Echocardiography, 6-Minute Walk Distance, and Distance-Saturation Product as Predictors of Pulmonary Arterial Hypertension in Idiopathic Pulmonary Fibrosis

• Published in: Respiratory care Vol. 55; no. 5; pp. 584 - 588
• Main Authors: MODRYKAMIEN, Ariel M, GUDAVALLI, Ravindra, MCCARTHY, Kevin, PARAMBIL, Joseph
• Format: Journal Article
• Language: English
• Published: Irving, TX Daedalus 01-05-2010; Daedalus Enterprises, Inc
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cardiac Catheterization; Care and treatment; Diagnosis; Echocardiography; Echocardiography - methods; Exercise Test - methods; Female; Humans; Hypertension, Pulmonary - diagnosis; Hypertension, Pulmonary - etiology; Hypertension, Pulmonary - physiopathology; Idiopathic Pulmonary Fibrosis - complications; Idiopathic Pulmonary Fibrosis - physiopathology; Idiopathic Pulmonary Fibrosis - surgery; Intensive care medicine; Lung Transplantation; Male; Medical sciences; Middle Aged; Mortality; Oximetry; Oxygen Consumption - physiology; Patient outcomes; Pneumology; Predictive Value of Tests; Pulmonary fibrosis; Pulmonary hypertension; Pulmonary hypertension. Acute cor pulmonale. Pulmonary embolism. Pulmonary vascular diseases; Pulmonary Wedge Pressure; Retrospective Studies; ROC Curve; Walking - physiology; Lung disease; Oxymetry; Intensive care; Echocardiography; Respiratory disease; Saturation; Idiopathic; Cardiovascular disease; oximetry; idiopathic pulmonary fibrosis; Pulmonary hypertension; Pulmonary fibrosis; echocardiogram; pulmonary function tests; pulmonary arterial hypertension; Resuscitation
• ISSN: 0020-1324; 1943-3654

Pulmonary arterial hypertension (PAH) is frequently seen in patients with idiopathic pulmonary fibrosis (IPF). We sought to examine the performance of echocardiography, 6-min walk test (6MWT) distance, distance-saturation product (DSP), and pulse oximetry (SpO2) in detecting underlying PAH in IPF.
626 lung transplanted patients from February 1990 to December 2007 were considered. Subjects with pre-transplant diagnosis of IPF were evaluated. Based on findings in pre-transplant right heart catheterization, the presence or absence of PAH was recorded. Right-ventricle systolic pressure, 6MWT distance, DSP, and lowest SpO2 during 6MWT were compared in PAH and non-PAH groups. Receiver operating characteristic curves for each variable to assess prediction of PAH were constructed.
131 patients were transplanted due to IPF. Of these 131 patients, 58 (44%) were eligible. PAH was diagnosed by right heart catheterization in 25 (43%) of 58 eligible patients. The mean pulmonary arterial pressure in PAH patients was 33 mm Hg, and 19 mm Hg in non-PAH patients (P = .001). 6MWT distance was 321 m in the PAH group, and 346 m in the non-PAH one (P = .38). DSP in PAH subjects was 272 meters% and 286 meters% in those with no PAH (P = .57). The lowest SpO2 in the PAH and non-PAH groups were 84% and 82%, respectively (P = .38). The diagnostic accuracy of the echocardiography exceeded that of the other variables (area under the curve 0.72).
Right-ventricle systolic pressure measured by echocardiography, by 6MWT distance, by DSP, or by SpO2 performs poorly in detecting PAH in IPF. Measured by right heart catheterization, right-ventricle systolic pressure performs better to predict PAH in IPF.