From the Guidelines
Elevated BNP levels in patients with cirrhosis should be interpreted with caution, considering the patient's clinical context and correlation with other cardiac assessments, rather than relying solely on BNP values. Brain natriuretic peptide (BNP) levels are often elevated in patients with cirrhosis, even in the absence of heart failure, due to hemodynamic changes and decreased liver function leading to reduced BNP clearance 1. Key factors to consider in the interpretation of BNP in cirrhotic patients include:
- Higher threshold values (typically 2-3 times normal cutoffs) should be used to diagnose heart failure
- Correlation of BNP levels with clinical findings, echocardiography, and other cardiac assessments
- Serial measurements showing significant increases from baseline may be more valuable than absolute values
- Consideration of cirrhotic cardiomyopathy, a condition where cardiac function is impaired due to cirrhosis, in the differential diagnosis. In the context of cirrhosis, it is essential to understand that hyponatremia, which can occur in these patients, is associated with increased mortality and morbidity, particularly neurological complications, and reduced survival after liver transplantation 1. However, the direct relationship between elevated BNP and cirrhosis is more closely related to the hemodynamic and cardiac function changes rather than electrolyte imbalances.
From the Research
Elevated BNP and Cirrhosis
- Elevated BNP levels are associated with the severity of liver disease in cirrhotic patients 2, 3, 4, 5
- BNP levels are significantly correlated with the Child score, the grade of esophageal varices, a history of spontaneous bacterial peritonitis, and the presence of ascites and collateral circulation 3
- High plasma BNP seems to be a good negative prognostic factor of death in cirrhosis 2, 3, 4, 5
- BNP levels above the median are associated with an increased occurrence of death within 12 months of discharge 3 and 90-day mortality 4
- BNP may serve as a practical and reliable marker of underlying disease severity in patients with cirrhosis, with potential to be included in prognostication tools for assessment of end-stage liver disease 4
Relationship between BNP and Cirrhosis Prognosis
- BNP levels are related to cardiac function and prognosis in hospitalized patients with decompensated cirrhosis 5
- Cardiac output and BNP are predictors of survival in univariate Cox regression analysis, and only BNP remains independently related to the outcome in multivariate analysis 5
- A BNP ≥ 300 pg/mL had specificity of 88.2% in predicting 90-day mortality 4
BNP and Liver Disease Severity
- Serum BNP levels are positively correlated with the stage of cirrhosis, suggesting that BNP levels might serve as a significant predictor for 1-year all-cause mortality 3
- BNP levels are significantly higher in patients with cirrhosis than in controls, and are correlated with the severity of liver failure assigned as Child's classification and MELD score 2