Echocardiographic and Lung Ultrasound Characteristics in Ambulatory Patients with Dyspnea or Prior Heart Failure

Abstract

The article by Platz et al. 1 investigates the association of sonographic B-lines, a stated marker of extra-vascular lung water, with cardiac structure and function. The study was performed in a relatively stable outpatient population undergoing transthoracic echocardiography and lung ultrasound imaging (LUS). The count of B-lines, which are "artifacts," is the diagnostic target, which, in our experience, appears inappropriate. 2 B-lines are visible and approximately measured in conditions different from pulmonary congestion, and notably in chronic obstructive pulmonary disease 3 and pulmonary fibrosis 4,5 : it is a challenge to "count" them, being not an actual "measurement." 6,7 However, the main concern is related to the methodology. The most relevant reference studies, quoted also by the authors, did not use phased array transducers, 1 but linear or convex probes. This makes all the difference as the number of B-lines is greater when using such transducers, particularly at the lower frequencies. 2 We perform yearly intraobserver/inter-observer variability assessments of several US measurements, and repeat them each year at the end of our institutional postgraduate course in Clinical Ultrasound. A convex multifrequency 2-8 mHz probe was used with a MyLab Twice-ElaXto Ultrasound equipment (Esaote-Biomedica, Genoa, Italy). In 2013, in a sample of 20 MDs, with >5 years US practice and expertise (10 operators) or with 6 months of training in clinical US (10 operators), we asked them to assess twice the same movie clips of LUS with B-lines in 5 different clinical conditions; a fair intra-observer internal consistency is observed and the standard deviation is around 33.0% of the averages for each condition, considering the reports of all observers. Nonetheless, ranges of the B-lines individual counts are exceedingly wide for identical cases of each condition: pulmonary edema (3-10), chronic obstructive pulmonary disease exacerbation (4-10), pulmonary fibrosis (3-11), pleural effusion in congestive heart failure (HF) (3-10), pulmonary cancer lymphangitis (4-10). Which is the range for any measurement that the observers reported in the cases studied by Platz et al.? 1 Overall, the straightforward use of B-lines as "quantitative" measurements of B-lines is questionable. But the greater weakness is in cardiological data presentation and interpretation. (1) the most relevant correlation (not association as stated by the authors) is between B-lines count and LV mass index (g/m 2 ): does it mean that we are dealing with a relationship of B-lines with left ventricular hypertrophy? (2) information on measures of left ventricular relaxation are available 1 : comments on the missing relationship of "lung congestion measures" with mechanisms involving left ventricular compliance should be interesting;(3) authors previously reported that "each additional B-line was associated with an increase in pulmonary artery systolic pressure of 1 mmHg" 10 even if in the current noninvasive study relationship is weaker than with invasively m...

Thoracic ultrasound: An adjunctive and valuable imaging tool in emergency, resource-limited settings and for a sustainable monitoring of patients

“…Also the observation of the increase of the B-lines with ageing, in subjects without specific heart or chest disease[ 45 , 46 ], is a further argument against any great expectation from this criterion. The use of a criterion with so relevant limitations is not neutral, since it averts from the use of more suitable criteria, such as echocardiography or radiology, or TUS itself, more adequately performed[ 47 - 52 ]. Despite it was claimed that TUS is a basic application in intensive care units and that can become a useful daily tool in these subsets, such application is not generally used and, actually and quite unexpectedly, after so many years, is still under assessment and evaluation.…”

Thoracic ultrasound: A complementary diagnostic tool in cardiology

“…Nonetheless, the knowledge of these limitations and the use of the few direct information provided by TUS are a substantial add-on to the clinical strategy of the cardiologist[12], also in emergency[13-15]. …”

A Farewell to B-Lines: Ageing and Disappearance of Ultrasound Artifacts as a Diagnostic Tool

“…According to their investigation, a specific diagnosis of any pulmonary condition is not reasonably supported on the basis of this criterion, because the measure of B-line number is erratic, as pointed out by others [2], subject to very severe inter- and intraobserver bias [3] and now, thanks to the study just published, strongly depending on the age of the observed patient [1]. Their experience is in agreement with the practice of most echo laboratories.…”