Mortality rates are high among patients with idiopathic pulmonary fibrosis (IPF). Pulmonary function studies measures are imprecise at predicting those patients at highest risk of dying. This could partially be explained by the development of pulmonary arterial hypertension (PAH) in some patients that is not appreciated with conventional physiologic measurements. We sought to characterize the prevalence and incidence of PAH by analyzing pulmonary artery (PAP) pressures at two time points in patients disease course.
Retrospective review of all patients with IPF who underwent lung transplantation from 2000-2005. PA pressures from the patients transplant evaluation and from the time of their transplant surgery were analyzed and compared. PAH was defined by a mean PAP>25mmHg.Pulmonary function data from their initial evaluation were analyzed for predictors of PAH and progression of PAH.
During the study period, there were 38 patients with IPF who underwent lung transplants and who had serial PAPs available for analysis. The mean PAP at the time of transplant evaluation was 22mmHg. 13/38 patients (34%) qualified as having PAH at this time. The mean PAP at the time of transplant was 33mmHg with 32/38 (84%) of patients qualifying as having PAH. The average time period between PAP measurements was 267 days (range: 33-814). The mean rate of change of PAPs was 3.9mmHg/month. Baseline FVC and Dlco did not predict the presence of PAH or the serial development thereof.
The prevalence of PAH is fairly common in patients with advanced IPF who require evaluation and listing for transplant. Based on serial measures of PAPs, it appears inevitable that most patients will develop PAH during their disease course.
PAH might be a significant contributor to the morbidity and mortality of patients with IPF.
Steven Nathan, None.