The Significance Of Serous And Right Atrial Myocardial BNP And SST₂ Protein Levels In The Patients With Tricuspid Regurgitation Secondary To Rheumatic Heart Disease

ObjectiveTo measure the serum and right atrial level of brain natriuretic peptide（BNP） and solube ST₂（s ST₂） in the patients with different degree tricuspid regurgitation secondary to rheumatic heart disease and estimate the correlation among them. To analyse the early outcomes of echocardiography of these patients after one month of the surgery, estimate the early postoperativesurgical effect of different degree of tricuspid regurgitation.Methods80 patients with rheumatic heart disease were enrolled in this study, who underwent mitral valve replacement with or without tricuspid surgery. Exclusion criteria: patients with dilated cardiomyopathy（DCM）, cornary heart disease, chronic obstructive pulmonary disease（COPD）, acute infective disease, autoimmune disease and malignancy. All of the patients completed the echocardiography, electrocardiogram and routine biochemical examination before surgery. They were divided into four groups based on the regurgitation area of tricuspid valve measured by echocardiography. Each group contained 20 patients(Regurgitation area: trival regurgitation（area<2.0 cm2, group A）, Mild regurgitation（2.0 cm2 to 5.0 cm2, group B）, moderate regurgitation（5.0 cm2 to 10 cm2, group C）, severe regurgitation（area≥ 10 cm2, group D）. The venous blood of patients were sampled with 4ml in EDTA anticoagulant tube before the operation, then the serum was collected by centrifuged for 10 minutes in 4℃, sucked up into EP tubes, kept in-80 refrigerator. ℃ All patients in general anesthesia surgery under extracorporeal circulation cardiac arrest with cold blood and cardioplegin,and get the specimen from right atrial appendage before extracorporeal circulation. The BNP and s ST₂ protein levels was measured by ELISA.Results1. Baseline characteristics: The age, gender, left ventricular ejection fraction（LVEF） and left ventricular diastolic diameter（LVDd） of the groups had no statistical difference（P > 0.05）. AF patients of group A was significantly less than other three groups（χ2=19.31,P <0.05）. The right atrium diameter of group A（39.33±2.65mm） was smaller than group B（41.47±4.30mm） and group C（41.47±4.30mm）（ P <0.05）. The right atrium diameter of group D（50.99±6.60mm） was the largest one of the four groups（P <0.05）. Compared with group A, the left atrium diameter of group C and group D was significantly increased（P <0.05）. The right ventricular diameter of group D（45.04±6.32mm） was clearly dilated than other groups（P<0.05）. There was no significant difference among group A（35.57±3.32mm）, group B（36.82±2.45mm）, and group C（37.72±4.05mm）（P >0.05）. The level of s Cr, AST and ALT had no difference among the four groups（P >0.05）. Compared with group A（11.88±3.63umol/L）, the level of TBIL of group B, group C and group D were much higher（P <0.05）,but there were no difference among group B（19.55±6.97umol/L）、group C（18.95±10.27umol/L） and group D（28.15±17.26umol/L）, so did the level of DBIL。2. The general situation of operation: the number of patient who was undergone the tricuspid ring implantantion of group D and group C were much more than group A（χ2=44.76,P<0.05）. The cardiopulmonary bypass time of group A（72.15±25.15min） was clearly shorter than other there groups（P <0.05）, and the time of group B was shorter than group D[（89.40±21.99min） vs（107.25±21.55min）, P <0.05]. The cross-clamping time of group A and group B were less than group C and group D[（42.51±18.88min）,（54.90±15.00min） vs（67.95±26.44min）,（70.70±18.75min）, P <0.05].3. The results of ELASA: compared with group A（142.71±83.71 pg/m L）, the serum BNP level of group C（422.52±376.62 pg/m L） and group D（436.90±290.40 pg/m L） increased significantly（P <0.05）, but there are no statistical difference between group C and group D（P >0.05）. Group B（210.62±181.83 pg/m L） had no significantly difference with group A. Compared with group A（35.25±23.33 pg/m L）, the serum s ST₂ level of group C（74.90±57.51 pg/m L） was much higher（P <0.05）. The correlation analysis showed that BNP level in preoperative serum had positive correlation with tricuspid regurgitation（r=0.54,P <0.05）, left atrium diameter（r=0.28,P <0.05）, right atrium diameter（r=0.40,P <0.05）and right ventricular diameter（r=0.32,P <0.05）. Meanwhile the serum level of s ST₂ and tricuspid regurgitation（r=0.35,P <0.05）, left atrium diameter（r=0.23,P <0.05）, right atrium diameter（r=0.32,P <0.05） were positively correlated（P <0.05）. Interestingly, the right atrial myocardium level of BNP and s ST₂ protein were not increased with the growing regurgitation area, and the BNP level of group A was the highest one of the four groups（p <0.05）.4. Comparison of preoperative and postoperative echocardiography: In group A, the left atrium diameter and right ventricular diameter were diminished than the number of preoperative（P <0.05）, and the EF% also higher than before（P <0.05）. The left atrium diameter, right ventricular diameter and area of tricuspid regurgitation of group C and group D were smaller than preoperative number（P <0.05）. In group C and group D, the left atrium diameter, right atrium diameter, right ventricular diameter and area of tricuspid regurgitation were significantly smaller than the number of preoperative（P <0.05）, but the left ventricular diameter and EF% were no significant difference（P >0.05）.Conclusions1. The serum BNP and s ST₂ levels before operation can evaluate to some extent of the degree of secondary tricuspid regurgitation, and may have clinical value of evaluating the right heart function..2. The serum BNP and s ST₂ levels rised with tricuspid regurgitation area increasing, but interestingly, the increased of right atrium BNP and s ST₂ levels was not obvious, and its souce is worth further reseach and discussion.3. The left valve surgery over the same period line of tricuspid valve surgery can significantly improve the right heart form and function, should be positive.