Peripartum Cardiomyopathy – ED Presentation, Evaluation, and Management
- Jul 4th, 2019
- Mary Rometti
Authors: Mary Rometti, MD (EM Resident Physician, Rutgers-Robert Wood Johnson Medical School) and Laryssa Patti, MD (EM Attending Physician, Rutgers-RWJMS) // Edited by: Tim Montrief, MD (@EMinMiami), Alex Koyfman, MD (@EMHighAK), and Brit Long, MD (@long_brit)
A 29-year-old female presents to the ED with shortness of breath for two days, which is worse with exertion or laying down. About one week ago, she delivered a healthy, full-term newborn after an uneventful cesarean section due to non-reassuring fetal heart tones. Exam reveals decreased breath sounds in bilateral lung bases, bilateral lower extremity edema, and SpO2 in 80’s on room air. Given these findings, what’s your approach?
Described in the patient presentation above, peripartum cardiomyopathy (PPCM) is a type of dilated cardiomyopathy with left ventricular (LV) dysfunction in the immediate peripartum period during the last month of pregnancy or in the postpartum period within the first 5 months after delivery.1-4 Most cases of peripartum cardiomyopathy (PPCM) present with signs and symptoms of heart failure, such as orthopnea, paroxysmal nocturnal or exertional dyspnea, and fatigue.1,3-7 Pregnant patients with pre-existing cardiovascular conditions that precede heart failure may present with similar symptoms, making a diagnostic conundrum for clinicians. To be diagnosed with PPCM, patients must not have a previous diagnosis of heart failure or reduced cardiac function. According to one study, approximately 56% of PPCM cases will present within the first week after delivery, and up to 75% of patients will be diagnosed within the first month postpartum.1,8 Within the U.S., 1,000 to 1,300 women will develop PPCM each year,2 and up to 1 in 1,000-4,000 U.S. live births per year result in the mother developing PPCM.1,3 Risk factors include older maternal age, African American race, presence of maternal pre-eclampsia or hypertension (HTN) during pregnancy, and a multiple gestation pregnancy.1,3,5 More than half of PPCM cases occur in southern U.S, possibly due to more African American women living in the South.1
Why does PPCM happen?
As a form of left heart failure, in PPCM the heart chambers dilate, thereby leading to lower LV ejection fraction (LVEF) and subsequent poor perfusion.1,3 The exact cause of peripartum cardiomyopathy is unknown, but current theories suggest it is most likely related to genetics and hormones present in late pregnancy. During late pregnancy, the placenta releases multiple chemical signals, including prolactin and tyrosine kinase, which may increase oxidative stress on cardiac vasculature, endothelium, and myocytes, ultimately decreasing cardiac function.1,3,6,9 Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) potentially help combat this hormonal response by afterload reduction.1,5 Other less likely causes include viral myocarditis, nutritional deficiencies, autoimmunity, fetal microchimerism, and hemodynamic stresses.1,4-6
What else should you consider?
Other diagnoses to consider include:1,3-7,15
- Pulmonary embolism
- Acute coronary syndrome (ACS)
- Other non-dilated cardiomyopathies, including Takotsubo cardiomyopathy
- Amniotic fluid embolism
- Severe anemia
- Normal pregnancy
How do you work it up?
The main diagnostic criteria of PPCM, per the National Heart, Lung, and Blood Institute, is the presence of heart failure within the last month of pregnancy to up to five months following delivery, as defined by a LV EF < 45%, with no other rationale for a reduced EF and history of pre-existing heart disease.1-4,6,7,9 With these diagnostic criteria in mind, the ED evaluation initially involves excluding other possibilities for the patient’s presentation. An electrocardiogram (EKG) usually shows normal sinus rhythm or sinus tachycardia, but it may also show nonspecific ST segment or T wave changes.1,3 Having these non-specific ST and T wave changes may correlate with myocardial ischemia risk profiles.9 An EKG is most useful to aid in ruling out other cardiac etiologies, such as ACS.1,3,7,9 A chest x-ray typically demonstrates findings of heart failure, including cardiac enlargement or pulmonary congestion. There are no pathognomonic EKG or CXR findings that definitively rule in or out PPCM.1,3,7
Although there is no specific biomarker for PPCM, an elevated brain natriuretic peptide (BNP) can be used to point to cardiac chamber distension and fluid overload, as can an elevated troponin.1,3,15 In healthy pregnancies, BNP values are typically within normal limits or mildly elevated, so a significant elevation of BNP indicates cardiac chamber distension and fluid overload.3,16,17 In the immediately post-partum population, obtaining a D-dimer is unlikely to be helpful since a D-dimer is commonly elevated in normal pregnancy.5 If there is a high suspicion for a PE, a CTA chest should be performed. To differentiate PPCM from pre-eclampsia, additional lab work should be performed, such as a complete blood count (CBC) or liver function tests (LFTs) to screen for thrombocytopenia or transaminitis that can be found with severe pre-eclampsia.5 Lactate dehydrogenase (LDH), uric acid, and fibrinogen are also recommended to assess for preeclampsia in the peripartum and early postpartum periods.
In PPCM, a cardiac point of care ultrasound (POCUS) can show LV dilation and LV systolic dysfunction. Echo can also reveal right ventricular and biatrial enlargement, mitral and tricuspid valve regurgitation, pulmonary HTN, or an intracardiac thrombus, due to decreased forward movement of blood through the heart.1,3 Up to 6% of patients with PPCM experience a thromboembolic event.1,3 An echo is vital for the diagnosis of PPCM, while the other evaluation tools described above serve primarily to rule out other diagnoses on the differential.7
What do you do about it?
