CTA Beneficial for Assessing Patients after CABG
Patients undergoing evaluation after coronary artery bypass graft (CABG) benefit from imaging with 64-slice CT angiography (CTA) according to results from a small study in Austria. The study was published in the American Journal of Roentgenology.
The research team evaluated the results of CTA for 41 patients. Within that group, there were 70 different grafts; 24 venous and 46 arterial. All of the grafts were visualized with CTA. Average time since CABG was 2.6 years. CABG was performed with either a conventional or minimally invasive approach.
The team evaluated the ability of CT to detect graft stenosis. Over 40 percent of the venous grafts were found to have vein graft disease; it was present in eight of the 19 patients.
Sensitivity for detection of stenosis between 50 and 90 percent was 75 percent and specificity was 95 percent. This was associated with a positive predictive value of 67 percent and a negative predictive value of 97 percent.
Overall detection of stenosis was calculated. Stenosis or occlusion greater than 50 percent had 85 percent sensitivity and 95 percent specificity. The positive and negative predictive values were 80 and 96 percent, respectively.
As well, this noninvasive imaging modality is capable of detecting disease at an early stage of development. Additionally, CTA provides additional information about the surrounding tissue. The Austrian team suggested that findings from CTA can be useful in planning before a repeat CABG.
CTA imaging does have limitations, however. The ability to detect distal anastomotic stenosis is limited. As well, the modality may overestimate the degree of stenosis. These shortcomings, however, appear to be outweighed by the benefits.
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September 26, 2007 Related topics: Imaging, Radiology, Cardiology