Comparison Of OCT Imaging Characteristics Of The In-stent Restenosis In Different Angiographic Classifications And Different Periods

ObjectiveThe presence of drug-eluting stents(DES)has greatly reduced the incidence of in-stent restenosis(ISR),but the ISR problem has not been conquered.With the prevalence of coronary heart disease and the increasing number of patients undergoing PCI,DES-ISR has once again attracted the cardiac interventionalists' attention.The DES-ISR has different clinical manifestations and characteristics compared with the bare-metal stent(BMS),indicating that the mechanism of ISR may be different.Optical coherence tomography(OCT),with high spatial resolution,provides an effective tool for humans to further understand ISR.In the DES era,whether different angiographic classifications and different periods of ISR have different characteristics are important to our interventions.The aim of this study was to use OCT to analyze the intraluminal imaging features of DES-ISR in different angiographic classifications and in different periods,to guide us to individualized treatment and improve long-term outcomes for the patients.MethodsA total of 50 patients with angiographic diagnosis of ISR after DES implantation were enrolled.OCT scans were performed on ISR lesions prior to intervention.The characteristics of Quantitative Coronary Angiography(QCA)and OCT images in different angiographic classifications and different periods were compared,and the complete stent,the minimum lumen area and the minimum stent area were qualitatively and quantitatively analyzed.QCA analysis:lesion vascular distribution,lesion length,reference vessel diameter,minimum lumen diameter,diameter stenosis rate.OCT quantitative analysis:lumen area,lumen average diameter,lumen minimum diameter,stent area,stent average diameter,stent minimum diameter,neointimal area,neointimal load.Qualitative analysis:homogeneous endometrium,heterogeneous endometrium,lipid-rich neointima,thin-cap fibroatheroma,rupture of endometrium,microvessels(peri-stent,intima),white thrombus,red thrombus,calcification,etc.Results1.ISR in different angiographic classificationsEntire stent analysis:The diffuse ISR group has a smaller lumen average diameter(1.76 mm vs 1.85 mn,P=0.016)and minimum diameter(1.56 mm vs 1.67 mm,P=0.002),while the lumen area has a smaller tendency(2.66 mm2 vs 2.87 mm2,P=0.054).The burden of neointima of the diffuse ISR group is more severe than the focal ISR group(62.25%vs 58.68%,P=0.002).There is no difference in intima type between the diffuse ISR and the focal ISR.The microvascular and calcification are more common in the diffuse ISR group.Minimal lumen area section analysis:Microvascular and calcification are not seen in the focal ISR group.Minimal stent area section analysis:Calcification is not seen in the focal ISR group.2.ISR in different periodsEntire stent analysis:The E-ISR group has a bigger stent area(7.43mm2 vs 6.87mm2,P=0.001),a longer stent average diameter(3.02mm vs 2.89mm,P=0.000),a longer stent minimum diameter(2.91mm vs 2.76mm,P=0.000),a bigger neointimal area(4.67mm2 vs 4.16mm2,p=0.000)and a heavier neointimal load(63.61%vs 60.05%,p=0.002).The E-ISR group has more homogeneous intima(58.8%vs 23.0%),while the L-ISR group has more heterogeneous intima(41.2%vs 77%).The lipid-rich neointima,disrupted intima with visible cavity,white thrombus and red thrombus are often seen in the L-ISR group.Minimal lumen area section analysis:The E-ISR group has more homogeneous intima(60.0%vs 28.6%),while the L-ISR group has more heterogeneous intima(40.0%vs 71.4%).Microvascular,lipid-rich neointima,white thrombus and calcification are not seen in the E-ISR group.Minimal stent area section analysis:Microvascular,lipid-rich neointima,thin-cap fibroatheroma,white thrombus and calcification are not seen in the E-ISR group.Microvascular,lipid-rich neointima,red thrombus are not seen in the L-ISR group.ConclusionsThe characteristics of ISR in different angiographic classifications are different.Compared with the focal ISR,the diffuse ISR has a small lumen diameter and a heavyneointimal load.The signs of microvascular and calcification are more common in diffuse ISR group.The characteristics of ISR in different periods are also different.The E-ISR group has a bigger stent area and a heavier neointimal load.The E-ISR group has more homogeneous intima,while the L-ISR group has more heterogeneous intima.Neoatherosclerotic changes such as lipid-rich neointima,thin-cap fibroatheroma,disrupted intima with visible cavity and white thrombus was often seen in the L-ISR groupseen in L-ISR.