[Non-invasive assessment of coronary artery bypass grafts by computed tomography: comparison with conventional coronary angiography]

Abstract

Introduction and objectives: Although it has been demonstrated that the diagnostic accuracy of computed tomography in the non-invasive assessment of major epicardial coronary arteries is high, only a few studies have evaluated the technique's reliability in assessing coronary artery bypass grafts. The aim of this study was to determine the diagnostic accuracy of multidetector computed tomography in the assessment of coronary grafts.

Patients and method: We prospectively evaluated 117 coronary grafts in 38 patients who had undergone coronary artery bypass graft surgery and who had a clinical indication for angiographic graft assessment. All patients were in sinus rhythm and had a heart rate below 75 bpm. A 16-detector scanner was used for non-invasive assessment of the coronary grafts at a slice thickness of 1.2 mm. The diagnostic accuracy of computed tomography in the non-invasive assessment of significant lesions (i.e., occluded lesions or those with a stenosis greater than 50%) in coronary artery bypass grafts was evaluated by comparison with the results of conventional angiography.

Results: Of the 117 grafts evaluated, 99 (84.6%) were visualized by conventional angiography and 109 (93.2%) by computed tomography. Overall, 98 grafts were analyzed using both techniques. The sensitivity and specificity of computed tomography in detecting significant lesions were: 92% and 97.3%, respectively, for all grafts; 89.5% and 97.6%, respectively, for venous grafts; and 100% and 96.8%, respectively, for arterial grafts.

Conclusions: The diagnostic accuracy of multidetector computed tomography in coronary artery bypass graft assessment was high.