Computed Tomography Coronary Angiography Versus Conventional Coronary Angiography in Assessment of Coronary Artery Bypass Graft

Document Type : Original Article


The Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Cairo University


Abstract Background: Coronary artery bypass graft (CABG) surgery is the optimal treatment for advanced coronary artery disease. Invasive coronary angiography is the gold standard tool for post operative assessment of graft patency. Recent advances in computed tomography coronary angiography increase its role in assessment of graft patency especially in patients with comorbidities decreasing the incidence of invasive coronary angiography associated complications. Aim of Study: This study was designed to detect the degree of accuracy of postoperative CT angiography as non-invasive imaging modalityin assessment of graft patencycompared with conventional angiography. Patients and Methods: The study population included 50 patients (35 males and 15 females) with a mean age of 55.58 years. The duration between CABG surgery and CTA ranged from 8 to 28 months. The period between CTA and ICA was 8-15 days. Thirty three patients were complaining of chest pain, ten patients presented withdyspnea on exertion. Only seven patients were asymptomatic and had come for check up. A total number of 118 grafts were assessed by 64-MDCT and ICA. Results: A total of 118 grafts (arterial-48 and venous-70) were studied.CTA images revealed 59 of total 118 grafts are patent, 23 were narrowed and 36 were occluded. The occlusion rate and graft failure were more in the venous grafts, constituted 64% of occluded grafts. We compared the results of postop-erative CTA and conventional angiography, and we noticed that both techniques detected the same number of occluded grafts (36); however, they detected different numbers of patent and narrowed grafts; on CTA images, patent grafts were 59, whereas, onconventional angiography, they were 69 (more sensitive). CTA, showed 23 narrowed grafts, whereas, con-ventional angiography, showed 13 narrowed grafts with CTA overestimation and false positive results among 10 grafts proving their patency with ICA. This difference reached statistical significance with a p-value of less than 0.001. Regarding the diagnostic indices of CTA in detecting graft patency, we found that it had a sensitivity of 100%, specificity of 86.2%, NPV of 100%, and PPV of 84%. Conclusion: We reported that CTA is anon-invasive im-aging modality with high sensitivity and specificity in assessing graft patency, which may limit the use of invasive conventional angiography especially in patients with comorbidities and liable for devolving complications with invasive conventional angiography.