Imaging of Perfusion with Indocyanine Green Fluorescence a Promising Approach

Summary Intraoperative graft patency verification is of major clinical importance for quality control after coronary artery bypass grafting (CABG). The purpose of this study was assessment of graft patency and stenosis of variable severity by fluorescence angiography (FA) using indocyanine green (ICG). For this purpose 32 domestic pigs (40–70 kg) were examined by FA technique. ICG induced fluorescence imaging was performed on the native coronary vessels (n = 6) and stenosis (n = 8) of the left anterior descending coronary artery (LAD). In 18 pigs CABG was performed using left internal mammary artery or vein graft to LAD on the beating heart. Artificial obstructions of LAD or bypass anastomosis at various grade were created. FA was compared to coronary angiography (CA) and transit time flow measurement (TTFM) after each intervention. In all cases coronary flow and flow reduction could be determined by FA, in good correlation to TTFM. Additionally, FA could measure myocardial perfusion and functional impairment of coronary bypass during graded stenosis, determined by the reduction of myocardial fluorescence. FA and CA identified stenosis as well as total occlusion of the LAD and the bypass anastomosis in all cases. Furthermore, using FA the degree of blood flow reduction in ischemic versus normal myocardium during graded coronary and bypass stenosis could be determined. In conclusion, FA is a highly sensitive and reproducible technique for intraoperative quality control in CABG.