An Experimental Study of the Effects of IABP on Coronary Artery Bypass Graft Flow Waveform

Purpose: Graft evaluation after coronary artery bypass grafting (CABG) is still not sufficient. This study analyzed the flow waveform of coronary arteries and grafts during intra-aortic balloon pumping (IABP) assist. Methods: Subjects were eight pigs that underwent off-pump CABG. Using transit-time flow measurement (TTFM) and occluder, blood flow waveforms were recorded while changing the degree of stenosis of Seg.6 and the left internal thoracic artery (LITA) and analyzed by percentage of reverse flow component to the total blood flow (R/T) and the ratio of diastolic blood flow of IABP operative and IABP inoperative (D1/D0). Result: Reverse flow of the LITA was reduced when stenosis of Seg.6 increased and R/T decreased. The average diastolic blood flow of Seg.8 and the LITA increased with IABP on showing a D1/D0 of 1 or more. R/T of the LITA increased when stenosis of Seg.6 was fixed and increasing the degree of LITA stenosis. D1/D0 increased up to a 75% LITA stenosis and is decreased in more severe stenosis. Conclusion: R/T is significantly higher in the antagonist or stenosis during IABP assist and was able to confirm the effectiveness of the graft as a functional assessment of graft. D1/D0 is useful as an indicator of the effectiveness of IABP on coronary blood flow.