Objectives:To analyze the impact of target lesion calcification evaluated by coronary angiography on immediate procedure success rate and long-term clinical outcome in patients underwent percutaneous coronary intervention(PCI). Methods:Consecutive patients received angiographic calcification evaluation and underwent PCI in Fuwai Hospital,Chinese Academy of Medical Sciences from January 2017 to December 2018 were prospectively enrolled in this study.Patients are divided into 4 groups,including non-calcification group(n=14 387),mild calcification group(n=8 231),moderate calcification group(n=3 208)and severe calcification group(n=886).The primary endpoint was immediate post-PCI procedure success rate,which was defined as residual stenosis<50%without major operational complications(including coronary artery perforation,coronary artery dissection,intraoperative stent thrombosis)and failure to cross the lesion.The long-term clinical endpoint was the 3-year major adverse cardiovascular events(MACE),which included composite endpoint events such as all cause death,myocardial infarction(MI),and revascularization. Results:The severe calcification group had a lower success rate of interventional therapy(80.59%vs.94.23%vs.94.29%vs.91.49%),a higher incidence of residual stenosis≥50%(17.72%vs.5.03%vs.4.84%vs.7.29%),a higher incidence of coronary artery dissection(1.81%vs.0.66%vs.0.78%vs.1.25%),and a higher incidence of coronary artery perforation(2.14%vs.0.51%vs.0.38%vs.0.69%),and a higher incidence of failure to cross the lesion(0.23%vs.0.12%vs.0.04%vs.0.16%)compared to the non-calcification group,mild calcification group,and moderate calcification group(all P<0.05).Multivariate Cox regression analysis showed that patients with severe calcification had a higher risk of MACE(12.98%vs.9.35%,HR=1.21,95%CI:1.00-1.47,P=0.046),all-cause mortality(4.29%vs.1.80%,HR=1.55,95%CI:1.10-2.18,P=0.013),and MI(2.14%vs.0.97%,HR=1.97,95%CI:1.21-3.20,P=0.006)compared to patients without calcification. Conclusions:Patients with angiographic-detected severe calcification after PCI treatment face higher risk of PCI procedure failure,MACE,all-cause death,and MI compared to patients without,with mild,and moderate calcification.