| Objective: In this study,coronary-computed tomography angiography derived fractional flow reserve(CT-FFR)and coronary computed tomography angiography(CCTA)were compared to coronary angiography(CAG).To explore the value of this technique in evaluating the severity of coronary artery disease and the performance of predicting the severity of coronary artery stenosis.In addition,subgroup comparisons were made between CT-FFR and invasive fractional flow reserve(FFR)to evaluate the relationship between the two methods in measuring the distal flow fraction of coronary lesions from different methods.Methods: Patients with suspected coronary artery disease who successfully completed CCTA and CAG in the First Hospital of China Medical University from January 2020 to September 2022 were enrolled.The basic clinical data,CCTA,CAG and some FFR results of the patients were collected,and the CCTA image data were uploaded to the CT-FFR working platform to obtain the CT-FFR results.A coronary artery stenosis ≥70% was defined as a positive result of CAG.CAD RADS grade 4 or higher was defined as a positive result of CCTA.CAD-RADS grade N or inconsistent qualitative results was defined as an indeterminate result.A FFR value of 0.8 or less was defined as a positive result of CT-FFR.According to the results of CCTA,the patients were divided into indeterminate result group and definite result group.The consistency degree of CT-FFR and CAG in indeterminate result group and definite result group was analyzed respectively.The receiver operating curve(ROC)and the area under the curve(AUC)were used to evaluate the predictive ability of CT-FFR and CCTA for severe coronary lesions.Spearman correlation coefficient and Bland-Altman analysis were used to describe the relationship between CT-FFR and FFR.Results:(1)259 patients completed CT-FFR analysis,of which 15 patients were detected to have history of coronary artery bypass grafts,1 patient was unable to conduct further study due to vascular malformation,and 2 patients had artifacts due to insufficient brightness of CTA images.A total of 723 vessels in 241 patients received CT-FFR results.(2)Compared with the definite result group,the proportion of women,older age,diabetes history,and mean heart rate at completion of CCTA examination were significantly higher in the indeterminate result group(P < 0.05).(3)There was a good consistency between CT-FFR and CCTA in the definite result group(Kappa=0.675,P < 0.05).CT-FFR data were obtained in all the CCTA in the indeterminate result group,including 77 positive vessels and 84 negative vessels.(4)CT-FFR was highly consistent with CAG in both the definite result group and the indeterminate result group.Although the consistency of CT-FFR in the indeterminate result group was relatively reduced,it was still at the same level(Kappa=0.864,0.827,P<0.05),which was better than that of CCTA and CAG(Kappa=0.690,P < 0.05).The area under the curve of CT-FFR for predicting CAG severe coronary lesions was 0.92(95%CI: 0.898-0.956),which was better than that of CCTA(AUC=0.86,95%CI: 0.827-0.892).When the overall expected specificity is greater than0.80,the predictive ability of CT-FFR is obvious.In this sample,the specificity of CT-FFR was 98% regardless of whether the vessels in the indeterminate result group were included.Therefore,CT-FFR had a significant advantage in predicting the severity of coronary artery disease in this sample.6.CT-FFR was highly positively correlated with invasive FFR(Spearman correlation coefficient =0.831,P < 0.05)and had good consistency(93% of the data were within the 95% confidence interval of Bland-Altman plot).Conclusion: 1.CT-FFR and CAG have a high degree of consistency in assessing the presence of severe coronary artery disease.It can also complete the difficult parts of CCTA without significant reduction in accuracy.CT-FFR is superior to CCTA in predicting severe coronary lesions,and this advantage is significant when the expected specificity is > 0.80.3.The correlation and consistency between CT-FFR and invasive FFR are excellent. |
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