Intraoperative bypass graft flow in intra-aortic balloon pump–supported patients: Differences in arterial and venous sequential conduits

Abstract

The intra-aortic balloon pump is used worldwide as an anti-ischemic strategy. However, little is known about the modifications of the graft flowmetry during use of intra-aortic balloon pump. An observational study aimed at analyzing transit-time flow measurements during 1:1 intra-aortic balloon pump use and during its cessation in 138 consecutive patients using intra-aortic balloon pump before coronary artery bypass grafting (n = 442 graft segments) was reported. In normally functioning grafts, the mean diastolic and mean blood flow improved significantly during 1:1 intra-aortic balloon pump use compared with during intra-aortic balloon pump cessation (P < .001), although mean and diastolic arterial pressures were significantly lower (P = .001). Arterial and sequential saphenous vein grafts showed greater improvements in mean diastolic and mean flow compared with single venous grafts. Surplus graft flow (defined as mean flow during 1:1 intra-aortic balloon pump use/mean flow with intra-aortic balloon pump off) was recorded (surplus graft flow > 1) during 1:1 intra-aortic balloon pump use in all normally functioning grafts, with higher values in single arterial or sequential saphenous vein grafts versus single venous grafts (both P < .001). In the 9 cases of graft failure, the mean diastolic, mean systolic, and mean flow were significantly lower and the pulsatility index greater, compared with normally functioning grafts (all P <or= .001). Blood flow did not change appreciably during 1:1 intra-aortic balloon pump use in failed bypass grafts; thus the surplus graft flow approached 1. In this analysis, use of intra-aortic balloon pump was associated with improved diastolic and mean blood flow in bypass grafts. Arterial and sequential grafts were associated with greater improvements in blood flow and surplus graft flow. Graft failure was associated with poor transit-time flow results, high pulsatility index values, and absent surplus graft flow.