Evaluation of recently validated non- invasive formula using basic lung functions as new screening tool for pulmonary hypertension in idiopathic pulmonary fibrosis patients

Abstract

BACKGROUND:A prediction formula for mean pulmonary artery pressure (MPAP) using standard lung function measurement has been recently validated to screen for pulmonary hypertension (PH) in idiopathic pulmonary fibrosis (IPF) patients.OBJECTIVE:To test the usefulness of this formula as a new non invasive screening tool for PH in IPF patients. Also, to study its correlation with patients' clinical data, pulmonary function tests, arterial blood gases (ABGs) and other commonly used screening methods for PH including electrocardiogram (ECG), chest X ray (CXR), trans-thoracic echocardiography (TTE) and computerized tomography pulmonary angiography (CTPA).MATERIALS AND METHODS:Cross-sectional study of 37 IPF patients from tertiary hospital. The accuracy of MPAP estimation was assessed by examining the correlation between the predicted MPAP using the formula and PH diagnosed by other screening tools and patients' clinical signs of PH.RESULTS:There was no statistically significant difference in the prediction of PH using cut off point of 21 or 25 mm Hg (P = 0.24). The formula-predicted MPAP greater than 25 mm Hg strongly correlated in the expected direction with O2 saturation (r = −0.95, P < 0.000), partial arterial O2 tension (r = −0.71, P < 0.000), right ventricular systolic pressure measured by TTE (r = 0.6, P < 0.000) and hilar width on CXR (r = 0.31, P = 0.03). Chest symptoms, ECG and CTPA signs of PH poorly correlated with the same formula (P > 0.05).CONCLUSIONS:The prediction formula for MPAP using standard lung function measurements is a simple non invasive tool that can be used as TTE to screen for PH in IPF patients and select those who need right heart catheterization.

Pulmonary Hypertension in Idiopathic Pulmonary Fibrosis: A Review

“…Although the formula has a low positive predictive value of only 51%, it provides a high negative predictive value of 96%, thus identifying patients with IPF that have a low risk of PH. A recent evaluation of this formula showed that it is a useful tool which can be used like TTE to screen for PH in IPF patients [57]. …”

Saudi guidelines on the diagnosis and treatment of pulmonary hypertension: 2014 updates

“…[ 38 ] The degree of reduction in DLco in relation to vital capacity has shown a strong correlation with peak oxygen uptake, peak work rate, and modified NYHA class, but not with the degree of severity of PH itself. [ 39 40 41 ]…”

Pulmonary Hypertension Complicating Interstitial Lung Disease and COPD

“…The ratio of forced vital capacity (FVC)/DL CO % combined with PaO 2 improved the ability to predict PH in IPF patients. 20 This prediction model was validated in two studies 51,52 with a higher reported sensitivity, specificity, PPV, and NPV of 95, 58, 51, and 96%, respectively. 51 Shorter 6minute walk distance (6MWD) and severe desaturation were also predictive of PH in IPF patients.…”