Diagnostic performance of Multislice Computed Tomography in evaluation of coronary artery bypass grafts in diabetic and non-diabetic patients

We sought to evaluate the diagnostic accuracy of noninvasive dual-source multi-slice computed tomography (MSCT) angiography in the assessment of graft patency and degree of stenosis in patients after coronary artery bypass grafting (CABG).Background: Assessment of bypass grafts body and their anastomotic sites by invasive coronary angiography have a risk of potentially life-threatening complications and often require extra procedure time, contrast load, and radiation exposure.Methods: 64-dual-source MSCT was performed to 51 (49 men, mean age 58.6 ± 8 years, range from 38 to 76) post-CABG symptomatic patients. Control of heart rate was done with oral beta blockers, sublingual nitrates was given 2-3 min before the scan. Mean interval between CABG surgery and MSCT was 73.41 ± 65.84 (range 3 to 252) months. Mean heart rate during scanning was 62.5 ± 13.2 (range 52–72) beats/min. Ninety-four percent of patients had both arterial and venous grafts. A total of 142 graft body and 142 anastomotic sites were analyzed. Two grafts body and 4 anastomotic sites were excluded because they were non-evaluable by MSCT. A semi-quantitative assessment of the graft stenosis severity was done according to the recommendation of the Society of Cardiovascular Computed Tomography (SCCT) A significant stenosis was defined as equal to or >70%, moderate stenosis 40–69% and mild <40% lumen diameter reduction. A reference standard invasive coronary angiography was done according to conventional technique through standard trans-femoral approach and was evaluated by an observer blinded to the MSCT results.Results: The diagnostic accuracy of MSCT for the detection or exclusion of significant stenosis in grafts body and their anastomotic sites was 99.28%, sensitivity, specificity, positive and negative predictive values were 97.75%, 100%, 100%, 98.95%. The diagnostic accuracy for detection of degree of graft stenosis (mild, moderate, severe or occluded) was 97.18%.Conclusion: Noninvasive MSCT angiography is an excellent tool for evaluating patency or degree of stenosis of bypass grafts body and their anastomotic sites in post-CABG patients