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Abstract
Coronary artery bypass graft surgery (CABG) is the standard of care in the treatment of advanced coronary artery disease. Invasive coronary angiography has been used to assess the status of graft. Recently, multidetector computed tomography (MDCT) has emerged as an important diagnostic tool for the evaluation of graft patency. Many studies have shown that MDCT has a high sensitivity and specificity in detecting graft occlusion or high-grade stenosis. However, there are several diagnostic pitfalls in evaluating CABG graft patency due to several factors, including technical factors, patient factors, and flow competition. Acknowledgment of these pitfalls and remedies to avoid wrong interpretation is essential to improve diagnostic accuracy. In addition, MDCT yields additional information such as plural effusion, pericardial effusion, sternal infection, pneumonia, pulmonary embolism, and so on. The continuing advance in the MDCT technology suggests that MDCT will be a rapid, convenient, and noninvasive tool in evaluating CABG patients in the near future.
Figures and Tables
Figure 1
Patent internal mammary artery graft anastomosed to left anterior descending artery. Coronal image and volume rendered image (A and B) show the patent, contrast-filled internal mammary artery (arrows), which is well correlated with conventional angiogram (C)
Figure 2
Variable coronary artery bypass grafts. Patent saphenous vein graft from ascending aorta, anastomosed to distal right coronary artery (arrow) is shown in both volume rendered MDCT (A) and conventional angiogram (B). Patent radial artery graft to an obtuse marginal branch is also visualized on both images (C and D). The left internal mammary artery graft to left anterior descending artery is not visualized on MDCT images (A and C). Insteads, multiple surgical clips around left anterior descending artery are shown as nodular lesions (arrowhead in C). Catheter angiogram confirmed the graft failure (not shown)
Figure 3
Patent right gastroepiploic artery graft anastomosed to posterior descending artery. Both volume rendered MDCT image (A) and conventional angiogram (B) show patent graft
Figure 4
A saphenous graft stenosis. Volume rendered MDCT images (A) shows vocal narrowing of distal portion of saphenous vein graft (arrow), which is confirmed at conventional angiogram (arrow in B)
Figure 5
Saphenous vein graft occlusion in immediate postoperative period due to acute thrombosis. MDCT image shows saphenous vein graft filled with thrombus with soft tissue density (arrows)
Figure 6
False negative interpretation due to surgical clip at anastomosis site. Oblique MDCT image (A) shows good opacification of left internal mammary artery graft (arrow) anastomosed to left anterior descending artery. Metallic surgical clips (arrowhead) hamper the detailed evaluation of anastomosis site. Catheter angiogram (B) shows focal stenosis, resulting in false negative interpretation of MDCT
Figure 7
Vasospasm of graft mimicking significant stenosis. Volume rendered MDCT image (A) obtained 5 days after CABG shows multifocal areas of luminal narrowing at radial artery graft (arrows). MDCT image (B) obtained 6 months later shows patent graft, confirming the vasospasm at early postoperative period
References
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