Study On The Left Ventricular Function And Plasma Concentration Of BNPs In Diastolic Heart Failure In The Elderly

Background Heart failure occurs frequently in the elderly, and when the symptoms present with preserved left ventricular ejection fraction (LVEF), diastolic heart failure(DHF) can be diagnosed. The state of systolic function in DHF is not certain, neither is the relation between systolic and diastolic dysfunction, in particular, the degree to which systolic and/or diastolic dysfunction may contribute to the heart failure state is unknown. Brain natriuretic peptides (BNPs) are believed to increase in heart failure and can be used to make the diagnosis of heart failure, however, the ability of BNPs to discriminate DHF from systolic heart failure (SHF) is rarely discussed.Methods Echocardiography was performed in subjects with heart failure and preserved LVEF (LVEF ≥ 50%,n=129), in subjects with heart failure and systolic dysfunction (LVEF < 45%,n=109) and healthy senile adults (n=77) who were age and gender matched to the DHF group. Left ventricular (LV) thickness and dimension were derived from M-mode echocardiography, LV volume and LVEF were calculated with Simpson's biplane method. Pulsed wave Doppler imaging was used to obtain the trans-mitral flow velocities: E wave and A wave. Decelerating time (DT) and A duration (AD) were measured. The Doppler sample volume were placed 1cm into the right upper pulmonary vein to get the S wave (PVs), D wave (PVd) and a reversal wave (PVa). PVa duration (PVaD) was measured to calculate the value of PVaD minus AD. The early diastolic flow propagation velocity in left ventricle (Vp) was measured using color M-mode echocardiography. Tissue Doppler imaging (TDI) were performed and the mitral septal, lateral, anterior and inferior wall, and the peak regional myocardial sustained systolic (Sm) and early diastolic (Em) velocities were measured. Blood samples of these patients were obtained within 12 hours after or before theechocardiography exam. BNP were tested using sandwich immunoassay and NT-proBNP were tested by electrochemiluminescence immunoassay. Data were analyzed with a statistic software program (SPSS version 12.0 for windows). Results 1. Compared with the controls, The elder DHF and SHF patents present significant ventricular dilatation and overt atrial enlargement with evident hypertrophy. 2. Sm in 4 sites of mitral annulus in elder DHF and SHF decrease significantly compared with controls, so dose the mean Sm. The relation among the 3 groups is: Normal (10.35±1.41cm/s) >DHF (8.79±1.48cm/s) >SHF(6.05±1.30cm/s) .2. Em of 2 in 4 sites, mean Em and Vp decreased significantly and E/Em and E/Vp rised higer in DHF and SHF, all of which were related to the decrease of Sm.3. BNP and NT-proBNP were upregulated significantly in DHF and SHF (269.93 pg/ml and 874.75pg/ml respectively), and the elevation was related to Sm and NYHA classification(b=0.619 vs -0.273, p<0.001). 4. Although the mean level of BNP and NT-proBNP were obviously higher in SHF than in DHF(p<0.001), but the elevation in DHF patients overlap SHF group. 5. BNP and NT-proBNP can identify CHF with AUC of 0.872 (95%CI:0.835-0.910) and 0.916 (95%CI:0.885-0.947) respectively, and the cut-off of 129pg/ml for BNP and 240pg/ml for NT-proBNP showed a sensitivity of 80% and 88% ,with a specificity of 79% and 82% respectively. To distinguish DHF from SHF, BNP and NT-proBNP showed AUC of 0.746 (95%CI:0.677-0.815) and 0.765(95%CI:0.694-0.836) respectively, and the cut-off of 1500pg/ml for BNP and 500pg/ml for NT-proBNP only showed a sensitivity of 70% and 63% ,with a specificity of 72% and 76% respectively.Conclusions 1. The left atrial and ventricle size increased significantly in elderly DHF, and by TDI, systolic dysfuntion were evident in elder patients diagnosed as DHF by LVEF and to a much lesser extent than SHF. 2. Parameters of diastolic function showed an obvious relationship with those of systolic function, indicating the common coexistence of systolic and diastolic dysfunction in a spectrum of different severity in the pathophysiological process of heartfailure. 3. BNP and NT-proBNP are upregulated significantly in DHF and SHF in the elderly, with DHF to a significantly lesser extent than SHF.4. In accord with LV filling pressure derived by E/Em or E/Vp, BNP and NT-proBNP were related to the NYHA classification and Sm significantly, and the elevation in these two group patients overlap partly 5. BNP and NT-proBNP can be used to identify CHF with high AUC, however, they might add modest discriminatory value in differentiating DHF from SHF.