- ABCs + IV/O2/monitor: In the event of severe respiratory distress, consider non-invasive positive pressure ventilation (NIPPV), which will assist in optimizing preload and afterload. If NIPPV fails, intubate. Since pregnant patients have lower functional residual capacity and a higher basal oxygen consumption rate, they are at higher risk for becoming hypoxic when apneic.5,11 Apneic oxygenation is advised during intubation, including during pregnancy.18 Bag-mask ventilation can aid in maintaining adequate oxygenation saturations during rapid sequence intubation.19
- Call your friends: Cardiology and obstetrics should be consulted to assist in definitive management of new-found heart failure in an obstetrical patient and the establishment of outpatient follow up for future monitoring.5
- Control volume status: Consider loop diuretics and nitrates. Loop diuretics help remove excess fluid from the body and thereby decrease preload.7,20 Consider afterload reduction to assist with poor LV function with vasodilators, like hydralazine or nitrates.1,5,7 Assess for hypotension and poor uterine perfusion as a result of over-diuresis in the pre-partum patient.1,3,5,6,20 Fetal monitoring can assist in evaluating uterine perfusion.10,21 If the patient becomes hypotensive or there is concern for low cardiac output, consider starting vasopressors or inodilators.5,20 Limited human data exists on the best agent to initiate during pregnancy. Dopamine and ephedrine increase maternal blood pressure and blood flow to the uterus. If possible, avoid phenylephrine and norepinephrine due to increased vasoconstriction of uterine arteries leading to placental insufficiency.5,11,20
- Neutralize hormonal responses: ACE inhibitors or ARBs are a viable option for postpartum patients.1,5,20 They should not be given to pregnant patients due to potential teratogenicity.3 Some small trials have proposed using bromocriptine, which acts as a dopamine receptor agonist to inhibit prolactin.9
- Avoid thromboembolic events: Since patients are in a hypercoagulable state during pregnancy and in the immediate peripartum period, consider anticoagulation for any patient with an EF < 30% during pregnancy and within 2-3 months following delivery.1,6 Heparin, including low molecular weight heparin, is compatible for use during pregnancy or while breastfeeding. Warfarin and direct-acting oral anticoagulants (DAOCs) should be avoided during pregnancy due to potential harm to a developing fetus.3,9
- Prevent arrhythmias: Beta-blockers have shown to improve survival in dilated cardiomyopathies and are safe in pregnancy, but should not be given in acute decompensated heart failure.1,5 Beta-blockers are usually continued for at least six months after symptoms of PPCM resolve.7,20
What happens after the ED?
Further management generally depends on the severity of LV impairment.
In patients with moderately diminished LVEF, conservative management with exogenous oxygen, diuresis, ACE inhibitors, beta-blockers, and anti-coagulation may be sufficient to treat symptoms and limit life threatening complications.
In patients with significantly diminished LVEF with signs of cardiogenic shock, support should be initiated with inotropes and evaluation should be made for the possibility of a cardiac assist devices (e.g. intra-aortic balloon pumps, LV and biventricular assist devices, or extracorporeal membrane oxygenation (ECMO)).1 Arrhythmias, including ventricular tachycardia, are common sequelae of PPCM, occurring in about 4% of PPCM cases.22 Evaluation for a cardiac defibrillator may be indicated, especially at LVEF<35%.3 A wearable cardioverter/defibrillator may be indicated for 3-6 months, regardless of LVEF, due to potential for arrhythmias and sudden cardiac death.23 However, implantable cardiac defibrillators are usually not recommended due to the high recovery rate of PPCM, and wearable defibrillators are recommended in indicated.3,6,21
The likelihood of further PPCM complications were increased by having a LVEF<25%, delayed diagnosis, and subsequent thromboembolic disease.9 A majority (50-80%) of patients with PPCM will recover in 3-6 months of onset of the condition, but subsequent pregnancies have a high risk of disease recurrence, risk of incomplete return to baseline cardiac function, and increased maternal mortality.1,3 Maternal mortality rates have reached about 15% worldwide.9
So, what happened with our patient?
The patient was placed on 3-4 liters of supplemental oxygen via nasal cannula, which increased her oxygen saturation to the mid 90’s. She was admitted to the hospital with obstetrics and cardiology consults. An echocardiogram revealed an LV EF of 40% and dilated LV. Furosemide was given, and her volume status was monitored. She was started on an ACE inhibitor and beta-blocker. Due to her improving symptoms with medical management, further surgical interventions were not pursued.
Take Home Points
- The highest risk for PPCM is in the month prior and the five months following delivery. Diagnosis includes heart failure within this timeframe with no other known underlying etiologies.
- Consider this diagnosis in patients who are presenting with dyspnea on exertion or other signs of heart failure. Be wary of confusing these with common symptoms of late pregnancy.
- Initial management should evaluate and support the patient’s respiratory status, with oxygen supplementation and consideration of non-invasive or invasive ventilation as dictated by the stability of the patient, as well as consideration of nitroglycerin (preload) and diuretics (systemic congestion). Patients in cardiogenic shock require resuscitation with vasopressors, inotropes, and consideration of ventricular assist devices.
- In the still pregnant patient, consider early fetal monitoring in order to evaluate for uterine perfusion.
- In the pregnant patient, avoidACE-Is, ARBs, warfarin, and DOACs for concern for teratogenicity. These are acceptable in the post-partum patient.
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- Peripartum cardiomyopathy (PPCM). American Heart Association. 2015, July. Online. https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/peripartum-cardiomyopathy-ppcm.
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- Sliwa K, et al. Current state of knowledge on aetiology, diagnosis, management, and therapy of peripartum cardiomyopathy: a position statement from the Heart Failure Association of the European Society of Cardiology Working Group on peripartum cardiomyopathy. European Journal of Heart Failure. 2010; 12(8): 767-778. PMID: 20675664. DOI: 10.1093/eurjhf/hfq120.
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