B-Type Natriuretic Peptide and Clinical Judgment in Emergency Diagnosis of Heart Failure

Abstract

for the BNP Multinational Study InvestigatorsBackground-We sought to determine the degree to which B-type natriuretic peptide (BNP) adds to clinical judgment in the diagnosis of congestive heart failure (CHF). Methods and Results-The Breathing Not Properly Multinational Study was a prospective diagnostic test evaluation study conducted in 7 centers. Of 1586 participants who presented with acute dyspnea, 1538 (97%) had clinical certainty of CHF determined by the attending physician in the emergency department. Participants underwent routine care and had BNP measured in a blinded fashion. The reference standard for CHF was adjudicated by 2 independent cardiologists, also blinded to BNP results. The final diagnosis was CHF in 722 (47%) participants. At an 80% cutoff level of certainty of CHF, clinical judgment had a sensitivity of 49% and specificity of 96%. At 100 pg/mL, BNP had a sensitivity of 90% and specificity of 73%. In determining the correct diagnosis (CHF versus no CHF), adding BNP to clinical judgment would have enhanced diagnostic accuracy from 74% to 81%. In those participants with an intermediate (21% to 79%) probability of CHF, BNP at a cutoff of 100 pg/mL correctly classified 74% of the cases. The areas under the receiver operating characteristic curve were 0.86 (95% CI 0.84 to 0.88), 0.90 (95% CI 0.88 to 0.91), and 0.93 (95% CI 0.92 to 0.94) for clinical judgment, for BNP at a cutoff of 100 pg/mL, and for the 2 in combination, respectively (PϽ0.0001 for all pairwise comparisons). Conclusions-The

Comparison of a basic lung scanning protocol against formally reported chest x‐ray in the diagnosis of pulmonary oedema

“…These figures are supported by the findings of the Breathing Not Properly multinational study, where bedside clinician judgement ‘80% certain’ using chest x‐ray, had a sensitivity of 49%, a specificity of 96% and an overall diagnostic accuracy of 74% for identifying the presence or absence of heart failure 9 . Our own ‘clinical acumen’ results were commensurate with these figures.…”

“…, 9 Alternatively, when non‐radiologist x‐ray interpretation is added to clinical assessment, the diagnostic formulation is incorrect in up to 25% of breathlessness presentations 5 9 , 10 …”

“…Not surprisingly, clinicians are examining low cost modalities that improve diagnostic precision, in particular B‐type natriuretic peptide 2 , 9 , 12 , 13 and bedside lung ultrasound 12 14 – 21 The first lung ultrasound studies (LUS) were conducted in intensive care on patients with pulmonary oedema of various aetiologies, and aimed to identify radiographic changes labelled ‘alveolar interstitial syndrome’ 22 …”

“…– 24 Lung ultrasound for interstitial syndrome produced sensitivities and specificities 15 ,, 17 , 21 , 22 , 25 that suggested it may surpass chest x‐ray 2 4 , 7 – 9 Some research groups now recommend that a negative lung scan protocol be used as a screening tool to reduce redundant chest x‐ray in breathless patients 16 20 …”

Diagnostic accuracy of basic lung ultrasound in breathless patients over 60 years of age; stressing the protocol

“…– 10 One in four elderly patients who present with breathlessness may be misdiagnosed 11 , 12 and possibly mismanaged in the emergency department. Rapid reliable tests evoke interest as pressure grows from increased geriatric presentations, while National Emergency Access Targets reduce time available for investigation.…”