Combined Assessment of Relaxin and B-Type Natriuretic Peptide Improves Diagnostic Value in Patients With Congestive Heart Failure

Abstract Background To improve the poor prognosis of congestive heart failure (CHF), early and accurate diagnosis is necessary. Relaxin is an endogenous cardiovascular peptide, and its plasma level is usually increased in patients with CHF. In this pilot study, we aimed to determine the diagnostic value of relaxin and B-type natriuretic peptide (BNP) in patients with and without CHF. Materials and Methods The plasma level of relaxin was measured by enzyme-linked immunosorbent assay and plasma level of BNP by fluorescence immunoassay. The area under the receiver operating characteristic curve was used to assess the diagnostic value of relaxin and BNP. Results We included 81 patients with decompenstated CHF and 36 controls. Plasma levels of relaxin and BNP were both higher in CHF patients than in controls. The correlation between plasma levels of relaxin and BNP and between relaxin or BNP and cardiac function was nonlinear. Relaxin had medium diagnostic value, and BNP had higher value for cardiac function and CHF. At a cutoff of 39.76 pg/mL relaxin, sensitivity was 82.7%, specificity 55.6%, sum of the highest positive predictive value 80.5% and negative predictive value 58.8%. Although the diagnostic value was not better for relaxin than BNP, their combined assessment improved the sensitivity and specificity of diagnosis for CHF as compared with BNP alone. Conclusions Combined assessment of relaxin and BNP may improve the diagnosis of decompensated CHF, which may have potential application in the clinic.