[Validity and usefulness of B-type natriuretic peptide (BNP) for early detection of left ventricular dysfunction in high-risk patients in primary care].

OBJECTIVE: The aim of this study was to determine the accuracy of BNP test for early diagnosis of left ventricular dysfunction in patients at high-risk for heart failure.
DESIGN: Cross-sectional descriptive study.
SETTING: 7 Primary Care Centres in Madrid (Spain). PARTICIPANTS: A consecutive sample of 204 consecutive asymptomatic patients with high risk for heart failure (Stages A-B, AHA/ACC Classification). MAIN MEASUREMENTS: BNP plasma levels were measured in the clinical setting using Triage BNP Test(®) (Biosite(®)) and an echocardiography was performed in the following 3 days in a single hospital unit as a reference standard. Plasma BNP levels were compared depending on the presence/absence of left ventricular dysfunction (LVD), type and severity degree. Sensitivity, specificity, positive and negative predictive values, and Área under the receiver operating characteristic curve (ROC) for BNP assay were calculated.
RESULTS: BNP values were significantly higher (P<.001) in patients with left ventricular systolic dysfunction (LVSD). No significant differences were found for diastolic dysfunction. The best cut-off value to discriminate the patients with LVSD was 71.00 pg/ml, with an Área under the ROC curve of 0.757 (95% CI 0.64-0.87). Sensitivity for LVD diagnosis was 75% (95% CI 50.66-99.34), specificity 70.19% (95% CI 62.81-77.57), positive predictive value (PPV) 20% (95% CI 9.05-30.95), and negative predictive value (NPV) 96.58% (95% CI 92.86-100), with LVSD prevalence of 9.04% in this population.
CONCLUSIONS: BNP determinations are of value in diagnosing LVSD in a primary care setting, with similar sensitivities and specificities. Due to the high NPV is useful to rule-out patients for echocardiography.