Value of NT-proBNP combined with Doppler E/E' in the evaluation of left ventricular diastolic dysfunction in patients with hypertension

Objective To investigate the relationship between plasma N-terminal pro brain natriuretic peptide(NT-proBNP) level and left ventricular(LV) diastolic dysfunction in hypertensive patients without systolic dysfunction.Methods Forty-four cases of primary hypertensive patients with left ventricular ejection fraction more than 50％ were enrolled,14 cases in normal diastolic function group,30 cases in diastolic dysfunction group(18 cases in delayed relaxation group and 12 cases in pseudo normalization filling group).LV diastolic function was assessed with conventional Doppler by means of mitral inflow and with tissue Doppler echocardiography by means of mitral annulus.The ratio of early diastolic transmitral E wave velocities to tissue Doppler mitral annulus early diastolic E' wave velocities (E/E') was used to detect LV filling pressures.Patients were divided into three groups according to E/E' ratios.Plasma concentrations of NT-proBNP were also measured.All related data were statistically analyzed.Results The levels of NT-proBNP were (115.2 ± 78.9)ng/L in LV diastolic dysfunction group,(34.7 ± 17.5) ng/L in normal filling group and (206.6 ± 75.8) ng/L in pseudonormal filling group.The level of NT-proBNP significantly elevated (F =85.263,P =0.000) along with the severity of lefi ventricular diastolic dysfunction.There was significant difference between each of the two groups among the three groups(all P ＜0.01).According to E/E' ratios,the patients were divided into three groups:E/E' ＜10(n =16),10 ＜ E/E ＜ 15(n =18),E/E' ＞ 15(n =10).The level of NT-proBNP were (39.5 ± 20.1) ng/L,(71.2 ± 26.4) ng/L and (203.7 ± 75.2) ng/L respectively in the three groups.The NT-proBNP blood level was positively correlated significantly with E/E' ratio (r =0.80,P ＜ 0.01).The sensitivity was 87％ and the specificity was 100％ for diagnosis of left ventricular filling pressure (E/E' ＞ 15)according to a NT-proBNP value of 119 ng/L.Conclusion Combining of plasma NT-proBNP and Doppler E/E'have potential value for identification of those patients with hypertension to detect early cardiovascular changes,especially LV diastolic dysfunction. Key words: Primary hypertension;  N-terminal pro brain natriuretic peptide;  Left ventricular diastolic dysfunction;  Tissue doppler imaging