Echocardiographic signs of pulmonary hypertension in patients with newly recognized hypersensitivity pneumonitis, prevalence and clinical predictors

Abstract

Background: Hypersensitivity pneumonitis (HP) is the third, according to frequency, interstitial lung disease, with the estimated incidence rate of 1-2/100,000. In HP patients, the extensive inflammatory lesions encompassing both small airways and lung parenchyma, as well as subsequent development of lung fibrosis, may result in respiratory insufficiency and secondary pulmonary hypertension (PH). The aim of the present retrospective study was to assess the prevalence of echocardiographic signs of PH and its' clinical predictors, in newly recognized HP patients. Methods: Consecutive HP patients, recognized in single pulmonary unit between 2005 and 2017, in whom echocardiography was performed at diagnosis, entered the present study. HP diagnosis was verified in every patient according to current diagnostic recommendations. The results of high resolution computed tomography of the chest (HRCT) were re-evaluated by two independent radiologists, blinded to clinical data. Echocardiographic signs of PH were defined as pulmonary artery systolic pressure (PASP) exceeding 36 mmHg. Regression analysis was applied to calculate PH risk, and receiver operator characteristic curves (ROC) were plotted to investigate diagnostic utility of various parameters in PH prediction. Results: PASP exceeding 36 mmHg was noted in 26 out of 70 patients (37%)-with equal frequency among patients with fibrotic and non-fibrotic HP. Significant predictors of PH on echocardiography were: partial oxygen tension in arterialized capillary blood (PaO2) <69 mmHg, lung transfer capacity for carbon monoxide (TLCO) <42% of predicted, six minutes walking test (6MWT) distance <455 meters, and 6MWT desaturation rate >8%. In case of TLCO <42% of predicted, probability of PH on echocardiography was increased by five-fold, in case of 6MWT desaturation rate >8%-by four fold. Conclusions:The best predictors of PASP >36 mmHg on echocardiography in HP patients at diagnosis were: TLCO <42% and 6MWT desaturation rate >8%. Neither the presence of lung fibrosis on HRCT, nor the duration of the disease or patients age, were helpful in PH prediction.

Predictors of pulmonary hypertension in patients with hypersensitivity pneumonitis

“…More recent study conducted on 70 patient with HP considered PH diagnosis in 37% of patients based on echocardiography, authors noticed that patient with HP and PH has significant reduction of resting PO 2 and 6MWD and O 2 desaturation rate, this was close to our results [ 4 ].…”

“…Dybowska et al found that fibrotic HP was not a predictor of PH on echocardiogrsphy when they use PASP 36 mmHg as cut off of diagnosis of PH, but PASP > 50 mmHg was exclusively observed in fibrotic HP. So, they declared that role of pulmonary fibrosis as predictor of PH in HP was not clear, which is not in line with our findings [ 4 ].…”

“…The inflammatory process in HP affect small airways and lung parenchyma with development of pulmonary fibrosis, which lead to impairment of exercise capacity and pulmonary hypertension (PH) [ 4 ], due to subsequent affection of oxygen diffusion [ 5 ].…”

Predictors of Pulmonary Hypertension and Right Ventricular Dysfunction in Patients with Hypersensitivity Pneumonitis

“…Attention should be paid to a significant difference in the frequency of PH between medical documentation at the time of a patient’s inclusion in the study and the results obtained after the patient’s examination (TTE)—32.9% vs. 48.2%. The problem of underestimating PH in patients with HP has been confirmed by Wälscher et al, who assessed comorbidity in patients with chronic HP and showed a frequency of PH as high as 9.5% (20 out of 211 patients); this is significantly lower than the frequency of PH diagnosis based on medical records [ 8 , 10 , 15 ]. An important advantage of our study is an assessment of right heart size and function by TTE.…”

“…At the same time, PH can also be detected in patients with IPF without hypoxemia with mild to moderate impairment of lung function [ 7 ]. Data on PH prevalence among patients with HP are more limited; most authors report a frequency of 28.3–44.0% [ 8 , 9 , 10 ]. Several studies have confirmed a significant impact of PH on the risk of mortality in patients with IPF [ 7 , 11 , 12 , 13 ].…”