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Wipper, Sabine (2006): Validierung der Fluoreszenzangiographie für die intraoperative Beurteilung und Quantifizierung der Myokardperfusion. Dissertation, LMU München: Medizinische Fakultät



BACKGROUND: Intraoperative graft patency verification is of major clinical importance for quality control after coronary artery bypass grafting (CABG), especially if surgery is performed on the beating heart. This is one of the first reports of fluorescence coronary angiography (FCA) using the dye indocyanine green (ICG), a noninvasive technology for direct visualization of coronary arteries and myocardial perfusion. METHODS: Twenty-five domestic pigs underwent FCA of the left anterior descending coronary artery (LAD). In the first group (n = 6 pigs), FCA was used to visualize the native coronary vessels and myocardial perfusion. In the second group (n = 8 pigs), 14 stenoses of various degrees and 4 total vessel occlusions were created by snares on different segments of the LAD, and FCA was used to visualize the effects of these obstructions. In the third group (n = 11 pigs) defined stenoses (25%; 50%, 75%, 100% flow reduction) on the distal part of the LAD were created by a custom-made screw occluder and determined using TTFM (transit-time-flow measurement). ICG was intravenously applied, and the heart was illuminated with near-infrared light emitted by laser diodes. The fluorescence emission was detected by an adapted charge-coupled device camera system. The images were displayed in real time on a high-resolution monitor. Subsequently, images obtained with FCA were correlated with fluorescent microspheres data (n = 11 pigs). RESULTS: In all cases, high-quality FCA images of coronary arteries and myocardial perfusion were obtained. All stenoses resulted in an impairment of the myocardial perfusion visualized by FCA. Occlusion of the LAD or the diagonal branch resulted in a total perfusion defect of the corresponding anterior myocardial wall with immediate reperfusion after releasing the snare. Correlation between FCA and fluorescent microspheres in determination of myocardial perfusion was excellent. CONCLUSION: With the fluorescence technique using ICG, visualization of blood flow in coronary vessels and myocardial perfusion, is feasible. FCA is a highly sensitive and reproducible method and an excellent technique for intraoperative quality control in CABG.