Ultrasound and Congestive Heart Failure (CHF)
Lung ultrasound guided diuretic therapy can reduce hospital readmission risk by 56% vs physical exam.
Overview
Diuretic treatment can be applied earlier and more precisely using B-line counts.
Lung congestion has negative implications for the prognosis and survival of patients with chronic heart failure. Much like chest radiography (chest x-ray), lung ultrasound is capable of assessing lung congestion, with increasing numbers of B-lines indicating increasingly severe lung congestion. Use of therapies for lung decongestion are currently guided by changes in patient-reported symptoms, auscultation, and other benchmarks such as weight loss and urine output. The use of lung ultrasound can add an (at least semi-) quantitative benchmark to prevent over- or under-treatment using lung decongestion therapies.
B-line counts in lung ultrasound substantially reduced in heart failure patients after diuretic or dialysis treatment within minutes to a few hours, suggesting its usefulness as a non-invasive and accessible benchmark to guide therapy. For example, in hospitalized patients with acute heart failure, change in lung congestion after treatment can be tracked over 3 hours to 4.2 days by lung ultrasound scans of 11 lung zones. Lung ultrasound was used to detect up to 40% of residual pulmonary congestion missed by physical exam, and reduced rehospitalization risk due to acute decompensated heart failure in patients with chronic heart failure by 56%.
Patient Outcome Improvements
Publication
A randomized controlled trial of lung ultrasound-guided therapy in heart failure (CLUSTER-HF study).
Key Findings
- Lung ultrasound guided treatment in clinical follow-up was associated with a 45% risk reduction in a composite measure of urgent heart failure visits, rehospitalization and death
- The largest reduction in risk was in urgent heart failure visits to the hospital
- No significant risk reduction for rehospitalization for heart failure or death was found
Paper Implications
- Incorporating lung ultrasound into clinical follow-up can reduce the risk of urgent hospital visits for worsening heart failure
Publication
Lung ultrasound-guided therapy reduces acute decompensation events in chronic heart failure.
Key Findings
- Rehospitalization because of acute decompensated heart failure rate for chronic heart failure patients examined with lung ultrasound and physical exam were significantly less than rate for patients with physical exam only (9.4% vs 21.4%)
- Use of lung ultrasound + physical exam showed a risk reduction for rehospitalization because of acute decompensated heart failure of 56% compared to physical exam only
Paper Implications
- Lung ultrasound guided therapy can reduce rehospitalization rate and risk in patients with chronic heart failure
Lung Congestion's Role
Publication
Lung congestion in chronic heart failure: haemodynamic, clinical, and prognostic implications.
Key Findings
- In patients with heart failure, lung congestion was directly correlated with pulmonary vascular resistance (PVR) and inversely correlated with pulmonary artery (PA) compliance and the diffusion limit for carbon monoxide (DLCO).
- Lung congestion was associated with reduced survival in heart failure patients, even after adjusting for pulmonary artery wedge pressure, NT-proBNP (a ventricular natriuretic peptide), anaemia, coronary artery disease, and renal dysfunction.
Paper Implications
- Lung decongestion may help deter progression of biventricular heart failure and pulmonary vascular disease.
Comparison: Physical Exam
Publication
Key Findings
- Lung ultrasound detected up to 40% of pulmonary congestion cases missed by physical exam (subclinical pulmonary congestion) in chronic heart failure patients at hospital discharge
- Subclinical pulmonary congestion is a risk factor for hospital readmission (37% readmission rate for patients with subclinical pulmonary congestion versus 7% for those without)
Paper Implications
- The use of lung ultrasound for follow-up could enhance detection of patients with pulmonary congestion missed by physical exam
Guidance: B-Line Counts
Publication
Key Findings
- In hospitalized patients with acute heart failure, change in lung congestion after treatment can be tracked over 3 hours to 4.2 days by lung ultrasound scans of 11 lung zones.
- Patient position during serial assessments should be kept constant to prevent measuring changes resulting from position change.
- At discharge, finding 15 or more B-lines in a 28-zone lung ultrasound can identify acute heart failure patients with a greater than five-fold risk for hospital readmission or death
- At discharge, finding 3 or more B-lines in a 5 or 8 zone lung ultrasound can identify ambulatory chronic heart failure patients with a nearly four-fold risk for hospital readmission or death
Paper Implications
- High B-line counts can identify patients at greater risk of rehospitalization and mortality for both acute and chronic heart failure.
- There is potential for lung ultrasound studies utilizing fewer chest zones (five to eight) to provide similar prognostic information as studies with higher numbers of zones (28 zones).
Publication
Ultrasound of extravascular lung water: a new standard for pulmonary congestion.
Key Findings
- In a 28-region scanning protocol on the anterior chest, a patient in supine position can be expected to have absent lung congestion with 0-5 B-lines, mild with 6-15 B-lines, moderate with 16-30 B-lines, and severe with over 30 B-lines.
- In clinical settings, lung ultrasound B-lines are reasonably well correlated with chest radiography and CT scores.
- The specificity of B-lines is reduced in patients presenting with comorbidities that present dry B-lines (e.g. systemic sclerosis, when the interlobular septa thicken).
- B-line counts reflect changes in lung congestion after diuretic or dialysis treatment within minutes to a few hours.
Paper Implications
- Lung ultrasound has the potential to be a new standard for the assessment and monitoring of extravascular lung water.