Chest
Volume 129, Issue 3, March 2006, Pages 746-752
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Original Research: INTERSTITIAL LUNG DISEASE
Prevalence and Outcomes of Pulmonary Arterial Hypertension in Advanced Idiopathic Pulmonary Fibrosis

https://doi.org/10.1378/chest.129.3.746Get rights and content

Study objectives:

The development of pulmonary arterial hypertension (PAH) can complicate many interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF). We sought to characterize the prevalence of PAH and its impact on survival in patients with advanced IPF.

Design:

Retrospective analysis of consecutive IPF patients undergoing pretransplantation right heart catheterization.

Setting:

Lung transplant and IPF referral center.

Methods:

PAH was defined as a mean pulmonary artery pressure (mPAP) of > 25 mm Hg. We compared demographic, spirometric, 6-min walk test (6MWT) results, and survival outcomes between those with PAH and those without PAH.

Measurements and results:

Seventy-nine patients were included in the study. PAH was present in 31.6% of patients (mean [± SD] mPAP, 29.5 ± 3.3 vs 19.1 ± 3.7 mm Hg, respectively). Those patients with PAH had a lower mean diffusing capacity of the lung for carbon monoxide (Dlco) (37.6 ± 11.3% vs 31.1 ± 10.1%, respectively; p = 0.04) and were more likely to require supplemental oxygen (66.7% vs 17.6%, respectively; p < 0.0001). Mean distance walked (143.5 ± 65.5 vs 365.9 ± 81.8 m, respectively; p < 0.001) and mean pulse oximetric saturation nadir (80.1 ± 3.7% vs 88.0 ± 3.5%, respectively; p < 0.001) during the 6MWT were also lower among those with PAH. PAH was associated with a greater risk of death during the study period (mortality rate, 60.0% vs 29.9%, respectively; odds ratio, 2.6; 95% confidence interval [CI], 2.3 to 3.1; p = 0.001). One-year mortality rates were higher in those with PAH (28.0% vs 5.5%, respectively; p = 0.002). As a predictor of mortality, PAH had a sensitivity, specificity, and accuracy of 57.1%, 79.3%, and 73.4%, respectively. There was a linear correlation between mPAP and outcomes with higher pressures associated with a greater risk of mortality (hazard ratio, 1.09; 95% CI, 1.02 to 1.16). FVC and Dlco did not predict outcomes.

Conclusions:

PAH is common in advanced cases of IPF and significantly impacts survival. A reduced Dlco, supplemental oxygen requirement, or poor 6-min walk performance should raise suspicion of the presence of underlying PAH. Identifying PAH might be an important adjunct in monitoring disease progression, triaging for transplantation, and guiding therapy.

Section snippets

Subjects

We retrospectively reviewed all patients with IPF who were seen at our clinic between June 1998 and December 2004. Our clinic serves as both an IPF and lung transplant referral center. We included patients who had undergone right-sided cardiac catheterization as part of their initial evaluation prior to being listed for lung transplantation. Spirometry obtained within 1 month of the catheterization was required for inclusion in the study. When available, we included data from the 6MWT performed

Results

During the study period, 79 patients with IPF who were evaluated in our clinic were referred for lung transplant evaluation and underwent right-heart catheterization. These individuals comprised the final cohort included in this analysis. No subjects were lost to follow-up, and none were excluded. The mean mPAP was 23.4 ± 5.1 mm Hg (range, 8 to 46 mm Hg) among the cohort (Fig 1). The criteria for PAH were present in 25 subjects (31.6%), with a mean mPAP of 29.5 ± 3.3 mm Hg, compared with 19.1 ±

Discussion

We have reported on the prevalence of PAH and its impact on survival among a large cohort of patients with advanced IPF, all of whom had pulmonary artery (PA) pressure measurements determined by right heart catheterization. Although it has been previously reported that PAH affects the prognosis of patients with IPF, most of the prior studies12, 13, 30, 31 were smaller, did not report outcomes, relied on estimates of PA pressures, and/or included a broader mix of patients. In our cohort, PAH is

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    The authors have no potential financial conflicts of interests to disclose.

    The opinions expressed herein are not to be construed as official or as reflecting the policies of either the Department of the Army or the Department of Defense.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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