Traditionally, diagnosing heart failure (HF) in clinical practice relied on comprehensive medical history, physical examination, and laboratory and imaging tests. However, recent advancements have shed light on more accurate and efficient diagnostic approaches. Drs. Dancel and Janjigian reviewed comparisons of traditional methods to the use of point-of-care ultrasound (POCUS) in diagnosing and assessing HF.
POCUS for HF diagnosis: The speakers assessed the likelihood ratios (LRs) of various diagnostic methods for heart failure. While the traditional approaches yielded LRs ranging from 1.8 (for rales on exam) to 4.8 (for chest X-ray showing pulmonary edema) and 8.9 (for B-type Natriuretic Peptide (BNP) >2,500), the positive LR for POCUS findings of B-line patterns was higher at 12.4. The negative LR for the traditional methods was 0.1 (for BNP <100) and 0.01 (for pro-BNP <300) but others were closer to or higher than 0.5. In comparison, POCUS with no B-lines yielded a negative LR of 0.06. The speakers concluded that routine evaluation might be good enough if the diagnosis is reasonably certain either for or against acute chronic heart failure, but clinicians might save time by performing a focused lung ultrasound looking for a B-line pattern if they are in doubt.
Jugular venous pressure (JVP) assessment: Accurate measurement and interpretation of JVP are crucial in assessing heart failure. The speakers emphasized using the right side of the patient, either internal or external jugular vein, and positioning the patient appropriately to evaluate the top of the column of blood, comparing it to the sternal angle of Louis. An elevated JVP greater than eight cm of water (six mm Hg) indicates increased venous pressures. The positive LR for elevated JVP (more than eight cm water) compared to central venous pressure (CVP) was 8.9, while the absence of an elevated JVP had a negative LR of 0.3.
Inferior vena cava (IVC) measurement: POCUS can also aid in estimating right atrial pressures through IVC measurements. A normal IVC diameter is less than 2.1 cm with greater than 50% collapse during inspiration. Conversely, an IVC diameter greater than 2.1 cm with less than 50% collapse indicates elevated right atrial pressures. However, other combinations and values yield less accurate results. JVP and IVC measurements moderately correlated with CVP, and additional data points might be necessary in uncertain or intermediate cases. Venous congestion scoring could be an additional data point to guide therapy and improve outcomes in the appropriate clinical setting.
Lung ultrasound (US) for discharge readiness: Observational analyses suggest that lung US, specifically assessing B-line patterns, may help determine the readiness for discharge of patients with acute heart failure. Studies have shown that patients with more than 15 B-lines at discharge have an increased risk of readmission and/or death. However, limitations exist regarding exclusion criteria and no clinical trials currently support this approach. The American College of Cardiology does not formally support lung ultrasound for heart failure management, while the European Society of Cardiology supports its use for diagnosis but not discharge.
- POCUS, specifically assessing B-line patterns, shows promise in improving the diagnostic accuracy of heart failure compared to traditional methods.
- Accurate measurement and interpretation of the diameters of JVP and IVC provide valuable insights into, respectively, venous pressure and right atrial pressure, aiding in the assessment of heart failure.
- Lung ultrasound, particularly evaluating B-line patterns, has the potential to predict outcomes and readiness for discharge in patients with acute heart failure, although further research is needed for its widespread use.
- While the European Society of Cardiology supports the use of lung ultrasound for heart failure diagnosis (but not discharge), the American College of Cardiology does not currently formally endorse its implementation for management or discharge decisions.
Dr. Mehta is an academic hospitalist at the University of Cincinnati in Ohio. He is also an assistant professor of medicine and core clinical faculty with the internal medicine residency and has roles in quality improvement, program evaluation and improvement, and medical education.