Objective To investigate the relationship between pregnancy-associated plasma protein A(PAPP-A)level and restenosis after elective coronary stenting by coronary artery angiography(CAG)and intravascular ultrasound(IVUS). Methods The study consisted of 132patients with successful coronary stent placement:left anterior descending coronary artery(LAD)62,left circumflex coronary artery(LCX)36,right coronary artery(RCA)34.The follow-up CAG and IVUS were Derformed at the 6th month after stent placement.Diameter stenosis≥50%on CAG was regarded as in-stent restenosis.Neointimal areas(IA),stent volume(SV)and neointimal volume(IV)were measured by IUVS during follow-up.According to the PAPP-A level,lesions were divided into 2groups:high PAPP-A group(PAPP-A level≥12.11 mIU/L)and low PAPP-A group(PAPP-A level＜12.11 mIU/L). Results Total restenosis rate was 31.8%.There were no significant differences in age.sex and risk factors of coronary heart disease(hypertension,diabetes,smoking)between restenotic and nonrestenotie groups(all P＞0.05).The restenotic group had higher PAPP-A level than nonrestenotic group[(18.14±2.26)mIU/L vs. (10.95±2.12)mlU/L,P＜0.01].Angiographic restenosis occurred in 28 of 66 lesions(42.4%)in the high PAPP-A group and in 14 of 66 lesions(21.2%)in the low PAPP-A group(P＜0.01).Plasma PAPP-A level was positively correlated with IA,IV(r=0.47 and 0.54 respectively,all P＜0.05). Conclusions Elevated PAPP-A level is correlated well with the severity of the intimal hyperplasia.Plasma PAPP-A level affects restenosis after elective stent placement by promoting intimal hyperplasia.