Pre-Capillary, Combined, and Post-Capillary Pulmonary Hypertension: A Pathophysiological Continuum

Area of Science:

• Cardiology
• Pulmonology
• Medical Research

Background:

• Pulmonary hypertension (PH) is classified as pre-capillary (e.g., idiopathic pulmonary arterial hypertension [IPAH]) or post-capillary (e.g., heart failure with preserved ejection fraction [HFpEF]).
• Overlapping clinical features exist between IPAH and PH-HFpEF, complicating diagnosis and treatment.
• Some patients with risk factors for left heart disease present with pre-capillary PH, while HFpEF patients may exhibit combined pre- and post-capillary PH.

Purpose of the Study:

• To compare clinical characteristics, hemodynamics, and treatment responses in patients with typical IPAH, atypical IPAH, and PH-HFpEF.
• To investigate the relationship and potential continuum between these distinct pulmonary hypertension phenotypes.

Main Methods:

• Analysis of registry data from patients receiving PH-targeted therapy.
• Categorization into typical IPAH (<3 left heart disease risk factors), atypical IPAH (≥3 left heart disease risk factors), and PH-HFpEF.
• Evaluation of clinical parameters, hemodynamic measurements, 6-minute walking distance, and response to therapy.

Main Results:

• Atypical IPAH and PH-HFpEF groups were older, had higher BMI, more comorbidities, and lower 6-minute walking distance compared to typical IPAH.
• Mean pulmonary artery pressure and cardiac index were comparable across all three groups.
• All groups improved with PH-targeted therapy, but the effect was most pronounced in typical IPAH, least in PH-HFpEF, with atypical IPAH in between. Survival rates were similar across groups.

Conclusions:

• Atypical IPAH patients exhibit characteristics of both typical IPAH and PH-HFpEF.
• These findings suggest a potential continuum of disease between typical IPAH, atypical IPAH, and PH-HFpEF.
• Understanding these overlaps is crucial for accurate diagnosis and tailored therapeutic strategies in pulmonary hypertension.