Angiographic evaluation of flow distribution in sequential and composite arterial grafts for three vessel disease

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.

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.

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).

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.