| BackgroundCardiovascular disease is the leading cause of death in modern society, some of which can cause pulmonary hypertension.The serious obvious early symptom in pulmonary hypertension such as shortness of breath and other non-specific symptoms occurred when it developed to a certain extent.The monitoring of pulmonary artery presure through the righ heart catheterization was recognized as the best method for diagnosis of pulmonary hypertension. But it is invasive, leading to some potential risks, and can only provide hemodynamic information. Looking for a simple, noninvasive indicator for the diagnosis, prognosis and follow-up is the focus of research on pulmonary hypertension.Ultrasound testing methods is used commonly in clinical. Doctors are interested in uric acid and NT-proBNP as blood indices in recent years.Nucleic acid and other purine compounds are decomposed into serum uric acid in cells and food. It was indicated that the higher concentrations of uric acid, the faster proliferation of blood vessels smooth muscle cell, because uric acid increases intracellular calcium concentration by a dose dependent manner;with the increase of volume overload or pressure overload, the myocardium muscle synthesizes and releases BNP / NT-pro BNP proportionally, and NT-proBNP plasma concentration is significantly increased. So it was speculated that serum uric acid and NT-proBNP and the pulmonary artery pressure are significantly associated, which is much helpful for diagnosis, and prognosis of pulmonary hypertension.ObjectiveIn this study, pulmonary artery pressure monitored by right heart catheterization was worked as the standard, and was divided into four groups . Compared with ultrasound, uric acid and NT-proBNP levels in each group was measured in order to explore their relationship with the pulmonary artery pressure, to evaluate their clinical value, providing the theoretical basis in pulmonary arterial hypertension for clinical treatment, evaluation and follow- up .MethodsAll the procedures were approved by the Ethical Committee, Henan University and all the patients agreed with the procedure. Selected subject came from Henan province People's Hospital through the right-heart–cathete test from March 2010.to October 2010, meeting the selected conditions,no fitting to any exclusion criteria. There is a total of 40 patients, including 19 males and 21 females, age 23.18±16.108 years, 11 cases of atrial septal defect, 16 cases of ventricular septal defect, 9 cases of patent ductus arteriosus, 2 cases of ventricular septal defect and atrial septal defect, 2 cases of pulmonary stenosis. The data of uric acid level came from the automatic biochemical analyzer Olympus Au5400. The concentration of NT-proBNP was detected by the Roche cobas h 232.Transthoracic echocardiography was specially operated by experienced docters prior to the right-heart-cathete test . Left ventricular ejection fraction, right atrial diameter, right ventricular diameter ware measured. Systolic pulmonary artery pressure measured with transthoracic echocardiography was calculated by the formula: pulmonary artery systolic pressure (PASP) = right atrial pressure + tricuspid transvalvular pressure gradient. Right atrial pressure was estimated at 5 mm Hg (1 mmHg = 0.133 kPa), and if significant tricuspid regurgitation and inferior vena cava dilation existed, it was estimated at 10 mm Hg. When right heart failure occurred,it was estimated at 15 mm Hg. Tricuspid transvalvular pressure gradient is equal to 4V2 (V is the maximum velocity of tricuspid regurgitation).Right heart catheterization using MPA1 or MPA2 right heart catheter goes through this way: righ femoral vein→external iliac vein→common iliac vein→inferior vena cava→right atrium→right ventricle→main pulmonary artery. The pulmonary artery systolic pressure, pulmonary artery diastolic pressure and pulmonary artery mean pressure were recorded by pressure transducer. The patients were divided into 4 groups according to the date of right heart catheterization: normal group, pulmonary arterial pressure (PASP) <30mmHg, slightly increased group(PASP 30-40mmHg), moderately increased group(PASP 41-70mmHg), and severely increased group(PASP> 70mmHg) .Results1.No statistically significant difference was detected among groups for the clinical data, such as age, right ventricular outflow tract diameter, left ventricular end systolic diameter, left ventricular ejection fraction, left ventricular end diastolic diameter (P>0.05), which indicated the good comparability of each group.2.Of uric acid concentration, there was no significant difference between the slightly increased group or the moderately increased group, and the normal group (P> 0.05). But significant difference was found between the severely increased group and the normal group (P <0.05). It showed that the significant correlation existed between pulmonary artery systolic pressure and serum uric acid (r = 0.556, P <0.01). 3.Of NT-proBNP compared , there was gradually increased trend in the normal group, the slightly increased group, moderately increased group and severely increased group, a significant difference existed between groups (P <0.05). NT-proBNP concentration was significantly correlated with mean pulmonary artery pressure (r =0.591, P <0.01).4.Serum uric acid concentration was not significantly correlated with NT-proBNP concentration, no statistically difference(r = 0.247, P = 0.125).5.All subjects were examined by transthoracic echocardiography. Because tricuspid regurgitation was not detected, no pulmonary artery systolic pressure was recorded in 14 patients, including 2 cases in the normal group, 8 cases in slightly increased group, 4 cases in moderately increased group,and 0 patient in severely increased group, with a detection rate of 65%(26/40). The mean values of pulmonary artery systolic pressure was almost equal for echocardiography and right heart catheterization in 26 cases. The two group data was significantly correlated (r =0.697, P <0.01). Two sets of data were compared with paired t test( t = 0.005, P = 0.996), No significant difference,and no statistically significance were tested.Conclusion1. In general, there is a certain positive correlation between serum uric acid and pulmonary artery pressure, but the correlation is not very strong. Serum uric acid concentration did not significantly increased especially when pulmonary arterial pressure slightly increased. Serum uric acid concentration also increased when pulmonary arterial pressure increased, especially in pulmonary arterial pressure severely increased group, The data of uric acid and pulmonary artery pressure do not have a simple linear relationship, suggesting that the higher the concentration of uric acid, the greater the value of diagnosis and prognosis in pulmonary hypertension.2.NT-proBNP has a positive moderate correlation with the pulmonary artery pressure, but it is not a single linear relationship. The higher the concentration of NT-proBNP , the higher the pulmonary artery pressure. But NT-proBNP did not change significantly when pulmonary artery pressure slightly increased. So NT-proBNP is not highly sensitive to pulmonary artery pressure.3.NT-proBNP was not correlated with serum uric acid, suggesting the existence of different mechanisms of pulmonary artery hypertension. A combination of both indice may be a better indicator pulmonary arterial pressure.4.On the whole, pulmonary artery pressure estimated with transthoracic echocardiography based on the bunulli,s principle formula to measure tricuspid valve largest regurgitation velocity was well correlated and with that from right heart catheterization.there was no significant difference between values, which indicated that transthoracic echocardiography can be used as a means of screening and follow-up for pulmonary arterial pressure. But the detection rate is not very high. For individual, there are some differences between the data from transthoracic echocardiography and that from the right heart catheterization. |
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