P4664N-terminal pro-B-type natriuretic peptide and its relationship with cardiac function and prognosis in elderly patients with valvular heart disease
Authors: Zhang B , Zhang H T , Xu H Y , Wu Y J 
Published: October 2019

Abstract

Background
N-terminal pro-B-type natriuretic peptide (NT-proBNP) may provide incremental prognostic value in valvular heart disease (VHD). We aimed to elaborate its value in elder VHD patients and relationship with ventricular function and prognosis.

Methods
From China elDerly Valvular heart Disease (China-DVD) cohort study, elder VHD patients (age ≥60 years) with concomitant echocardiography and NT-proBNP measurements at baseline were included. Patients were followed every six months. The primary endpoint was 1-year all-cause mortality regardless of valvular intervention.

Results
In total, 6025 patients were included in the study (mean age of 71.08±7.61 years, 52.6% male, 78.6% NYHA class > I). The overall median NT-proBNP was 268.92 pmol/L (interquartile range [IQR]: 89.94 to 828.70 pmol/L). Among various VHD, the highest NT-proBNP levels were detected in patients with multivalvular heart disease (379.96 pmol/L [IQR: 146.07 to 1188.53 pmol/L]) and mitral regurgitation (294.88 pmol/L [IQR: 98.44 to 917.75 pmol/L), and the lowest levels were observed in patients with aortic regurgitation (112.04 pmol/L [IQR: 31.92 to 408.04 pmol/L). NT-pro BNP levels correlated with age (r=0.131, p<0.0001). Noteworthily, no significant difference was found between men and women. In general, NT-proBNP correlated with left ventricular ejection fraction (LVEF, r=−0.438, p<0.001), left ventricular end-diastolic dimension (LVEDD, r=0.16, p<0.001) and left atrial dimension (LA, r=0.081, p<0.001). All those correlations were stronger in aortic valve disease than mitral valve disease. Diagnostic ability of NT-proBNP to differentiate severe VHD was limited and varied among different VHD (AUC: 0.62 [0.54, 0.69] in AS, 0.61 [0.53, 0.69] in MS, 0.58 [0.53, 0.63] in AR, 0.49 [0.47, 0.53] in MR). Spline curves revealed a strong association between NT-proBNP and mortality. In the overall population, after adjustment of propensity score accounting for age, sex, coronary heart disease, diabetes, cardiomyopathy, symptoms, severity, LVEF, and valvular intervention, NT-proBNP was a powerful, independent, and incremental predictor of mortality (log transformation, HR: 1.38; [95% CI: 1.30 to 1.46], p<0.001). Moreover, we dichotomized NT-proBNP in severe and nonsevere using median values in various VHD. Except for MS, other VHDs all incurred excess mortality with severe NT-proBNP, especially in aortic stenosis (HR: 17.21; [95% CI: 4.08 to 72.60], p<0.001) and aortic regurgitation (HR: 5.10; [95% CI: 2.13 to 12.22], p<0.001).

Conclusion
Levels of NT-proBNP significantly differ by diagnosis in VHD patients and correlate with echocardiographic parameters to varying degrees, reflecting different hemodynamic changes. In patients with VHD other than single mitral stenosis, NT-proBNP is a powerful, independent, and incremental predictor of mortality. Thus, measurement of NT-proBNP should be considered in the VHD population for further risk stratification.

Acknowledgement/Funding
Key Projects in the National Science & Technology Pillar Program during the 12th five-year Plan