PURPOSE: Severe pulmonary hypertension (PH) can complicate interstitial lung disease but both the prevalence and predictors of severe PH in idiopathic pulmonary fibrosis (IPF) are unknown.
METHODS: We reviewed the records of patients with IPF listed for lung transplant (LT) in the US (Jan. 1995 and June 2004) and defined severe PH as a mean pulmonary artery (PA) pressure of > 40 mm Hg. Patients with severe PH were compared to those with normal PA pressures, and we examined multiple demographic and clinical variables. We also recorded the cardiac index (CI) and pulmonary capillary wedge pressure (PCWP).
RESULTS: During the study period, 3,667 subjects with IPF were listed for LT and 73.4% had undergone right heart catheterization. Severe PH was infrequent (n=241, 8.9%) In univariate analysis, persons with severe PH were: younger, more often African American, and more likely to require supplemental O2. The FVC was similar between the groups. Independent factors associated with severe PH & their adjusted odds ratios (ORs) were: need for any O2 (OR 2.28, 95% CI: 1.23-4.25), need for > 3 L/min of O2 (OR 2.15, 95% CI: 1.54-3.01); African American race (OR 1.98, 95% CI: 1.28-3.09); need for assistance with activities of daily living (OR 1.58, 95% CI: 1.11-2.25), and the PCWP (OR per 1 unit increase above mean 1.19, 95% CI: 1.15-1.23).
CONCLUSION: Severe PH is infrequent in patients IPF listed for LT. Race is a strong predictor of severe PH. The extent of IPF as measured by FVC does not correlate with the presence of severe PH, suggesting mechanisms other than progressive fibrosis contribute to the development of PH. Given the relationship with PCWP, occult left heart dysfunction may add to severe PH or may indicate ventricular interdependence.
CLINICAL IMPLICATIONS: Physicians should consider evaluating selected IPF patients for severe PH. Severe PH may be an important correlate of survival. Identifying subjects with severe PH may improve outcomes by prompting earlier referral for LT.
DISCLOSURE: Andrew Shorr, None.