Sensitivity and specificity of ICG angiography in free flap reexploration

Microscope-integrated indocyanine green near-infrared videoangiography (ICGA) is a new imaging technique to assess vascular flow through diminutive vessels used in microvascular surgery. The purpose of this investigation was to evaluate the diagnostic accuracy of ICGA in detecting microvascular thrombosis in reexploration surgery. Patients undergoing emergent reexploration surgery after free tissue transfer were enrolled in this clinical study. After the patients had been returned to the operating room the pedicle vessels were exposed and a microangiography was performed. Independent of the result, the anastomoses were opened and surgically explored. Sensitivity and specificity was calculated, using the result of exploration surgery as a reference standard. Of 200 free flaps 20 (10%) underwent reexploration surgery. The most common surgical finding was microvascular thrombosis (55%). In one case vascular compromise was due to confusion of artery and vein with anastomosis of two veins. In 40% of patients an intact vascular pedicle was found. The sensitivity and specificity of ICGA to detect microvascular thrombosis was 100% and 86%, respectively. ICGA provides an excellent diagnostic accuracy for detecting microvascular thrombosis in reexploration surgery. Routine implementation of this technique may expedite a correct diagnosis and facilitate the surgical approach by preventing unnecessary surgical manipulation of intact anastomoses.