Pulmonary hypertension (PH) can complicate various forms of interstitial lung disease (ILD)& may adversely affect survival. Both the prevalence and predictors of PH in IPF are unknown.
We reviewed the records of all patients with IPF listed for lung transplant (LT) in the US between Jan. 1995 and June 2004 to identify those who underwent right heart catheterization (RHC). We defined PH as a mean pulmonary artery (PA) pressure of ≥ 25 mmHg. Patients with PH were compared to those lacking PH with respect to demographics, pulmonary function, functional status, need for supplemental oxygen, and requirement for corticosteroid therapy. We also recorded the cardiac index (CI) and pulmonary artery wedge pressure (PAWP).
During the study period, 3,667 subjects with IPF were listed for LT and 73.4% had undergone RHC. Among those with PH (n=1210), the mean PA measured 34.3 ± 10.1 mm Hg and 19.9% had severe PH (defined as PA > 40 mm Hg) In univariate analysis, persons with PH had slightly worse lung function (FVC: 48.6 ± 16.9% predicted vs. 49.1 ± 15.1 % predicted, p=0.07; FEV1: 50.0 ± 17.6 % predicted vs. 52.7± 17.2 % predicted, p<0.01), required more supplemental oxygen (3.0 ± 2.2 l/min vs. 2.3 ± 1.8 l/min, p<0.01), and had lower cardiac performance (CI 2.87 ± 0.8 l/min/m2 vs. 2.81 ± 0.7 l/min/m2, p=0.02). Independent factors associated with PH in IPF are shown in the table. As a screening test for the presence of PH, clinical criteria had poor sensitivity and specificity.
PH is common in patients IPF listed for LT. The degree of the PH, though, is mild. Race is a strong independent predictor of PH. That FVC does not correlate with PH suggests that mechanisms other than progressive parenchymal destruction contribute to the development of PH.
Physicians should consider evaluating selected IPF patients for PH. PH may be an important correlate of survival and identifying subjects with PH may improve outcomes by allowing earlier referral for LT.
VariableOdds Ratio95% CIAfrican American1.51(1.15, 1.99)Supplemental O2 l/min1.20(1.15, 1.26)PAWP (mean) mm Hg1.19(1.17, 1.21)FEV1 % predicted0.99(0.99, 1.00)
Andrew Shorr, None.