Objective: Physiological reaction to competitive flow is considered as the primary mechanism of arterial graft occlusion. Reopening of graft lumen had been also reported, but details remain unknown. We sought to delineate the effect of management of the moderately stenotic targets on the occurrence of competitive flow and clinical results.
Methods: Clinical records and angiograms of 3263 bypass grafts in 852 patients, who underwent off-pump coronary revascularization using the internal thoracic artery (ITA) and radial artery without aortic manipulation since 2000, were examined. Dominant flow direction was graded as antegrade, competitive, and no flow (occlusion). Late angiography was performed in 157 patients with 561 bypass grafts for clinical reasons. The follow-up period was 55.5 ± 31.1 months.
Results: The early graft patency rate was 98.0% (3197/3263). The rate of antegrade flow was 91.5% (2986/3263), while competitive flow was detected in 6.5% (211/3263). The actuarial patency rates of bypass grafts with antegrade flow were significantly higher than those with competitive flow (87.9% at 5 years and 71.3% at 8 years, vs 25.8% at 5 years and 9.2% at 8 years, p<0.0001). In the univariate and multivariate analyses for 852 patients, territory of right coronary artery (odds ratio (OR)=2.20, p=0.0002), composite radial artery (OR=1.90, p=0.03), and the distal end of the graft (OR=2.90, p=0.0003), were identified as the significant predictors of competitive flow from the target with 51-75% stenosis. Individual grafting inversely correlated with occurrence of competitive flow (OR=0.48, p=0.04). Reopening of the graft lumen associated with progression of native stenosis was not observed in these patients.
Conclusions: Competitive flow can be efficiently avoided by appropriate graft arrangement and patients' selection. Selection of the target of the graft end would be crucial to achieve antegrade bypass flow and long-term patency of entire sequential bypass grafts. For the composite graft, functional recovery of the occluded graft would be extremely rare.
Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.