What is the post-operative management for a 34-year-old lady with chronic heart disease (CHD) induced pulmonary arterial hypertension (PAH) and compromised right ventricular (RV) function, who underwent medical termination of pregnancy?

Post-Operative Management of a Patient with CHD-Induced PAH After Medical Termination of Pregnancy

The patient should be closely monitored in the CCU for at least 24-48 hours with continuous hemodynamic assessment, as the major cardiovascular implications of surgery often manifest a day or two following the procedure. 1

Initial Monitoring in CCU

Hemodynamic Monitoring

• Implement continuous monitoring of:
  • Vital signs (heart rate, blood pressure, respiratory rate, oxygen saturation)
  • Central venous pressure via central line placement
  • Mixed venous oxygen saturation
  • Consider pulmonary arterial catheter for direct pressure measurements
  • Maintain systemic vascular resistance (SVR) greater than pulmonary vascular resistance (PVR) 1

Laboratory Monitoring

• Serial NT-proBNP measurements (baseline 500, monitor for changes)
• Arterial blood gases
• Complete blood count
• Renal and liver function tests
• Coagulation profile

Echocardiographic Monitoring

• Perform comprehensive echocardiography within 24 hours post-procedure
• Schedule follow-up echocardiograms every 4-8 weeks to monitor RV function 1

16-Point RV Assessment via 2D Echocardiography

1. RV Size Parameters:

   • RV basal diameter
   • RV mid-cavity diameter
   • RV longitudinal diameter
   • RV end-diastolic area
   • RV end-systolic area

2. RV Systolic Function:

   • TAPSE (Tricuspid Annular Plane Systolic Excursion) - baseline 1.9 cm
   • RV fractional area change
   • RV ejection fraction
   • S' velocity by tissue Doppler
   • RV myocardial performance index (Tei index)
   • RV free wall strain
   • RV longitudinal strain

3. RV Pressure Estimates:

   • Tricuspid regurgitation velocity/gradient
   • Pulmonary valve acceleration time
   • Interventricular septal flattening/eccentricity index

4. Right Atrial Assessment:

   • Right atrial size/volume

Pulmonary Vasodilator Therapy Management

Initial Approach

• Continue pre-existing PAH-specific therapy without interruption
• If patient was not previously on therapy, initiate treatment based on risk assessment:

Titration Protocol

1. Phosphodiesterase-5 Inhibitors (PDE-5i):

   • Start with sildenafil 20 mg three times daily
   • Assess for hypotension after 24-48 hours
   • If tolerated without side effects, maintain dose
   • Monitor for headaches, flushing, or hypotension

2. Endothelin Receptor Antagonists (ERA):

   • Begin with lower doses (bosentan 62.5 mg twice daily or ambrisentan 5 mg daily)
   • Monitor liver function tests weekly for first month, then monthly
   • If tolerated, increase to target dose after 4 weeks (bosentan 125 mg twice daily or ambrisentan 10 mg daily)

3. Prostacyclin Pathway:

   • For high-risk patients, consider IV epoprostenol starting at 2 ng/kg/min
   • Increase by 1-2 ng/kg/min every 24 hours as tolerated
   • Target dose based on symptoms and hemodynamic response

4. Combination Therapy:

   • Consider early combination therapy if patient shows signs of RV dysfunction
   • Most common combination is PDE-5i plus ERA 1, 2

Anticoagulation Management

• Initiate prophylactic LMWH (e.g., enoxaparin 40 mg subcutaneously once daily) within 12-24 hours post-procedure if no bleeding complications 1

• Consider therapeutic anticoagulation if:

  • Patient has atrial arrhythmias
  • Severely reduced RV function
  • History of thromboembolism
  • Immobility expected to be prolonged

• If therapeutic anticoagulation indicated:

  • Enoxaparin 1 mg/kg subcutaneously twice daily
  • Monitor anti-Xa levels to maintain therapeutic range (0.5-1.0 IU/mL)
  • Transition to oral anticoagulation if long-term therapy needed

Additional Management Considerations

Volume Management

• Maintain euvolemia - avoid both volume overload and depletion
• Consider diuretics if signs of right heart failure develop
• Target slightly negative fluid balance in first 24-48 hours

Inotropic Support

• If RV dysfunction worsens, consider:
  • Dobutamine (2-5 μg/kg/min) - preferred over milrinone due to shorter half-life 1
  • Add vasopressin (0.01-0.04 units/min) to maintain systemic vascular resistance if needed

Arrhythmia Management

• Monitor for atrial arrhythmias which are common in PAH-CHD
• Use beta-blockers with extreme caution, if at all, as they may worsen RV function 1

Discharge Planning

• Plan for discharge only when hemodynamically stable for >48 hours
• Arrange follow-up within 1-2 weeks
• Schedule comprehensive echocardiographic assessment at 4-8 weeks 1

Pitfalls and Caveats

1. Avoid Systemic Vasodilation: Sedation-related hypoxia or hypotension can precipitate acute increases in PVR and stress the failing RV 1

2. Beta-Blocker Caution: Use beta-blockers with extreme caution as patients with CHD-induced PAH may have underlying bradycardia or junctional rhythm 1

3. Fluid Management Challenges: Volume status is notoriously difficult to assess in PAH patients; non-invasive estimates of central venous pressure may be misleading 1

4. Pregnancy Considerations: Though the pregnancy has been terminated, hormonal changes during and immediately following pregnancy may still be detrimental from a pathophysiologic standpoint 1

5. Irreversible RV Decline: An irreversible decline in RV function has been described in 10% of cases with systemic RV pressure 1, necessitating vigilant monitoring

The management of this complex patient requires a multidisciplinary approach involving pulmonary hypertension specialists, cardiac intensivists, and cardiac imaging experts to optimize outcomes and prevent deterioration of right ventricular function.