B‐type Natriuretic Peptide for Diagnosis of Heart Failure in Emergency Department Patients: A Critical Appraisal

Abstract

The diagnosis of heart failure in the outpatient setting can be difficult. A rapid assay for B-type natriuretic peptide (BNP) has been advocated for the diagnosis of heart failure, using a single cutoff of 100 pg/mL. BNP is produced by both the right and left cardiac ventricles and is elevated in a variety of conditions, including heart failure, pulmonary hypertension, cor pulmonale, pulmonary embolism, left ventricular hypertrophy, renal failure, circulatory overload, acute coronary syndromes, atrial fibrillation, lung cancer, and sepsis. This multitude of causes of BNP elevation imposes limits on its diagnostic use for heart failure. The literature on the use of BNP testing for diagnosis of heart failure is reviewed, and improved guidelines for its interpretation are suggested.

Medical and Economic Long-term Effects of B-Type Natriuretic Peptide Testing in Patients with Acute Dyspnea

“…Overall, functional status at 360 days was satisfying, with two-thirds of patients having either no or only slight limitations of their daily activities due to dyspnea. These long-term follow-up data are reassuring given recent criticism regarding the value of BNP testing in clinical medicine and considerably extend the evidence regarding the safety and effectiveness of the use of this marker (13)(14)(15).…”

Lung cancer patients frequently visit the emergency room for cancer-related and -unrelated issues

“…Blood sampling may be useful for differential diagnosis. Other possible tools for rapid diagnosis in the ER are reportedly lung ultrasound (9) and B-natriuretic peptide assay (10,11).…”

Tips for learners of evidence-based medicine: 5. The effect of spectrum of disease on the performance of diagnostic tests

“…5 When only patients in this subgroup were considered in a number of studies, the sensitivity and specificity of the BNP test at a cutoff point of 100 pg/mL were only 88% and 55% respectively. 7 The range of disease states found among the patients in the population upon which a test is to be used is commonly referred to as "disease spectrum." In making your final assessment on the value of a test, consider the spectrum of the disease or condition in which you are interested.…”

“…Commentaries have challenged the investigators' estimates of the sensitivity and specificity of the BNP test at the proposed cutoff point on the basis that clinicians were already confident with respect to the likelihood of congestive heart failure in most of the patients in the study. 6,7 Ideally, the ability of a test to correctly identify patients with and without a particular disease would not vary between patients. However, if you are a clinician, you already intuitively understand that a test may perform better when it is used to evaluate patients with more severe disease than it would with patients whose disease is less advanced and less obvious.…”