| Coronary heart disease(CHD)is the first cause of death in China.Functional stenosis of coronary artery has been paid more and more attention in recent years because of its ability to directly detect whether stenosis causes ischemia,which can help to optimize the treatment plan and assess the prognosis(ischemia-guided revascularization improves overall patient outcomes).Fractional flow reserve(FFR),which is measured during invasive coronary angiography,is regarded as the gold standard for determining functional coronary stenosis.Because of FFR is invasive,it is difficult to accept for most patients.It is urgently needed for an non-invasive method to evaluate the functional stenosis of coronary artery.Coronary CT angiography(CCTA)has a high sensitivity and specificity in the detection of coronary stenosis,but there are still 2 points of difficulties:(1)The artifacts caused by serious calcification of coronary artery may overestimate the real stenosis degrees of coronary artery;(2)how to evaluate the functional stenosis of coronary artery by using the CCTA information.The definition of transluminal contrast attenuation gradient(TAG)proposed in 2010,is considered to be a noninvasive indicator of functional stenosis of coronary artery in CCTA,but there are many disturbances.The studies from the indicators of corrected coronary opacification(CCO)and transluminal attenuation gradient-corrected coronary opacification(TAG-CCO)were obtained but not ideal.A new method of modified TAG-CCO on the basis of previous research work will be improved and discussed in our study and applied it to the clinic.It is expected that this new modified method can not only reduce the cost of diagnosis and treatment of patients,the rate of surgery,but also reduce the rate of disability and the overall mortality of CHD.The research contents included the following three parts:PART 1 The Assessment of Modified Methods of Transluminal Contrast Attenuation Gradient of Coronary Artery in CT AngiographyBackground and goal: To compare the correlation of luminal attenuation of LAD,LCX,and RCA and of the same layer vessel/ combination of vessels seperately,so as to obtain more accurate method of modified TAG-CCO.The results were verified in normal coronary arteries.Methods: This part was a retrospective study.The subjects were consecutive nega tive patients who underwent CCTA examination from December 2015 to January 2016.The research contents included:(1)The measurements of luminal attenuation of LAD,LCX and RCA and each vessel/ combination of vessels on the same layer were obtained and the correlation between them were further calculated;(2)Based on the above results,the TAG,TAG-CCO and modified TAG-CCO of normal coronary arteries were further calculated,and the difference between the groups were compared.Results: 130 normal branches of coronary arteries of 53 patients were included.There was the strongest correlation of luminal attenuation between LAD and ascending aorta +RCA(0.782),LCX and ascending aorta +RCA(0.701),and between RCA and ascending aorta + descending aorta(0.839).There was significant difference between TAG-CCO and modified TAG-CCO of 130 branches of normal coronary arteries(P=0.042).The gradient of the modified TAG-CCO was close to 0 when compared with that of TAG-CCO.Conclusions: 1.The comparison results of intraluminal contrast correlation in the same layers provided theoretical basis for the correction of modified TAG-CCO;2.The values of modified TAG-CCO were more in line with the principles of hemodynamics of normal coronary artery when compared with TAG-CCO.PART 2 The Relationship between Transluminal Attenuation Gradient and Coronary Artery StenosisBackground and goal: The aim of this study was to further explore the the relationship of TAG,modified TAG-CCO and coronary stenosis grading and between different types of atherosclerotic plaques using a large sample.Method: Patients with coronary artery stenosis were recruited in this retrospective