The Predictive Value Of Coronary CTA For Vulnerable Plaques Diagnosed By OCT

Background The rupture of unstable plaques and thrombosis are primary causes of acute coronary syndrome.In addition,vulnerable plaques on non-culprit vessels are predictors of future cardiovascular events.Therefore,how to identify vulnerable plaques accurately and non-invasively has always been a research hotspot and difficulty in the cardiovascular field.Optical coherence tomography(OCT)has a very high resolution(10μm)and has high consistency with pathological slices,so it is called"optical biopsy".It has high sensitivity and specificity in the identification of vulnerable coronary plaques,but as an invasive examination,its wide application is limited to a certain extent.Coronary CT angiography(coronary computed tomography angiography,CCTA)is a non-invasive cardiovascular examination method,which is more suitable for clinical extensive use and promotion.Objective Using OCT as the gold standard,to find the plaque characteristics evaluated by CCTA that can predict the occurrence of vulnerable plaques diagnosed by OCT.Methods A total of 76 patients who underwent CCTA examination diagnosed as coronary heart disease from February 2017 to November 2020 in the First Affiliated Hospital of Dalian Medical University were retrospectively selected and all the patients underwent OCT examination within 15 days after CCTA.15 patients with missing coronary angiography images were excluded.3 patients with poor OCT or CCTA images were excluded.And 25 patients were finally selected according to strict inclusion and exclusion criteria.Then we selected the culprit lesion part of 25 criminal vessels in 25 patients,and used the branches of the vessels as a reference to match accurately the CCTA with OCT lesions.We divided all lesions into 415 pairs of segments at every 1mm interval(the CCTA and OCT images each have 415 segments,matching each other into 415 pairs of segments)and divided all the segments into thin-cap fibroatheroma(TCFA)group and non-thin-cap fibroatheroma(non-TCFA)group using OCT as the gold standard.The relevant indicators evaluated by CCTA of the two groups were measured respectively.The main measurement indicators of plaque characteristics evaluated by CCTA included plaque type(non-calcified plaque,calcified plaque,and mixed plaque),low attenuation plaque(LAP),napkin ring sign(NSR),spotty calcification,positive remodelling(PR),lumen diameter,lumen area,plaque area,plaque load and CT value of non-calcified plaque,etc.Results(1)Using OCT examination as the standard,415 segments were divided into 41segments in the TCFA group and 374 segments in the non-TCFA group.(2)In univariate analysis,the non-calcified plaques,calcified plaques,and mixed plaques displayed by CCTA accounted for 85.75%,14.63%,and 0.00%in the TCFA group,89.57%,1.60%,and 8.82%in the non-TCFA group,P<0.001;LAP accounted for48.78%in the TCFA group,and 17.11%in the non-TCFA group,P<0.001;NSR accounted for 29.27%in the TCFA group,10.96%in the non-TCFA group,P=0.001;PR accounted for 43.90%in the TCFA group,22.99%in the non-TCFA group,P=0.003;The mean and standard deviation of the lumen diameter were 2.18±0.59mm in the TCFA group,1.92±0.64mm in the non-TCFA group,P=0.02;The mean and standard deviation of the lumen area were 1.36±1.64mm~2in the TCFA group,3.85±1.99mm~2in the non-TCFA group,P=0.009;The mean and standard deviation of the CT value of non-calcified plaque were 50.78±11.56Hu in the TCFA group,65.96±21.77 Hu in the non-TCFA group,P<0.001;While there were no statistically significant differences in spotty calcification,plaque area,P>0.05.(3)Multivariate analysis used binary logistic regression analysis.LAP and the CT values of non-calcified plaques showed statistical significance.The OR value of LAP was 2.56,and the 95%confidence interval was1.11-5.89,P=0.027;The OR value of the CT values of non-calcified plaque was 0.96,the 95%confidence interval was 0.94-0.98,P<0.001;While the type of plaque,napkin ring sign,positive remodeling,lumen diameter and lumen area were not statistically significant(P>0.05).The probability of occurrence of TCFA in plaques with LAP is2.56 times than that in plaques without LAP.The smaller the CT value of non-calcified plaques are,the more easily the plaques appear TCFA.Conclusion LAP and the CT values of non-calcified plaques evaluated by CCTA are independent predictors of TCFA diagnosed by OCT.