Article Figures & Data
Tables
- Table 1.
Comparing the Validity of Studies Using B-Type Natriuretic Peptide (BNP) to Diagnose Heart Failure.
1. Was there an independent, blind comparison with a reference standard of diagnosis? Cowie et al, 1995–199613 May be assumed while blindness was not explicitly stated Dao et al, 199911 Yes Maisel et al, 1999–200012 Yes Morrison et al, 1999–200015 Yes 2. Was the diagnostic test (BNP level) evaluated in a appropriate spectrum of patients (ie, NYHA class I–IV)? Cowie et al, 1995–199613 Yes Dao et al, 199911 Yes Maisel et al, 1999–200012 Yes Morrison et al, 1999–200015 Yes 3. Was the reference standard applied (ie, echocardiogram) regardless of the diagnostic test result? Cowie et al, 1995–199613 Yes Dao et al, 199911 Yes Maisel et al, 1999–200012 Yes Morrison et al, 1999–200015 Yes 4. Was the test validated in a second independent group of patients? Cowie et al, 1995–199613 No Dao et al, 199911 No Maisel et al, 1999–200012 Yes* Morrison et al, 1999–200015 No Adapted from Evidence-Based Medicine: How to Practice and Teach EBM, by Sacket DL et al, 2nd edition; Churchill Livingston, 2000.
* The study by Dao et al may be considered as a second group by some authors.
- Table 2.
List of Findings in Studies Using B-Type Natriuretic Peptide to Diagnose Heart Failure.
N BNP value pg/mL Sensitivity % Specificity % +LR PPV % NPV % AUC Cowie et al, 1995–199613 122 76 97 84 6.1 70 98 0.96 Dao et al, 199911 250 80 98 92 12.3 90 98 0.98 Maisel et al, 1999–200012 1586 80 93 74 3.6 77 92 0.91 Morrison et al, 1999–200015 321 94 86 98 43.0 98 83 0.97 N = study population; BNP = B-type natriuretic peptide; +LR = positive likelihood ratio; PPV = positive predictive value; NPV = negative predictive value; AUC = area under the curve for receiver-operator curves.
- Table 3.
B-Type Natriuretic Peptide (BNP) Levels Among Patients in Each New York Heart Association (NYHA) Classification.
NYHA Classification Level Mean BNP Level pg/mL ± SD I 244 ± 286 II 389 ± 374 III 640 ± 447 IV 817 ± 435 SD = standard deviation.
- Table 4.
Comparing the Validity of Studies Evaluating the Prognostic Value of B-Type Natriuretic Peptide (BNP) in Heart Failure.
1. Was a defined, representative sample of patients assembled at a common point in the course of the disease?† Harrison et al, 1999–200018 No, patients admitted to an emergency center with an dyspnea (acute) were recruited for the study Koglin et al, 199919 Yes, all patients had chronic heart failure and were included after optimization of medical therapy 2. Was follow-up sufficiently long and complete? Harrison et al, 1999–200018 Borderline, follow-up was at 6 months. Koglin et al, 199919 Yes, the mean follow-up period was 398 days. 3. Were objective outcome criteria applied in a blind fashion? Harrison et al, 1999–200018 Yes Koglin et al, 199919 Yes Adapted from Evidence-Based Medicine: How to Practice and Teach EBM by Sacket DL et al, 2nd edition; Churchhill Livingston, 2000.
† Range of the severity of heart failure was accepted for the prognostic interpretation of a laboratory test, such as BNP.
- Table 5.
Recommended Clinical Use of B-Type Natriuretic Peptide (BNP) and Congestive Heart Failure.
Clinical Scenario BNP Level Recommendation Diagnostic uses of BNP* Screening asymptomatic patients for left ventricular dysfunction and heart failure Not available No evidence supports use of BNP for mass screening Acute symptoms without a history of left ventricular dysfunction or CHF >80 pg/mL Suggestive of an acute exacerbation of CHF Acute symptoms with history of left ventricular dysfunction >80 pg/mL–<200 pg/mL Limited diagnostic value Without known BNP baseline >200 pg/mL Limited diagnostic value but possible acute exacerbation of CHF Correlate with New York Heart Association classification (Table 3) With known BNP baseline Increase of BNP >2–3 times baseline suggests acute exacerbation of CHF. Mild to moderate increases can suggest natural progression of CHF or other causes Prognostic utility or therapeutic monitoring value of BNP Hospitalized patient Without known BNP baseline Consider observing a downward trend of BNP before discharge With known BNP baseline Consider observing a downward trend of BNP before discharge or attempt to bring BNP level back to patient’s baseline Outpatient Left ventricular dysfunction CHF, well controlled Goal: <100 pg/mL Consider aggressive management based on BNP level. Adjust therapy when BNP >200 pg/mL. Consider monitoring effects of therapy by BNP levels. Left ventricular dysfunction, CHF poorly controlled or deteriorating Maintain baseline BNP Monitor effects of therapy by BNP levels. Limited diagnostic value otherwise Conditions affecting BNP levels Cause Cardiovascular Myocardial infarction Cardiomyopathy Ventricular hypertrophy Pulmonary Pulmonary embolism COPD Lung cancer Infectious Tuberculosis Renal Renal failure CHF—congestive heart failure, COPD—chronic obstructive pulmonary disease.
* Include thorough history and physical examination. Consider other causes of elevated BNP based on clinical signs and symptoms (dyspnea, chest pain, peripheral edema, paroxysmal nocturnal dyspnea, dyspnea with exertion, dry cough, etc).
