Yoo DK, et al. - In patients with fibrosing interstitial pneumonias (FIP), researchers sought for the possible independent contribution of associated pulmonary hypertension (APH) to exercise intolerance, irrespective of the extent of underlying fibrosis. They found pulmonary vascular resistance (PVR) significantly contributed to six-minute walk distance (6MWD), independently from the extent of fibrosis on high-resolution chest computed tomography (HRCT), in patients with FIP. These findings strengthen both the rationale to use 6MWD as endpoint in FIP and to target APH with specific therapies.

Methods

• This study involved patients diagnosed with FIP (September 2009 to June 2017) who had right heart catheterization, high-resolution chest computed tomography (HRCT), and 6MWD within 3 months.
• Patients undergoing lung transplant assessment were not the only to be recruited.
• The definition of APH was mean pulmonary artery pressure (mPAP) ≥25 mm Hg.
• Using a visual fibrosis score, 2 separate observers quantified the extent of fibrosis on HRCT.

Results

• Researchers identified a total of 72 patients (60 with IPF); APH was present in 55 patients.
• They noted no significantly different mPAP was demonstrated by subgroups stratified according to the extent of fibrosis on HRCT.
• Both univariate and stepwise regression analyses revealed pulmonary vascular resistance (PVR) to be the strongest predictor of 6MWD, and it remained so considering only patients with normal wedge pressure (< 15 mm Hg) (n = 61).
• No significant correlation of HRCT fibrosis score and pulmonary function tests with 6MWD was reported.