How is brain-type natriuretic peptide (BNP) testing used in the evaluation of cardiogenic pulmonary edema (CPE)?

Updated: Jul 23, 2020
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Gyanendra K Sharma, MD, FACC, FASE  more...
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Answer

CHF is the most common form of CPE. Several observational studies and clinical trials have shown the important diagnostic value of BNP measurements in differentiating heart failure from pulmonary causes of dyspnea.

Characteristics of BNP and points to consider in BNP testing include the following:

  • BNP testing decreases the total cost of treatment and the length of hospitalization; this is a cost-effective diagnostic test in this setting

  • Although reports differ, a cutoff value of 100 pg/mL is generally accepted; by using this cutoff value, measurement of BNP has a high negative predictive value; that is, in patients with BNP value of under 100 pg/mL, heart failure is unlikely

  • The level of BNP increases with age and is slightly higher in women than in men; BNP levels also tend to be lower in obese patients

  • In one study, a value of 400 pg/mL and above in patients aged 60-75 years was considered equal to a value of 800 pg/mL and above in patients older than 75 years to guide heart failure therapy [3]

  • Renal dysfunction may be associated with a significantly increased level of BNP

  • In the Breathing Not Properly Multinational Study, the mean BNP level in patients without heart failure and with a glomerular filtration rate (GFR) below normal was 300 pg/mL [4]

  • The levels of BNP are generally higher in critically ill patients who are in the intensive care unit (ICU) due to some of the common acute diseases in these patients, such as sepsis and acute lung injury. Elevated BNP levels in critically ill patients may be a sign of relatively poorer prognosis; however, this should be carefully considered in the context of the patient’s clinical condition. [5]


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