A Study Of The Evaluation Effects Of Plasma Brain Natriuretic Peptide And Cardiac Tei Index To The Early Cardiac Function In Children With Left To Right Shunt Congenital Heart Disease

Background and objective: Congenital heart disease (CHD) is a kind ofcommon cardiovascular diseases in young children, most of which is left to fightshunt type. It's often complicated with feeding disorder, physical developmentretardation and frequent respiratory infections if diagnosis and treatment are delayed.Pulmonary hypertension (PH), heart failure (HF) and Eisenmenger syndromechallenge the surgery opportunity. To evaluate exactly the cardiac function of thesechildren in early stage is important. But there is still no unified assessment markerwith good sensitivity and specificity as well.B-type natriuretic peptide (BNP), also named as brain natriuretic peptide, wasfirstly identified from brain tissues of pig in 1988 by Sudoh et al. Human BNP is a 32amino acid peptide and produced mainly by the myocardial cells. Increasedventricular end diastolic pressure and ventdcular wall tension, which is the result ofchronic hypervolemia, can stimulate the synthesis and secretion of BNP. The mainphysiological functions of BNP are diuresis and vasodilation etc. through antagonismeffect to the renin-angiotensin-aldosterone system (RAAS). Recently it's reported thatchanges of BNP levels were associated with the cardiac dysfunction and could helpassessing the cardiac function in adult patients. European Society of Cardiology hadchosen BNP levels as a new diagnosis index of HF from 2005. The pathophysiologicchanges of CHD are associated with the structural and hemodynamic abnormalities,which result in volume and pressure overload to the heart. It was found that the BNPlevels were correlated with the severity of heart failure and the ventricular fillingpressures. So BNP concentration should be a useful marker in diagnosing andevaluating cardiac function in children with CHD.Tei index is a new Doppler index to assess the systolic and diastolic ventricularfunction, which has a good correlation with the result of cardiac cathetefization—thegold standard for evaluation of cardiac function. It is not affected by age, gender, heartrate, cardiac loading condition and ventricular geometry. So it's presumed that Tei index should be a sensitive indicator of ventricular dysfunction in children with CHD.This study was designed to check the levels of plasma BNP and cardiac Teiindexes and to investigate the evaluation effects of them to the early cardiac functionand surgery effect in children with left to fight shunt CHD.Methods: 44 cases with left to right shunt CHD (21 males, 23 females) aged3-9 years (mean: 6.50 years) with gradeⅠ～Ⅱcardiac function were studied asexperimental groups from Feb. 2005 to Feb. 2006, which were subdivided into towgroups according to their ventricular volume loading condition—left ventricle volumeoverload (LV-CHD) group included ventricular septal defect (VSD, n=20) and patentductus arteriosus (PDA, n=9) and right ventricle volume overload (RV-CHD) groupincluded atrial septal defect (ASD, n=15). 20 healthy children aged 3-8 years (mean:6.28 years) were chosen as control group who were matched with experimental groupin age and genders. The plasma BNP levels were measured by enzyme-linkedimmunosorbent assay (ELISA). Echocardiograms (Philips SONOS 5500) were doneand the indexes such as left ventricular end-diastolic diameter (LVEDD), rightventricular end-diastolic diameter (RVEDD), pulmonary to systemic flow ratio(Qp/Qs), left ventricular ejection fraction (LVEF), left ventricular fraction shortening(LVFS), mitral flow E/A, tricuspid flow E/A, pulmonary artery systolic pressure(PASP), LV Tei index and RV Tei index were measured and calculated in all groups.22 patients with left to fight shunt CHD (8 VSD, 6 PDA and 8 ASD) were undertakenoperation and the level of plasma BNP as well as LVEDD, RVEDD, Qp/Qs, LVEF,LVFS, mitral flow E/A, tricuspid flow E/A, PASP, LV Tei index and RV Tei indexwere measured before and 3 months after operation. Data were analyzed by SPSS10.0for Windows.Results:1. The levels of plasma BNP were 64.32±22.19 pg/ml, 61.20±27.84 pg/ml, 33.67±10.82 pg/ml in LV-CHD group, RV-CHD group and control group respectively. Theplasma BNP levels in two CHD groups were both higher than those in control group(P＜0.01) and the differences between two CHD groups were not significant (P＞0.05).2. There were significant differences among LV-CHD group, RV-CHD group andcontrol group as for the Echo indexes (P＜0.01). LVEDD (45.38±7.51 mm) , PASP(21.19±5.62 mmHg) , Qp/Qs (1.79±0.26 ) in LV -CHD group were all higher thanthose in control group (P＜0.01) . RVEDD (25.07±5.54 mm) , PASP (19.31±3.75mmHg), Qp/Qs (1.75±0.26) in RV-CHD group were also higher than those in controlgroup (P＜0.01).3. The differences of LVEF, LVFS, mitral flow E/A and tricuspid flow E/Aamong LV-CHD group, RV-CHD group and the control group were not significant(P＞0.05) , however, the LV Tel index and RV Tel index in LV- group (0.36±0.13and 0.35±0.11), RV-CHD group (0.35±0.10 and 0.37±0.08) were both higher thanthose in control group (0.29±0.05 and 0.28±0.05)(P＜0.05). There were no significantdifferences between two CHD groups (P＞0.05).4. In LV-CHD group, the plasma BNP levels were significantly correlated withLVEDD (r=0.50, P＜0.01) , Qp/Qs (r=0.86, P＜0.01) , LV Tel index (r=0.78,P＜0.01) and RV Tel index (r=0.65, P＜0.01) . In RV-CHD group, the plasma BNPlevel were significantly correlated with RVEDD (r=0.64, P＜0.01), Qp/Qs (r=0.73,P＜0.01) , LV Tel index (r=0.66, P＜0.01) and RV Tel index (r=0.74, P＜0.01).There were no significant correlations between the plasma BNP levels and the LVEF,LVFS, mitral flow E/A, tricuspid flow E/A and PASP (P＞0.05).5. The plasma BNP levels after cardiac operation were lower than those beforeoperation in 22 patients with left to right shunt CHD. LVEDD, PASP, Qp/Qs, LV Telindex, RV Tel index in LV-CHD group and RVEDD, PASP, Qp/Qs, LV Tel index, RVTel index in RV-CHD group were both decreased after operation (P＜0.01).Conclusions:1. The plasma BNP levels increased in patients with left to right shunt CHD inthe early stage of the disease, and the left and/or right ventricular enlargement andelevated pulmonary pressure were also observed in these children. It indicated that thehypervolemia and ventricles volume overload might stimulate the synthesis and secretion of BNE2. The LV Tei index and RV Tei index of the CHD patients with gradeⅠ～Ⅱcardiac function significantly increased compared with no changes of EF and FS,which might indicate that the change of Tei index had reflected cardiac dysfunction inchildren with left to fight shunt CHD in early stage.3. There were significant correlations between plasma BNP levels and the Teiindexes in children with CHD, which indicated that the plasma BNP level might be anew sensitive index in evaluation of cardiac function in this kind of children.4. The cardiac operations stopped the abnormal shunting and eliminated thehypervolemia to the heart and the BNP levels as well as Tei index decreased inchildren with left to right shunt CHD. It indicated that the plasma BNP concentrationsand Tel index could be used to evaluate the surgery effects in this kind of children.