Value of N-Terminal proBNP in the Diagnosis of Left Ventricular Systolic Dysfunction in Primary Care Patients Referred for Echocardiography

Background: Echocardiography is the method of choice to detect left ventricular systolic dysfunction (LVSD), but access to this examination is limited. Therefore, simpler diagnostic tests would be of clinical importance. Objectives: We sought to evaluate the performance of a new N-terminal pro-brain natriuretic peptide (NT-proBNP) analysis in diagnosing LVSD in primary care patients with a provisional diagnosis of heart failure referred for echocardiography. Methods: Serum levels of NT-proBNP were measured with an immunoassay and left ventricular ejection fraction (LVEF) was assessed by echocardiography in 367 patients. Results: Mean age of the patients was 68.8 years (39.0–84.0 years), and 54% were female. Ten percent of the patients had LVEF <0.40. Depending on which cutoff values were used, NT-proBNP analysis detected patients with LVEF <0.40 with a sensitivity of 91–100% and specificity of 46–60%. If the limit for LVSD was set to 0.30, the sensitivity was 100% and the specificity ranged from 44 to 58%. The area under the receiver operating characteristics curves for detecting LVEF ≤0.30 and LVEF ≤0.40 was 0.93 and 0.87, respectively. Conclusion: Irrespective of which cut off value is used, normal NT-proBNP levels effectively rule out LVSD in primary care patients referred for echocardiographic evaluation of possible heart failure.