Peripartum Cardiomyopathy

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What is Peripartum Cardiomyopathy? 

  • Definitions:

    • Potentially life-threatening pregnancy-associated disease that typically arises in the peripartum period and is marked by left ventricular dysfunction and heart failure - from Arany Z, Elkayan U. Peripartum Cardiomyopathy in Circulation from April 2016.

      • It’s not a precisely defined entity, because timing can vary. 

    • The US National Heart, Lung, and Blood Institute (NHLBI) in the 1990s defined PPCM as heart failure that develops in the last month of pregnancy or up to 5 months postpartum

      • This excludes patients that have pre-existing cardiomyopathies, but there are patients who otherwise meet criteria for PPCM who are <36 weeks.

    • Many definitions require cardiomyopathy to demonstrate reduced LV systolic function, where LVEF < 45%, fractional shortening <30%, or both.

  • Epidemiology:

    • Ranges from 1/1000 to 1/4000 live births, but potentially increasing.

    • Proposed reasons: 

      • Increasing maternal age, preeclampsia, and multiple gestations, which are all risk factors for PPCM.

      • Also increasing HTN, diabetes, and obesity.

      • Also just growing recognition of PPCM as a disease entity.

  • Symptoms/Signs:

    • Usual symptoms of heart failure:

      • Ie. fatigue, shortness of breath, increased extremity swelling, sometimes arrhythmias from overstretching of the heart.

    • Signs on exam:

      • Evidence of left sided congestion (pulmonary rales), right side congestion (ie. increased JVP and edema) 

      • Elevated BNP (Malhame in Green Journal 2019) 

      • EKG may show non-specific changes like LBBB pattern

      • Chest Xray: may show pulmonary edema and enlarged cardiac silhouette 

      • Echo: LV dilation of variable degrees, LV systolic dysfunction, RV and bi-atrial enlargement; LVEF < 45%  

What causes PPCM? 

  • Older hypothesis: triggered by viral myocarditis 

    • However, a study that looked at endomyocardial biopsies in patients with PPCM and other types of cardiomyopathies, the same proportion of specimens in each group had detectable viral genomes (30%).

  • Current hypothesis: “two hit” model 

    • Vascular insult - due to antivascular or hormonal effects of late pregnancy and early postpartum period → cardiomyopathy in women with an underlying predisposition.

    • There is also question of genetic predisposition 

    • High prevalence of pre-eclampsia in women with PPCM suggests a possible shared pathophysiology - perhaps some type of placental angiogenic factor.

How do we manage PPCM? 

  • Prognosis: 

    • 50-80% of women with PPCM recover to normal range LVEF (>50%) with most recovery occurring within the first 6 months.

      • This is pretty good considering that in the early 1970s, the mortality of PPCM was 30-50%.

    • LV size and EF at time of diagnosis most strongly predict LV recovery.

      • LVEF <30% and LV end-diastolic diameter > 6 cm are indicative of decreased likelihood of left ventricular recovery and increased risk of mechanical support, transplant, and death.

    • 25% of patients will develop chronic heart failure, and mortality rate is still 6-10% in the United States (depending on follow up defined for mortality rate by study).

  • Complications

    • One study found that 2.6% of women with PPCM in the US had cardiogenic shock, 1.5% of them needed mechanical circulatory support, and 0.5% of women underwent cardiac transplantation.

    • VTE is one of the most common severe complications of PPCM - affect 6.6% of women.

      • Mechanism: underlying intracardiac thrombosis in PPCM d/t cardiac dilatation and hypocontractility → blood stasis.

      • Also pregnancy is a hypercoagulable state.

    • Arrhythmias - can contribute to morbidity and mortality d/t death from VTach.

      • 2.1% of women with PPCM had cardiac arrest and 2.9% underwent implantation of a cardiac device.

  • Treatment 

    • Few studies performed specifically in women with PPCM, so management strategies are generally extrapolated from other forms of heart failure.

    • Multidisciplinary care: MFM, anesthesia, and cardiology.

    • Individualized discussion of delivery timing for optimal maternal-neonatal outcome.

    • Usually don’t need to do a cesarean.

      • Hemodynamic shifts may be mitigated by slow epidural and assisted second stage of labor.

    • Care overall is usually supportive, directed toward managing heart failure symptoms.

      • Diuresis (but don’t go overboard and cause hypotension) 

      • If hemodynamics permit, beta blockers should be used, with preference of B1 selective ones (ie. metoprolol).

        • B2 blockers may prompt uterine activity, so better to avoid.

      • ACE-inhibitors and ARBs are considered contraindicated in pregnancy, but can use them postpartum.

      • Consider anticoagulation in PPCM if LVEF < 30% 

      • If arrhythmias, may require acute or chronic administration of antiarrythmic drugs.

    • Cardiac assisted devices - may be indicated if severe depression of LV function or if concerned for rapid deterioration.

  • After PPCM, future pregnancy: 

    • Avoid future pregnancy if EF fails to improve, as mortality increases up to 50% if EF does not improve!