Computed tomography (CT) plays a pivotal role in pulmonary arterial hypertension (PAH), as many patients undergo this imaging exam along with lung function assessment. Remarkably, a study published in ERJ Open Research suggests that routine CT reports describing the presence of simultaneous pulmonary disease have diagnostic and prognostic utility in patients with PAH.

The authors analyzed 660 patients diagnosed with idiopathic PAH or PAH associated with lung disease between 2001 and 2019. Reports for all CT scans performed 1 year before diagnosis were examined for common lung parenchymal patterns. 

Centrilobular ground-glass (CGG) changes (hazard ratio [HR], 0.29) and ground-glass opacification (HR, 0.53) predicted improved survival. CGG changes were present in 23.3% of patients with idiopathic PAH and no lung disease and 5.8% of PAH patients with lung disease. The authors found no difference in survival between patients with idiopathic PAH and no lung disease with or without CGG changes. 


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Conversely, honeycombing (HR, 2.79), emphysema (HR, 2.09), and fibrosis (HR, 2.38) predicted worse survival (all P <.001). Likewise, PAH patients with lung disease who had fibrosis had worse survival than those with emphysema.

“Fibrosis was an independent predictor after adjusting for baseline demographics, [pulmonary hypertension] severity and diffusing capacity of the lung for carbon monoxide (HR, 1.37; P <.05),” the authors noted.

Furthermore, PAH patients without parenchymal lung disease on CT demonstrated improved 2-year survival compared to patients with PAH and coexistent lung disease on CT.

The study suggests that patients receiving a PAH diagnosis who have concurrent lung disease portray distinctive clinical and survival features, which may differentiate them from patients with idiopathic PAH alone. In addition, it suggests that CGG changes are not unusual in patients with idiopathic PAH, and although they usually correspond with more severe pulmonary hemodynamics, survival is not negatively affected.

The authors concluded that lung parenchymal descriptions on routine CT have diagnostic and prognostic value in patients with idiopathic PAH and those with PAH associated with chronic lung disease. “Chest CT features should therefore be considered in patient assessment and risk stratification,” the authors wrote. 

Reference

Dwivedi K, Condliffe R, Sharkey M, et al. Computed tomography lung parenchymal descriptions in routine radiological reporting have diagnostic and prognostic utility in patients with idiopathic pulmonary arterial hypertension and pulmonary hypertension associated with lung disease. ERJ Open Res. 2022;8(1):00549-2021. doi:10.1183/23120541.00549-2021