Graft design strategies with optimum antegrade bypass flow in total arterial off-pump coronary artery bypass.

OBJECTIVE

In arterial conduits, graft flow is one of the major determinants of long-term patency. We sought to delineate the effect of strategy for graft arrangement and design to three-vessel disease by evaluation of the dominant flow direction in each segment of a bypass graft.

MATERIALS AND METHODS

We reviewed coronary angiograms of 1571 bypass grafts in 395 patients who underwent total arterial off-pump coronary revascularization without aortic manipulation for three-vessel disease since December 2000. The graft flow graded as A (antegrade), B (competitive), C (reverse), and O (no flow=occlusion). The current arrangement and design has been introduced since March 2003, and consists of the in-situ left internal thoracic artery (ITA) to the anterior descending artery and the composite I-graft of the right ITA and radial artery to the left circumflex (LCX) and right coronary artery (RCA) territories. Either clockwise or counterclockwise orientation, the I-graft was chosen to achieve a sufficient antegrade flow. Group I consisted of 181 patients with a single in-situ ITA as a composite Y-graft. Group II consisted of 214 patients with bilateral in-situ ITAs, which subdivided into Subgroup II-A consisted of 80 patients with bilateral in-situ ITAs until February 2003, and Subgroup II-B consisted of 134 patients with bilateral in-situ ITAs since March 2003.

RESULTS

The number of distal anastomoses was 3.52+/-0.63 in Group I, and 4.36+/-0.83 in Group II, respectively (p<0.0001). The overall graft patency rate was 98.6% (1549/1571), and there was no significance different between the groups. The rate of grade A in Group II was 863/933 (92.5%) and was significantly higher (p=0.049) than that of Group I 572/638 (89.7%). The rate of functioning bypass in Subgroup II-B was (95.8%) 568/593, and was significantly higher (p=0.03) than that in Subgroup II-A (92.4%) 314/340. In Subgroup II-B, 233/268 (86.9%) of the conduits had completely grade A bypass flow, and this ratio was significantly higher (p=0.04) than that in Subgroup II-A (79.4%) 127/160.

CONCLUSION

Usage of bilateral ITAs and selecting the orientation of the I-graft to LCX and RCA branches provide maximal distal anastomotic sites with satisfactory graft patency rate, and simultaneously minimized the incidence of reverse and competitive flow.