Evaluation of coronary artery bypass grafts patency using CT angiography: a reports of multi-center study

Objective To investigate the diagnostic value of computed tomography angiography (CTA) for assessing patency of coronary artery bypass grafts (CABG) using conventional coronary artery angiography (CAG) as the reference standard.Methods This study was a multicenter study in China.A total of 83 participants had been enrolled,including 63 male patients (75.9％),age of (64 ± 9) years (44-84 years).The inclusion criteria were patients who had been performed both CAG and CTA within 3 months.Thirty of them had been scanned by 64 multidetector row spiral CT,and 53 of them had been scanned by dual source CT scanner.Two groups of radiologists evaluated CAG and CTA datasets blindly,and the results of CTA for assessing both stenosis (≥50％) and occlusion of CABGs were compared with the CAG results.Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of CTA.Results Among 83 cases,the median follow-up time after CABG surgery was 58.6 (1.0-227.1) months.A total of 240 CABG vessels were analyzed,including 80 arterial grafts and 160 venous grafts.The patent grafts to left anterior descending were 93 (78.8％,93/118),to left circumflex were 34 grafts (58.6％,34/58),and to the right coronary artery were 35 grafts (54.7％,35/64),derived a total patency of 67.5％ (162/240).In comparison to CAG results,the sensitivity and specificity of CTA for detecting CABG stenosis (≥50％) were 88.6％ (93/105) and 94.1％ (127/135),area under ROC curve was 0.917.For detecting CABG occlusion,the sensitivity and specificity were 97.4％ (76/78)and 96.9％ (157/162),area under ROC curve was 0.972.For the detection of native coronary artery stenosis and occlusion,the areas under ROC curves were 0.889 and 0.836,respectively.Conclusions CTA is a tool with high diagnostic sensitivity and specificity to evaluate stenosis and occlusion of CABG.The diagnostic efficacy is higher than the evaluation of native coronary arteries. Key words: Coronary artery disease;  Coronary revascularization;  Tomography,X-ray computed; Coronary angiography