Off-pump coronary arterial bypass grafting and new surgical apparatus and techniques have decreased the mortality rate associated with this procedure to approximately 1.5%. If we could detect problems in the constructed coronary anastomoses by an alternative imaging system to coronary angiography during surgery, decisions to revise the surgical procedure could be made without hesitation. Meanwhile, the intraoperative direct evaluation of intestinal blood flow during abdominal aortic aneurysmal surgery is required to prevent ischemic colitis, which is a devastating complication. Indocyanine green (ICG) has recently improved ophthalmic angiography and the navigation systems of oncological surgery. The fluorescence illumination of ICG with a near-infrared light is captured on camera. In coronary arterial surgery, the ICG imaging system is also becoming increasingly useful. A new ICG imaging system, the HyperEye Medical System (HEMS), provides a clear view of the blood flow and ischemic area with color visualization. Furthermore, its combination with a quantitative blood flow assessment tool such as transit time flow measurement could improve the accuracy of intraoperative examination. In this review, we evaluate the current strategies of assessing blood flow intraoperatively with an ICG imaging system in cardiovascular surgery.