Treatment of WHO Group 3 Pulmonary Hypertension
The foundation for managing WHO Group 3 pulmonary hypertension is to treat the underlying lung disease, minimize further insults to the lungs, avoid atelectasis, and normalize oxygenation and ventilation when possible. 1
Understanding WHO Group 3 PH
WHO Group 3 PH is related to underlying lung disease and/or hypoxemia, affecting up to one-third of children with pulmonary hypertension. Common underlying conditions include:
- Bronchopulmonary dysplasia (most common in infants)
- Congenital diaphragmatic hernia
- Pulmonary hypoplasia
- Severe lung disease
- Sleep-disordered breathing
- Chronic obstructive pulmonary disease (COPD)
- Interstitial lung disease
Treatment Algorithm
Step 1: Optimize Treatment of Underlying Lung Disease
- Treat the primary lung condition aggressively
- Ensure optimal bronchodilator therapy for obstructive lung disease
- Appropriate anti-inflammatory treatment for interstitial lung disease
- Address sleep-disordered breathing with CPAP or other appropriate interventions
Step 2: Oxygen Therapy
- Long-term oxygen administration is the only treatment proven to slow progression of pulmonary hypertension in COPD 2
- Maintain oxygen saturation >90% (or as clinically indicated)
- Consider in-flight oxygen administration for patients in WHO-FC III and IV with arterial blood O₂ pressure consistently <8 kPa (60 mmHg) 1
Step 3: Supportive Measures
- Diuretics for fluid overload and right heart failure symptoms
- Pulmonary rehabilitation and supervised exercise training for physically deconditioned patients 1
- Immunization against influenza and pneumococcal infection 1
- Psychosocial support for patients dealing with chronic disease 1
Step 4: Consider PH-Specific Pharmacotherapy
Despite concerns about worsening V/Q mismatch, certain PH-specific medications may be considered in selected cases:
- Sildenafil has been successfully used in infants with bronchopulmonary dysplasia and congenital diaphragmatic hernia 1
- Inhaled treprostinil has shown efficacy in PH associated with interstitial lung disease in adults, though pediatric data is limited 1
Special Considerations
- Avoid vasodilators in COPD-related PH due to minimal clinical efficacy and potential to impair pulmonary gas exchange 2
- Lung transplantation is an accepted treatment option for children with Group 3 PH who have progressive disease despite optimal therapy 1
Monitoring Response
- Regular assessment of functional class
- Serial 6-minute walk tests when applicable
- Echocardiographic evaluation of right ventricular size and function
- Monitor for potential adverse effects of therapy 3
Pitfalls and Caveats
- Avoid indiscriminate use of pulmonary vasodilators as they may worsen V/Q mismatch in patients with lung disease
- Long-term outcomes after lung transplantation are less favorable in Group 3 PH compared to Group 1 PH 1
- Response to therapy varies by lung disease phenotype, with poorer outcomes in patients with interstitial lung disease and emphysema 4
- Transitory increases of pulmonary artery pressure may occur during exacerbations, exercise, and sleep in COPD patients 2
By focusing on treating the underlying lung disease while carefully considering PH-specific therapies in selected cases, clinicians can optimize outcomes for patients with WHO Group 3 pulmonary hypertension.