What is the best treatment approach for a 30-week pregnant patient diagnosed with peripartum cardiomyopathy, considering the use of Angiotensin-Converting Enzyme inhibitors (ACEi) and heparin?

Treatment of Peripartum Cardiomyopathy at 30 Weeks Gestation

ACE inhibitors are absolutely contraindicated during pregnancy and must not be used at 30 weeks gestation; instead, use hydralazine combined with long-acting nitrates for afterload reduction, along with beta-1 selective beta-blockers (metoprolol), diuretics as needed, and consider therapeutic anticoagulation with heparin if LVEF <30-35%. 1, 2

Immediate Medical Management During Pregnancy

Contraindicated Medications

• ACE inhibitors, ARBs, ARNIs, MRAs, SGLT2 inhibitors, ivabradine, and vericiguat are all contraindicated during pregnancy due to significant fetal harm, including renal toxicity and teratogenicity. 1, 2
• These medications can only be initiated after delivery once postpartum bleeding has stopped 1, 3

Safe Medications During Pregnancy

Afterload Reduction:

• Use hydralazine combined with long-acting nitrates as the safe alternative for afterload reduction while still pregnant 1, 2
• This combination replaces the role of ACE inhibitors/ARBs during the antepartum period 2

Beta-Blockers:

• Initiate beta-1 selective beta-blockers immediately, preferably metoprolol (NOT atenolol) 1, 2, 4
• Beta-blockers are safe during pregnancy and should be started if hemodynamically stable 1, 2
• Monitor newborn for 24-48 hours after delivery for hypoglycemia, bradycardia, and respiratory depression 4, 3

Diuretics:

• Use furosemide 20-40 mg IV bolus for pulmonary congestion and volume overload 1, 2, 4
• Diuretics should be used sparingly during pregnancy but are necessary for symptomatic relief 2

Anticoagulation with Heparin

Anticoagulation is reasonable and should be strongly considered in this clinical scenario: 1

• The 2022 ACC/AHA/HFSA guidelines state that anticoagulation may be reasonable at diagnosis for LVEF <30%, continuing until 6-8 weeks postpartum 1
• Use unfractionated heparin or low-molecular-weight heparin (NOT warfarin during pregnancy) 1, 2, 3
• The rationale is the pro-thrombotic nature of PPCM combined with increased procoagulant activity in the peripartum phase, leading to high risk of ventricular thrombi and cerebral embolism 1, 3
• Monitor anti-Xa levels if using LMWH 3
• Critical timing: Do not give heparin after contractions have started; restart anticoagulation postpartum only after bleeding has stopped and epidural/spinal catheter has been removed 1, 3

Acute Decompensation Management

If presenting with acute heart failure symptoms:

• Administer oxygen to achieve saturation ≥95% 2, 4
• Apply non-invasive ventilation with PEEP 5-7.5 cmH2O if hypoxemia persists 2, 4
• IV nitroglycerin 10-20 up to 200 μg/min if systolic BP >110 mmHg 2, 4
• Inotropic support (dobutamine or levosimendan) if signs of hypoperfusion persist despite vasodilators and diuretics 2, 4, 3
• Establish continuous invasive hemodynamic monitoring and urinary catheter drainage 2, 4, 3

Obstetric Management Considerations

Timing of Delivery:

• Unless there is maternal hemodynamic instability or fetal distress, there is no need for early delivery at 30 weeks 1
• However, urgent delivery regardless of gestational age must be considered if the patient presents with or remains in advanced heart failure with hemodynamic instability 1, 4
• The primary consideration should be maternal cardiovascular benefit 1

Mode of Delivery:

• For stable patients with well-controlled cardiac condition, spontaneous vaginal birth is preferable 1, 2
• Planned cesarean section is preferred for critically ill women requiring inotropic therapy or mechanical support 1, 2, 3

Postpartum Transition (After Delivery)

Once the baby is delivered and postpartum bleeding has stopped:

• Immediately transition to standard heart failure therapy including ACE inhibitors or ARBs 1, 2, 3
• Continue beta-blockers 2, 3
• Add aldosterone antagonists 2
• Restart anticoagulation once bleeding controlled and epidural catheter removed 1, 3
• Consider single IV dose of furosemide after delivery to manage auto-transfusion from contracted uterus 1, 2

Bromocriptine Consideration:

• May be considered postpartum to enhance cardiac recovery (LVEF improvement from 27% to 58% at 6 months versus 27% to 36% with standard care) 2
• Must be accompanied by therapeutic anticoagulation due to increased thrombosis risk 2, 3

Breastfeeding Considerations

• Several ACE inhibitors (captopril, enalapril, quinapril) have been adequately tested and can be used in breastfeeding women if needed 2
• Beta-blockers are compatible with breastfeeding 1

Critical Pitfalls to Avoid

• Never use ACE inhibitors or ARBs during pregnancy 1, 2
• Never use atenolol as the beta-blocker choice 3
• Never use ergometrine for third-stage labor management—it is absolutely contraindicated; use single dose IM oxytocin instead 1, 2, 3
• Do not underestimate thrombotic risk—anticoagulation is essential given LVEF <30% 1, 3
• Do not delay mechanical circulatory support if inotropes are required beyond the first hour 4, 3

Prognosis and Monitoring

• LV end-diastolic diameter >60 mm and LVEF <30% predict poor recovery 2, 4, 3
• Approximately 50% of PPCM patients show substantial improvement or normalization of LV function within 6 months 1, 3
• Most pregnancy-related deaths occur in the first 4 weeks postpartum, requiring intensive monitoring during this period 2, 4, 3
• Defer ICD placement for at least 6 months given the high spontaneous recovery rate 2, 3