B‐Lines in Assessment of Pulmonary Hypertension in Patients With Interstitial Lung Diseases

Objectives This study was conducted to evaluate the value of sonographic B‐lines (previously called “comet tail artifacts”) in assessment of pulmonary hypertension in patients with interstitial lung diseases. Methods One hundred thirty‐four patients with clinically diagnosed interstitial lung diseases complicated by pulmonary hypertension underwent transthoracic lung sonography and Doppler echocardiography for assessment of the presence of B‐lines, the distance between them, and the pulmonary artery (PA) systolic pressure. A correlation analysis and a receiver operating characteristic curve analysis were performed. Results All patients had diffuse bilateral B‐lines. The maximum number of B‐lines seen in any positive zone (not a summation) was significantly correlated with the severity of PA systolic pressure ( r = 0.812; P < .0001), and a linear regression equation could be demonstrated: that is, y = 6.06 x + 17.57, where x and y represent the number of B‐lines and PA systolic pressure, respectively. A cutoff of more than 4 B‐lines seen in any positive zone had 89.5% sensitivity, 85.0% specificity, and 87.2% accuracy in predicting elevated PA pressure (>30 mm Hg). Conclusions The number of B‐lines is useful in assessment of pulmonary hypertension, especially when tricuspid regurgitation and pulmonary valve regurgitation do not exist or cannot be satisfactorily measured by Doppler echocardiography.