Use of B‐Type Natriuretic Peptide in the Evaluation and Management of Acute Dyspnea

Abstract. Background. B-type natriuretic peptide levels are higher in patients with congestive Heart failure than in patients with dyspnea from other causes. Methods. We conducted a prospective, randomized, controlled study of 452 patients who presented to the emergency department with acute dyspnea: 225 patients were randomly assigned to a diagnostic strategy involving the measurement of B-type natriuretic peptide levels with the use of a rapid bedside assay, and 227 were assessed in a standard manner. The time to discharge and the total cost of treatment were the primary end points. Results. Baseline demographic and clinical characteristics were well matched between the two groups. The use of B-type natriuretic peptide levels reduced the need for hospitalization and intensive care; 75% of patients in the B-type natriuretic peptide group were hospitalized, as compared with 85% of patients in the control group (p=0.008), and 15% of those in the B-type natriuretic peptide group required intensive care, as compared with 24% of those in the control group (p=0.01). The median time to discharge was 8.0 days in the B-type natriuretic peptide group and 11.0 days in the control group (p=0.001). The mean total cost of treatment was $5410 (95% confidence interval, $4516–$6304) in the B-type natriuretic peptide group, as compared with $7264 (95% confidence interval, $6301–$8227) in the control group (p=0.006). The respective 30-day mortality rates were 10% and 12% (p=0.45). Conclusions. Used in conjunction with other clinical information, rapid measurement of B-type natriuretic peptide in the emergency department improved the evaluation and treatment of patients with acute dyspnea and thereby reduced the time to discharge and the total cost of treatment.—Mueller C, Scholer A, Laule-Kilian K, et al. Use of B-type natriuretic peptide in the evaluation and management of acute dyspnea. N Engl J Med. 2004;350:647–654. Comment. This is an interesting study about the use of B-type natriuretic peptide (BNP) and its utility in clinical evaluation of patients who present to the emergency department with acute dyspnea. This is a prospective, randomized, controlled singleblind study done in a Switzerland hospital between May 2001 and April 2002 involving 452 patients. Four hundred fifty-two patients were randomized to either the BNP arm (n=225) or control arm (n=227). The baseline characteristics were similar in both groups. Patients with traumatic cause, severe renal disease, cardiogenic shock, and patients who requested early transfer to another hospital were excluded. Rapid bedside BNP measurements were used. The patients underwent initial assessment with history, physical examination, ECG, and chest x-ray. The primary end points were length of stay and cost of treatment. Secondary end points were in-hospital and 30-day mortality. The results showed convincing evidence that patients in the BNP arm had consistently shorter length of stay and lower cost of treatment. The BNP arm also demonstrated lower admission rate and lower 30-day mortality. This study is designed specifically to address the question of whether BNP testing reduces the cost of treatment for patients. BNP testing reduced the total cost of treatment by 26%. This study supports the previous research trials which advocated BNP use in the evaluation of dyspnea. Other than congestive heart failure, exacerbation of chronic obstructive pulmonary disease is the most common alternative diagnosis in patients with dyspnea. There is a considerable dilemma regarding the cause of acute dyspnea, especially in patients who suffer from both of these common chronic conditions. The treatment of one can cause adverse outcomes in the other. This, in turn, can prolong the hospital stay and the recovery period and sometimes may cause increased morbidity and mortality. The limitations of this study include the small number of enrolled patients and the experience of a single center. However, the investigators' attempt at identifying the financial consequences of the use of BNP is commendable. It has been a common experience among many practitioners that this test is useful in certain challenging patients who present with a typical symptoms and signs. However, the physical examination advocates may not embrace the idea of the routine use of BNP in every patient who presents to the emergency department with acute dyspnea. We support the use of BNP in patients with unclear diagnosis. However, we find that this can only be utilized in association with other important traditional evaluation of the patient, including thorough history taking and physical examination and use of ECG, chest x-ray, and other laboratory studies. This study does not advise the use of BNP in routine evaluation. It only supports the concept that BNP use lowers cost in the routine evaluation of patients presenting with acute dyspnea.