Maximal blood flow acceleration analysis in the early diastolic phase for aortocoronary artery bypass grafts: a new transit-time flow measurement predictor of graft failure following coronary artery bypass grafting
BACKGROUND Early graft failure is a common cause of cardiac morbidity and mortality after coronary artery bypass grafting (CABG), and there is particular concern about graft patency in off-pump CABG. We describe our preliminary experience with a novel imaging technique (the SPY system), based on fluorescence of Indocyanine Green when exposed to near infrared light, for the intraoperative assessment of coronary graft patency. METHODS Graft patency was assessed in patients undergoing off-pump and on-pump total arterial revascularization. The imaging technique requires injection of a 1-mL bolus of Indocyanine Green into the central venous line, followed by imaging with the SPY system. RESULTS We assessed intraoperative graft patency in 213 conduits in 84 patients (mean, 2.54 grafts per patient), of which, 65 (77%) were done off-pump. It took approximately 3 minutes to image each graft. Skeletonized conduits provided better visualization than pedicled ones. Fluorescence, confirming graft patency, was observed in all but four (1.9%) conduits in 4 (5%) patients. In these latter cases, graft revision was necessitated. CONCLUSIONS Fluorescence imaging of coronary grafts using the SPY is a uniquely simple, safe, noninvasive, and reproducible technique for intraoperative confirmation of graft patency. In 4 patients, it necessitated revision of the initial intraoperative procedure. Quantification of graft flow would enhance the value of the system.