study as coronary artery stenosis group and divided into 1-5 groups according to the diameter stenosis(DS)grades:group 1:DS≦24%;group 2:25%≦DS≦49%;group 3:50%≦DS≦69%;group 4:70%≦DS≦99%;group 5:DS=100%.Coronary artery stenosis group were also divided into soft plaque,calcification plaque group and mixed plaque group.And the the normal coronary artery of part 1 as a normal control group.All the TAG,modified TAG-CCO values of coronary arteries measured and compared between 1-5 group and the normal control group,different plaque groups respectively.Result: 186 patients-53 patients with 130 vessles(normal control group)and 133 patients with 302 vessles(coronary artery stenosis group)were included in this study.The TAG of normal group and group1-5 was-12.39± 4.401、-16.02±7.334、-16.21±6.059、-17.72±7.259、-19.72±7.349 和-22.035±7.790HU/10 mm,The average modified TAG-CCO was-0.01446±0.005、-0.01865±0.0065、-0.02227±0.00777、-0.02988± 0.01541、-0.03274±0.01146 和-0.03697±0.00923/10 mm.When comparing between groups,TAG has significant difference between normal vs 1-5group,1 vs 4 group,1 vs 5 group,2 vs 4 group,2 vs 5 group,3 vs 5 group(P<0.005).Modified TAG-CCO was significant difference between normal vs 1-5group,1 vs 1-5 group,2 vs 1-5 group,3 vs 5 group,4 vs 5 group(P <0.005).The TAG of soft plaque group(92 vessles),calcification plaque group(82 vessles)and mixed plaque group(128 vessles)was-18.0414±7.1617、-18.789±7.5134、-17.943±7.5881(P=0.7018);modified TAG-CCO was-0.0286±0.0124、-0.0266±0.0104、-0.0269±0.0107 respectively(P=0.4295).The modified TAG-CCO has significant difference in group 3(50%≦DS≦69%).There was significant difference between soft plaque group and calcification plaque group,soft plaque group and mixed plaque group(P> 0.05).Conclusion: 1.Modified TAG-CCO is more likely to reflect coronary anatomy stenosis than TAG;2.Modified TAG-CCO may be more capable of correcting the grade 3 stenosis caused by plaque.PART 3 The Preliminary Study of Diagnostic Value of Transluminal Attenuation Gradient of Coronary Artery Functional StenosisBackground and goal: The aim of this study was compared the TAG and modified TAG-CCO in assessing coronary artery functional stenosis with invasively measured fractional flow reserve FFR as the gold standard.Method: This prospective study recuited coronary artery stenosis patients who intented to do CCTA and FFR examination.2 groups(non-functional stenosis group(FFR> 0.80)and functionalstenosis group(FFR≤0.80))were divided by FFR of all the vessels as well as vessels with DS≥70%.The TAG,modified TAG-CCO and FFR values of each coronary artery were recorded.All the TAG,modified TAG-CCO in the 2 group to compare respectively.The diagnosis value of TAG,modified TAG-CCO,CCTA and modified TAG-CCO combined with CCTA,TAG combined with CCTA evaluated and compared;the Correlation of TAG and modified TAG-CCO,TAG and FFR,modified TAG-CCO and FFR were calculated。Result: 35 patients(37 coronary arteries)were recuited.The TAG of non-functional stenosis group and functional stenosis group was-15.39 ± 2.250,-19.87 ± 2.054HU/10mm(P=0.1561),modified TAG-CCO of the 2 group was-0.02521 ± 0.001867,-0.03260 ± 0.002369/mm(P=0.0179).TAG and modified TAG-CCO has no significant difference between the 2 groups in DS≥70%(P>0.05).The cut-off value of TAG、modified TAG-CCO of-10.68HU/10mm、-0.032/10mm;In the area under the ROC curve of TAG-CCO,TAG-CCO,CCTA,TAG + CCTA,modified TAG-CCO + CCTA,there was significant difference(P = 0.034)except CCTA and TAG-CCO combined with CCTA,There was no significant difference between the other methods(P> 0.05).TAG and modified TAG-CCO had moderate correlation(r = 0.5139).Conclusion: 1.Modified TAG-CCO has the potential to further differentiate coronary artery functional stenosis compared with TAG;2.Modified TAG-CCO + CCTA has higher sensitivity and specificity,with obvious advantages;3.There is a moderate correlation between TAG and modified TAG-CCO. |
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