Noninvasive Follow-Up of Coronary Artery Bypass Graft Patency Using Multi-Slice Computed Tomography

PURPOSE: We wanted to evaluate the utility of multi-slice computerized tomography (MSCT) for assessing coronary artery bypass graft patency and/or occlusion. MATERIALS AND METHODS: For 24 patients, both conventional angiography and CT angiography with 4-MSCT were performed within seven days of one another in order to evaluate the accuracy of MSCT with regard to graft patency and/or occlusion. A follow-up CT angiogram was performed in patients with and without symptoms (n=11, n=34, respectively) with 4- or 16-MSCT. We retrospectively compared the results of MSCT to those of conventional coronary graft angiography. RESULTS: Sixty-five grafts were evaluated for the accuracy of MSCT. Six of those 65 were occluded. The sensitivity, specificity, positive predictive value and negative predictive values of MSCT for the diagnosis of graft occlusion were 100% (6/6), 98% (58/59), 86% (6/7) and 100% (58/58), respectively. Patency could not be determined by angiography in two grafts; however, the grafts proved to be patent on MSCT. On follow-up, new graft occlusions in the asymptomatic patients were detected by MSCT in 8.2% of the previously patent grafts at the two years post-op, and in 15.2% at the three years post-op. CONCLUSION: MSCT is a practical and accurate noninvasive diagnostic tool for following up coronary artery bypass grafts.

Endovascular Therapy of Left Subclavian Artery Stenosis in Patients with Left Internal Mammary-Coronary Artery Bypass Graft

PURPOSE: We wanted to evaluate the clinical usefulness of percutaneous transluminal angioplasty (PTA) and stenting of left subclavian artery (LSA) stenosis in the patients with a left internal mammary artery (LIMA)-coronary artery bypass graft. MATERIALS AND METHODS: From September 1998 to November 2005, significant proximal LSA stenoses were treated with PTA and stenting in 22 patients (15 men and 7 women) who had a prior LIMA-coronary artery bypass graft or who were willing to undergo LIMA-coronary artery bypass grafting. The technical success rates, complications and restenosis during the follow-up period were retrospectively evaluated. RESULTS: Six patients had a prior LIMA bypass graft and 16 patients were treated before their coronary artery bypass surgery. The etiology of the LSA stenosis was atherosclerosis in all patients. Four patients were treated with PTA only, and stents were placed in 18 patients. Technical success was achieved in all patients. An embolism in the proximal LIMA occurred after stenting in one patient, and the LIMA was recanalized with transcatheter thrombolysis. During a mean follow-up of 30 months, only one patient was found to have recurrent LSA stenosis 29 months after stenting and this patient was successfully managed with angioplasty. CONCLUSION: Endovascular therapy is useful and efficacious for the treatment of LSA stenosis in patients with a LIMA-coronary artery bypass graft.