Evaluation of Aortocoronary Bypass Stents with Cardiac MDCT Compared with Conventional Catheter Angiography

Muhlenbruch G, Mahnken AH, Das M, Blindt R, Hohl C, Wildberger JE, Gunther RW, Kuhl HP, Koos R.

OBJECTIVE: The objective of our study was to determine the accuracy of 16-MDCT for evaluation of stent patency and in-stent stenosis in venous coronary bypass grafts.

SUBJECTS AND METHODS: Fourteen patients who had previous stent placements in stenosed venous coronary bypass grafts underwent contrast-enhanced MDCT of the heart (col-limation, 16 x 0.75 mm; 120 kV; 550 mAseff) and invasive coronary angiography. A total of 20 stents were evaluated: Vessel and stent diameters proximal to, distal to, and at various sites inside the stent were measured on both techniques, and Bland-Altman plots and correlations were calculated. Image noise and image quality were also assessed applying a Students t test for data comparison of image noise.

RESULTS: All 20 bypass stents were correctly classified as patent. Vessel diameters outside the stent showed an excellent correlation (r = 0.90) and in-stent diameters showed a good correlation (r = 0.72), with lower values for MDCT due to blooming artifacts. All significant in-stent stenoses were correctly classified.

CONCLUSION: In patients suspected of bypass in-stent stenosis, 16-MDCT may be considered as a valuable alternative to conventional angiography for evaluating bypass patency and in-stent stenosis.