Non-invasive screening for pulmonary hypertension in idiopathic pulmonary fibrosis

Abstract

Background Pulmonary hypertension (PH) is a common complication of idiopathic pulmonary fibrosis (IPF) that is associated with poor prognosis. Noninvasive screening for PH in IPF patients is challenging and a combination of several noninvasive determinations can improve discrimination. Methods We included 235 IPF patients who underwent right heart catheterization (RHC) as part of the lung transplant evaluation. We measured electrocardiographic (ECG) and echocardiographic variables as well as the pulmonary artery (PA) and ascending aorta (AA) diameters on chest CT. We recorded results of arterial blood gases (ABG), pulmonary function (PFT) and 6-min walk tests (6MWT). Results Several variables were predictors of PH in IPF patients in univariable models including a lower arterial oxygenation and 6MWT distance; worse right ventricular (RV) function, rightward deviation of the QRS axis and a higher FVC/DLCOc ratio, PA/AA diameter ratio, and estimated RV systolic pressure. In multivariable analysis, a worse RV function and higher PA/AA ratio remained predictors of PH (c-index 0.75 (0.65–0.84)). Similarly, a worse RV function, a higher PA/AA ratio and a rightward QRS axis deviation were independent predictors of precapillary PH (c-index 0.86 (0.76–0.92)). A combination of PA/AA diameter ratio <1.1, a QRS axis <90° and normal RV function showed a negative predictive value of 85% for precapillary PH. Conclusions There are significant differences in ECG, echocardiographic, chest CT, PFT and ABG parameters between IPF patients with and without PH. However, these noninvasive tests alone or combination have limited discrimination ability for PH screening in IPF.

CT‐determined pulmonary artery to aorta ratio as a predictor of elevated pulmonary artery pressure and survival in idiopathic pulmonary fibrosis

“…We have demonstrated that the CT‐determined PA:A significantly correlates with mPAP as determined by RHC in patients with IPF at initial evaluation. The major strength of our study is that we included a large cohort of patients with IPF, similar to other recently published studies . We demonstrated that the PA:A, %DL CO and 6MWD were independent explanatory variables of elevated mPAP.…”

“…The major strength of our study is that we included a large cohort of patients with IPF, similar to other recently published studies. 27,28 We demonstrated that the PA:A, %DL CO and 6MWD were independent explanatory variables of elevated mPAP. A cut-off value of 0.9 was optimal to predict mPAP > 20 mm Hg and patients with a PA:A > 0.9 had a worse prognosis than those with a PA:A ≤ 0.9.…”

“…Zisman et al 29 reported that the CTdetermined PA:A was not correlated with mPAP in advanced IPF patients. On the other hand, Alkukhun et al 28 demonstrated that a higher PA:A was an independent predictor of PH. In their study, most of the patients underwent evaluation for lung transplantation, indicating that they were patients with more advanced IPF than our cohort.…”

“…reported that the CT‐determined PA:A was not correlated with mPAP in advanced IPF patients. On the other hand, Alkukhun et al . demonstrated that a higher PA:A was an independent predictor of PH.…”

Associated Pulmonary Hypertension Is an Independent Contributor to Exercise Intolerance in Chronic Fibrosing Interstitial Pneumonias

“…The relationship was significant, which is in line with previous reports [62][63][64][65]. However, in our study, PA size and PA:A ratio did not show a significant correlation with 6MWD, and, from this perspective, they may not serve as surrogates for RHC for the assessment of exercise capacity, until further, larger studies are obtained.…”