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OBJECTIVES We sought to delineate the effects of the severity of target lesions and their combinations on the occurrence of competitive flow, especially in the composite Y-graft and to establish an optimal strategy for graft arrangement and patient selection. METHODS We reviewed early and late angiograms of 2514 bypass grafts in 601 patients, who underwent off-pump coronary revascularization to three-vessel vascular regions using the internal thoracic artery (ITA) and radial artery (RA) without aortic manipulation. As a standard technique, the left anterior descending artery (LAD) was bypassed with the in situ ITA, and the left circumflex and right coronary arteries (RCA) were bypassed with the composite RA. Bypass flow was graded as antegrade, competitive or no flow. RESULTS The early patency rate was 98.1% (2466/2514), while competitive flow was detected in 6.4% (162/2514). For the LAD, the individual and sequential in situ ITA provided lower incidence of competitive flow than the composite graft (0.3% (1/298) versus 7.6% (23/303), P < 0.0001). Regarding the RA to non-LAD bypass, 86.3% (113/131) of competitive flow occurred at the distal end of the I- or Y-graft, and the cumulative patency rate was significantly lower than that of sequential proximal anastomosis (80.1 versus 56.6% at 5 years, P < 0.0001). The number of sequential anastomoses did not affect the cumulative patency rate (P = 0.09). For the composite Y-graft to three-vessel regions, the rate of antegrade flow in patients with 76–100% stenosis in both the LAD and the RCA was 95.7% (178/186), which was significantly higher than that of 78.1% (100/128) in patients with 76–100% stenosis in the LAD and 51–75% stenosis in RCA (P < 0.0001). CONCLUSIONS Sequential and composite grafting was considered reliable, exclusively in appropriately selected situations. To secure entire patency of the Y-graft to three-vessel regions, balanced bypass flow toward LAD and RCA would be crucial. [ABSTRACT FROM AUTHOR]

Abstract: 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 &y& Elsevier]