Diagnostic value of 64-slice spiral CT coronary angiography for restenosis after bypass surgery

Objective: To assess the accuracy of 64-slice spiral CT in diagnosis of restenosis of coronary artery bypass grafts (CABG) and native coronary arteries in patients after bypass surgery.

Methods: Fifty-eight patients receiving bypass surgery with totally 140 CABG (43 arterial and 97 venous grafts) were examined using 64-slice spiral CT. CABG and all native coronary arteries with a diameter of >1.5 mm were evaluated for the presence of significant stenoses (>50% diameter reduction) in comparison with the results by coronary angiography as the golden standard.

Results: Of the 140 CABG examined, 38 were occluded and 104 remained patent, all of which were accurately identified by 64-slice spiral CT. The sensitivity of CT for restenosis detection in the patent graft was 100% (18/18) with a specificity of 95.2% (80/84). In the segmental evaluation of the native coronary arteries, the sensitivity of the CT in identifying significant stenosis in the evaluable segments (90%) was 84% (87/103) with a specificity of 74% (384/518). The accuracy of CT in detecting the presence of at least 1 stenosis in the CABG, distal runoff vessels or nongrafted arteries was 91% (53/58).

Conclusions: CT allows noninvasive angiographic evaluation of both the native coronary arteries and bypass grafts after bypass surgery.