risk category C), and their effects on the fetus are therefore unknown. Metoprolol tartrate has been more commonly used in pregnancy for the management of hypertension, arrhythmias, mitral stenosis, and myocardial ischemia.
In addition, the use of beta-1-selective beta-blockers is preferred during pregnancy, because nonselective beta-blockade could facilitate uterine activity. There is no report of a teratogenic effect of spironolactone in humans, but there is concern regarding the antiandrogenic effect of the drug in humans and feminization reported in male rat fetuses.
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