Plasma NT-proBNP levels associated with cardiac structural abnormalities in asymptomatic health examinees with preserved ejection fraction: a retrospective cross-sectional study

Abstract

Objectives: Stage B heart failure (HF) is defined as an asymptomatic abnormality of the heart structure or function. The circulating level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) is elevated in symptomatic patients with left ventricular (LV) dysfunction caused by a structural or functional abnormality. This study investigated the association of the NT-proBNP level with echocardiography-detected cardiac structural or diastolic abnormalities in asymptomatic subjects with preserved LV systolic function (ejection fraction >50%).

Methods: We retrospectively studied 652 health examinees who underwent echocardiography and an NT-proBNP test at a health-promotion centre in Seoul, between January 2016 and September 2018. The left ventricular mass index (LVMI) and the left atrial dimension (LAD) were used as markers for structural abnormalities, and the mean e' velocity and mitral early flow velocity/early diastolic tissue velocity (E/e') ratio were used as markers for diastolic dysfunction. The plasma NT-proBNP level was measured using electrochemiluminescence immunoassay (DPC Immulite 2000 XPi, Siemens Healthcare Diagnostics, Tarrytown, New York, USA).

Results: Subjects with preclinical structural abnormalities were older and had a higher body mass index (BMI), higher blood pressure, lower high-density lipoprotein cholesterol level, higher NT-proBNP level, and higher E/e' (p<0.05). Multivariate regression analysis indicated that the factors associated with a higher NT-proBNP level were older age, female sex, lower BMI, higher creatinine level, higher LVMI and higher LAD (p<0.01).

Conclusion: Diastolic dysfunction is not associated with higher NT-proBNP levels, whereas preclinical cardiac structural abnormalities, as well as older age, female sex, lower BMI, and higher creatinine level, are associated with higher NT-proBNP levels.

Keywords: NT-proBNP; diastolic dysfunction; echocardiography; heart failure; preclinical structural abnormalities.

Figure 1

Study flow diagram. LVEF, left ventricular ejection fraction.

Figure 2

NT-proBNP levels according to sex and age categories. Box limits and horizontal lines within boxes represent interquartile ranges and the median, respectively. The upper and lower whiskers indicate the 97.5th and 2.5th percentiles, respectively. NT-proBNP, N-terminal pro-B-type natriuretic peptide.

Figure 3

NT-proBNP levels of subjects with and without structural abnormalities according to age categories. Box limits and horizontal lines within boxes represent interquartile ranges and the median, respectively. The upper and lower whiskers indicate the 97.5th and 2.5th percentiles, respectively. NT- proBNP, N-terminal pro-B-type natriuretic peptide.

Figure 4

Receiver operating characteristic curve and cut-off value of N-terminal pro-B-type natriuretic peptide in predicting cardiac structural abnormalities. NPV, negative predictive value; PPV, positive predictive value.