Abstract 14074: Real-Time Visual Confirmation of Competitive Flow in Arterial Grafts at CABG
Objective: Long-term patency of arterial bypass grafts is believed to be influenced by ‘competitive flow’ (CF) from the native epicardial coronary artery, in turn assumed to be related to the degree of proximal stenosis. Experimental data have described the flow dynamics of CF in arterial grafts, including reversal of flow in early and late systole. The purpose of this study was to use a novel imaging technology and analysis to visualize both the native epicardial coronary and the bypass graft simultaneously, and test whether these experimental findings occur in human arterial grafting at CABG.
Methods: Intraoperative Fluorescence Vascular Angiography (SPY-Cardiac Angiography and Perfusion, Novadaq Technologies, Inc.) was used to image in real time the flow relationship and dynamics of 60 arterial grafts distal to > 70% stenoses in the left anterior descending (LAD) of patients undergoing OPCAB (n=32) or beating heart, on-pump CABG. The 34-sec Image Data Sequence (IDS) captures the arterial, microvascular and venous phases of angiography and perfusion. The native LAD and arterial graft fluoresce sequentially, because blood with ICG dye reaches the epicardial LAD before the in-situ arterial graft, creating the opportunity to assess flow dynamics visually in real time.
Results: All 60 grafts were imaged without difficulty, and all grafts were widely patent angiographically. The experimental findings of antegrade flow in diastole, retrograde arterial graft flow in early systole, and reversal of the graft/coronary flow relationship in late systole was easily documented visually when present. CF that was deemed ‘potentially significant’ (PSCF) was identified in 30% of these arterial grafts, based upon 1) clearly visible reversibility of flow in systole, 2) retrograde flow in the distal arterial graft during early systole, and > 3 beats of pulsatile flow distal to the anastomosis in the LAD.
Conclusions: This study confirms in vivo with imaging the flow dynamics described experimentally for CF. For the first time, this novel imaging technology permits surgeons to visualize CF in real time at CABG. Documenting PSCF in angiographically patent arterial grafts has obvious implications on long-term patency, and on a better understanding of the physiology of CABG.
- © 2011 by American Heart Association, Inc.