The Effect Of Iloprost On Hemodynamics And BNP Secretion In Patients With Pulmonary Artery Hypertension

Background:Pulmonary arterial hypertension (PAH) was a progressive disease characterized by progressive pulmonary vascular resistance increased, eventually leading to right heart failure and death. Right heart failure is a common pathway of death and disability in patients with all types of PAH, and PAH is also the main reason for right heart failure. Brain natriuretic peptide (BNP) is mainly secreted from the cardiac ventricular in response to ventricular volume expandion and pressure overload quickly. Studies showed that BNP would be an index for diagnose heart dysfunction with higher sensitivity and specificity than other natriuretic peptides. As an analogue of prostacyclin, nebulized iloprost have the favorable effect of selective vasodilation and may be a prospective agent to control the PAH.Objective:The study is to explore the BNP secretion in different position (femoral vein, right atrium, right ventricle, left ventricle, femoral artery) of PAH patients, and the effect of hemodynamic parameters and the BNP plasma levels on acute pulmonary vasodilator test after iloprost inhalation.Method:Randomly selected 13 cases from the patients hospitalized in our hospital from 2008 to 2010, all of them were diagnosed of pulmonary hypertension through Color Doppler. In these patients, there were 10 females and 3 males, mean age 43.8. After being admitted to hospital, we collected the baseline data (blood, blood biochemistry, electrocardiogram, chest X-ray, Transthoracic echocardiography); 6 minutes walk distance (6MWD) and Borg dyspnea rating (Borg scale); Determination of pulmonary artery systolic pressure (PASP), mean pulmonary artery pressure (mPAP), diastolic pulmonary artery pressure, right atrium pressure, right ventricular pressure and right ventricular end-diastolic pressure with right catheterization; Subsection blood oxygen saturation were measured (superior vena cava, inferior vena cava, pulmonary artery, right atrium, right ventricle) for calculation the pulmonary vascular resistance, cardiac output, cardiac index, total pulmonary resistance. With left catheterization, left ventricular end-diastolic pressure was detemined. Blood sample were measured for plasma BNP levels in different position (femoral vein, right atrium, right ventricle, left ventricle, femoral artery). All patients inhaled iloprost via nebulized aerosol at a dose of 20μg for 15min continuously, then the hemodynamic parameters and the plasma BNP levels were determined again. Measurement of BNP plasma levels:All samples were collected by puncture into ethylene diamine tetra acetic acid (EDTA) tubes. The blood samples were kept at room temperature and analyzed within 4h,250μl of the whole blood was added to the Triage BNP. Then the device was placed into the Triage Meter, which measures the fluorescence intensity of the BNP assay zone. The assay was completed in approximately 15min.Results:13 patients have complete data acquisition.1. Both of the right atrium and ventricular were enlarged with Transthoracic echocardiography in PAH patients, PASP, BNP, Uric acid (UA), PAH heart functions class, Borg scale were increased. There were negative correlation between the 6MWD and mean right atrium pressure (r=-0.594, P<0.05), right ventricular end-diastolic diameter (r=-0.692, P<0.05), and PAH heart functions class (r=-0.843, P<0.01). Multiple regression analysis showed that right ventricular end-diastolic diameter, PAH heart functions class were independent determinants of 6MWD.2. After iloprost inhalation, the right atrium mean pressure, right ventricle mean pressure, PASP, mPAP, total pulmonary resistance were all significantly declined. Cardiac index, mixed venous oxygen saturation were both increased.3. The plasma BNP levels was in the patient with PAH before inhaling drug, the secretion level for plasma BNP were left ventricle> femoral artery> right atrium> right ventricle> femoral vein, but there were no statistical significance. Plasma BNP levels were significantly related with mean right atrium pressure, mean right ventricle pressure, right ventricle diastolic pressure, 6MWD, Borg scale, PAH heart functions class. Multiple regression analysis showed that there were positive correlation between the plasma BNP levels and RA systolic pressure or and RV mean pressure or and PAH heart functions class respectively.4. After iloprost inhalation, BNP secretion declined significantly in right atrium (P<0.05), femoral vein (P<0.05), left ventricle (P<0.05). Right ventricle and femoral artery had been a downward trend, but had no statistical significance. The BNP secretion of right atrium was more than right ventricle before inhalation, but after inhalation the latter more than the former. Conclusions:1.6MWD, Borg scale, plasma BNP levels, PAH heart functions class, UA and join TTE were effective index to evaluate PAH patients'condition.2. Iloprost inhalation had important influence to PAH patients hemodynamic. After iloprost inhalation, right atrium pressure, right ventricular pressure, PASP, mPAP, total pulmonary resistance were decreased and cardiac index, mixed venous oxygen saturation were increased.3. BNP secreted was increased in PAH patients, and each part of the highest was left ventricular. This situation show that left ventricular also had certain degree of damage in PAH patients.4. Iloprost had influenced to plasma BNP levels. After iloprost inhalation, each part of plasma BNP levels had decreased and left ventricular, right atrium, femoral veins dropped significantly.