Pulmonary hypertension in interstitial lung disease: today's realities, tomorrow's possibilities.

Abstract

Interstitial lung disease-associated pulmonary hypertension (ILD-PH) is a frequent and life-limiting complication of fibrotic lung disease, associated with substantial morbidity, impaired functional capacity, and significantly reduced survival. Under-recognition remains common due to overlapping symptoms with ILD, evolving hemodynamic definitions, and the limited accuracy of current noninvasive screening tools. ILD-PH prevalence varies widely across ILD subtypes, ranging from 3-15% in early disease to more than 60% in lung transplant candidates. Even modest elevations in mean pulmonary artery pressure are prognostically meaningful, while right ventricular dysfunction represents a key determinant of mortality. Pathophysiology reflects a complex interaction between parenchymal fibrosis, chronic hypoxemia, endothelial injury, and progressive pulmonary vascular remodeling. Diagnostic evaluation requires a multimodal approach, with right heart catheterization remaining essential for definitive confirmation. Historically, vasodilator therapies have shown limited benefit; however, inhaled treprostinil has demonstrated improvements in exercise capacity, biomarkers, and clinical worsening, establishing the first evidence-based treatment for ILD-PH. Additional inhaled and targeted agents are in development, and the role of combination therapy is an emerging area of investigation. Optimal management also includes supplemental oxygen, pulmonary rehabilitation, and timely evaluation for lung transplantation. ILD-PH represents a distinct vascular phenotype requiring early detection and tailored treatment strategies. Continued advances in screening algorithms, precision therapeutics, and mechanistic research are critical to transforming ILD-PH from a terminal complication into a modifiable component of the ILD spectrum.