In the last 15 years, a new imaging application of sonography has emerged in the clinical arena: lung ultrasound (LUS). From its traditional assessment of pleural effusions and masses, LUS has moved towards the revolutionary approach of imaging the pulmonary parenchyma, mainly as a point-of-care technique. Although limited by the presence of air, LUS has proved to be useful in the evaluation of many different acute and chronic conditions, from cardiogenic pulmonary edema to acute lung injury, from pneumothorax to pneumonia, from interstitial lung disease to pulmonary infarctions and contusions. It is especially valuable since it is a relatively easy-to-learn application of ultrasound, less technically demanding than other sonographic examinations. It is quick to perform, portable, repeatable, non-ionizing, independent from specific acoustic windows, and therefore suitable for a meaningful evaluation in many different settings, both inpatient and outpatient, in both acute and chronic conditions.

For many years the lung has been considered off-limits for ultrasound. However, it has been recently shown that lung ultrasound (LUS) may represent a useful tool for the evaluation of many pulmonary conditions in cardiovascular disease. The main application of LUS for the cardiologist is the assessment of B-lines. B-lines are reverberation artifacts, originating from water-thickened pulmonary interlobular septa. Multiple B-lines are present in pulmonary congestion, and may help in the detection, semiquantification and monitoring of extravascular lung water, in the differential diagnosis of dyspnea, and in the prognostic stratification of chronic heart failure and acute coronary syndromes.

Background: Acute dyspnoea as a presenting symptom is a frequent diagnostic challenge for physicians. The main differential diagnosis is between dyspnoea of cardiac and non-cardiac origin. Natriuretic peptides have been shown to be useful in this setting. Ultrasound lung comets (ULCs) are a simple, echographic method which can be used to assess pulmonary congestion. Aim: To evaluate the accuracy of ULCs for predicting dyspnoea of cardiac origin compared to natriuretic peptides. Methods: We evaluated 149 patients admitted with acute dyspnoea. Chest sonography and NT-proBNP assessments were performed a maximum of 4 h apart and independently analyzed. ULCs were evaluated via cardiac probes placed on the anterior and lateral chest. Two independent physicians, blinded to ULCs and NT-proBNP findings, reviewed all the medical records to establish the aetiologic diagnosis of dyspnoea. Results: Cardiogenic dyspnoea was confirmed in 122 patients and ruled-out in 27 patients. The number of ULCs was significantly correlated to NT-proBNP values (r=.69, p<.0001). Receiver operating characteristic analysis, showed an area under the curve of .893 for ULCs and .978 (p=.001) for NT-proBNP, in predicting the cardiac origin of dyspnoea. Conclusions: In patients admitted with acute dyspnoea, pulmonary congestion, sonographically imaged as ULCs, is significantly correlated to NT-proBNP values. The accuracy of ULCs in predicting the cardiac origin of dyspnoea is high.

Pulmonary congestion is highly prevalent and often asymptomatic among patients with ESRD treated with hemodialysis, but whether its presence predicts clinical outcomes is unknown. Here, we tested the prognostic value of extravascular lung water measured by a simple, well validated ultrasound B-lines score (BL-US) in a multicenter study that enrolled 392 hemodialysis patients. We detected moderate-to-severe lung congestion in 45% and very severe congestion in 14% of the patients. Among those patients with moderate-to-severe lung congestion, 71% were asymptomatic or presented slight symptoms of heart failure. Compared with those patients having mild or no congestion, patients with very severe congestion had a 4.2-fold risk of death (HR=4.20, 95% CI=2.45–7.23) and a 3.2-fold risk of cardiac events (HR=3.20, 95% CI=1.75–5.88) adjusted for NYHA class and other risk factors. Including the degree of pulmonary congestion in the model significantly improved the risk reclassification for cardiac events by 10% (P<0.015). In summary, lung ultrasound can detect asymptomatic pulmonary congestion in hemodialysis patients, and the resulting BL-US score is a strong, independent predictor of death and cardiac events in this population.