Intraoperative control of extracranial-intracranial bypass patency by near-infrared indocyanine green videoangiography

Object. Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial-intracranial bypass patency. Methods. Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moyamoya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA-posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass Surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter-equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA-MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG vidcoangiography could be positively validated during the postoperative course by performing DS or CT angiography. Conclusions. Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG vidcoangiography may help reduce the incidence of early bypass graft failure.