Real-time fluorescence angiography by intra-arterial indocyanine green injection to identify obscure gastrointestinal bleeding territory: proof of concept in the porcine model.

Abstract

Despite intensive preoperative localization workouts, intraoperative localization of the bleeding source in case of obscure gastrointestinal bleeding (OGIB) can be cumbersome and time-consuming. Our aim was to assess the feasibility of image-guided laparoscopic identification of the small bowel loop containing the bleeding source with and without near-infrared angiographic enhancement. Angiography of superior mesenteric artery (SMA) branches was performed in 11 pigs using a right femoral artery approach, followed by a three-port laparoscopy, using a near-infrared-equipped laparoscope. Two pigs were used to identify the optimal intra-arterial indocyanine green (ICG) dose. Eight pigs were divided into two groups: ICG near-infrared angiography-assisted laparoscopy (n=4) and fluoroscopic-assisted laparoscopy (n=4). Finally, in one pig, a novel OGIB model was created and used to evaluate the ICG enhancement pattern in the presence of active bleeding. Mean time to identify the fluorescence signal from the small bowel segment fed by the catheterized SMA branch was 13.75±7.8s, which was statistically significantly shorter than the time required to identify the tip of the catheter by fluoroscopic guidance, i.e., 243.25±107s (p=0.02). Near-infrared fluorescence angiography using intra-arterial ICG injection provides a fast image-guided intraoperative localization of the small bowel loop fed by the arterial territory identified as bleeding by digital subtraction angiography and could help target the bleeding source during OGIB surgery.