The Study On The Effect Of L-Arginine In Pulmonary Hypertension Therapy

Objective : Pulmonary hypertension is a syndrome of the augment of pulmonary vascular resistance caused by various factors.It is divided into two kinds by the genesis: primary pulmonary hypertension and secondary pulmonary hypertension. Secondary pulmonary hypertension met in cardiac surgery is often caused by the augment of pulmonary blood flow or the increase of pulmonary venous pressure. Besides operation can treat pulmonary hypertension through treating primary disease,drug therapy is very important in treating pulmonary hypertension in perioperation.Traditional vasodilators are not satisfied in the effect and side-effect, though they have different effects. So people are trying hard to seek a drug which can selectively dilate pulmonary vessel and have slighter side-effect. It has approved that inhaling nitric oxide (NO) can reverse acute hypoxic pulmonary vascular constriction and apparently decrease pulmonary arterial pressure caused by chronic obstructive pulmonary disease, congenital heart disease and adult respiratory distress syndrome, and inhaling NO don't have any side-effect in low concentration and short time.Therefore,NO may be a potential selective pulmonary vasodilator.But NO is a kind of hardly dissolvable gas, it's half-time in tissue is only about 10 seconds. Some patients' pulmonary arterial pressure bounces after stopping inhaling NO. So using L-arginine,the precursor of NO in body to treat pulmonay hypertension becomes a hot task to many doctors.It has been widely proved that L-arginine has a significant effect to treat pulmonary hypertension in animal experiment,but there is few researches about it used in clinic.So this study is to explore the curative effect of L-arginine on left to right shunt induced pulmonary hypertension in ventricular septal defect patients in clinic.Method : Randomly select 50 cases from the patients hospitalized in ourinfirmary from feb to nov in 2004,all of them having been diagnosed of ventricular septal defect and pulmonary hypertension through ultrasonic cardiogram.These patients had been divided into 25 couples whose pathological typing and the state of illness are matched.Every couple had been seperated into two groups being administered L-arginine and prostaglandin El respectively.Before the treatment,all of them had been examed their pulmonary arterial pressure,ejection fraction and cardiac index through echocardiogram and PaO2, PaCO2, SaO2 and PH through their arterial blood gas analysis.Evaluate the changes of hemodynamics and blood gas analysis of the patients separately after accepting L-arginine and prostaglandin E1(PGE1), and compare the therapeutic effects of these two groups.Results : In the 25 couples,there are 32 male cases and 18 female cases,aged 12.3 dr 3.8, body weight 30 dr 12.8kg .All of them had been diagnosed of ventricular septal defect and pulmonary hypertension through ultrasonic cardiogram.The diameter of defect is 11 dr 3mm and 5 patients in them had patent ductus arteriosus at the same time .Healthy people's pulmonary arterial pressure is 29.58 ±6.76mmHg .Before using drug,the pulmonary arterial pressure of L-arginine group is 55.46± 12.01mmHg and the pulmonary arterial pressure of PGE1 group is 56.41 ± 15.74mmHg.The pressures of two groups are higher than healthy people's and has significant difference,but there is no significant difference between each other of two drug used groups.Meanwhile there are no significant difference in the level of cardiac index, ejection fraction and mean arterial pressure among healthy people group , L-arginine used group and PGEj used group.After using L-Arg and PGEi, the pulmonary artery pressure of these patients in two groups decreaed significantly,and the therapic effect to pulmonary hypertension has no significant difference between them.The cardiac index and ejection fraction raise higher than before,but have no significant difference while the mean arterial blood pressure shows few changes.Comparing the blood gas analysis,we can find that after using L-arginine ,PaO2 and SaO2 raise markedly and have significant difference while the PH and PaCO2show few changes .These effects have no difference with those of PGEi .Conclusion : According to the result of our clinical study,we can draw the following conclusions:L-arginine can decrease pulmonary hypertension induced by left to right shunt in ventricular septal defect patients while show few influence on systemic circulation pressure.There are no phenomenon of instable hemodynamics about low cardiac output ,low blood pressure and so on.L-arginine can raise oxygen content of arterial blood through dilate pulmonary arteria and ameliorate cardiac function while has no influence on balance of acid and base in body fluid.So it is an ideal means in the clinical therapy of left to right shunt induced pulmonary hypertension for it's utility,high selective of pulmonary circulation,less side-effect and low price.