Effects of Intra-Aortic Balloon Pump on Coronary Artery Bypass Grafts Blood Flow: Differences by Graft Type and Coronary Target

The intra-aortic balloon pump (IABP) is used worldwide as an anti-ischemic strategy. However, little is known about the modifications of the graft blood flow during IABP. A retrospective study aimed at analyzing transit-time flow measurements during 1: 1 IABP and during its cessation in 401 consecutive patients receiving IABP before coronary artery bypass grafting (n = 880 graft segments) was reported. All normally functioning grafts were considered. Mean diastolic and mean blood flow improved significantly during 1: 1 IABP compared with during IABP cessation (P < 0.001), although mean and end-diastolic arterial pressures were significantly lower (P = 0.001). Arterial and sequential saphenous vein (SV) grafts showed greater improvements in mean diastolic and mean flow compared with single venous grafts. Higher flows were also observed in the grafts directed to the circumflex territory. Surplus graft flow (SGF, defined as mean flow during 1: 1 IABP/mean flow with IABP off) was recruited (SGF >1) during 1: 1 IABP, with higher values in single arterial or sequential SV grafts versus single venous grafts (both P < 0.001). Y-conduit radial artery (RA) grafts showed higher maximum diastolic flow, mean flow, and SGF compared to aortocoronary RA or SV grafts. In this retrospective analysis, IABP was associated with improved diastolic and mean blood flow in bypass grafts. Arterial, sequential, and Y-conduit grafts were associated with greater improvements in blood flow and SGF than aortocoronary SV grafts.