PAH in Congenital Heart Disease: Expert Q&A on Challenges and Advances

Because of advances in pharmacologic, catheter, and surgical treatment for congenital heart disease in recent decades, more than 90% of patients now reach adulthood.¹ According to findings published in 2016, approximately 1.4 million adults in the United States had congenital heart disease.² It is estimated that pulmonary arterial hypertension (PAH) ultimately develops in 5% to 10% of those with congenital heart disease, increasing morbidity and mortality significantly in these individuals.^1,3

Although the survival of patients with PAH and congenital heart disease is “significantly better⁴ compared [with] other patients in group 1 of the classification — for instance, those with idiopathic PAH or connective tissue disease-related PAH —and they respond fairly adequately to current PAH therapy, their overall survival is decreased compared [with] other adults, in particular if they have significant elevation in pulmonary vascular resistance (PVR),” Paul M. Hassoun, director of the Pulmonary Hypertension Program at Johns Hopkins Medicine in Baltimore, told Cardiology Advisor. “There is currently no cure for the remodeling of the pulmonary vessels that these patients have because of their congenital malformations, thus the importance of early diagnosis and repair before irreversible PAH [develops].”

A review published in Heart provided an overview of the main subgroups of PAH-congenital heart disease.³ Key management strategies for each are highlighted below.

Eisenmenger Syndrome (PAH with severe pulmonary vascular disease [PVD])

• Defect closure is contraindicated, as the “defect functions as a ‘relief valve’ for the high pulmonary artery pressures, maintaining systemic cardiac output through right-to-left shunting at the expense of cyanosis,” and closure may lead to right heart failure and death
• Endocarditis prophylaxis for certain types of defects
• Routine screening for iron deficiency, with supplementation if indicated
• Avoid routine venesections
• Proactive treatment with PAH disease-targeting therapy (DTT)
• Lung transplantation with repair of the underlying defect or heart and lung transplantation when other strategies have been exhausted

PAH With Persistent Systemic to Pulmonary Shunts (PAH with variable severity of PVD)

• Closure of moderate to large defects can be considered in cases where there is mildly elevated PVR and significant systemic to pulmonary shunt
• Defect closure when PVR is <2.3 Wood units and PVR index <4 Wood units m²; generally contraindicated when PVR is >4.6 Wood units and PVR index >8 Wood units m²
• Treat-and-repair approach or partial defect closure may be appropriate in selected patients from the “grey zone” (PVR between 2.3 and 4.6 Wood units m² and PVR index between 4 and 8 Wood units m²)
• Patients with high PVR and small systemic to pulmonary shunts may benefit from PAH DTT

PAH With Small or Coincidental Defect or PAH After Defect Closure (PAH with PVD)

• Defect closure is contraindicated
• Consider oral anticoagulation if no contraindications
• PAH DTT as in patients with idiopathic PAH
• Lung and/or heart transplantation if the patient’s condition is deteriorating despite maximum drug therapy

In addition, disease in patients with a Fontan circulation that does not meet the diagnostic criteria for PAH but in which there is increased PVR may be modulated with PAH DTT.^5,6

“Early recognition of PAH in [people with] congenital heart disease is key,” Dr Hassoun emphasized. “Once the PAH has developed, patients should be monitored in specialized centers of excellence, such as centers accredited by the Pulmonary Hypertension Association, where a multidisciplinary approach is important.”

To learn more about the management of these patients, Cardiology Advisor interviewed Neal Chaisson, MD, a pulmonologist and critical care expert at Cleveland Clinic in Ohio. 

Cardiology Advisor: What are some of the top challenges in treating adult congenital heart disease and PAH?

Dr Chaisson: In patients with congenital heart disease, there is no “routine” patient. Every patient, by virtue of their native anatomy or the surgeries they have had as a child to correct a defect, [has] unique physiology that can pose significant challenges to PAH care. It is important to remember 2 things that make PH-[congenital heart disease] unique from the more classic, and well studied idiopathic PAH. The first is that PH-[congenital heart disease] often manifests as a combination of both high flow (or hyperkinetic) factors and from resistive factors, whereas idiopathic PAH is often a consequence of the latter alone. The second is that congenital heart disease is not a single pathophysiologic entity — it includes everything from septal defects to systemic-to-pulmonary shunting. The treatment of one type of adult congenital heart disease may have [a] significant impact on one patient and virtually no impact — or even negative consequences — on another for these 2 reasons.