OBJECTIVE:To investigate the effect of preoperative use of high-dose simvastatin on the pulmonary artery pres-sure in congenital heart disease with left-to-right shunt. METHODS:86 patients with left-to-right shunt congenital heart disease who were planned to implement interventional occlusion therapy were randomly divided into control group(43 cases)and observa-tion group(43 cases). Patients in both groups were given digitalis,diuretics,anticoagulants and other basic treatments;On this basis, control group received Sildenafil citrate tablet,25 mg,3 times a day,orally given 1 h before a meal;observation group received Simvastatin tablet 80 mg,once every evening,orally. The treatment course for both groups was 7 d. Mean pulmonary hypertension (mPAP),N terminal prohormone brain natriuretic peptide (NT-proBNP),arterial oxygen saturation (SaO2),arterial oxygen ten-sion(PaO2),pulmonary blood circulation ratio(Qq/Qs),pulmonary pressure variation(Rp/Rs),pulmonary vascular resistance in-dex(PVRi)before and after treatment in 2 groups were observed,and related indicators of liver functions [alanine aminotransfer-ase (ALT),aspartate aminotransferase(AST)] and myocardial enzymes [lactate dehydrogenase (LDH),creatine kinase MB(CK-MB)] were detected. The incidence of adverse reactions were deteted. RESULTS:Before treatment,there were no significant differ-ences in mPAP,NT-proBNP,SaO2,PaO2,Qq/Qs,Rp/Rs,PVRi,ALT,AST,LDH and CKMB levels in 2 groups(P>0.05). Af-ter treatment,mPAP,NT-proBNP,Rp/Rs and PVRi levels were significantly lower than before,SaO2,PaO2,and Qq/Qs levels were significantly higher than before and Qq/Qs level in observation group was higher than these in control group.The difference was statistically significant(P<0.05). There was 1 patient showed severe liver injury in observation group and exited the test;the other 85 patients showed no obvious adverse reactions,with successful surgery and good prognosis. CONCLUSIONS:The preoper-ative use of high-dose simvastatin shows obvious effect on controlling mean pulmonary hypertension,reducing mPAP,NT-proB-NP,Rp/Rs and PVRi levels and increasing SaO2,PaO2,and Qq/Qs levels before operation,with good safety.