| Objective:Coronary atherosclerotic heart disease is ischemia and hypoxia of heart muscle because of stenosis or occlusion of coronary artery caused by atherosclerosis or(and) functional change(spasm).It is called by a joint name,coronary heart disease,which is also called CHD for short.The main surgical treatment of CHD is coronary artery bypass graft(CABG).CAB G can reconstruct blood supply and improve oxygen supply of ischemia of heart muscle.It also can release symptom of stenocardia and improve function of cardiac muscle and prolong longevity.The main way of rechecking the patient who was operated CABG is conventional coronary angiography(CAG) which is more expensive and more risky and more unacceptable for the most patient.In recent years,computed tomography coronary angiography is gradually becoming a hot spot in academic study.It display the tree of coronary artery and pathological changes of coronary artery efficiently. 64-slice computed tomography (64-SCT) is especially faster and better in functional software.The diagnostic value of 64-SCTA is bigger because of it's evaluation of danger-degree and development- tendency of patient who was operated CABG.Method: From June 2007 to March 2009,choose 27 patients rechecked from out-patient clinic in Tangshan Woker Hospital(17 males and 10 females; age range 49-78 years;mean age: 63.6±7.9years).(after CABG time:from 30-121months , mean time 59±18.7months).All of 27 patients underwent 64-SCTA.10 of them underwent CAG at same time. 5 of them previously underwent procedure of PCI with stent implantation. 1 of them underwent coronary artery bypass surgery (CABG).Others were treated by drugs.According to the suggestion of American Heart Association,the coronary arteries were devided to 9 segment.Bypass grafts were devided to 5-6 segment.The degree of bypass grafts stenosis divided into 4 classes:1, normol ; 2, slight stenosis (﹤50%) ;3, midrange stenosis(50%-75%) ;4, serious stenosis (≥75 % ) .The 64-SCTA'results were analyzed based on the CAG results.The results of the two methods were analyzed by a group of imageologic expert and cardiologists. Considering the blood vessel diameter of two sides of stenosis,Pathological changes and degree of stenosis of coronary artery was evaluated.Two groups do not kown the results of each other. The accuracy and sensitivity and specificity and positive predictive value and negative predictive value of 64-SCTA for diagnosis of stenosis of bypass grafts was evaluated,based on the CAG as a golden standard.Checking difference and consistency between two ways of diagnosis of bypass grafts by Chi-square test and Kappa value.Results:27 patients were operated 64-SCTA successfully.Each process takes 10～15min.There was no arrhythmia in 27 patients.(heart rate:52～85/min;CTA time: 9.0±1.2s; breath holding time:12～14s)There are Among the 427 coronary arteries segments in 78 bypass grafts,392(91.80%) were evaluated by 64-SCT successfully.(great saphenous vein:52;arterial bridge:23)35(8.20%) were unevaluated (movement shadow: 10 , serious calcification: 12 , metal clips-shadow:13). Evaluable-rate in each kind of bypass grafts: LIMA-LAD(103/115)89.57%, AO-LAD(18/18)100%, AO-RCA(139/150)92.67%, AO-LCX(132/144)91.67%.At the same time,10 of 27 patients were operated CAG.Two kind ways of diagnosis coincidence for 4 stenosis classes were 97.94%,88.24%,92.31%,90.00%. Sensitivity and specificity and accuracy in each groups,stenosis (stenosis≥25%),Up midrange stenosis(stenosis≥50%),Serious stenosis(stenosis≥75%),are 100% 97.94% 98.51% , 100% 100% 100% , 90.00% 100% 99.25%.In Chi-square test(α=0.05),0.95﹤p﹤0.975,we can not consider two ways of diagnosis of bypass grafts are different.Kappa=0.9350,we can consider there is high consistency between two ways of diagnosis of bypass grafts。Conclution:In evaluation of normal and stenosis and occlusion of coronary artery and bypass grafts, 64-SCTA takes more accuracy and sensitivity and specificity.It suit to evaluate bypass grafts of patient who was operated CABG because of the good quality of no-traumatic occlusion and convenience and low-price et al,although 64-SCTA can not replace CAG totally.
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