Value of navigator echo magnetic resonance angiography in detecting occlusion/patency of arterial and venous, single and sequential coronary bypass grafts

Aim of our work was to validate magnetic resonance angiography (MRA) in det ecting occlusion/patency of coronary artery bypass grafts. Twenty patients with previous history of bypass surgery and recurrent episodes of chest pai n were enrolled. Two patients could not be studied (claustrophobia, erratic breathing). Thus, 18 patients with 51 bypasses were examined using a navig ator echo sequence: 21 arterial grafts (six sequential) and 30 saphenous ve in grafts (five sequential). All patients had undergone contrast convention al angiography 3-15 days before MRA. The magnetic resonance (MR) data set w as analyzed by two independent readers blinded to the results of convention al angiography (occlusion of 12 of 51 grafts). At magnetic resonance, two b ypasses of the posterior descending artery, patent at conventional angiogra phy, could not be visualized because of imaging slab malpositioning. Intero bserver concordance was 96% (47/49). Magnetic resonance and conventional an giography provided identical answers in 47 out of 49 (96%) of the examined grafts. Eleven out of 12 occluded grafts and 36 out of 37 patent grafts wer e correctly identified with MR. As far as occlusion is concerned, the sensi tivity of MR was 91%, the specificity 97%. To summarize, a 30 min outpatien t MR examination is highly reliable in determining occlusion/patency of art erial and venous, single and sequential bypasses.