Diagnostic accuracy of echocardiography in identifying heart failure related pleural effusions

RATIONALE: Differentiating between congestive heart failure-related pleural effusion (CHF-PE) and non-CHF-PE is clinically important. However, this distinction can be challenging and often requires thoracentesis. Role of transthoracic echocardiography in the diagnosis of CHF-PE has never been evaluated. OBJECTIVE: Assess the diagnostic performance of echocardiography in differentiating CHF-PE from non-CHF-PE. METHODS: This is a single-center retrospective case-control study of patients with pleural effusions classified as either CHF-PE or non-CHF-PE based on a comprehensive clinical data analysis. Traditional indicators of CHF (reduced left ventricular ejection fraction) and contemporary echocardiographic parameters of elevated left atrial pressures (enlarged indexed left atrial volume - LAVI, increased E/A and E/e' ratios) were investigated. Echocardiographic evaluations were blinded to the clinical classification of pleural effusions. RESULTS: The study cohort included 167 patients; most patients (112/167) were diagnosed with non-CHF-PE. Echocardiographic parameters of E/e' > 14, E/A > 2, LAVI ≥34 ml/m2, and LVEF <40 % had high specificity (89 %, 98 %, 80 %, and 94 %, respectively) but low to modest individual sensitivity (45 %, 12 %, 72 %, and 27 %, respectively) in diagnosing CHF-PE. In a univariate logistic regression, both E/e' and LAVI performed well in identifying CHF-PE (AUC = 0.832 and 0.835, respectively), however, the best results were seen when E/e' and LAVI were combined (AUC = 0.903). Whereas reduced LVEF was not helpful in identifying CHF-PE (AUC = 0.635). CONCLUSION: Echocardiographic parameters indicative of elevated left atrial pressure can be helpful in diagnosis of pleural effusions associated with CHF and may reduce the need for invasive thoracentesis in selected patients with pleural effusion.