The Relationship Between The SYNTAX Score And Coronary Plaque Characteristics In Acute Coronary Syndrome

Background The SYNTAX score(SS)is a widely used clinical scoring system based on coronary angiography that can quantify the complexity of coronary lesions in patients with coronary artery disease and is mainly used to help clinicians choose the best approach of revascularization(percutaneous coronary intervention or coronary artery bypass grafting).Previous studies have demonstrated that the SYNTAX score can predict adverse cardiac events in patients with coronary artery disease in the short term(1 year-5 years)and provide risk stratification for adverse clinical outcomes in patients with coronary artery disease,and that SS is also valuable in predicting adverse cardiovascular events in acute coronary syndrome(ACS).However,the reason for the increased incidence of adverse cardiac events in ACS patients with high SS is unclear.Optical coherence tomography(OCT)is one of the only intracoronary imaging devices that has so far reached the histological level in humans and can be used for qualitative analysis and measurement of coronary plaques.Objective The aim of this study was to assess the relation between SS and plaque characteristics using optical coherence tomography in coronary artery in ACS.Methods There were 420 patients with ACS who were hospitalized in the Department of Cardiology of the First Hospital of Dalian Medical University and underwent coronary angiography and optical coherence tomography(OCT)from January2016 to June 2022.21 without preoperative OCT images,138 cases with poor imaging quality,22 cases with in-stent restenosis(ISR)were excluded,and then 202 patients(202offender lesions in total)were finally enrolled based on the primary and secondary exclusion criteria.Coronary angiography of the overall coronary vessels was used to calculate SS,and then the enrolled patients were grouped in three quartiles according to SS.In addition,SS was calculated only for offender vessels for offender lesion-SS analysis.Results In the qualitative analysis of whole vessel SS with plaque characteristics,there was a higher incidence of plaque rupture(20.6%:53.3%:72.9%,p<0.001)and Thrombus(20.6%:53.3%:76.3%,p<0.001)in group 3 compared to groups 1 and 2.Compared to group 1,groups 2 and 3 had higher incidence of plaque erosion(1.5%:12.0%:18.6%,p=0.005),white thrombus(8.8%:28.0%:35.6%,p=0.001),lipid plaques(25.0%:50.7%:45.8%,p=0.005),thin fibrous cap atherosclerotic plaques(TCFA,10.4%: 24.0%: 36.2 %,p=0.003),and macrophage(83.8%: 97.3%: 94.9%,p=0.007)incidence.In the quantitative analysis of whole vessel SS with plaque characteristics,lesion length was longer in groups 2 and 3 compared to group 1 [12.6(9.2-16.8): 15.4(12.2-22.3): 16.7(12.9-20.2),p=0.003].In the quantitative analysis of 82 lipid plaques showed that,compared to the group 1,the group 3 had a longer lipid core(3.8[1.5-6.4]mm:8.5[3.8-10.4]mm,p=0.001),smaller minimum fibrous cap thickness(90 [50-100] μ m:50 [40-60] μ m,p=0.007,p=0.030),greater of lipid index(623.4 [278.5-1011.5]: 1375.0[748.9-2049.9],p=0.009).In the single culprit vessel SS with plaque characterization,group 3 had a longer lipid core length compared to group 1(p=0.035).Conclusion High SS may suggest a higher incidence of plaque vulnerability of ACS patients.Our results may explain the higher incidence of events in ACS patients with higher SS from the perspective of plaque characteristics.