Usefulness of Lung Ultrasound in Ambulatory Management of Patients With Chronic Heart Failure

Purpose. The aim of this study is to evaluate whether lung ultrasound, in addition to physical examination, leads to a reduction of the admission rate for acute decompensated heart failure of patients with chronic heart failure (HF) followed in the outpatients heart failure clinic.

Methods. This is a prospective randomized study. The planned sample size consists of 440 patients with chronic HF.

The inclusion criteria are: (1) male and female aged between 18 and 90 years (2) signed written informed consent (3) history of HF for at least six months, (4) left ventricular ejection fraction \< 45%, (5) adequate medical therapy for HF for at least two months.

The exclusion criteria are: (1) concomitant enrollment in other clinical studies, or treatment with experimental drugs or devices within 30 days of clinical assessment, (2) inability to undergo to the planned follow-up and procedures (3) documented pulmonary infections (3) interstitial lung disease and class 4 chronic obstructive pulmonary disease according to GOLD classification.

Patients are randomized in two groups: group A, patients undergoing to lung ultrasound and physical examination; and group B, patients undergoing to physical examination only. Patients are evaluated at baseline and after three months with medical history, Quality of Life test, physical examination, blood sample for hematochemical (creatinine, electrolytes, BNP/NTpro-BNP).

The diuretic therapy is then optimized according to the presence and severity of B-lines in group A and physical examination in group B.

Only patients enrolled in group A undergo to a lung ultrasound examination to assess the extent of pulmonary congestion, through its evidence of B-lines. B-lines originate from the contrast between air-filled structures and water-thickened pulmonary interlobular septa. This leads to linear echogenic vertical artefacts that spread from the pleural layers downwards in the screen. The ultrasound examination is performed with a handheld echocardiography device. The physician carries out a scan of the pulmonary fields, from basal towards mid and apical fields, through the midaxillary line while the patient lies supine. The quantification of B-lines is performed according to their extent over the lung fields. All the information are recorded in dedicated forms.

The results are evaluated according to the following criteria. The primary end-point is a significant reduction of hospitalizations for acute decompensated HF in group A during the follow-up period. The secondary end-points are changes of NT-proBNP values, quality of life test (QLT) score and cardiac mortality.