Evaluation of neointimal coverage in patients with coronary artery aneurysm formation after drug-eluting stent implantation by optical coherence tomography

Background The vessel healing in patients with coronary artery aneurysms (CAA) that form after drug-eluting stent (DES) implantation is not clear.This study aims to assess the vessel healing in patients with CAA formation after DES implanation.Methods From June 2008 to August 2011,follow-up coronary angiography was conducted on 1160 patients who underwent percutaneous coronary intervention (PCI).The average period of follow-up was about (18.95+13.05) months.A total of 175 patients who underwent DES implantation into de novo lesions and who underwent coronary angiography and optical coherence tomography (OCT) examination during follow-up were identified.Patients were divided into the CAA group (n=31) and non-CAA group (n=144) based on the results of the coronary angiography.The cardiac events including angina and acute myocardial infarction were noted; in addition,the neointimal thickness and the frequency of strut malapposition and strut uncoverage were also noted.Results A greater proportion of incomplete neointimal coverage (17.17％ vs.1.90％,P ＜0.001) and strut malapposition (18.20％ vs.1.38％,P ＜0.001) were observed in the CAA group.The neointimal thickness in the CAA group was significantly thinner than that in the non-CAA group ((146.6+94.8) μm vs.(192.5+97.1) μm,P ＜0.001),as detected via OCT.Patients with CAA formation had a higher frequency of cardiac events including angina pectoris (25.81％ vs.6.25％,P=0.001) and acute myocardial infarction (9.68％ vs.0.13％,P=0.002) and thrombosis (16.13％ vs.0.69％,P ＜0.001).The longitudinal length of the CAA in the cardiac event group was significantly longer than in the no cardiac event group ((20.0+9.07) mm vs.(12.05+5.38) mm,P=-0.005).Conclusion CAA formation after DES implantation is frequently associated with cardiac events as a result of stent malapposition and incomplete neointimal coverage.