Competitive flow in arterial composite grafts and effect of graft arrangement in Off-Pump coronary revascularization

Background We sought to investigate the incidence of competitive flow in arterial composite grafts and to delineate the effect of the location of moderately stenotic branch, the extent of the revascularized territories and the arrangement of in situ and free arterial grafts in off-pump coronary artery bypass grafting (OPCAB). Methods Three hundred eighteen patients who underwent OPCAB with aorta no-touch technique using the composite graft with totally arterial materials between December 2000 and March 2003 were studied. A total of 362 composite grafts were used. We reviewed their coronary angiography before and early after operation. Competitive flow was defined as the phenomenon that at least one of the distal anastomotic sites of the composite graft was not opacified in in situ graft angiography, but clearly opacified in native coronary angiography. The number of distal anastomoses was 3.47 ± 0.93 per patient and 2.87 ± 0.81 per composite graft. Results Early patency rate of the distal anastomotic sites of composite grafts was 98.7%. Competitive flow was found in 53/362 (14.6%) composite grafts, and graft occlusion occurred in 13/362 (3.6%) composite grafts. In the multivariate analysis of 362 composite grafts, 75% stenosis in right coronary artery (RCA) territory (p< 0.0001) and the number of distal anastomoses (p = 0.004) were significant predictors of competitive flow and graft occlusion. Multivariate analysis of 318 patients demonstrated that 75% stenosis in RCA territory (p< 0.0001) and the total number of distal anastomoses (p = 0.003) were statistically significant predictors of competitive flow and graft occlusion. The use of more than two in situ grafts and the shape of composite graft (branched or straight) did not have significant correlation with the outcome. Conclusions Coronary artery revascularization using composite arterial grafts provided satisfactory early patency rates with an acceptable incidence of competitive flow. Because the implication of competitive flow in an arterial composite graft may differ from that in conventional bypass grafts unpredictably, long-term follow-up is mandatory.