Study On Diagnostic Performance Of Fractional Flow Reserve Based On CT In Patients With Myocardial Ischemia

Background Coronary heart disease is a common disease of the cardiovascular system.It has high incidence rate and mortality worldwide.Therefore,it is very important for early diagnosis and precise treatment of this disease.At present,the commonly used imaging examinations for the diagnosis of coronary heart disease include invasive coronary angiography(ICA)and coronary computed tomography angiography(CCTA),both of which evaluate the degree of coronary artery stenosis from the aspect of anatomy.However,the degree of coronary artery stenosis and myocardial ischemia are not absolutely matched in clinic.Therefore,a complete diagnosis of coronary heart disease includes not only anatomical evaluation,but also functional evaluation of the diseased coronary artery.Fractional flow reserve(FFR)is the "gold standard" to evaluate the physiological function of coronary artery.It is obtained by ICA examination,but its clinical application is limited because it is invasive examination.The noninvasive fractional flow reserve(CT-FFR)obtained by CCTA is a non innovative technology to evaluate the physiological function of coronary artery.The CT-FFR calculation software developed by heart flow company of the United States is relatively mature and has been approved by FDA for clinical application.This technique was introduced late in China,and the domestic CT-FFR analysis technology has not been fully verified for the performance of identifying specific myocardial ischemia.Objective The purpose of this study was to assess the diagnostic performance of noninvasive fractional flow reserve(CT-FFR)based on CCTA for myocardial ischemia in patients with coronary heart disease(CHD)using invasive FFR as a reference standard.Methods1.Subjects: prospective admission into the suspected coronary heart disease patients who were planned to undergo coronary angiography in the second Department of the heart of Shaanxi people’s Hospital from December 2019 to December 2020,and met the criteria for inclusion and exclusion of the study.A total of 28 patients were analyzed with 30 vessels;2.Data collection: Collect the clinical data of all patients: age,gender,height,weight,smoking,drinking,previous diabetes,hypertension,hyperlipidemia,family history of coronary heart disease,collect the results of liver function,serum creatinine,cholesterol,triglyceride,low density lipoprotein,glycosylated hemoglobin,cardiac color Doppler ultrasound,and record the degree of vascular stenosis.3.Examination protocol: all patients underwent CCTA examination and found that at least one vessel stenosis was between 30% and 90%.Based on CCTA images,CT-FFR value was calculated by CT-FFR analysis software,followed by invasive coronary angiography,and FFR value of target vessel was measured by pressure guide wire.FFR≤0.8 was defined as ischemia.4.Statistical methods: SPSS 20.0 and Med Calc statistical software was used for statistical analysis of the data.After non parametric test,all measurement data were in line with normal distribution,expressed by mean ± standard deviation(?± s),and count data(%).The accuracy,sensitivity,specificity,positive predictive value and negative predictive value of CT-FFR in the diagnosis of myocardial ischemia were calculated at the patient level and vascular level respectively.ROC curve of CT-FFR was drawn at the patient level and vascular level,and area under curve(AUC)was calculated.At the vascular level,Pearson correlation analysis was used to make scatter plot of correlation between CT-FFR and FFR,and Bland Altman plot was used to test the consistency between them.The difference was statistically significant(P < 0.05).Results1.At the patient level,the accuracy of CT-FFR diagnosis was 96.43%,and the sensitivity,specificity,positive predictive value and negative predictive value were 100%,94.12%,91.67%and 100% respectively;at the vascular level,the accuracy of CT-FFR diagnosis was 96.66%,and the sensitivity,specificity,positive predictive value and negative predictive value were100%,94.44%,92.31% and 100% respectively.2.The ROC AUC of CT-FFR was 0.995(95% CI,0.867-1.000,P < 0.001)at the patient level and 0.995(95% CI,0.876-1.000,P < 0.001)at the vascular level.3.Pearson correlation analysis showed that there was a positive correlation between them at the vascular level(r = 0.902,P < 0.0001).Bland Altman map was called to evaluate the consistency between CT-FFR and FFR.The average difference was-0.01,3.3%(1 / 30)fell outside the 95% consistency limit,and the maximum absolute value of the difference was0.15.Conclusion CT-FFR software developed by our country can effectively predict myocardial ischemia and accurately evaluate the physiological function of coronary artery stenosis lesions,which has good consistency with invasive FFR.