RESUMEN
Multi-detector computed tomography [MDCT] of the coronary arteries is currently considered as a promising alternative to conventional coronary angiography [CA] in both native coronary arteries and coronary artery bypass grafts. The purpose of this study was to compare the diagnostic accuracy of 64 MDCT with that of invasive angiography in the detection of graft disease, and to investigate the clinical value of 64 MDCT in determining the factors affecting graft patency. Fifty symptomatic patients, 7.2 +/- 5.1 years after bypass surgery, were referred for 64 MDCT coronary angiography and standard invasive coronary angiography. Two independent, blinded observers assessed separately the results of both. The study included 174 grafts, 65 arterial grafts [37.4%] and 109 venous grafts [62.6%], The arterial grafts are 50 left internal mammary arteries [LIMA], 3 right internal mammary arteries [RIMA], and 12 radial artery grafts [RA]. 496 segments were analyzed and yielded, Per-segment detection of graft disease, a 99% sensitivity [89/90] and 100% specificity [379/379]. Patients with diseased grafts had older surgery [8.68 +/- 4.32 vs. 4.79 +/- 3.98 year p<0.001]. There were more patent arterial than venous grafts [54/65 vs. 66/109 p<0.01], and more patent LIMA than RA grafts [44/50 vs. 7/12 p<0.05]. The target vessels included 63 SVG to RCA and branches, 21 SVG to LCX-marginal, 25 SVG to LAD-Diagonals, 6 arterial grafts to LCX-marginal, and 59 to LAD- Diagonals. There were more patent grafts targeting LAD-Diagonals than others [73/174 [42%] vs. 47/174 [27%] p<0.001]. The target vessels size was larger in patent than diseased grafts in both arterial [2.74 +/- 0.44 mm vs. 2.0 +/- 0.63mm p<0.01] and venous [2.05 +/- 0.6mm vs. 1.55 +/- 0.7mm p_0.001] grafts. The target vessel lesions were tighter in patent than diseased grafts in both arterial [95.76 +/- 4.38% vs. 89.91 +/- 4.25% p<0.001] and venous grafes [92.21 +/- 5.98% vs. 79.28 +/- 16.4% p<0.001]. 64 MDCT can accurately delineate the patency and disease of bypass coronary grafts. LIMA to LAD remains the best optional graft. Large caliber target vessels with tight lesions are major determinant of grafts patency