Angiographic follow-up results of a randomized study on angioplasty versus bypass surgery (GABI trial). GABI Study Group.

Although several randomized trials have been performed to compare the outcomes of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass surgery (CABG) in patients with multivessel disease, there is little data available on angiographic follow-up results. The present substudy of the German angioplasty versus bypass surgery investigation (GABI Trial) compares the angiographic revascularization status in these two cases 6 months after treatment. Follow-up angiograms were available in 102 CABG patients and 117 PTCA patients. Although the protocol excluded patients with total occlusion, on follow-up 6 months after treatment we found total occlusion of 94 native arteries (36.9%) in the CABG group and of six arteries (2.5%) in the PTCA group (P < 0.001). The rate of occluded native vessels did not correlate significantly with the severity of the lesion before bypass surgery. In the CABG group 31 bypass grafts (12.2%) were found to be occluded at the 6 month follow-up examination (29/225 vein grafts [12.9%]; 2/30 mammary artery grafts [6.7%]). The main pathway, defined as the nutrient vessel (native vessel or bypass graft) providing the least resistance to blood flow, was narrowed by a lesion with a diameter stenosis of 70-100% for 36 target lesions (14.1%) in the CABG group and 39 target lesions (16.2%) in the PTCA group (P, ns). However, the prevalence of moderately severe lesions with a 50-69% diameter reduction of the main pathway was significantly greater in the PTCA group (44 lesions, 18.3%) than in the CABG group (19 lesions, 7.5%, P < 0.01). Thus, 6 months after randomized allocation to PTCA or CABG, we found comparable rates of high-grade lesions in the main pathways of both treatment groups. Whereas moderately severe lesions of the main pathway were predominantly seen in the PTCA group, there was marked disease progression to total occlusion in the native circulation after bypass grafting.