Natriuretic Peptide Testing in Heart Failure

Case presentation 1: A 78-year-old woman with a history of morbid obesity, coronary artery disease, chronic obstructive pulmonary disease, and chronic kidney disease (serum creatinine 2.0 mg/dL) presented to the emergency department with worsening dyspnea. Her ECG shows no acute ischemic changes; her chest radiograph reveals chronic emphysematous changes with mild bilateral infiltrates. Her lung examination is notable for diffuse wheezing, and she has chronic lower extremity edema. Her amino-terminal pro-B-type natriuretic peptide ( NT-proBNP) level is 5500 pg/mL (upper limit of normal is 75 years). Does this patient have acutely decompensated heart failure (ADHF)?Many patients presenting with acute dyspnea (including those with ADHF) have multiple coexisting medical disorders that may complicate their diagnosis and management. Diagnostic uncertainty in the setting of acute dyspnea is associated with longer hospital length of stay, more diffuse diagnostic and therapeutic efforts, increased healthcare costs, and higher likelihood for repeat heart failure (HF) hospitalization or death.1 The addition of testing for brain natriuretic peptide (BNP) or NT-proBNP to standard clinical assessment has been shown to be valuable for an accurate and efficient diagnosis and prognostication of HF, and the use of BNP or NT-proBNP may be associated with improved clinical outcomes.2,–,4Circulating levels of BNP/ NT-proBNP are normally very low in healthy individuals. In response to increased myocardial wall stress due to volume- or pressure-overload states (such as in HF), the BNP gene is activated in cardiomyocytes. This results in the production of an intracellular precursor propeptide (proBNP108); further processing of this propeptide results in release of the biologically inert amino-terminal fragment ( NT-proBNP) and the biologically active BNP (Figure 1). In addition, a significant portion of BNP or NT-proBNP detected by current assays includes uncleaved proBNP108, whereas BNP concentrations …